Skip to main content
NCBI home page
ACS AuthorChoice logoLink to ACS AuthorChoice
. 2025 Jul 28;147(31):27561–27575. doi: 10.1021/jacs.5c05275

Electronic Textiles Based on Conductive Metal–Organic Frameworks as Scavengers and Sensors of Toxic Oxyanions from Water

Patrick Damacet †, Priyanshu Chandra †, Emma K Ambrogi †, Hyuk-Jun Noh †, Ericka L Asmus †, Elissa O Shehayeb †, Giovanni Barcaro ‡, Susanna Monti §,*, Katherine A Mirica †,*
PMCID: PMC12333345  PMID: 40719241

Abstract

Water contamination by toxic oxyanions poses a severe threat to ecosystems and human health. While various adsorbents have been developed for oxyanion sequestration, designing a single material that simultaneously achieves high selectivity, rapid adsorption kinetics, and real-time sensing capabilities remains a challenge. This study explores the first use of layered, conductive metal–organic frameworks (cMOFs) based on hexahydroxy- and hexaimino-triphenylene (HHTP and HITP) cores coordinated with nickel and copper for the dual sensing and filtration of oxyanions from water. Systematic investigations of Ni3(HHTP)2, Cu3(HHTP)2, Ni3(HITP)2, and Cu3(HITP)2 reveal that Ni3(HITP)2 exhibits unprecedented adsorption capacities, capturing up to 827 mg of MnO4 – and 497 mg of Cr2O7 2– per gram of MOF, while filtering up to 99% of these oxyanions within 10 min of exposure. Ni3(HITP)2 also demonstrates high applicability in real-world scenarios, maintaining a remarkable adsorption performance across various water matrices, pH conditions, and competing anion interferences. Spectroscopic and computational investigations reveal a multimechanistic scavenging process involving chemisorption, physisorption, and redox reactions. Grafting Ni3(HITP)2 onto cotton textiles via a layer-by-layer approach yields mechanically robust, easy to handle, and flexible electronic textile capable of filtering oxyanions for up to 32 cycles without performance loss, while allowing their detection with high sensitivity and low detection limits reaching 2.2 ppm for MnO4 – and 6 ppm for Cr2O7 2–. Taken together, these findings pave the way for MOF-based next-generation water treatment technologies that integrate efficient filtration and real-time sensing capabilities.

graphic file with name ja5c05275_0010.jpg

graphic file with name ja5c05275_0009.jpg

1. Introduction

The rapid proliferation of toxic metal oxyanions in water bodies, spurred by the exponential growth in industrialization and urbanization has recently surfaced as a critical environmental concern that imperils both, ecosystems and human health alike. − Among these oxyanions, dichromate (Cr2O7 2–) and permanganate (MnO4 –) are highly worrisome due to their acute mutagenic, cytotoxic, and carcinogenic effects, earning them recognition as hazardous substances under federal environmental guidelines. − The high discharge rate of these pollutants into natural water sources, driven by their widespread use in steel manufacturing, leather tanning, wood preservation, textile dyeing, and metal finishing, has created an urgent need for novel remediation technologies. − While a variety of techniques have been employed for scavenging oxyanions from water, including electrocatalytic reduction, , chemical precipitation, , photodecomposition, biological treatment, , and membrane filtration, , adsorptive decontamination remains one of the most promising and versatile approaches due to its high efficiency, cost-effectiveness, minimal waste generation, and ease of operation. − To date, several adsorbents based on layered double hydroxides (LDHs), , polyaniline-loaded materials, , carbonaceous materials, , and metal oxides , have been explored for oxyanion removal from water. However, their low specificity, limited reusability, suboptimal adsorption efficiency, and slow adsorption kinetics continue to pose significant challenges, restricting their practical implementation in real-world applications. − Moreover, most of these adsorbents are intrinsically monofunctional and therefore, lack the capability to simultaneously detect and remove oxyanion contaminants from water. This functional limitation hinders their practical utility, as oxyanions must be monitored at low parts-per-million (ppm) or even parts-per-billion (ppb) concentrations to meet environmental safety standards. , Consequently, there is a growing need for dual-function materials that can not only capture oxyanions efficiently, but also monitor their concentrations in real time, providing both remediation and early warning capabilities in contaminated water sources.

Metal–organic frameworks (MOFs) represent a promising class of porous, crystalline materials with significant potential for removing toxic pollutants from water. , Their permanent porosities, tunable functionalities, and high surface areas have made them highly effective adsorbents for a diverse range of contaminants, including heavy metals, pesticides, nanoplastics, pharmaceuticals, organic dyes, metal-derived oxyanions, and radioactive nuclear waste. Despite their advantages, traditional MOFs face four key limitations that hinder their widespread use. First, many reported MOFs suffer from metal ion and/or ligand leaching into solution during remediation, which can reduce their effectiveness in oxyanion scavenging and introduce additional water contamination. , Second, the high hydration energy, relatively large size, and high charge density of most oxyanions make their adsorption by conventional 3D and charge neutral MOFs challenging. − Third, the intrinsic electrical insulating nature and redox inactivity of most MOFs used in water filtration limits their multifunctional capabilities, preventing simultaneous sensing, filtration, and detoxification of toxic pollutants. Fourth, MOF powders are often difficult to handle due to their small particle size and tendency to agglomerate in solution, complicating their practical use in filtration systems. Integrating MOFs within textile fabrics offers a promising strategy to improve their handling and deployment in water filtration systems. However, achieving uniform and stable MOF deposition on textiles remains a significant challenge with the MOFs currently employed for water remediation. − Building upon these limitations, two-dimensional conductive MOFs (2D cMOFs) offer promising solutions due to their (i) multifunctional nature, (ii) ability to be deposited onto textiles, , (iii) relative stability in aqueous media, (iv) abundance of open metal sites and edge sites that act as Lewis acid–base sites, , (v) surface charge, and (vi) redox-activity, thus allowing for contaminant filtration through a synergistic mechanism involving chemisorption, physisorption, and redox reactions. Consequently, 2D cMOFs are expected to exhibit superior performance in oxyanion scavenging, overcoming the key challenges faced by conventional MOF adsorbents.

Herein, we present the first use of layered 2D cMOFs for the simultaneous capture, detection, and detoxification of two model oxyanions, Cr2O7 2– and MnO4 –, from water. The as-synthesized MOFs, based on hexahydroxy- and hexaimino-triphenylene (HHTP and HITP) cores coordinated with nickel and copper metal ions exhibit exceptional performance in oxyanion removal, excelling in both uptake capacity and adsorption kinetics. Concentration- and time-dependent adsorption studies demonstrate experimental uptakes of up to 827  ±  79 mg of MnO4 – and 497  ±  11 mg of Cr2O7 2– per gram of MOF, with a 99% removal efficiency achieved for 25 ppm contaminant solutions in under 10 minutes of contact. The best performing MOF, Ni3(HITP)2, is found to display adsorption capabilities across a broad pH range (4–10), high selectivity in the presence of competing anions, and consistent performance across diverse water matrices, making it highly suitable for real-world applications. Spectroscopic investigations at the molecular-level, coupled with Quantum Chemistry (QC) simulations using Density Functional Theory (DFT) reveal a synergistic scavenging mechanism involving chemisorption, physisorption, and redox reactions. To enhance practical handling, recovery, and deployment in water filtration systems, while simultaneously enabling their use as electrochemical sensors, we grafted Ni3(HITP)2 onto cotton fabrics using a layer-by-layer (LbL) approach. The resulting MOF@textile composite maintains an adsorption capacity comparable to the bulk material, exhibits high durability, and can be regenerated for up to 32 cycles without noticeable performance loss, while enabling oxyanion detection in the low ppm range. By combining high-efficiency adsorption with real-time sensing, this work not only introduces a new class of MOF-based adsorbents for oxyanion remediation but also establishes a foundation for the development of textile-integrated materials in next-generation water treatment nanotechnologies.

2. Experimental Design

Choice of Metal-Derived Oxyanions

We selected MnO4 – and Cr2O7 2– as representative model oxyanions for our dual adsorption and sensing studies for five major reasons. First, Cr2O7 2– is regarded as one of the most hazardous oxyanions, due to its mutagenic and carcinogenic effects on living organisms. It is known to cause DNA damage, chronic respiratory diseases, and extensive cell and tissue damage, and has consequently been classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC). In contrast, while MnO4 – is generally considered less toxic than Cr2O7 2–, it remains a potent neurotoxin, capable of causing Parkinsonism, tissue damage, and gastrointestinal distress in humans when present at relatively high concentrations. , Second, incidents of drinking water contamination involving manganese and chromium ions have been widely reported across various countries, ,, underscoring the urgent need for the development of cost-effective and efficient water remediation technologies. Third, the United States Environmental Protection Agency (USEPA) has established guideline values of 50 ppb for chromium ions and 300 ppb for manganese ions in drinking water, emphasizing the ongoing need to (i) monitor and (ii) limit the concentrations of these contaminants to protect public health. , Fourth, concentrations of these oxyanions in industrial wastewater have been reported to reach as high as 270 ppm, necessitating the development of high-efficiency adsorbent materials capable of reducing Mn­(VII) and Cr­(VI) levels well below the discharge standards set by environmental agencies for safe release into aquatic environment. − Well-documented cases of water contamination by these oxyanions include the Hinkley groundwater incident, as well as widespread manganese contamination in groundwater and drinking water sources in the United States and Bangladesh. − Fifth, MnO4 – and Cr2O7 2– differ in their hydration energies, molecular sizes, and charge densities. Understanding the interaction mechanisms between 2D cMOFs and these oxyanions through structure–property interconnections is expected to guide the future design of hierarchical adsorbent materials with tailored properties for efficient oxyanion removal from water.

Choice of MOF Materials

We selected four representative 2D cMOFs based on HHTP and HITP cores with copper and nickel metal nodes for the simultaneous sensing and filtration of MnO4 – and Cr2O7 2– for six major considerations (Figure ). First, these MOFs possess a unique combination of structural features, including (i) unsaturated open metal sites, (ii) vertically aligned porous channels, (iii) aqua-rich capping edge sites, and (iv) high chemical stability in aqueous solutions. ,, These properties endow 2D cMOFs highly effective for ion adsorption under various conditions. Second, the redox-active nature of 2D cMOFs allows not only for effective adsorption but also for the detoxification of oxyanions in water. In particular, the reduction of MnO4 – can result in the formation of the less toxic MnO2, which is known to have adsorptive remediation properties. , Likewise, the reduction of Cr2O7 2– to Cr­(III) species can substantially lower chromium toxicity in aqueous media, as Cr­(III) is significantly less harmful than Cr­(VI), and is even used in trace amounts as a nutritional and dietary supplement. Third, both experimental and computational studies have shown that HHTP- and HITP-based MOFs exhibit a measurable surface charge in water, which may promote electrostatic interactions with the charged oxyanions. , Fourth, the intrinsic electrical conductivity equips these materials with multifunctional capabilities, allowing their usage, besides adsorbents, as electrochemical sensors for monitoring oxyanion concentrations in water. Fifth, the unique structural features of this class of 2D cMOFs provide valuable insights into the structure–function relationships that govern oxyanion adsorption, particularly in terms of the roles of metal nodes and functional groups. Sixth, the synthetic precursors and preparation methods for these MOFs are readily accessible and well-established, , offering a cost-effective and straightforward route for fabricating high-performance adsorbents and sensors for water filtration applications.

1.

1

Open in a new tab

a) Simulated crystal structures b) SEM micrographs, and c) PXRD patterns of the series of HHTP- and HITP-based 2D cMOFs employed in this work.

3. Results and Discussion

Characterization of MOF Materials

We employed well-established solvothermal procedures to generate microcrystalline powders of four layered cMOFs: Cu3(HHTP)2 and Ni3(HHTP)2, based on HHTP cores, and Cu3(HITP)2 and Ni3(HITP)2, derived from HITP cores (see Section S2). In addition to differences in metal nodes (Cu2+ vs Ni2+) and functional groups (−OH vs -NH2), these MOFs exhibit distinct stacking arrangements. While Cu3(HITP)2 and Ni3(HITP)2 adopt a slipped-parallel stacking configuration, their HHTP-based counterparts display unique patterns. Specifically, Ni3(HHTP)2 forms a bilayered structure wherein extended two-dimensional sheets alternate with intercalated layers of nickel catecholate complexes, whereas Cu3(HHTP)2 adopts a near-eclipsed, C-centered monoclinic crystal structure (Figure a). , Prior to conducting the adsorption experiments, we characterized the house-made HATP·6HCl (Triphenylene-2,3,6,7,10,11-hexaamine hexahydrochloride) molecular precursor and the MOF adsorbents to confirm their purity and structural integrity. Nuclear magnetic resonance (NMR) and mass spectrometry (MS) analyses verified the successful synthesis and high purity of HATP·6HCl (Figures S1–S3). Powder X-ray diffraction (PXRD) measurements revealed the formation of highly crystalline MOF particles, with sharp, intense peaks that closely matched the simulated PXRD patterns of the corresponding crystal structures, suggesting the high phase purity of the resulting materials (Figures a,c and S4–S7). Scanning electron microscopy (SEM), in conjunction with energy-dispersive X-ray spectroscopy (EDX), revealed that the MOFs exhibit well-defined rod-like morphologies, with uniform elemental distributions throughout the crystals (Figures b and S8–S11). Importantly, these structural and morphological features remained consistent across two independent synthesis batches, confirming the reproducibility and reliability of the synthetic procedure in producing phase-pure 2D cMOF crystals (Figures S12–S17). Additionally, the activated MOFs exhibited satisfactory thermal stabilities of up to 200 °C as indicated by thermogravimetric analysis (TGA), highlighting their potential for use under various operational conditions (Figure S18). Detailed synthetic procedures and characterization features for the MOF series are provided in Section S2 of the Supporting Information.

Removal of Oxyanions from Water Using 2D cMOFs

We began our investigations by evaluating the uptake capacities of the four triphenylene-based MOFs toward two model oxyanions through batch adsorption experiments. We varied the concentrations of MnO4 – and Cr2O7 2– between 5 and 500 ppm, and estimated the equilibrium uptake capacities (Qe) of the MOFs following 24 h of adsorption using inductively coupled plasma mass spectrometry (ICP-MS) via Equation S1. As shown in Figure a, all MOFs exhibited high and comparable adsorption capacities for MnO4 – across the tested concentration range, as evidenced by the sharp and linear increase in Qe with the initial MnO4 – concentration. Notably, we found the MOFs to filter up to 94 ± 2% of MnO4 – from water at an initial concentration of 500 ppm, suggesting highly favorable interactions between the frameworks and Mn­(VII) (Figure S19). Estimating the experimental maximum uptake capacity (Q max) of these MOFs via saturation adsorption experiments revealed that Ni3(HITP)2 exhibits the highest uptake performance, reaching a Q max up to 827 ± 79 mg of MnO4 – per gram of MOF within 9 h (Figures S19–S20). To the best of our knowledge, this performance rivals that of the most efficient MOF-based adsorbents reported to date for MnO4 – (Figure S21).

2.

2

Open in a new tab

Concentration-dependent adsorption uptakes of MOFs toward a) MnO4 – and b) Cr2O7 2– oxyanions. c) Removal efficiency of Ni3(HITP)2 toward different concentrations of MnO4 – and Cr2O7 2–. Time-dependent adsorption uptakes of MOFs toward d) MnO4 – and e) Cr2O7 2– oxyanions. f) Selectivity of Ni3(HITP)2 to manganese and chromium species (20 ppm) with different charges and oxidation states. Error bars represent standard deviation from the mean value of three independent experiments. Conditions: mMOF = 2 mg, VSolution = 3 mL, and T = 298 K. Note the initial concentration of the oxyanions in the kinetic experiments is 25 ppm.

Turning our attention toward Cr2O7 2–, we noted Qe for all MOFs to exhibit an increase with rising initial oxyanion concentrations before approaching saturation at high-ppm concentrations, where the adsorptive sites likely became fully occupied (Figure b). Notably, HITP-based counterparts demonstrated a superior adsorption performance compared to their HHTP-based MOFs, reaching Qe values of 195 and 158 mg g–1 and Cu3(HITP)2, respectively, compared to 89 and 65 mg g–1 for their HHTP-based counterparts at an initial Cr2O7 2– concentration of 200 ppm (Figure S22). Saturation adsorption experiments further revealed that Ni3(HITP)2 reached a Q max of 497 ± 11 mg g–1 for Ni3(HITP)2 in 9 h of contact, more than twice that of Cu3(HHTP)2 and up to 3.7 times higher than the HHTP-based analogs (Figure S22–S23). To our knowledge, this Q max value for Ni3(HITP)2 exceeds those of most MOF-based adsorbents reported to date (Figure S24). To elucidate the surface charge properties of these MOFs and rationalize the superior Q max values observed for the HITP-based MOFs in oxyanion adsorption, we carried out both, zeta potential measurements, and dye adsorption experiments using cationic methylene blue (MB+) and anionic methyl orange (MO–). We found the HHTP-based MOFs to display a consistently negative surface charge under ambient aqueous conditions, as evidenced by their (i) negative zeta potential values ranging from −22.5 mV to −38.6 mV, and (ii) complete adsorption of MB+ alongside negligible uptake of MO– after 2 h of contact (Figures S25–S26 and S29–S30). In contrast, HITP-based MOFs exhibited amphoteric surface properties, with a net positive charge in water, as evidenced by their (i) complete removal of MO–, (ii) partial adsorption of MB+, and (ii) positive zeta potential values of +21.4 mV and +12.7 mV for Cu3(HITP)2 and Ni3(HITP)2, respectively (Figures S27–S28 and S31–S33). These findings underscore the role of electrostatic interactions between the MOF adsorbents and oxyanions in governing the removal capacity of the negatively charged oxyanions in water.

Despite the higher Q max values of Ni3(HITP)2 for MnO4 – compared to Cr2O7 2–, we found that the MOF exhibited a remarkably higher affinity toward Cr2O7 2– at low ppm concentrations (0.1–10 ppm). As shown in Figure c, the removal efficiency of Ni3(HITP)2 for Cr2O7 2– decreased from 100% to 47% as the contaminant concentration increased from 0.1 to 500 ppm, which aligns with the expected saturation of active adsorption sites at higher relative concentrations. In contrast, we observed the opposite trend for MnO4 –, where removal efficiency increased dramatically from 17% to 93% over the same concentration range, challenging conventional expectations. , We hypothesized that at low oxyanion concentrations (0.1–10 ppm), the limited concentration gradient of contaminants restricted both, their (i) availability near adsorptive active sites and (ii) their mass transport rate into the pores of Ni3(HITP)2, resulting in oxyanion-MOF interactions predominantly occurring at the MOF surface rather than within its internal pores. , Given that Cr2O7 2– has higher polarizability, multidentate potential, and a greater number of nucleophilic oxygen atoms compared to MnO4 –, we expect that it exhibited a (i) stronger physical interactions through hydrogen bonding with electrophilic hydrogen donor groups in HITP moieties and (ii) greater electrostatic attraction to charged open metal sites on the MOF surface. On the contrary, increasing the concentration of oxyanions will result in an increase in the adsorption mass transfer rate, which is expected to facilitate the diffusion of oxyanions onto the pores of the MOFs. Given that MnO4 – has a smaller radius in its hydrated form compared to Cr2O7 2–, it is expected to access the pores of Ni3(HITP)2 more readily at higher concentrations. ,

We further examined the adsorption kinetics of the frameworks by exposing them to 25 ppm solutions of MnO4 – and Cr2O7 2– at different time intervals. We reasoned that these experiments would provide insight into the adsorption rate and efficiency of these materials in real-world water remediation applications, where oxyanions commonly exist in similar ppm-level concentrations in industrial and polluted water sources. , For all MOF-oxyanion pairs, we observed a rapid and steady increase in the time-dependent adsorption capacity (Q t) with adsorption time, followed by a plateau after 7 min, suggesting the saturation of the MOF adsorption sites (Figure d-e). While all studied MOFs displayed comparable adsorption rates for MnO4 –, capturing between 92 and 99% of the oxyanion within 7 min, HITP-based MOFs outperformed their HHTP-counterparts in adsorbing Cr2O7 2–. This trend in oxyanion uptake aligned well with our concentration-dependent adsorption studies, where HITP-based MOFs, characterized by (i) a positive surface charge and (ii) an abundance of electrophilic hydrogen donors from their nickel­(bisdiimine) linkages demonstrated superior affinity toward Cr2O7 2–.

To elucidate the mode of interactions of the MOFs toward the oxyanions, we proceeded by fitting the kinetic uptake data into the linear forms of the pseudo-first-order and pseudo-second-order kinetic models, as described in Section S3.4 of the SI. We found the experimental adsorption data for all MOF-oxyanion pairs to align more closely with the pseudo-second-order kinetic model, as indicated by the higher correlation coefficients (0.94–0.99) obtained from their least-squares regression, compared to the pseudo-first-order model (0.42–0.67). These findings suggested that the adsorption process is predominantly chemisorption-driven, where covalent binding of MnO4 – and Cr2O7 2– to MOF active sites governs the overall adsorption rate (Figures S34–S43). Further examination of the kinetic data using the Weber–Morris intraparticle diffusion model indicated a multistage diffusion process governing the adsorption of oxyanions onto the MOFs, evidenced by the predominant triphasic nature of the plots obtained. , These diffusion processes involved (i) a rapid external surface adsorption in the initial stage, followed by (ii) gradual diffusion of oxyanions into the MOF pores, where chemical interactions with active sites occur, and last (iii) a saturation phase, where most adsorption sites become occupied, limiting further uptake (Figures S38 and S43).

Oxyanion Removal under Diverse Aquatic Environments

An essential requirement for an effective adsorbent is its ability to maintain a high performance in the presence of various environmental interferences. To assess the practical applicability of Ni3(HITP)2, the best-performing MOF in this study, we examined its removal efficiency under different aquatic conditions. We first spiked real water samples, including tap water (New Hampshire), river water (Connecticut river), and seawater (Atlantic Ocean) with 100 ppm solutions of MnO4 – and Cr2O7 2– and assessed their removal following 24 h of adsorption using ICP-MS. As shown in Figure a, Ni3(HITP)2 exhibited remarkably high removal efficiencies for both oxyanions, exceeding 89% in both, tap and river water, relative to its performance in DI water. In seawater, nonetheless, we found the removal efficiency to decrease to 82% for MnO4 – and 31% for Cr2O7 2–, which we attributed to the high salinity of the matrix, exceeding 34 practical salinity unit (psu). Expanding our investigation to the impact of coexisting ions, we spiked 25 ppm oxyanion solutions with equimolar concentrations of six potassium salts containing chloride, nitrate, carbonate, phosphate, acetate, and sulfate counterions, which were chosen to represent a range of ionic sizes and charge densities. ICP-MS analysis of the supernatants following 24 h of adsorption revealed a relatively high retention of adsorption performance, with Ni3(HITP)2 maintaining 96% uptake of Cr2O7 2– and 75% uptake of MnO4 – in the presence of competing anions (Figure b). These results indicated that, despite the presence of potentially interfering species, Ni3(HITP)2 effectively removed the target oxyanions, highlighting its robust adsorption capabilities.

3.

3

Open in a new tab

Removal efficiency of Ni3(HITP)2 toward MnO4 – and Cr2O7 2– oxyanions in a) different water sources, b) the presence of 25 ppm of coexisting ions and c) cyclic adsorption–desorption experiments.

Examining the removal capabilities of Ni3(HITP)2 across pH levels ranging from 4 to 10, revealed complete filtration (>99%) of MnO4 – under all tested conditions. In contrast, Cr2O7 2– removal experienced a gradual decline, decreasing from 68% under acidic conditions (pH 4) to 25% at pH 10, while the MOF maintained high crystallinity throughout the tested pH range (Figures S44–S45). We attributed this trend to the oxyanion speciation under varying pH levels in aqueous solutions. While Cr2O7 2– and hydrogen chromate (HCrO4 –) are the predominant Cr­(VI) species in acidic and neutral media, chromate (Cr2O4 2–) becomes predominant under alkaline conditions. , We hypothesized that this change in size, geometry, and number of nucleophilic oxygen atoms of Cr­(VI) likely reduced its affinity towards the MOF in basic environment. In contrast, the complete removal of MnO4 – can be attributed to its stability in the tested pH range. Although MnO4 – can disproportionate to form hypomanganate (Mn­(V)) under strongly alkaline conditions, and decompose under strong acidic conditions to form manganese dioxide (Mn­(IV)), these transformations likely did not occur within the examined pH range. To further evaluate the selectivity of Ni3(HITP)2 toward these oxyanions, we carried out adsorption experiments for manganese and chromium species with varying charges and oxidation states. Our results showed (i) a significantly higher affinity of Ni3(HITP)2 for Cr2O7 2– compared to CrO4 2– (80% vs 21% removal at 100 ppm), confirming the influence of Cr­(VI) speciation, and (ii) a strong preference for negatively charged oxyanions over metal cations (Mn2+, Mn3+, Cr2+, and Cr3+), reinforcing the role of electrostatic interactions and hydrogen-bonding in the adsorption mechanism (Figures f and S46). Next, we assessed the regeneration capability of Ni3(HITP)2 through cyclic adsorption test. Remarkably, the removal efficiencies for both, MnO4 – and Cr2O7 2–, remained consistently high (>83%) even after eight consecutive adsorption–desorption cycles (Figures c and S47). Moreover, PXRD analysis of the regenerated MOF confirmed its structural integrity following desorption with 1 M HCl for 24 h, highlighting its promising reusability for oxyanion removal (Figure S48).

Spectroscopic Assessment of MOF–Ion Interaction

To elucidate the interaction mechanism between the oxyanions and MOF adsorbents at the molecular level, we employed a suite of spectroscopic techniques to characterize the MOFs after exposure to MnO4 – and Cr2O7 2–. Attenuated Total Reflectance Fourier-Transform Infrared (ATR-IR) spectra revealed a blue shift in the C–N stretching peaks of HITP-based MOFs following oxyanion adsorption. Specifically, we noted shifts from 1304 cm–1 to 1315 cm–1 and 1318 cm–1 in Ni3(HITP)2 and from 1292 cm–1 to 1318 cm–1 and 1316 cm–1 in Cu3(HITP)2 after adsorption of Cr2O7 2– and MnO4 –, respectively. In contrast, the C–O stretching peaks of HHTP-based MOFs remained unchanged after adsorption (Figures a and S49). These findings suggested an increase in electron density within the C–N bonds, which we attributed to physisorptive interactions between the electronegative oxygen atoms of the oxyanions and the hydrogen atoms of the bis­(diimine) moieties, a feature absent in HHTP-based MOFs. , SEM micrographs confirmed that Ni3(HITP)2 crystals retained their morphology after adsorption, while energy-dispersive X-ray spectroscopy (EDX) verified the successful uptake of oxyanions by the MOF crystals (Figures S50–S57). The corresponding elemental analysis further revealed a correlation between the initial oxyanion concentration in solution and their corresponding weight percentages detected on Ni3(HITP)2. Specifically, as the MnO4 – concentration increased from 50 to 500 ppm, the manganese content (in terms of weight %) in Ni3(HITP)2 rose from 7.5% to 46%. Similarly, the chromium content increased from 6.7% to 17% over the same concentration range (Figures S58–S59), confirming the concentration-dependent adsorption process of Ni3(HITP)2.

4.

4

Open in a new tab

Mechanistic insights into the interaction between Ni3(HITP)2 and the oxyanions. (a) ATR-IR spectra of bulk Ni3(HITP)2 MOF before (black), and after (yellow and purple) adsorption of MnO4 – and Cr2O7 2–. (b) High-resolution Mn 2p XPS spectra of KMnO4 and Ni3(HITP)2@Mn. (c) High-resolution Cr 2p XPS spectra of K2Cr2O7 and Ni3(HITP)2@Cr.

X-ray photoelectron spectroscopy (XPS) measurements provided evidence of chemisorptive interactions between Ni3(HITP)2 and the oxyanions, supporting the adsorption mechanism proposed by the kinetic models. First, XPS survey spectra of Ni3(HITP)2 after adsorption confirmed both, the structural integrity of the MOF, and the successful adsorption of oxyanions, as indicated by the appearance of Mn and Cr binding energy peaks (Figure S60a). High-resolution Mn 2p, Cr 2p, and N 1s spectra, depicted in Figures and S61, revealed that redox reactions occurred during the adsorption process. Specifically, MnO4 –, initially present as Mn­(VII) underwent partial reduction to Mn­(IV), evidenced by the emergence of binding energy peaks at 642.2 and 645.0 eV, corresponding to Mn­(IV) and Mn­(VII), respectively (Figure b). We further confirmed the formation of Mn­(IV) through PXRD measurements and SEM imaging, which revealed the formation of amorphous MnO2 nanoparticles with a sheet-like morphology after adsorption (Figures S62–S63). , Photographs of the solutions before and after saturation adsorption experiments, shown in Figure S64, revealed a significant change in color of solutions from pink, the original color of MnO4 –, to red, which we attributed to the emergence of Mn­(IV) species such as MnO2. Similarly, Cr2O7 2–, initially present as Cr­(VI), underwent partial reduction during adsorption, as indicated by the appearance of a new peak at 577.1 eV in the high resolution Cr 2p spectrum, assigned to Cr­(III) (Figure c). , These transformations in oxyanions coincided with the partial oxidation of the HITP ligand. High-resolution N 1s spectra showed an increase in the ratio of quinoid imine (CN) to benzenoid amine (C–NH) from 43%/57% before adsorption to 50%/50% and 52%/48%, after MnO4 – and Cr2O7 2– capture, respectively (Figure S48). Meanwhile, Ni 2p spectra displayed no changes in oxidation state, suggesting that the metal nodes did not participate in the redox process (Figure 60b). We attributed the greater reduction of Mn­(VII) to Mn­(IV) compared to Cr­(VI) to Cr­(III) to the higher standard redox potential of MnO4 – (1.68 vs 1.33 eV), making the latter a stronger oxidizer and thus driving a more pronounced redox reaction and higher adsorption uptake. − Indeed, competitive adsorption experiments using mixtures of MnO4 – and Cr2O7 2– at varying initial concentrations consistently showed a preferential uptake of MnO4 – over Cr2O7 2–, further supporting this trend (Figures S65–S67). Notably, the redox-active Ni3(HITP)2 not only captured hazardous oxyanions from water but also detoxified them by reducing Mn­(VII) to Mn­(IV) and Cr­(VI) to Cr­(III) species, that are significantly less toxic and mobile in water. By mimicking the natural detoxification pathways of certain bacteria and fungi, which enzymatically reduce metal-derived oxyanions to less harmful species, , Ni3(HITP)2 demonstrates dual functionality that positions it as a promising candidate for real-world water remediation applications.

Computational Modeling

The modeling activity was focused on the most performant MOF, i.e. Ni3(HITP)2, to disclose the atomistic origin of its capture properties. We employed QC simulations at the Density Functional level of theory to estimate the interaction energy of Cr2O7 2– and MnO4 – oxyanions with the framework at low concentrations of the adsorbates. We considered both the slipped-parallel (SP) arrangement shown in Figure a and the structure shown in Figure , in which the individual layers are organized in stacking sequences analogous to those of fcc crystals (ABC type). This latter configuration was identified by RMD (Reactive Molecular Dynamics) in a previous investigation of the Cu3(HHTP)2 system. QC calculations of a reduced 4L-ABCB (1 × 1) unit cell demonstrated, as for the Cu-based systems, a close energy competition between the two types of morphologies. The peculiar characteristics of this new arrangement are the presence of open-metal sites (OMS), environmentally exposed regions (highlighted in red circles in Figures and S68), and undulated layers, which more favorably interact with the environment. The results of the calculations are displayed in Figure , which shows the optimized structures with a quantitative analysis of the adhesion energies. Due to periodic boundary conditions, we had to model the oxyanions as neutral species (namely, the respective acids). Still, we verified that, for finite-size systems where a charge could be included (see Figure S69), the trend of interaction energy difference was comparable.

5.

5

Open in a new tab

(Top panel) Optimized configurations and correspondent adhesion energies (in kcal/mol) of the HMnO4 and H2Cr2O7 adsorbates interacting with the Ni3(HITP)2 system in both SP arrangement and ABC reconstruction. (Bottom panel) On the left, the structure of the unit cell, replicated twice in both x and y directions, of the Ni3(HITP)2 MOF adopting ABC morphology; on the right, a finite model of two partial layers of the Ni3(HITP)2 material interacting with MnO4 – when surrounded by four water molecules; most characteristic distances (in Angstrom) are reported. Color coding: Ni light blue, O red, N blue, C gray, H white, Mn purple, and Cr green.

From the examination of the adsorption regions of the MOF, it can be noticed that Ni3(HITP)2 is terminated only by hydrogens. Those belonging to the amine moieties can be donors of hydrogen bonds. Both adsorbates have strong nucleophilic oxygens, which are potential acceptors of such a type of bonding. As confirmation, in the SP configuration, we observe the formation of strong hydrogen bonds between the nucleophilic O atoms of the guest and the H atoms of the metal core (distances between 1.9 and 2.2 Å), and we find that the interaction is roughly proportional to the number of bonds established. H2Cr2O7, in its elongated configuration in the MOF channel, exposing four O atoms to the electrophilic MOF hydrogens, is, in fact, characterized by an adhesion that is almost double the one where HMnO4 exposes only two oxygens. In the reconstructed structure, the situation is slightly different: the electrophilic oxygens of the guests can interact with the positive metal centers of OMS, although this further contribution does not change the values of adhesion energy much. We found a weak interaction between the O atoms of the guests and Ni; instead, the adsorbates preferred to maximize the formation of H bonds, which can provide very similar adhesion energy to that characterizing the SP arrangement for both guest species. The obtained values for both morphologies are compatible with the pseudo-second-order kinetic models, suggesting an interaction of chemical type between the adsorbates and the MOF.

For a further comparison, we also examined the interaction of both adsorbates with the less performant MOF, i.e., Cu3(HHTP)2. In agreement with the experimental findings, the weaker adhesion energies can be due to the hydrogens of the linkers and oxygens in the metal core; repulsive interactions between the O-terminated metal core and the nucleophilic guests move the adsorbates to longer distances from the metal core and are only partially compensated by weak attractive van der Waals dispersive forces between the guests and the H atoms at the edges of the linkers (distances around 2.2–2.3 Å). In the reconstructed structure of the MOFs, we observe an increased interaction between the adsorbates and the Cu centers, although the final values of the adhesion energies (Figure S70) are still well below the strength of those characterizing the Ni3(HITP)2 system.

To estimate the effect of water on the sorption performances of Ni3(HITP)2, we included four water molecules in the optimized geometry of HMnO4 adsorbed in the SP MOF structure and reoptimized the whole complex. The added molecules created a network of hydrogen bonds (Figure S71), inducing a slight elongation of the direct connections between the adsorbate and the MOF. The adhesion between the adsorbate and the MOF in the configuration perturbed by the water molecules was approximately −43.3 kcal/mol, which was very similar to that estimated in the absence of water (−43.9 kcal/mol). This is further proof of the adaptability of the Ni3(HITP)2 framework in maximizing its interaction with adsorbate species. We also performed a test calculation on the MnO4 – ion by using the finite model shown in the bottom panel of Figure , and we observed that the ion also undergoes the same slight elongation of the adsorbate/MOF equilibrium bond lengths induced by water in the neutral counterpart.

In Situ Growth of Ni3(HITP)2 on Cotton Textile

Despite its promising and record-high adsorption capabilities, Ni3(HITP)2 crystals, similar to other MOF powders, present challenges for practical applications due to their small crystal size and tendency to agglomerate in solution. These challenges not only complicate the handling, deployment, and recovery of the materials in conventional water filtration systems, but also limit their reusability, leading to material loss over successive adsorption cycles. To overcome these limitations, we sought to immobilize Ni3(HITP)2 onto textile substrates, which would not only improve handling and flexibility, but also enable reusability across multiple adsorption cycles. Our group previously reported the deposition of Ni3(HITP)2 on cotton via a direct solution-phase self-assembly approach. While the resulting MOF-textile composite demonstrated promising chemiresistive gas sensing, uptake, and filtration performance, it suffered from significant mass loss and high sheet resistance upon handling, which could limit its suitability for both, water remediation and oxyanion sensing. Thus, we developed a continuous stepwise layer-by-layer (LbL) deposition method. While this method is well-established for achieving robust MOF anchoring onto textile surfaces, it has not been previously employed for anchoring cMOFs onto textile fabrics. − This approach, illustrated in Figure a, involved the sequential immersion of plasma-cleaned 5 × 2 cm2 cotton swatches in a) a metal-containing solution and b) a ligand-containing solution, followed by intermediate washing steps. Repeating this process for a total of 10 LbL cycles resulted in uniform Ni3(HITP)2 growth on the cotton fabric. The mass difference of the fabric measured before and after MOF deposition indicated a loading of 8.5 ± 1.5 mg of Ni3(HITP)2 per cm2 of textile, corresponding to approximately a 2.5-fold increase in the mass of the pristine textile fabric (see Section S7 for experimental details).

6.

6

Open in a new tab

a) Schematic illustration of the preparation procedure of Ni3(HITP)2@textile via a layer-by-layer deposition method. b) Sheet resistance values of Ni3(HITP)2@textile swatches (2 cm × 1 cm) upon mechanical manipulation, showcasing their consistent electronic performance under physical stress. Inset: photographs of mechanically manipulated Ni3(HITP)2@textile swatches. c) SEM micrographs of Ni3(HITP)2@textile at two different magnifications. d) PXRD traces and e) BET surface area measurements of bare cotton (red), bulk Ni3(HITP)2 (gray), and Ni3(HHTP)2@cotton (blue).

PXRD analysis of the resulting composite, termed Ni3(HITP)2@textile, confirmed the successful formation of crystalline MOF on the cotton fabric, as evidenced by the high relative intensities of the (100), (200), and (001) crystallographic planes, which closely matched those of the bulk MOF (Figure d). SEM measurements, combined with elemental mapping revealed the formation of rod-like crystals uniformly coating the textile surface (Figures c and S72–S73). ATR-IR and XPS measurements confirmed the presence of the Ni3(HITP)2 coordination network on the fabric swatches (Figures S74–S75). Sheet resistance measurements, performed using a two-point probe, demonstrated the high stability and preserved functional properties of the swatches under various mechanical manipulations, with swatches achieving a sheet resistance of ≈ 0.3 kΩ per cm2 under all tested conditions (Figures b and S76–S79). Nitrogen adsorption–desorption isotherms, shown in Figures e and S80, revealed a 290-fold increase in the BET surface area, from 0.3 m2 g–1 for bare cotton up to 87 m2 g–1 for Ni3(HITP)2@textile, highlighting the substantial enhancement in porosity of the textile fabric upon MOF deposition. Additionally, scotch tape test confirmed the exceptional adhesion of Ni3(HITP)2 to the cotton textile, as indicated by negligible mass loss and unchanged resistance values post-test (Figures S81–S82).

To assess the adsorption capabilities and filtration rate of the fabricated MOF membranes, we utilized Ni3(HITP)2@textile swatches as filtration media, following the setup illustrated in Figure a. We placed the swatches in a glass core sand crucible, and allowed aqueous solutions of Cr2O7 2– (30 ppm) or MnO4 – (10 ppm) solutions to pass through them under vacuum to facilitate oxyanion transport. We selected these concentrations based on reported cases of potable and irrigation water contamination involving manganese and hexavalent chromium species, which typically fall within the low ppm range of 4 to 20 ppm. , We found Ni3(HITP)2@textile to efficiently filter out 96% of a 10 ppm MnO4 – solution and 81% of a 30 ppm of Cr2O7 2– solution in less than 1 min (Figures b and S83), highlighting the composite potential in remediation systems requiring rapid and effective filtration. To quantitatively compare the adsorptive performance of the bulk and composite forms of Ni3(HITP)2, we conducted batch adsorption experiments using 100 ppm oxyanion solutions. We immersed 1 cm2 swatches of Ni3(HITP)2@textile, corresponding to a MOF loading of 8.5 ± 1.5 mg, in 13 mL of 100 ppm oxyanion solutions and stirred them at room temperature for 24 h, maintaining a volume/mass ratio of 1.5. ICP-MS analysis of the supernatants revealed 99% removal for MnO4 – and 73% for Cr2O7 2–, comparable to the adsorption efficiencies of bulk Ni3(HITP)2, while PXRD and SEM measurements revealed the retention in morphology and crystallinity of the MOF composite (Figures c and S84–S88). Cyclic adsorption–desorption experiments using 25 ppm oxyanion solutions, shown in Figure d-e, demonstrated that Ni3(HITP)2@textile retained removal efficiencies above 94% for both, MnO4 – and Cr2O7 2–, over 32 consecutive cycles. Interestingly, the deposition of Ni3(HITP)2 on textiles significantly improved the reusability and long-term operational stability of the MOF. Compared to bulk Ni3(HITP)2, which exhibited nickel leaching levels of 2.19 and 2.11 ppm after exposure to 20 ppm of MnO4 – and Cr2O7 2–, respectively, Ni3(HITP)2@textile demonstrated a significantly reduced nickel leaching, averaging 4.1 ± 1.5 ppb and 9.9 ± 3.6 ppb when exposed to 25 ppm of MnO4 – and Cr2O7 2–, respectively (Figure S89). These values are well below the safe drinking water limits for nickel set by the WHO (70 ppb) and U.S. EPA (100 ppb) agencies, underscoring the potential of Ni3(HITP)2@textiles for practical water filtration applications. Based on initial leaching values, MOF@textile composite can sustain up to ≈16 continuous adsorption cycles with Cr2O7 2– and 8 cycles with MnO4 – before nickel levels approach the WHO drinking water threshold, demonstrating good recyclability and safe operational performance over repeated use. Additionally, a 1 cm × 2 cm swatch of Ni3(HITP)2@textile continuously filtered up to 115 mL of MnO4 – solution (10 ppm) and 40 mL of Cr2O7 2– solution (10 ppm) while maintaining >90% removal efficacy, without any intermediate washing or regeneration (Figure S90). PXRD and ATR-IR measurements indicated that crystallinity is still present and the coordination network of Ni3(HITP)2 remains intact on the textile, suggesting structural robustness during the continuous filtration experiments (Figure S91).

7.

7

Open in a new tab

Proof-of-concept filtration tests for MnO4 – and Cr2O7 2– through Ni3(HITP)2@textile swatches. a) Schematic illustration of the filtration assembly, showcasing the vacuum filtration system employed. b) Photographs of the filtration system and the oxyanion solutions, before, and after filtration. c) Comparison of the removal efficiency of bulk Ni3(HITP)2 and Ni3(HITP)2@textile swatches toward 100 ppm of oxyanion solutions. Cyclic adsorption tests of Ni3(HITP)2@textile to 25 ppm solutions of d) MnO4 – and e) Cr2O7 2–.

Chemiresistive Detection of Oxyanions Using E-textile

Encouraged by the robustness and conductive nature of Ni3(HITP)2@textile, we sought to utilize this composite as an electrochemical sensor for detecting MnO4 – and Cr2O7 2– in water. We hypothesized that this approach would eliminate the need for sample pretreatment, such as drying and extraction, providing a faster and more cost-effective alternative to conventional water quality monitoring techniques. To evaluate its potential, we designed an electrochemical sensing setup, employing the MOF@textile composite as a chemiresistor (Figure S92). In brief, we partially immersed a swatch of Ni3(HITP)2@textile in water, applied a constant potential at both ends of the swatch, and allowed the system to equilibrate until we observed a constant current (see Section S8). Upon the subsequent additions of different concentrations of MnO4 – or Cr2O7 2– to the system, we recorded an increase in the output current within seconds, indicating a rise in the conductivity of the MOF composite due to its interaction with the oxyanions (Figures and S93–94). Estimating the theoretical limit of detection (LoD) from these experiments using the protocol described in Section S8.4, we determined LoDs of 2.2 ± 1.1 ppm for MnO4 – and 6.0 ± 4.5 ppm for Cr2O7 2– (Figures S95–S96). These results suggested that Ni3(HITP)2@texitle can achieve dual sensing and capture with high efficiency, outperforming most reported fluorescent MOF materials in adsorption capacity while demonstrating moderate sensing capabilities (Tables S2–S3). To further assess the suitability of Ni3(HITP)2@textile for real-world applications, we evaluated additional sensing parameters, including sensitivity and selectivity. We estimated the sensitivity, defined as the change in output signal per unit concentration of the analyte to be 0.49 μA ppm–1 for MnO4 – and 0.47 μA ppm–1 for Cr2O7 2–, suggesting effective oxyanion detectability and signal transduction. Moreover, we found the sensor to retain its sensing capability toward MnO4 – even in the presence of 50 ppm sulfate ions, whereas a control experiment using carbon cloth showed insignificant response to oxyanion addition (Figures S97–S99). Overall, the low ppm-level LoD, high sensitivity, rapid response time, and selectivity in the presence of interfering species highlight the potential of Ni3(HITP)2@textile as a promising candidate for real-time water quality monitoring.

8.

8

Open in a new tab

Chemiresistive detection of oxyanions with Ni3(HITP)2@textile swatches. a) Amperometric sensing traces showing the change in the current response of Ni3(HITP)2@textile at 0.5 V upon the successive additions of aliquots of K2Cr2O7 and KMnO4 in DI water. b) Response (change in current) vs concentration curves of Ni3(HITP)2@textile swatches exposed to K2Cr2O7 and KMnO4 in DI water. c) Calculated sensitivity (μA/ppm) and theoretical limit of detection (based on 3× S/N) for the MOF@textile swatches in response to each analyte of detection (based on 3× S/N). Error bars represent the standard deviation of three replicates.

While the MOF@textile demonstrated a chemiresistive response to increased ionic strength, the adsorption of oxyanions into the framework can also be detected using impedance measurements, which have previously been employed for MOF-based detection of redox-inactive analytes. , As a proof of concept, we used electrochemical impedance spectroscopy (EIS) to detect the adsorption of MnO4 – oxyanions by a thin film of Ni3(HITP)2, dropcasted onto a glassy carbon electrode (see Section S9). EIS was conducted before and after the addition of MnO4 – to the cell (Figures S100–S101), and the resulting data was fit to the equivalent circuit shown in the inset of Figure S100, based on previously reported EIS experiments with 2D cMOFs. We observed the impedance of the electrode to increase following exposure to 15.8 ppm KMnO4 in 0.1 M KCl (Figure S102). In contrast, the addition of KCl alone did not result in any increase in impedance, while a bare glassy carbon electrode showed a decrease in impedance in response to the addition of MnO4 – (Figure S103). The high selectivity of Ni3(HITP)2 toward the oxyanions, even in the presence of chloride and sulfate species, are likely arising from the favorable binding interactions between the oxyanions and host sites of the MOF. These interactions likely include (i) hydrogen-bonding interactions between the nucleophilic oxygen of oxyanions and hydrogen donor groups in HITP moieties, (ii) electrostatic interactions between oxyanions and the nickel­(bisdiimine) linkages, (iii) chemical interactions at the adsorptive sites of the MOF, and (iv) redox interactions, where the oxyanions are reduced and HITP is oxidized.

4. Conclusion

This work presents the first demonstration of triphenylene-based, layered cMOFs with varying metal nodes and functionalities for the dual sensing and filtration of oxyanions from water. The as-synthesized cMOFs exhibited exceptional adsorption performance, surpassing most previously reported MOF-based adsorbents. Among them, Ni3(HITP)2 demonstrated unprecedented adsorption capacities, filtering up to 827 mg of MnO4 – and 497 mg of Cr2O7 2– per gram of MOF, while displaying rapid kinetics, achieving 99% removal within 10 min. Examining the performance of Ni3(HITP)2 in various aqueous environments, further highlighted its selectivity and efficiency, demonstrating (i) adsorption capabilities across a broad pH range (4–10), (ii) high selectivity in the presence of competing anions, and (iii) consistent performance across diverse water matrices. Spectroscopic and computational investigations revealed a multifaceted scavenging mechanism, involving chemisorption, hydrogen-bonding, electrostatic interactions, and redox reactions. Additionally, depositing Ni3(HITP)2 onto cotton fabrics produced mechanically robust, flexible, multifunctional electronic textiles, capable of simultaneously capturing (for at least 32 adsorption cycles) and detecting Cr2O7 2– and MnO4 – at low ppm concentrations (2.2 ppm for MnO4 – and 6.0 ppm for Cr2O7 2–). This durability underscores the potential of these MOF@textile composites for long-term, sustainable water filtration and sensing applications.

With these advantages in mind, we identified two key challenges that must be addressed to further advance the practical application of 2D cMOFs in water filtration. First, while conducting adsorption studies on the bulk MOF over a 24-h period, we observed significant nickel ion leaching and structural degradation, with concentrations reaching as high as 10 ppm at elevated Mn­(VII) and Cr­(VI) levels (Figure S89). Given the fast kinetics demonstrated by these MOFs in oxyanion removal, reducing exposure time is thus necessary. Further studies should determine the optimal exposure duration for complete oxyanions remediation, while minimizing framework degradation. Second, the sensing experiments we performed relied mostly on changes in the ionic strength of the contaminated solution, which were monitored via impedance and chemiresistive measurements. While these proof-of-concept experiments demonstrated the feasibility of using these frameworks as sensors, they remain less sensitive compared to fluorescent-based sensors. To achieve ultrasensitive and selective detection, enhancing device fabrication and integration is essential. Taken together, we believe our study lays the foundation for the development of next-generation environmental remediation technologies for use as point-of-use (POU) devices and portable filtration systems. By combining high-efficiency adsorption with real-time sensing, Ni3(HITP)2 cMOF not only purifies water but also enables continuous monitoring, making this class of materials highly promising for advanced water treatment applications in both fixed installations and mobile units.

Supplementary Material

ja5c05275_si_001.pdf (9.8MB, pdf)
Download video file (4.5MB, mpg)
Download video file (4.5MB, mpg)
Download video file (4.6MB, mpg)
Download video file (4.8MB, mpg)

Acknowledgments

The authors acknowledge financial support from the NSF CAREER Award (#1945218), NSF Research Traineeship Award (#2125733), NIH MIRA Award (R35GM138318), and the U.S. Army Research Office Grant No. W911NF2320020. P.D. and E.O.S. acknowledge support from the Dartmouth Guarini School PhD Innovation Program. P.D. would like to thank Prof. Jack Hoopes and PhD student Yanqing Zhong for their help in acquiring the zeta potential measurements.

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/jacs.5c05275.

  • Experimental methods, additional characterization, adsorption capacities, kinetic models, computational data, electrochemical sensing measurements (PDF)

  • Mn­(VII) filtration demo (MPG)

  • Control experiment for Mn­(VII) filtration (MPG)

  • Cr­(VI) filtration demo (MPG)

  • Control experiment for Cr­(VI) filtration (MPG)

#.

P.D. and P.C. contributed equally to this work.

The authors declare no competing financial interest.

References

  1. Podgorski J., Berg M.. Global threat of arsenic in groundwater. Science. 2020;368(6493):845–850. doi: 10.1126/science.aba1510. [DOI] [PubMed] [Google Scholar]
  2. Winkel L. H. E., Trang P. T. K., Lan V. M., Stengel C., Amini M., Ha N. T., Viet P. H., Berg M.. Arsenic pollution of groundwater in Vietnam exacerbated by deep aquifer exploitation for more than a century. Proc. Natl. Acad. Sci. U. S. A. 2011;108(4):1246–1251. doi: 10.1073/pnas.1011915108. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Eaton A.. Assessment of manganese occurrence in drinking water in the United States. ACS EST Water. 2021;1(11):2450–2458. doi: 10.1021/acsestwater.1c00293. [DOI] [Google Scholar]
  4. Costa M., Klein C. B.. Toxicity and carcinogenicity of chromium compounds in humans. Crit. Rev. Toxicol. 2006;36(2):155–163. doi: 10.1080/10408440500534032. [DOI] [PubMed] [Google Scholar]
  5. Wijerathna T. M., Mohamed F., Gawarammana I. B., Wunnapuk K., Dissanayake D. M., Shihana F., Buckley N. A.. Cellular injury leading to oxidative stress in acute poisoning with potassium permanganate/oxalic acid, paraquat, and glyphosate surfactant herbicide. Environ. Toxicol. Pharmacol. 2020;80:103510. doi: 10.1016/j.etap.2020.103510. [DOI] [PubMed] [Google Scholar]
  6. Keith L., Telliard W.. ES&T special report: priority pollutants: Ia perspective view. Environ. Sci. Technol. 1979;13(4):416–423. doi: 10.1021/es60152a601. [DOI] [Google Scholar]
  7. Willhite C., Bhat V., Ball G., McLellan C.. Emergency Do Not Consume/Do Not Use concentrations for potassium permanganate in drinking water. Hum. Exp. Toxicol. 2013;32(3):275–298. doi: 10.1177/0960327112456316. [DOI] [PubMed] [Google Scholar]
  8. Dixit S., Yadav A., Dwivedi P. D., Das M.. Toxic hazards of leather industry and technologies to combat threat: a review. J. Clean. Prod. 2015;87:39–49. doi: 10.1016/j.jclepro.2014.10.017. [DOI] [Google Scholar]
  9. Pasquali E. A., Demaman Oro C. E., Bernardi J. L., Venquiaruto L. D., Treichel H., Mossi A. J., Dallago R. M.. Adsorption of Cr­(VI) by wet blue leather: Sustainable solution for leather industry effluents. J. Water Process Eng. 2025;69:106807. doi: 10.1016/j.jwpe.2024.106807. [DOI] [Google Scholar]
  10. Knežević M., Kramar A., Hajnrih T., Korica M., Nikolić T., Žekić A., Kostić M.. Influence of potassium permanganate oxidation on structure and properties of cotton. J. Nat. Fibers. 2022;19(2):403–415. doi: 10.1080/15440478.2020.1745120. [DOI] [Google Scholar]
  11. Srinivas S., Senthil Kumar A.. High-Performance Electrocatalytic Reduction and Sensing of Hazardous Hexavalent Chromium Using a Redox-Active Binol Species-Impregnated Carbon Nanofiber-Modified Electrode. J. Phys. Chem. C. 2022;126(19):8296–8311. doi: 10.1021/acs.jpcc.2c00317. [DOI] [Google Scholar]
  12. Ma S., Qian J., Wang D., Chan E. M., Jain A., Tong W.. Integrated Electrocatalyst Platform for Electroreduction of Oxyanions in Water. ACS Appl. Energy Mater. 2024;7(9):4224–4232. doi: 10.1021/acsaem.4c00631. [DOI] [Google Scholar]
  13. Khadse G. K., Patni P. M., Labhasetwar P. K.. Removal of iron and manganese from drinking water supply. Sustain. Water Resour. Manag. 2015;1(2):157–165. doi: 10.1007/s40899-015-0017-4. [DOI] [Google Scholar]
  14. Peng C., Meng H., Song S., Lu S., Lopez-Valdivieso A.. Elimination of Cr (VI) from electroplating wastewater by electrodialysis following chemical precipitation. Sep. Sci. Technol. 2005;39(7):1501–1517. doi: 10.1081/SS-120030788. [DOI] [Google Scholar]
  15. Gibbard J. A., Reppel J., Verlet J. R. R.. Photodissociation of permanganate (MnO4−) produces the manganese dioxide anion (MnO2−) in an excited triplet state. Phys. Chem. Chem. Phys. 2023;25(48):32939–32947. doi: 10.1039/D3CP04576E. [DOI] [PubMed] [Google Scholar]
  16. Shang Y., Xu X., Jiang P., Qi S., Ren Z., Song W., Gao B.. Biosorption and Bioreduction of Perchlorate Using the Nano-Fe3O4-Laden Quaternary-Ammonium Chinese Reed: Considering the Coexisting Nitrate and Nano-Fe3O4. ACS Sustain. Chem. Eng. 2017;5(3):2471–2482. doi: 10.1021/acssuschemeng.6b02815. [DOI] [Google Scholar]
  17. Sinharoy A., Lens P. N.. Biological selenate and selenite reduction by waste activated sludge using hydrogen as electron donor. J. Environ. Manag. 2022;319:115745. doi: 10.1016/j.jenvman.2022.115745. [DOI] [PubMed] [Google Scholar]
  18. Kumar A., Thakur A., Panesar P. S.. Extraction of hexavalent chromium by environmentally benign green emulsion liquid membrane using tridodecyamine as an extractant. J. Ind. Eng. Chem. 2019;70:394–401. doi: 10.1016/j.jiec.2018.11.002. [DOI] [Google Scholar]
  19. Akula V. V., Philip L.. Removal of harmful oxyanions from contaminated water by Donnan dialysis. J. Water Process Eng. 2023;55:104085. doi: 10.1016/j.jwpe.2023.104085. [DOI] [Google Scholar]
  20. Dutta S., Fajal S., Ghosh S. K.. Heavy Metal-Based Toxic Oxo-Pollutants Sequestration by Advanced Functional Porous Materials for Safe Drinking Water. Acc. Chem. Res. 2024;57(17):2546–2560. doi: 10.1021/acs.accounts.4c00348. [DOI] [PubMed] [Google Scholar]
  21. Rafryanto A. F., Eka, Charlie D. A., Diguna L. J., Zhang L., Rachmantyo R., Wibowo A., Rochman N. T., Noviyanto A., Arramel. Effective Remediation Strategy for Acidic Wastewater: Integrating Ozone Nanobubbles with Sustainable Adsorption Techniques. ACS Sustainable Resour. Manage. 2024;1(12):2583–2592. doi: 10.1021/acssusresmgt.4c00358. [DOI] [Google Scholar]
  22. Luo J., Fu K., Yu D., Hristovski K. D., Westerhoff P., Crittenden J. C.. Review of Advances in Engineering Nanomaterial Adsorbents for Metal Removal and Recovery from Water: Synthesis and Microstructure Impacts. ACS EST Engg. 2021;1(4):623–661. doi: 10.1021/acsestengg.0c00174. [DOI] [PubMed] [Google Scholar]
  23. Goh K.-H., Lim T.-T., Dong Z.. Application of layered double hydroxides for removal of oxyanions: a review. Water Res. 2008;42(6–7):1343–1368. doi: 10.1016/j.watres.2007.10.043. [DOI] [PubMed] [Google Scholar]
  24. Wijitwongwan R. P., Ogawa M.. NiFe Layered Double Hydroxides with Controlled Composition and Morphology for the Efficient Removal of Cr­(VI) from Water. Langmuir. 2024;40(2):1408–1417. doi: 10.1021/acs.langmuir.3c03076. [DOI] [PubMed] [Google Scholar]
  25. Hsini A., Haounati R., Imgharn A., Naciri Y., Malekshah R. E., Shaim A., Szunerits S., Boukherroub R., Albourine A.. 1,2,4,5-Benzene Tetracarboxylic Acid-Doped Polyaniline/Protonated Carbon Nitride Nanostructures for Cr­(VI) Adsorption in Water. ACS Appl. Nano Mater. 2024;7(11):13050–13061. doi: 10.1021/acsanm.4c01503. [DOI] [Google Scholar]
  26. Zahid A., Nawaz H. H., Siddique A., Ahmed B., Razzaque S., Liu X., Razzaq H., Umar M.. Enabling improved PSF nanocomposite membrane for wastewater treatment with selective nanotubular morphology of PANI/ZnO. Mater. Adv. 2024;5(23):9471–9487. doi: 10.1039/D4MA00859F. [DOI] [Google Scholar]
  27. Salaenoi J., Jurejan N., Yokthongwattana C., Pluempanupat W., Boonprab K.. Characteristics of Coconut Husk Cellulose and its Effectiveness as a Potassium Permanganate Absorbent for Fishery Applications. Case Stud. Chem. Environ. Eng. 2024;10:100975. doi: 10.1016/j.cscee.2024.100975. [DOI] [Google Scholar]
  28. Wen T., Wang J., Yu S., Chen Z., Hayat T., Wang X.. Magnetic Porous Carbonaceous Material Produced from Tea Waste for Efficient Removal of As­(V), Cr­(VI), Humic Acid, and Dyes. ACS Sustain. Chem. Eng. 2017;5(5):4371–4380. doi: 10.1021/acssuschemeng.7b00418. [DOI] [Google Scholar]
  29. Pan Z., Zhu X., Satpathy A., Li W., Fortner J. D., Giammar D. E.. Cr­(VI) Adsorption on Engineered Iron Oxide Nanoparticles: Exploring Complexation Processes and Water Chemistry. Environ. Sci. Technol. 2019;53(20):11913–11921. doi: 10.1021/acs.est.9b03796. [DOI] [PubMed] [Google Scholar]
  30. Li T., Zhu F., Gao Y., Iribagiza M. R., Hu G., Guan J.. Efficient elimination of Cr­(vi) in groundwater using nano zero-valent iron synthesized with Ginkgo biloba extracts: enhanced mechanism and reduced toxicity. Environ. Sci. Water Res. Technol. 2024;10(2):339–352. doi: 10.1039/D3EW00479A. [DOI] [Google Scholar]
  31. Huang X., Dognani G., Hadi P., Yang M., Job A. E., Hsiao B. S.. Cationic Dialdehyde Nanocellulose from Sugarcane Bagasse for Efficient Chromium­(VI) Removal. ACS Sustain. Chem. Eng. 2020;8(12):4734–4744. doi: 10.1021/acssuschemeng.9b06683. [DOI] [Google Scholar]
  32. Wei C., Jiang F., Cao Q., Liu M., Wang J., Ji L., Yu Z., Shi M., Li F.. Insights into the Mechanism of Efficient Cr­(VI) Removal from Aqueous Solution by Iron-Rich Wheat Straw Hydrochar: Coupling DFT Calculation with Experiments. Langmuir. 2024;40(26):13355–13364. doi: 10.1021/acs.langmuir.4c00387. [DOI] [PubMed] [Google Scholar]
  33. Ahmed I. A., Badawi M., Bonilla-Petriciolet A., Lima E. C., Seliem M. K., Mobarak M.. Insights into the Mn (VII) and Cr (VI) adsorption mechanisms on purified diatomite/MCM-41 composite: Experimental study and statistical physics analysis. Front. Chem. 2022;9:814431. doi: 10.3389/fchem.2021.814431. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Saha R., Nandi R., Saha B.. Sources and toxicity of hexavalent chromium. J. Coord. Chem. 2011;64(10):1782–1806. doi: 10.1080/00958972.2011.583646. [DOI] [Google Scholar]
  35. Furukawa H., Cordova K. E., O’Keeffe M., Yaghi O. M.. The Chemistry and Applications of Metal-Organic Frameworks. Science. 2013;341(6149):1230444. doi: 10.1126/science.1230444. [DOI] [PubMed] [Google Scholar]
  36. Lal S., Singh P., Singhal A., Kumar S., Singh Gahlot A. P., Gandhi N., Kumari P.. Advances in metal–organic frameworks for water remediation applications. RSC Adv. 2024;14(5):3413–3446. doi: 10.1039/D3RA07982A. [DOI] [PMC free article] [PubMed] [Google Scholar]
  37. Jrad A., Damacet P., Yaghi Z., Ahmad M., Hmadeh M.. Zr-Based Metal–Organic Framework Nanocrystals for Water Remediation. ACS Appl. Nano Mater. 2022;5(8):10795–10808. doi: 10.1021/acsanm.2c02128. [DOI] [Google Scholar]
  38. Jiao W., Xu W., Cheng J., Zhou C., Li H.. Porous Organic Frame Materials for Adsorption and Removal of Pesticide Contaminants: A Review. ACS Agric. Sci. Technol. 2024;4(11):1163–1178. doi: 10.1021/acsagscitech.4c00459. [DOI] [Google Scholar]
  39. Modak S., Kasula M., Esfahani M. R.. Nanoplastics Removal from Water using Metal–Organic Framework: Investigation of Adsorption Mechanisms, Kinetics, and Effective Environmental Parameters. ACS Appl. Energy Mater. 2023;1(2):744–755. doi: 10.1021/acsaenm.2c00174. [DOI] [Google Scholar]
  40. Svensson Grape E., Chacón-García A. J., Rojas S., Pérez Y., Jaworski A., Nero M., Åhlén M., Martínez-Ahumada E., Galetsa Feindt A. E., Pepillo M., Narongin-Fujikawa M., Ibarra I. A., Cheung O., Baresel C., Willhammar T., Horcajada P., Inge A. K.. Removal of pharmaceutical pollutants from effluent by a plant-based metal–organic framework. Nat. Water. 2023;1(5):433–442. doi: 10.1038/s44221-023-00070-z. [DOI] [Google Scholar]
  41. Jiang D., Chen M., Wang H., Zeng G., Huang D., Cheng M., Liu Y., Xue W., Wang Z.. The application of different typological and structural MOFs-based materials for the dyes adsorption. Coord. Chem. Rev. 2019;380:471–483. doi: 10.1016/j.ccr.2018.11.002. [DOI] [Google Scholar]
  42. Li J., Wang X., Zhao G., Chen C., Chai Z., Alsaedi A., Hayat T., Wang X.. Metal–organic framework-based materials: superior adsorbents for the capture of toxic and radioactive metal ions. Chem. Soc. Rev. 2018;47(7):2322–2356. doi: 10.1039/C7CS00543A. [DOI] [PubMed] [Google Scholar]
  43. An Y., Lv X., Jiang W., Wang L., Shi Y., Hang X., Pang H.. The stability of MOFs in aqueous solutionsresearch progress and prospects. Green Chem. Eng. 2024;5(2):187–204. doi: 10.1016/j.gce.2023.07.004. [DOI] [Google Scholar]
  44. Oladoye P. O., Adegboyega S. A., Giwa A.-R. A.. Remediation potentials of composite metal-organic frameworks (MOFs) for dyes as water contaminants: A comprehensive review of recent literatures. Environmental Nanotechnology, Monitoring & Management. 2021;16:100568. doi: 10.1016/j.enmm.2021.100568. [DOI] [Google Scholar]
  45. Dutta S., Samanta P., Joarder B., Let S., Mahato D., Babarao R., Ghosh S. K.. A Water-Stable Cationic Metal–Organic Framework with Hydrophobic Pore Surfaces as an Efficient Scavenger of Oxo-Anion Pollutants from Water. ACS Appl. Mater. Interfaces. 2020;12(37):41810–41818. doi: 10.1021/acsami.0c13563. [DOI] [PubMed] [Google Scholar]
  46. Pincus L. N., Rudel H. E., Petrović P. V., Gupta S., Westerhoff P., Muhich C. L., Zimmerman J. B.. Exploring the Mechanisms of Selectivity for Environmentally Significant Oxo-Anion Removal during Water Treatment: A Review of Common Competing Oxo-Anions and Tools for Quantifying Selective Adsorption. Environ. Sci. Technol. 2020;54(16):9769–9790. doi: 10.1021/acs.est.0c01666. [DOI] [PMC free article] [PubMed] [Google Scholar]
  47. Banerjee D., Kim D., Schweiger M. J., Kruger A. A., Thallapally P. K.. Removal of TcO4– ions from solution: materials and future outlook. Chem. Soc. Rev. 2016;45(10):2724–2739. doi: 10.1039/C5CS00330J. [DOI] [PubMed] [Google Scholar]
  48. Bhardwaj S. K., Bhardwaj N., Kaur R., Mehta J., Sharma A. L., Kim K.-H., Deep A.. An overview of different strategies to introduce conductivity in metal–organic frameworks and miscellaneous applications thereof. J. Mater. Chem. A. 2018;6(31):14992–15009. doi: 10.1039/C8TA04220A. [DOI] [Google Scholar]
  49. Han J., Xu D., Huang Y., Hua Y., Ding X., Lin Z., Zhou J., Lin H., Chen G., Wang J., Xu X., Liu J., Liu G.. Developing fine-tuned MOF membranes for highly efficient separation and adsorption of chemical pollutant in water. Chem. Eng. J. 2024;497:154508. doi: 10.1016/j.cej.2024.154508. [DOI] [Google Scholar]
  50. Li W., Yu Z., Zhang Y., Lv C., He X., Wang S., Wang Z., He B., Yuan S., Xin J., Liu Y., Zhou T., Li Z., Tan S. C., Wei L.. Scalable multifunctional MOFs-textiles via diazonium chemistry. Nat. Commun. 2024;15(1):5297. doi: 10.1038/s41467-024-49636-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
  51. Patel K. U., Kanzariya D. B., Chaudhary M. Y., Jana A., Pati R. K., Das S., Pal T. K.. Fluorescent MOF and Its Gel Composite for the Fluorescence Recovery “Turn-On” Detection of Al3+ Ions and “Turn-Off” Detection of Oxo-Anions. Inorg. Chem. 2024;63(5):2352–2362. doi: 10.1021/acs.inorgchem.3c03121. [DOI] [PubMed] [Google Scholar]
  52. Gang R.-T., Luo R., Wang W., Yu H.-J., Li Y.-L., Zhang D.-M., Wang Y., Li Z.-H., Shao F.. Cd­(II)-Based Coordination Polymer as a Multiresponsive Fluorescent Sensor for Efficiently Detecting Zn2+, Cr2O72–, and Phenylglyoxylic Acid. Cryst. Growth Des. 2024;24(17):7212–7221. doi: 10.1021/acs.cgd.4c00836. [DOI] [Google Scholar]
  53. Sun Z., Sun J., Xi L., Xie J., Wang X., Ma Y., Li L.. Two Novel Lanthanide Metal–Organic Frameworks: Selective Luminescent Sensing for Nitrobenzene, Cu2+, and MnO4–. Cryst. Growth Des. 2020;20(8):5225–5234. doi: 10.1021/acs.cgd.0c00432. [DOI] [Google Scholar]
  54. Zhang S.-R., Zhang W.-T., Li X., Xu G.-J., Xie W., Xu Y.-H., Xu N., Su Z.-M.. Multifunctional Lanthanide Metal–Organic Frameworks Act as Fluorescent Probes for the Detection of Cr2O72–, Fe3+, and TNP, White Light-Emitting Diodes, and Luminescence Thermometers. Inorg. Chem. 2025;64(6):2990–2999. doi: 10.1021/acs.inorgchem.4c05262. [DOI] [PubMed] [Google Scholar]
  55. Ko M., Mendecki L., Mirica K. A.. Conductive two-dimensional metal–organic frameworks as multifunctional materials. Chem. Commun. 2018;54(57):7873–7891. doi: 10.1039/C8CC02871K. [DOI] [PubMed] [Google Scholar]
  56. Zhong Z., Damacet P., Sánchez-González E., Eagleton A. M., Vereshchuk N., Wongratanaphisan R., Anderson J. T., Goncalves S., Peterson G. W., Blount B., Monti S., Barcaro G., Ibarra I. A., Mirica K. A.. Scalable templated fabrication of Cu-based MOF on textiles for simultaneous sensing, filtration, and detoxification of SO2. Chem. 2025;11:102580. doi: 10.1016/j.chempr.2025.102580. [DOI] [Google Scholar]
  57. Smith M. K., Mirica K. A.. Self-Organized Frameworks on Textiles (SOFT): Conductive Fabrics for Simultaneous Sensing, Capture, and Filtration of Gases. J. Am. Chem. Soc. 2017;139(46):16759–16767. doi: 10.1021/jacs.7b08840. [DOI] [PubMed] [Google Scholar]
  58. Balhatchet C. J., Gittins J. W., Shin S.-J., Ge K., Liu X., Trisukhon T., Sharma S., Kress T., Taberna P.-L., Simon P., Walsh A., Forse A. C.. Revealing Ion Adsorption and Charging Mechanisms in Layered Metal–Organic Framework Supercapacitors with Solid-State Nuclear Magnetic Resonance. J. Am. Chem. Soc. 2024;146(33):23171–23181. doi: 10.1021/jacs.4c05330. [DOI] [PMC free article] [PubMed] [Google Scholar]
  59. Hong Z., Yuan H., Wu H., Sun J., Yang J., Zhang Y. W., Wang J., Wang J.. 2D Vertically Conductive Metal–Organic Framework Electrolytes: Will They Outperform 3D MOFs for Solid State Batteries? Small. 2025;21(5):2408394. doi: 10.1002/smll.202408394. [DOI] [PubMed] [Google Scholar]
  60. Stolz R. M., Mahdavi-Shakib A., Frederick B. G., Mirica K. A.. Host–Guest Interactions and Redox Activity in Layered Conductive Metal–Organic Frameworks. Chem. Mater. 2020;32(18):7639–7652. doi: 10.1021/acs.chemmater.0c01007. [DOI] [Google Scholar]
  61. Meaza I., Williams A. R., Wise S. S., Lu H., Wise J. P.. Carcinogenic Mechanisms of Hexavalent Chromium: From DNA Breaks to Chromosome Instability and Neoplastic Transformation. Curr. Environ. Health Rep. 2024;11:484–546. doi: 10.1007/s40572-024-00460-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
  62. den Braver-Sewradj S. P., van Benthem J., Staal Y. C., Ezendam J., Piersma A. H., Hessel E. V.. Occupational exposure to hexavalent chromium. Part II. Hazard assessment of carcinogenic effects. Regul. Toxicol. Pharmacol. 2021;126:105045. doi: 10.1016/j.yrtph.2021.105045. [DOI] [PubMed] [Google Scholar]
  63. Benedetto A., Au C., Aschner M.. Manganese-Induced Dopaminergic Neurodegeneration: Insights into Mechanisms and Genetics Shared with Parkinson’s Disease. Chem. Rev. 2009;109(10):4862–4884. doi: 10.1021/cr800536y. [DOI] [PubMed] [Google Scholar]
  64. Khan K., Factor-Litvak P., Wasserman G. A., Liu X., Ahmed E., Parvez F., Slavkovich V., Levy D., Mey J., van Geen A., Graziano J. H.. Manganese exposure from drinking water and children’s classroom behavior in Bangladesh. Environ. Health Perspect. 2011;119(10):1501–1506. doi: 10.1289/ehp.1003397. [DOI] [PMC free article] [PubMed] [Google Scholar]
  65. Ball J. W., Izbicki J.. Occurrence of hexavalent chromium in ground water in the western Mojave Desert, California. Appl. Geochem. 2004;19(7):1123–1135. doi: 10.1016/j.apgeochem.2004.01.011. [DOI] [Google Scholar]
  66. Georgaki M.-N., Charalambous M.. Toxic chromium in water and the effects on the human body: a systematic review. J. Water Health. 2023;21(2):205–223. doi: 10.2166/wh.2022.214. [DOI] [Google Scholar]
  67. Bratovcic A., Buksek H., Helix-Nielsen C., Petrinic I.. Concentrating hexavalent chromium electroplating wastewater for recovery and reuse by forward osmosis using underground brine as draw solution. Chem. Eng. J. 2022;431:133918. doi: 10.1016/j.cej.2021.133918. [DOI] [Google Scholar]
  68. Li Y., Xu Z., Ma H., Hursthouse A. S.. Removal of manganese (II) from acid mine wastewater: A review of the challenges and opportunities with special emphasis on Mn-oxidizing bacteria and microalgae. Water. 2019;11(12):2493. doi: 10.3390/w11122493. [DOI] [Google Scholar]
  69. Du C., Xu N., Yao Z., Bai X., Gao Y., Peng L., Gu B., Zhao J.. Mechanistic insights into sulfate and phosphate-mediated hexavalent chromium removal by tea polyphenols wrapped nano-zero-valent iron. Sci. Total Environ. 2022;850:157996. doi: 10.1016/j.scitotenv.2022.157996. [DOI] [PubMed] [Google Scholar]
  70. Izbicki, J. A. ; Groover, K. D. . A plan for study of hexavalent chromium, CR (VI) in groundwater near a mapped plume, Hinkley, California, 2016; pp 2331–1258; US Geological Survey: 2016. [Google Scholar]
  71. Aiken M. L., Pace C. E., Ramachandran M., Schwabe K. A., Ajami H., Link B. G., Ying S. C.. Disparities in Drinking Water Manganese Concentrations in Domestic Wells and Community Water Systems in the Central Valley, CA, USA. Environ. Sci. Technol. 2023;57(5):1987–1996. doi: 10.1021/acs.est.2c08548. [DOI] [PMC free article] [PubMed] [Google Scholar]
  72. McMahon P. B., Belitz K., Reddy J. E., Johnson T. D.. Elevated Manganese Concentrations in United States Groundwater, Role of Land Surface–Soil–Aquifer Connections. Environ. Sci. Technol. 2019;53(1):29–38. doi: 10.1021/acs.est.8b04055. [DOI] [PubMed] [Google Scholar]
  73. Rahman M. A., Hashem M. A., Rana M. S., Islam M. R.. Manganese in potable water of nine districts, Bangladesh: human health risk. Environ. Sci. Pollut. Res. 2021;28:45663–45675. doi: 10.1007/s11356-021-14016-z. [DOI] [PubMed] [Google Scholar]
  74. Liu W., Yuan G., Jiang S., Shi Y., Pang H.. Two-Dimensional (2D) Conductive Metal-Organic Framework Thin Films: The Preparation and Applications in Electrochemistry. Chem.Eur. J. 2024;30(70):e202402747. doi: 10.1002/chem.202402747. [DOI] [PubMed] [Google Scholar]
  75. Yang R., Fan Y., Ye R., Tang Y., Cao X., Yin Z., Zeng Z.. MnO2-based materials for environmental applications. Adv. Mater. 2021;33(9):2004862. doi: 10.1002/adma.202004862. [DOI] [PubMed] [Google Scholar]
  76. Kim H., Watthanaphanit A., Saito N.. Simple Solution Plasma Synthesis of Hierarchical Nanoporous MnO2 for Organic Dye Removal. ACS Sustain. Chem. Eng. 2017;5(7):5842–5851. doi: 10.1021/acssuschemeng.7b00560. [DOI] [Google Scholar]
  77. Sawicka E., Jurkowska K., Piwowar A.. Chromium­(III) and chromium­(VI) as important players in the induction of genotoxicity-current view. Annals of Agricultural and Environmental Medicine. 2020;28(1):1–10. doi: 10.26444/aaem/118228. [DOI] [PubMed] [Google Scholar]
  78. Ko M., Mendecki L., Eagleton A. M., Durbin C. G., Stolz R. M., Meng Z., Mirica K. A.. Employing Conductive Metal–Organic Frameworks for Voltammetric Detection of Neurochemicals. J. Am. Chem. Soc. 2020;142(27):11717–11733. doi: 10.1021/jacs.9b13402. [DOI] [PubMed] [Google Scholar]
  79. Debela T. T., Yang M. C., Hendon C. H.. Ligand-Mediated Hydrogenic Defects in Two-Dimensional Electrically Conductive Metal–Organic Frameworks. J. Am. Chem. Soc. 2023;145(20):11387–11391. doi: 10.1021/jacs.3c02741. [DOI] [PubMed] [Google Scholar]
  80. Ambrogi E. K., Damacet P., Stolz R. M., Mirica K. A.. Mechanistic Insight into the Formation and Deposition of Conductive, Layered Metal–Organic Framework Nanocrystals. ACS Nano. 2025;19(1):1383–1395. doi: 10.1021/acsnano.4c14018. [DOI] [PMC free article] [PubMed] [Google Scholar]
  81. Chen T., Dou J.-H., Yang L., Sun C., Libretto N. J., Skorupskii G., Miller J. T., Dincă M.. Continuous Electrical Conductivity Variation in M3­(Hexaiminotriphenylene)­2 (M = Co, Ni, Cu) MOF Alloys. J. Am. Chem. Soc. 2020;142(28):12367–12373. doi: 10.1021/jacs.0c04458. [DOI] [PubMed] [Google Scholar]
  82. Gittins J. W., Balhatchet C. J., Chen Y., Liu C., Madden D. G., Britto S., Golomb M. J., Walsh A., Fairen-Jimenez D., Dutton S. E., Forse A. C.. Insights into the electric double-layer capacitance of two-dimensional electrically conductive metal–organic frameworks. J. Mater. Chem. A. 2021;9(29):16006–16015. doi: 10.1039/D1TA04026J. [DOI] [PMC free article] [PubMed] [Google Scholar]
  83. Deng Z., Lin T., Li H., Chen W., Zheng R., An S., Song Y.-F.. Structured PAN@MgAl-NO3 for highly efficient removal of CrO42–, SeO32–, MnO4–, and AsO2–. Sep. Purif. Technol. 2025;359:130460. doi: 10.1016/j.seppur.2024.130460. [DOI] [Google Scholar]
  84. Fajal S., Mandal W., Mollick S., More Y. D., Torris A., Saurabh S., Shirolkar M. M., Ghosh S. K.. Trap inlaid cationic hybrid composite material for efficient segregation of toxic chemicals from water. Angew. Chem., Int. Ed. 2022;61(32):e202203385. doi: 10.1002/anie.202203385. [DOI] [PubMed] [Google Scholar]
  85. Zhang Y., Zheng H., Zhang P., Zheng X., Zuo Q.. A facile method to achieve dopamine polymerization in MOFs pore structure for efficient and selective removal of trace lead (II) ions from drinking water. J. Hazard. Mater. 2021;408:124917. doi: 10.1016/j.jhazmat.2020.124917. [DOI] [PubMed] [Google Scholar]
  86. Bhadane P., Mahato P., Menon D., Satpathy B. K., Wu L., Chakraborty S., Goyal P., Lynch I., Misra S. K.. Hydrolytically stable nanosheets of Cu–imidazolate MOF for selective trapping and simultaneous removal of multiple heavy metal ions. Environ. Sci. Nano. 2024;11(6):2385–2396. doi: 10.1039/D3EN00754E. [DOI] [Google Scholar]
  87. Bhuyan A., Ahmaruzzaman M.. Metal-organic frameworks: A new generation potential material for aqueous environmental remediation. Inorg. Chem. Commun. 2022;140:109436. doi: 10.1016/j.inoche.2022.109436. [DOI] [Google Scholar]
  88. Marcus Y.. A simple empirical model describing the thermodynamics of hydration of ions of widely varying charges, sizes, and shapes. Biophys. Chem. 1994;51(2):111–127. doi: 10.1016/0301-4622(94)00051-4. [DOI] [Google Scholar]
  89. Śmiechowski M., Persson I.. Hydration of Oxometallate Ions in Aqueous Solution. Inorg. Chem. 2020;59(12):8231–8239. doi: 10.1021/acs.inorgchem.0c00594. [DOI] [PMC free article] [PubMed] [Google Scholar]
  90. de Meyer C. M. C., Rodríguez J. M., Carpio E. A., García P. A., Stengel C., Berg M.. Arsenic, manganese and aluminum contamination in groundwater resources of Western Amazonia (Peru) Sci. Total Environ. 2017;607–608:1437–1450. doi: 10.1016/j.scitotenv.2017.07.059. [DOI] [PubMed] [Google Scholar]
  91. Sharma P., Bihari V., Agarwal S. K., Verma V., Kesavachandran C. N., Pangtey B. S., Mathur N., Singh K. P., Srivastava M., Goel S. K.. Groundwater contaminated with hexavalent chromium [Cr (VI)]: a health survey and clinical examination of community inhabitants (Kanpur, India) PLoS One. 2012;7(10):e47877. doi: 10.1371/journal.pone.0047877. [DOI] [PMC free article] [PubMed] [Google Scholar]
  92. Hu Q., Ma S., He Z., Liu H., Pei X.. A revisit on intraparticle diffusion models with analytical solutions: Underlying assumption, application scope and solving method. J. Water Process Eng. 2024;60:105241. doi: 10.1016/j.jwpe.2024.105241. [DOI] [Google Scholar]
  93. Wu F.-C., Tseng R.-L., Juang R.-S.. Initial behavior of intraparticle diffusion model used in the description of adsorption kinetics. Chem. Eng. J. 2009;153(1–3):1–8. doi: 10.1016/j.cej.2009.04.042. [DOI] [Google Scholar]
  94. Park I.-H., Yeh S.-W., Cai W., Wang G., Min S.-K., Lee S.-K.. Present-day North Atlantic salinity constrains future warming of the Northern Hemisphere. Nat. Clim. Change. 2023;13(8):816–822. doi: 10.1038/s41558-023-01728-y. [DOI] [Google Scholar]
  95. Pilarski B., Wyrzykowski D.. A novel approach to study ascorbic acid oxidation using hexavalent chromium speciestheoretical and practical perspectives of the use of potentiometric titration technique. Transition Met. Chem. 2025;50:1–33. doi: 10.1007/s11243-024-00602-w. [DOI] [Google Scholar]
  96. Duan L., Cheng T., Zhu Y., Wang Y., Gao Y., Bi J.. Lanthanide-Porphyrin MOF as a Multifunctional Platform for Detection and Integrated Elimination of Cr­(VI) and Ciprofloxacin. Inorg. Chem. 2025;64(4):1983–1993. doi: 10.1021/acs.inorgchem.4c04753. [DOI] [PubMed] [Google Scholar]
  97. Dash S., Patel S., Mishra B. K.. Oxidation by permanganate: synthetic and mechanistic aspects. Tetrahedron. 2009;65(4):707–739. doi: 10.1016/j.tet.2008.10.038. [DOI] [Google Scholar]
  98. Chatterjee S., Qin J., Li X., Liang F., Rai D. K., Yang Y.-W.. Safranin O-functionalized cuboid mesoporous silica material for fluorescent sensing and adsorption of permanganate. J. Mater. Chem. B. 2020;8(11):2238–2249. doi: 10.1039/D0TB00036A. [DOI] [PubMed] [Google Scholar]
  99. Hou S., Liu F., Xie H., Sha F., Fahy K. M., Wang X., Zhang C., Chen Y., Li Z., Farha O. K.. Cationic Metal–Organic Framework with Amino-Functionalized Isonicotinic Acid for Chromium­(VI) Removal. Cryst. Growth Des. 2024;24(11):4645–4651. doi: 10.1021/acs.cgd.4c00288. [DOI] [Google Scholar]
  100. Dong Z.-Y., Lin Y.-L., Zhang T.-Y., Hu C.-Y., Pan Y., Pan R., Tang Y.-L., Xu B., Gao N.-Y.. Enhanced coagulation and oxidation by the Mn­(VII)-Fe­(III)/peroxymonosulfate process: Performance and mechanisms. Water Res. 2022;226:119200. doi: 10.1016/j.watres.2022.119200. [DOI] [PubMed] [Google Scholar]
  101. Tan B., Chen N., Huang L., Gao X., Tan L., Feng H.. Enhanced the electrochemical performance of Ni-doped α-MnO2 prepared with one-pot process for supercapacitors. J. Ind. Eng. Chem. 2025;141:319–327. doi: 10.1016/j.jiec.2024.06.041. [DOI] [Google Scholar]
  102. Ragupathy P., Park D. H., Campet G., Vasan H. N., Hwang S.-J., Choy J.-H., Munichandraiah N.. Remarkable Capacity Retention of Nanostructured Manganese Oxide upon Cycling as an Electrode Material for Supercapacitor. J. Phys. Chem. C. 2009;113(15):6303–6309. doi: 10.1021/jp811407q. [DOI] [Google Scholar]
  103. Kim H., Watthanaphanit A., Saito N.. Synthesis of colloidal MnO2 with a sheet-like structure by one-pot plasma discharge in permanganate aqueous solution. RSC Adv. 2016;6(4):2826–2834. doi: 10.1039/C5RA20416J. [DOI] [Google Scholar]
  104. Liao M., Wang X., Cao S., Li M., Peng X., Zhang L.. Oxalate Modification Dramatically Promoted Cr­(VI) Removal with Zero-Valent Iron. ACS EST Water. 2021;1(9):2109–2118. doi: 10.1021/acsestwater.1c00183. [DOI] [Google Scholar]
  105. Liu J., Gao X., Dai C., Zhang S., Kong S., Wang L., Hu Y.. Cr­(iii)-incorporated Fe­(iii) hydroxides for enhanced redox conversion of As­(iii) and Cr­(vi) in acidic solution. Environ. Sci. Nano. 2025;12(3):2064–2075. doi: 10.1039/D4EN01068J. [DOI] [Google Scholar]
  106. Chemistry Fundamentals, Part A. In Environmental Chemistry: Fundamentals; Ibanez, J. G. , Hernandez-Esparza, M. , Doria-Serrano, C. , Fregoso-Infante, A. , Singh, M. M. , Eds.; Springer New York: New York, NY, 2007; pp 11–42. [Google Scholar]
  107. Chávez-Guajardo A. E., Medina-Llamas J. C., Maqueira L., Andrade C. A., Alves K. G., de Melo C. P.. Efficient removal of Cr (VI) and Cu (II) ions from aqueous media by use of polypyrrole/maghemite and polyaniline/maghemite magnetic nanocomposites. Chem. Eng. J. 2015;281:826–836. doi: 10.1016/j.cej.2015.07.008. [DOI] [Google Scholar]
  108. Ghernaout D.. Advanced oxidation phenomena in electrocoagulation process: a myth or a reality? Desalin . Water Treat. 2013;51(40–42):7536–7554. doi: 10.1080/19443994.2013.792520. [DOI] [Google Scholar]
  109. Cheung K., Gu J.-D.. Mechanism of hexavalent chromium detoxification by microorganisms and bioremediation application potential: a review. International Biodeterioration & Biodegradation. 2007;59(1):8–15. doi: 10.1016/j.ibiod.2006.05.002. [DOI] [Google Scholar]
  110. Yan G., Chen X., Du S., Deng Z., Wang L., Chen S.. Genetic mechanisms of arsenic detoxification and metabolism in bacteria. Current genetics. 2019;65:329–338. doi: 10.1007/s00294-018-0894-9. [DOI] [PubMed] [Google Scholar]
  111. Liang F., Xu Y., Chen S., Zhu Y., Huang Y., Fei B., Guo W.. Fabrication of Highly Efficient Flame-Retardant and Fluorine-Free Superhydrophobic Cotton Fabric by Constructing Multielement-Containing POSS@ZIF-67@PDMS Micro–Nano Hierarchical Coatings. ACS Appl. Mater. Interfaces. 2022;14(50):56027–56045. doi: 10.1021/acsami.2c14709. [DOI] [PubMed] [Google Scholar]
  112. Lee S., Ahn S., Lee H., Kim J.. Layer-by-layer coating of MIL-100­(Fe) on a cotton fabric for purification of water-soluble dyes by the combined effect of adsorption and photocatalytic degradation. RSC Adv. 2022;12(27):17505–17513. doi: 10.1039/D2RA02773A. [DOI] [PMC free article] [PubMed] [Google Scholar]
  113. Li W., Zhang Y., Yu Z., Zhu T., Kang J., Liu K., Li Z., Tan S. C.. In Situ Growth of a Stable Metal–Organic Framework (MOF) on Flexible Fabric via a Layer-by-Layer Strategy for Versatile Applications. ACS Nano. 2022;16(9):14779–14791. doi: 10.1021/acsnano.2c05624. [DOI] [PubMed] [Google Scholar]
  114. Benyettou F., Jrad A., Matouk Z., Prakasam T., Hamoud H. I., Clet G., Varghese S., Das G., Khair M., Sharma S. K.. Tunable wettability of a dual-faced covalent organic framework membrane for enhanced water filtration. J. Am. Chem. Soc. 2024;146(33):23537–23554. doi: 10.1021/jacs.4c07559. [DOI] [PMC free article] [PubMed] [Google Scholar]
  115. Dalmieda J., Kruse P.. Metal cation detection in drinking water. Sensors. 2019;19(23):5134. doi: 10.3390/s19235134. [DOI] [PMC free article] [PubMed] [Google Scholar]
  116. Rauf S., Vijjapu M. T., Andrés M. A., Gascón I., Roubeau O., Eddaoudi M., Salama K. N.. Highly Selective Metal–Organic Framework Textile Humidity Sensor. ACS Appl. Mater. Interfaces. 2020;12(26):29999–30006. doi: 10.1021/acsami.0c07532. [DOI] [PMC free article] [PubMed] [Google Scholar]
  117. Andrés M. A., Vijjapu M. T., Surya S. G., Shekhah O., Salama K. N., Serre C., Eddaoudi M., Roubeau O., Gascón I.. Methanol and Humidity Capacitive Sensors Based on Thin Films of MOF Nanoparticles. ACS Appl. Mater. Interfaces. 2020;12(3):4155–4162. doi: 10.1021/acsami.9b20763. [DOI] [PubMed] [Google Scholar]
  118. He T., Zhang Y.-Z., Kong X.-J., Yu J., Lv X.-L., Wu Y., Guo Z.-J., Li J.-R.. Zr­(IV)-Based Metal-Organic Framework with T-Shaped Ligand: Unique Structure, High Stability, Selective Detection, and Rapid Adsorption of Cr2O72– in Water. ACS Appl. Mater. Interfaces. 2018;10(19):16650–16659. doi: 10.1021/acsami.8b03987. [DOI] [PubMed] [Google Scholar]
  119. Roh H., Quill T. J., Chen G., Gong H., Cho Y., Kulik H. J., Bao Z., Salleo A., Gumyusenge A.. Copper-Based Two-Dimensional Conductive Metal–Organic Framework Thin Films for Ultrasensitive Detection of Perfluoroalkyls in Drinking Water. ACS Nano. 2025;19(6):6332–6341. doi: 10.1021/acsnano.4c16212. [DOI] [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

ja5c05275_si_001.pdf (9.8MB, pdf)
Download video file (4.5MB, mpg)
Download video file (4.5MB, mpg)
Download video file (4.6MB, mpg)
Download video file (4.8MB, mpg)

Articles from Journal of the American Chemical Society are provided here courtesy of American Chemical Society

RESOURCES