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. 2024 Feb 29;9(10):11658–11670. doi: 10.1021/acsomega.3c09016

Adsorption Characteristics of Ball Milling-Modified Chinese Medicine Residue Biochar Toward Quercetin

Lanqing Li †, Yue Xie †,*, Keyan Chen †, Jun Zhou ‡, Min Wang §, Wenqiang Wang †, Zhifan Zhang †, Fan Lu †, Yadong Du †, Yinghao Feng †
PMCID: PMC10938329  PMID: 38496992

Abstract

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Using traditional Chinese medicine residues as raw materials, different biochars (BC) were prepared through oxygen-limited pyrolysis at 300 °C, 500 °C, and 700 °C, and BC was ball-milled to produce ball-milled biochar (BMC). Using these adsorbents to adsorb the allelopathic autotoxic substance quercetin. The physical and chemical properties of various biochars derived from traditional Chinese medicine residues were characterized using the Brunauer–Emmett–Teller-N2 surface areas (BET), scanning electron microscopy (SEM), Fourier transform IR spectroscopy (FTIR), X-ray diffraction (XRD), and Raman spectroscopy (Raman). The study investigated the effects of the initial pH value, different humic acid concentrations, and multiple adsorption–desorption experiments on the removal of quercetin from the solution. The article discusses the adsorption mechanism of quercetin in solution by biochar from a traditional Chinese medicine residue, based on the results of adsorption kinetics and adsorption isotherm fitting. The findings indicate that increasing the pyrolysis temperature reduces the oxygen-containing functional groups of BC, enhances the aromaticity, and stabilizes the carbon structure. The pore structure of BMC becomes more complex after ball milling, which increases the number of oxygen-containing functional groups on the surface. Among the samples tested, BMC700 exhibits the best adsorption performance, with an adsorption capacity of 293.3 mg·g–1 at 318 K. The adsorption process of quercetin by BMC700 follows the pseudo-second-order kinetic model and the Freundlich adsorption isotherm model. The process is primarily a form of multimolecular layer adsorption. Its mechanism involves the pore-filling effect, hydrogen-bonding interaction, electrostatic interaction, and π–π coexistence, as well as the yoke effect. Additionally, they are highly recyclable and show promise in addressing continuous cropping issues.

1. Introduction

Intensive cultivation of crops can block the long-term continuous cropping growth process of plant development, leading to serious soil-borne diseases and a significant reduction in the yield of economic crops.1 Quercetin, a flavonoid allelopathic chemical, is one of the most important causes of continuous cropping obstacles. Flavonoids are a type of 2-phenylchromone compounds. The plant’s autotoxicity mechanism involves producing and secreting a substance into the soil that inhibits cell division frequency in the root meristem region.2,3 This leads to inhibited formation of root hairs and resting cells in root cap cells, resulting in imperfect plant root development.4 For instance, certain studies have discovered that quercetin, which is secreted due to the long-term continuous cropping of leguminous forage plants, such as alfalfa and clover, has a notable inhibitory effect on the development of their seeds.5 Additionally, quercetin strongly inhibits the growth of lettuce roots.6

At present, the methods of regulating continuous cropping obstacles are mostly concentrated in intercropping rotation, organic material application, and soil biological regulation.7,8 The use of crop intercropping can improve the soil environment, but the management is complex, and competition between different crops may cause crop productivity to decline.9 Rotation can effectively reduce the accumulation of allelopathic chemicals in soil.10 However, the residual branches of plants are closely linked, which requires high planting technology, and the urgent cycle may lead to the decrease of crop productivity.11 Although the application of organic materials can reduce the allelopathic chemicals in the soil, the continuous accumulation of organic materials in the soil during continuous cropping can aggravate the risk of soil salinization and acidification.12 The introduction of microorganisms to regulate the soil environment has been a research hotspot in recent years. The principle is to use microorganisms to degrade allelopathic chemicals, thereby reducing the toxicity of allelopathic chemicals.13,14 However, microorganisms are sensitive to the soil environment, climatic conditions, and other factors, so the application effect is not stable.15 The cultivation of disease-resistant varieties cannot be the main way to control continuous cropping obstacles because of the limitations of a long cultivation cycle and high technical requirements.8 Therefore, it is urgent to explore a new governance scheme.

As a new, green, environmentally friendly, economical, and easily available adsorption material, biochar has become one of the hot spots of international scholars.16,17 Biochar is an aromatized carbon-rich material formed by high-temperature pyrolysis (250–700 °C) of biomass under anaerobic conditions. It has a large specific surface area, a developed pore structure, abundant surface functional groups, and excellent adsorption performance. It can be used as an ideal adsorbent for environmental remediation.18−20 As the remaining waste after the utilization of Chinese herbal medicine, Chinese medicine residue has a total emission of 60 to 70 million tons per year, which can be used as a typical biomass resource for the preparation of biochar.

Many studies have shown that biochar can adsorb organic pollutants in soil and increase the reproduction of beneficial bacteria.21 However, there are few reports on flavonoids. This study used traditional Chinese medicine residues to prepare biochar (BC) at different pyrolysis temperatures and ball-milling modifications to prepare ball-milled biochar (BMC), and studied the adsorption effects of different adsorption materials on quercetin. Six materials were tested, compared for their adsorption properties, and characterized. The goal of this study is to investigate the material adsorption mechanism via adsorption experiments and a material characterization analysis. This objective is aimed at reinforcing the study’s scientific foundation and identifying the best adsorption materials to enhance the practical application of biochar. This approach will help overcome the continuous cropping obstacles and provide alternative solutions.

2. Materials and Methods

2.1. Experimental Materials

Chrysanthemum residues (Chuju, Chrysanthemum morifolium) were obtained from the Chuzhou chrysanthemum planting base. The surface soil and stones were removed, and the residue was rinsed with deionized water. Next, the residue was dried in an oven at 60 °C until it reached a constant weight. Finally, the residue was ground into a powder by using a grinder.

2.2. Experimental Reagents and Drugs

Methanol, acetonitrile, and ethanol were all of chromatographic grade (Sigma, Germany). Quercetin (QR) was purchased from Shanghai Yuanye Biotechnology Co., Ltd. with a purity greater than 95%. All other reagents were of analytical grade, and the water was ultrapure.

2.3. Preparation of Biochar and Ball-Milled Biochar

2.3.1. Preparation of Biochar

A certain amount of chrysanthemum Chinese medicine residue powder was weighed and placed in a crucible in a tubular heating furnace (Figure 1). Under the condition of a nitrogen atmosphere, the temperature was increased from room temperature to 300, 500, 700 °C at a heating rate of 5 °C·min–1, maintained for 2 h, and naturally cooled to room temperature. The yield of biochar was calculated. The prepared biochars were labeled as BC300, BC500, and BC700.

Figure 1.

Figure 1

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Preparation diagram of biochar and ball-milling materials.

2.3.2. Preparation of Biochar Modified by Ball Milling

Biochar was weighed and put into a 50 mL agate tank, and grinding beads were added (the mass ratio of grinding beads to biochar was 100:1). Run at 300 rpm for 6 h and change the rotation direction every 3 h. The prepared ball-milled biochars were labeled BMC300, BMC500, and BMC700.

2.4. Analysis and Detection

The elemental composition (C, H, and N) of the selected adsorbents (BC300, BC500, BC700, BMC300, BMC500, and BMC700) was determined by an elemental analyzer. The surface morphology of these materials was observed by SEM. The BET-specific surface area and pore volume of these materials were determined by the nitrogen adsorption method. The thermal stability was measured at a heating rate of 20 °C·min–1 in the range of 35 to 900 °C on a thermogravimetric analyzer. The crystal phase of the selected adsorbent was determined by X-ray diffraction. The scanning range (2θ) was 10–90°, and the scanning speed was 2°·min–1. Raman spectroscopy was used to detect the number of functional groups and the degree of graphitization of the adsorbent, and the use range was 500–2000 cm–1. Fourier transform infrared spectroscopy was used to record the distribution of functional groups in the range of 4000–500 cm–1.

The chromatographic peaks in the solution were analyzed by a high-performance liquid chromatograph, and the corresponding solution concentration was calculated according to the standard curve. Chromatographic conditions: Shim-pack VP-ODS column (250 × 4.6 mm, 5 μm); the column temperature was 30 °C and the detection wavelength was 210 nm. The flow rate was 1.0 mL/min. The injection volume was 10 μL. Mobile phase A was acetonitrile and mobile phase B was 0.1% phosphoric acid aqueous solution. Isocratic elution: 0–6 min, 30% A, 70% B. All solutions were filtered through a 0.22 μm filter membrane before injection.

2.5. Adsorption Experiment

2.5.1. Adsorption Kinetics Experiments

The experiment used a QR solution with an initial concentration of 100 mg/L as the mother liquid; 23 plugged conical flasks were filled with 40 mL of QR solution and 0.050 g of biochar, resulting in a solid–liquid ratio of 1.25:1 (g/L). The flasks were then placed in a constant temperature shaker. The rotation speed was set at 160 rpm, and the temperature was set at 25 °C. Samples were taken at a preset time point, 10 mL each time, and the concentration of the adsorption solution was determined after passing through a 0.45 μm filter membrane.

2.5.2. Adsorption Isotherm Experiment

According to the solid–liquid ratio of adsorption kinetics of 1.25:1  (g/L), 0.050 g of biochar was weighed in a conical flask with a stopper, and then 40 mL of QR solution with a mass concentration gradient of 50–400 mg·L–1 was added. The solution was placed in a thermostatic shaker with a speed of 160 r/min and shaken for 48  h. The solution obtained after the adsorption reaction was filtered through a 0.45 μm filter membrane and measured at 25, 35, and 45 °C.

2.5.3. Effect of pH on Adsorption Effect

0.050 g of biochar was weighed in a conical bottle with a plug, and 40 mL of QR solution with a concentration of 100 mg·L–1 was added. The pH values were adjusted to 3, 5, 7, 9, 11 with 0.1 mol·L–1 hydrochloric acid solution or sodium hydroxide solution, respectively, at 25 °C and 160 r/min. After 24  h of oscillation, the sample was filtered through a 0.45 μm filter membrane and determined.

2.5.4. Regeneration Adsorption Performance

The saturated biochar was ultrasonically shaken and desorbed with 0.5 mol·L–1 sodium hydroxide solution for 12  h. After washing and drying, the adsorption experiment was carried out again, and the adsorption experiment was carried out again. The concentration of the QR solution was 100 mg·L–1, and the solid–liquid ratio of the solution to biochar was 1.25:1  (g/L). Repeat the above operation 5 times, and set 3 parallel samples for each biochar.

2.5.5. Effect of Humic Acid

A 0.050 g portion of biochar was weighed in a conical bottle with a plug, and 40 mL of QR solution with different concentrations of humic acid at 100 mg·L–1 was added. Under the conditions of 25 °C and 160 r/min, the constant temperature was oscillated for 24  h, and the concentration of QR was determined by sampling.

2.6. Data Analysis

The amount of adsorption was calculated as the amount of QR in the initial test solution minus the amount of QR in the solution after adsorption. The experimental data were analyzed using adsorption capacity equations, removal rate equations, Freundlich, Langmuir, and Temkin adsorption isotherm models, pseudo-first-order, pseudo-second-order adsorption kinetics, and intraparticle diffusion models, which are described in detail in the Supporting Information. The data in this article collected signals from high-performance liquid chromatography LabSolutions and exported them in text file format (*.txt). The exported raw data were plotted using Originpro 2022 software.

3. Results and Discussion

3.1. Characterization Results

3.1.1. Elemental Analysis

Carbonization temperature and ball-milling modification will have a certain impact on the elemental composition of biochar to a certain extent. Table 1 presents the compositions of carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and other elements in various biochar samples. With increasing pyrolysis temperature, the ash content and C content of BC increased, and the content of N, H, and O decreased. This occurred due to the escalation of dehydrogenation and condensation degree brought about by the rise of the pyrolysis temperature. According to a study,22 organic compounds, such as cellulose, hemicellulose, and lignin, present in the residue of Chinese medicine break down to produce gaseous components, including CO, CH4, NH3, and small molecular organic compounds.23 Pyrolysis is a process that leads to carbon enrichment and weakening of the polar functional groups. This process is favorable for creating biochar with a relatively high carbon content and relative stability. BMC has the same pattern of elemental change as BC; however, the oxygen content in BMC is higher than that in BC. This signifies that ball milling boosts both the specific surface area of carbon materials and corresponding oxygen-containing functional groups. This result is in harmony with the findings of FTIR. The ash content of BC and BMC increases with the increase of temperature. This is due to the precipitation of alkali metals and inorganic ions, including K, Si, and Cl, during the pyrolysis of the Chinese medicine residue. The inorganic ions are more likely to precipitate and fuse at higher temperatures, resulting in the formation of inorganic minerals and an increase in the ash content.24 The H/C atomic ratio can be used to characterize the aromaticity of biochar. The smaller the ratio, the stronger the aromaticity and the more stable the biochar structure is. The O/C atomic ratio can be used to characterize the hydrophilicity of biochar. The smaller the ratio, the worse the hydrophilicity of biochar. (O+N)/C can be used to characterize the polarity of biochar. The smaller the ratio is, the smaller the polarity of biochar is.25 It can be known from Table 1 that the atomic ratios of H/C, O/C, and (O+N)/C of BC and BMC decreased with the increase of temperature, indicating that under high temperature conditions, BC changed from low aromatic and unsaturated carbon to high aromatic, saturated, and stable carbon, and the hydrophilicity and polarity of carbon decreased. Ball-milled biochar exhibits increased polarity and hydrophilicity, resulting from the introduction of oxygen-containing functional groups. The carbon surface structure undergoes changes during mechanical impact and friction of the carbon particles, leading to the formation of polar functional groups, such as hydroxyl and carbonyl groups, with a high oxygen content. Because oxygen is electronegative, it can form hydrogen bonds with water molecules in a solution, increasing the material’s polarity and hydrophilicity.26

Table 1. Physicochemical Properties of Different Chinese Medicine Wastes Biochar.
  physical property
 C, H, N, O contents/%
 atomic ratios
biochar yield/% ash/% C H N O H/C O/C (O  +  N)/C
BC300 52.13 14.85 51.50 3.81 3.77 40.92 0.074 0.795 0.868
BC500 38.65 28.52 55.20 3.49 3.24 38.07 0.063 0.690 0.748
BC700 27.55 31.02 61.72 3.12 3.29 31.87 0.051 0.516 0.570
BMC300 — 16.54 44.19 1.86 3.14 50.81 0.042 1.150 1.221
BMC500 — 26.42 46.92 1.61 2.75 48.72 0.034 1.038 1.097
BMC700 — 35.76 49.45 1.47 2.63 46.45 0.030 0.939 0.991
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3.1.2. Specific Surface Area

The adsorption performance of an adsorbent is significantly influenced by its pore structure and specific surface area. From Table 2, it can be seen that with the increase in the pyrolysis temperature, the specific surface area of BC increased from 0.427 m2g–1 to 2.390 m2g–1, and the total pore volume increased from 0.001943 cm3g–1 to 0.007992 cm3g–1, indicating that the pyrolysis temperature is conducive to the formation of carbon pore structure. This is because the increase in the pyrolysis temperature leads to the decomposition of cellulose in the Chinese medicine residue. There is a certain amount of oxygen in the heat treatment process, which will be accompanied by the production of CO and CO2 gas and the release of some volatile substances to cause the development of pores.27 However, the surface properties of BC after direct pyrolysis are poor. Comparing the micropore-specific surface area and micropore volume, it can be seen that the micropore specific-surface area and micropore volume of BC and BMC increase with the increase in temperature. This is because the pyrolysis temperature and the overall pore parameters caused by ball milling increase but the micropore area and volume of BMC700 decrease. The reason for this result may be that the micropore wall of the BMC700 material collapses and combines into mesopores or macropores during ball milling.

Table 2. Surface Properties of BC and BMC.
biochar SBET Smic Smes Vtot Vmic Davg Dmes
BC300 0.427 0.100 0.327 0.001943 0.000005 18.21 38.30
BC500 1.397 0.554 0.843 0.007105 0.000266 20.35 32.56
BC700 2.390 1.118 1.272 0.007992 0.000540 13.38 29.12
BMC300 6.036 1.786 4.250 0.043053 0.000547 28.53 38.87
BMC500 10.01 2.277 7.731 0.059240 0.001062 23.68 24.07
BMC700 17.99 0.420 17.57 0.086178 0.000012 19.16 21.33
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The N2 adsorption–desorption curves of BC and BMC are shown in Figure 2. At p/p0 < 0.1, the adsorption and desorption curves of BC and BMC showed a slow upward trend. This stage was mainly monolayer adsorption, and p/p0 = 0.1 was the critical point of monolayer saturated adsorption. When 0.1 < p/p0 < 0.9, there is no obvious slow increase in this stage, which belongs to multilayer adsorption; when p/p0 > 0.9, capillary condensation occurs, showing a rapid growth trend. According to the IUPAC classification,28 BC and BMC conform to type IV isotherm characteristics. From Figure 2, we can find that the N2 adsorption–desorption curve of BC has a desorption hysteresis phenomenon when p/p0 > 0.4, forming an H4 hysteresis loop. When the N2 adsorption–desorption curve of BMC is p/p0 > 0.8, the desorption hysteresis phenomenon appears, and the H4-type hysteresis loop is also formed. This situation is because the mesopores only undergo capillary condensation during desorption, which is different from the corresponding pressure point during adsorption, resulting in a hysteresis effect. These results show that the material has rich mesopores, macropores, and a small amount of micropores,29 which is the same as the SEM results, and the pore size distribution of each material is shown in Figure 2.

Figure 2.

Figure 2

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Nitrogen adsorption and desorption isotherms and pore volume distribution of BC and BMC (a) BC300, (b) BC500, (c) BC700, (d) BMC300, (e) BMC500, and (f) BMC700.

3.1.3. SEM Analysis

Field emission electron microscopy was utilized to observe the microscopic morphology of BC and MBC. Figure 3 shows the SEM images of BC and BMC. It can be seen from Figure 3a,b that the shape and pore structure of BC are roughly the same, retaining the original skeleton structure of biomass, showing wrinkled and layered tube bundles, with a large number of pore structures, well-developed pore structure, and the surface smoothness decreases with the increase of the pyrolysis temperature. This is due to the gradual decomposition of cellulose, hemicellulose, and lignin in the raw materials of Chinese medicine residue caused by pyrolysis temperature, and the carbon skeleton left after carbonization of lignin, while pyrolysis leads to the analysis of volatile groups, resulting in the complex pore structure of BC.30 Compared with the bulk structure of pyrolytic carbon BC, the ball-milled BMC becomes irregular granular particles, which are caused by the friction and collision between the material and the ball-ink medium.31 The rougher surface and larger specific surface area of BMC are the keys to improving its adsorption performance.

Figure 3.

Figure 3

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SEM patterns of biochars.

3.1.4. XRD Analysis

Figure 4a shows the XRD patterns of BC and BMC. The 2θ of the six biochars has obvious amorphous broad peaks at 10–30°, and 2θ = 26.5° is the characteristic peak of graphite.32 The diffraction peaks of the six biochars appeared at 2θ of 28.3° and 40.4°, and the peak shape was sharp and narrow, indicating that the biochar existed in a carbonaceous crystal structure.33 The Chinese medicine residue contains a large amount of K, which appears in the form of KCl or other types of mineral potassium during high temperature pyrolysis, which corresponds to the crystal structure characteristic peak of KCl in the figure, and its crystal faces are 200, 220, 222, and 420.34 As the temperature increases, the peak intensity decreases. This is because after the temperature rises, KCl precipitates in the gas phase, resulting in a decrease in its crystallization properties.35 When the carbonization temperature increases, the diffraction peaks of CaCO3 and SiO2 crystals at 2θ = 29.48° and 73.92° become obvious. It may be because as the temperature increases, the biomass slowly decomposes completely, resulting in an increase in the ash content of biochar and an increase in the crystallinity of biochar.36

Figure 4.

Figure 4

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(a) XRD patterns of biochars, (b)FTIR patterns of biochars, (c) Raman patterns before adsorption and (d) Raman patterns after adsorption.

3.1.5. FT-IR Analysis

FT-IR analysis enables the identification of specific functional groups in the material. The FT-IR spectra of BC and BMC are shown in Figure 4b. BC and the corresponding BMC show similar infrared absorption peaks, indicating that they contain roughly the same functional group structure. The bending vibration of the C–H bond of an aromatic compound occurs at 875 cm–1 in BMC.37 There is a symmetrical C–O–C bond stretching vibration near 1060 cm–1, which is the characteristic peak of the cellulose and hemicellulose structure in biomass after carbonization. With the increase of temperature, the peak intensity decreases, indicating that it is decomposing.38 The −OH stretching vibration of the carboxylic acid dimer at 2358 cm–1 indicates the formation of −COOH; near 2854 and 2925 cm–1 are the absorption peaks generated by the symmetric and antisymmetric stretching vibrations of the methylene C–H bonds of aliphatic substances or cycloalkane structures (−CH3 and −CH2).39 There is a hydrogen bond stretching vibration of −OH at a wide peak band of 3410–3510 cm–1 ,40 and the peak decreases with the increase of carbonization temperature, which may be caused by the detachment of bound water and the fracture of the hydroxyl group bound by the hydrogen bond. In general, with the increase of pyrolysis temperature, the difficult-to-decompose substances in Chinese medicine residue gradually decomposed, dehydrogenated, and deoxygenated; the degree of carbonization and aromatization gradually increased; and the oxygen-containing functional groups were less. After ball milling, the corresponding peak of oxygen-containing functional groups increased, and aromatic functional groups appeared, indicating that ball milling can effectively expose the oxygen-containing functional groups on the surface of the material.31

3.1.6. Raman Analysis

Figure 4c,d shows the Raman spectra of BC and BMC before and after adsorption. It can be clearly observed that there are two different peaks at 1360 and 1600 cm–1. The D peak represents the defect site or disordered structure, reflecting the carbon defect of the lattice. The G peak represents the sp2 hybrid carbon of graphite, reflecting the degree of carbonization of the material, which is reflected in BC500, BC700 and BMC500, BMC700, while BC300 and BMC300 because of their low degree of carbonization, much data noise, and there is no obvious D peak and G peak display. The area ratio of the two peaks (ID/IG) is negatively correlated with the degree of graphitization of the carbon material and the order of the carbon structure.41 As can be seen from Figure 4c, the ID/IG of BC500 = 1.321, while that of BC700 rises to 1.924. BMC500 (ID/IG = 0.819) is also smaller than BMC700 (ID/IG = 1.686). This shows that as the carbonization temperature increases, the carbon atomic crystals have more defects and will contain more defective sites and disordered states, and the adsorption performance will also improve.42,43 BMC500 (ID/IG = 0.819) is smaller than BC500 (ID/IG = 1.321). This is because the G peak comes from the stretching vibration of the sp2 carbon atoms, which represents the aromatic ring structure. The aromatic functional groups of BMC increase, so the ratio decreases. XRD and the characterization results of FT-IR can be demonstrated. Comparing Figure 4c and d, we can find that the ID/IG of the carbon material after adsorption is greater than the ratio before adsorption. The possible reason is that during the adsorption process, the surface functional groups of the carbon material are enriched with C=C, −OH, and −COOH functional groups, which can be used as It is a strong π electron donor, and the QR molecule interacts strongly with the surface of the carbon material due to its strong π electron acceptor properties (it can lend electrons to the benzene ring, etc.), thus affecting the stretching vibration of the sp2 carbon atom, resulting in a larger ratio.44,45

3.2. Analysis of Adsorption Performance

3.2.1. Adsorption Kinetics

Adsorption kinetics is a crucial research topic in the adsorption process. It enables the calculation of the adsorption rate and the description of the diffusion mechanism of pollutants. The adsorption kinetic curves of BC and BMC on QR are shown in Figure 5. Adsorption kinetics describes the diffusion process of the adsorbate on the adsorbent surface. As can be seen from Figure 7a,b below, the adsorption process of the six biochars can be divided into two stages. During the initial adsorption process, QR in the solution rapidly adsorbs onto carbon and enters its pores, occupying the adsorption sites on the biochar surface. In the slow adsorption stage, the number of active sites on the biochar surface decreases, limiting the diffusion rate of QR molecules in the pores and causing a decrease in the adsorption efficiency. As more QR molecules occupy the material’s surface, the electrostatic repulsion between adsorbates also increases, further weakening the material’s adsorption rate.46,47 The order of adsorption capacity is BMC700 > BMC500 > BMC300 > BC700 > BC500 > BC300.

Figure 5.

Figure 5

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Adsorption kinetics and intraparticle diffusion fitting curves of QR on BC and ball-milled BMC at different pyrolysis temperatures: (a) BC kinetics, (b) BMC kinetics, (c) BC intraparticle diffusion, and (d) BMC intraparticle diffusion.

Figure 7.

Figure 7

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(a) The effect of pH value on the adsorption of QR by BC(BMC). (b) Effect of humic acid concentration on the adsorption of QR by BC(BMC). (c) Regeneration adsorption performance of QR by BC(BMC).

The adsorption kinetics fitting data are shown in Table 3 below. It can be seen from the kinetic parameter R2 and equilibrium adsorption capacity Qe that the pseudo-second-order kinetics R2 (0.912–0.995) of the six biochar materials are larger than the corresponding pseudo-first-order kinetics. First-order kinetics R2 (0.853–0.984), which shows that the pseudo-second-order kinetic model can better fit the adsorption process of QR. It shows that these six types of biochar are not simple physical diffusion processes but processes related to both physical adsorption and chemical adsorption.48,49

Table 3. Pseudo-First-Order and Pseudo-Second-Order Kinetic Parameters.
  pseudo-first-order
 pseudo-second-order
biochar Qe k1 R2 Qe k2 R2
BC300 15.14 0.443 0.951 16.00 0.492 0.995
BC500 35.12 0.558 0.947 40.15 0.014 0.985
BC700 66.26 0.440 0.984 73.17 0.006 0.991
MBC300 48.48 0.781 0.863 50.08 0.023 0.912
MBC500 67.90 0.423 0.853 66.59 0.011 0.952
MBC700 99.82 0.201 0.905 119.0 0.002 0.948
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In order to further explore the diffusion mechanism of QR on biochar, this paper refers to the intraparticle diffusion model, and the fitting process is shown in Figure 5c,d and Table S2 below. Except for BMC700, the adsorption rate-controlling process of the other five biochars was divided into three stages. The first stage was the rapid diffusion of QR to the surface of biochar, and the slope K1 value was higher than that of the second stage K2 and the third stage K3. The second stage is the diffusion process of QR in the large pores of biochar particles, and the K2 value decreases slightly.,50 The third stage is the diffusion process of QR to mesopores and micropores in biochar particles, and the K3 value is the smallest, which indicates that the main third stage is the main speed control stage.51 The two-stage intraparticle diffusion model can better describe the BMC700. Combined with the BET data analysis, the reason for this result may be that part of the micropore wall of BMC700 after ball milling collapses to form mesopores and lacks micropore filling for speed control. Referring to Table S2 below, in the whole adsorption stage, the intercept C is not zero, indicating that intraparticle diffusion is not the only step limiting the adsorption process of the six biochar materials,52 and the adsorption process is more complicated. The K value of BMC is larger than that of the corresponding BC, which may be due to the larger specific surface area and richer pore structure of the biochar material after ball milling.

3.2.2. Adsorption Isotherm

The adsorption results were fitted using Langmuir, Freundlich, and Temkin isothermal adsorption models. The results are shown in Table 4 and Figure 6. It can be concluded from the fitting results in Figure 6 and Table 4 that the Langmuir adsorption isotherm curve can better reflect the adsorption performance of BC300 and BC500 on QR. The calculated theoretical adsorption amount is close to the experimental maximum adsorption value, which shows that adsorption occurs in the monolayer adsorption on the surface,53,54 chemical adsorption plays a dominant role. Compared with the Langmuir phase isothermal model fitting, the data fitted by the Freundlich model can better describe the adsorption performance of BC700 on QR, which shows that the adsorption sites on the surface of BC700 are not uniform, which may be due to the high carbonization temperature resulting in BC700 surface functional groups and pores. It is related to changes in surface properties, such as structure. The Freundlich model fitting results RF2 (0.848–0.993) of BMC are larger than the corresponding Langmuir model fitting results RL2 (0.624–0.951). The Freundlich model equation can better fit the adsorption of QR by BMC materials, which shows that after ball milling. The biochar adsorption process is no longer a simple single-molecule adsorption. The adsorption mechanism is more complex than that of BC-pyrolysis biochar. This may be because the biochar structure changed during the ball-milling process. The BMC adsorption process is dominated by multimolecular layer physical adsorption, such as π–π electron donor–acceptor interaction, hydrogen bonding, etc., all of which participate in the adsorption process.55,56 In the Freundlich model fitted to the six biochars, 1/n is the heterogeneity factor, and its values are all less than 0.5, which shows that the adsorption of QR by the six materials is relatively easy to occur.57 As the ambient temperature increases, the maximum adsorption capacity Qm of the six biochars increases with the increase in temperature, which shows that the adsorption process is an endothermic reaction. The increase in temperature intensifies the thermal movement of molecules, increasing the relationship between QR molecules and BC(BMC), thereby increasing the adsorption amount. It can be concluded from Figure 6 and Table 4 that the coefficient RT2 of the Temkin model fitting is close to 1, with the highest fitting value being 0.987, indicating that strong electrostatic interaction or ion exchange exists in the adsorption process of QR by BC(BMC).

Table 4. Isothermal Adsorption Fitting Parameters of BC and BMC for QR.
    Llangmuir
 Freundlich
 Temkin
biochar T/K Qm KL RL2 1/n Kf RF2 KT b RT2
BC300 298 71.55 0.005 0.948 0.462 2.920 0.909 0.040 150.6 0.947
308 113.8 0.007 0.740 0.424 5.648 0.656 0.047 106.1 0.727
318 115.5 0.009 0.940 0.395 8.230 0.893 0.068 102.5 0.929
BC500 298 109.1 0.009 0.983 0.394 8.154 0.970 0.074 100.3 0.981
308 113.4 0.039 0.928 0.182 37.31 0.983 2.088 158.2 0.978
318 135.5 0.926 0.864 0.048 105.6 0.984 3.652 442.5 0.987
BC700 298 124.9 0.037 0.918 0.200 36.97 0.978 1.362 130.2 0.971
308 182.1 0.559 0.735 0.123 99.64 0.993 181.7 143.3 0.976
318 215.0 3.660 0.492 0.129 124.2 0.895 702.3 134.8 0.840
BMC300 298 125.2 0.006 0.941 0.497 4.168 0.971 0.047 93.64 0.940
308 122.3 0.010 0.951 0.382 10.15 0.990 0.097 98.11 0.969
318 138.3 0.023 0.935 0.275 25.92 0.980 0.347 100.8 0.970
BMC500 298 104.1 0.034 0.841 0.197 30.46 0.957 1.382 160.9 0.935
308 142.1 0.061 0.919 0.174 51.48 0.964 3.740 131.2 0.963
318 174.5 0.407 0.950 0.106 102.6 0.952 383.2 166.7 0.971
BMC700 298 169.7 1.407 0.624 0.095 106.0 0.952 3315 191.8 0.922
308 266.5 1.538 0.857 0.194 119.2 0.957 18.52 69.16 0.954
318 293.3 2.032 0.931 0.167 172.1 0.938 117.3 72.28 0.961
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Figure 6.

Figure 6

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Adsorption isothermal fitting curves of QR at different pyrolysis temperatures BC and ball milling at different temperatures: (a) BC300, (b) BC500, (c) BC700, (d) BMC300, (e) BMC500, and (f) BMC700.

3.2.3. Adsorption Thermodynamics

The study of thermodynamics can intuitively judge the physical and chemical effects in the adsorption process as well as the driving force and energy changes in the adsorption process. The thermodynamic parameters are mainly calculated by Gibbs free energy changes ΔGθ, ΔHθ (enthalpy change), and ΔSθ (entropy change). It can be seen from Figure 6 that the adsorption amount of BC (MBC) increases with the increase in temperature, which indicates that the adsorption of BC (MBC) on QR is an endothermic reaction, which can be proven by the fact that ΔHθ is greater than zero in Table S3. In Table S3, ΔGθ at different temperatures is less than zero, indicating that the adsorption of QR by BC(BMC) is a spontaneous process. With the increase of temperature, the value of ΔGθ decreases, indicating that the increase of temperature is beneficial to the adsorption process. In addition, the ΔGθ values of BC300 and BMC700 are less than −20 kJ·mol–1, indicating that there is chemical adsorption in the adsorption process, while the ΔHθ values of the remaining BC(BMC) are greater than 20 kJ·mol–1, indicating that the adsorption process becomes physical and chemical adsorption.58 The values of ΔSθ are all positive, indicating that the QR molecules are adsorbed from the disordered state to the BC(MBC) surface to form a regular state during the adsorption of QR by BC(BMC), resulting in a decrease in the degree of freedom, while the analysis process of water on the BC(MBC) surface is from ordered to disordered. Since the volume of QR molecules is much larger than that of water molecules, when QR molecules are fixed on the BC(MBC) surface, multiple water molecules will be released, thus increasing the degree of freedom of the solid–liquid two-phase interface.59

3.2.4. Effect of pH on Adsorption Effect

The pH of the solution mainly affects the charge state of the biochar surface by changing the ionization degree of the adsorbate, so that the electrostatic interaction between the biochar and the solute changes, and the adsorption effect also changes.58,60 It can be seen from Figure 7a that the overall adsorption effect increases with the increase in pH value. Especially when the pH value is less than 7, the adsorption effect increases rapidly. When the pH value exceeds 7, the adsorption efficiency slows down, and the adsorption capacity of BC300 and BC500 also decreases slightly. The reason for the above trend is mainly due to the change of pH, which leads to the change of electronegativity of QR. The dissociation constant of QR is pKa = 6.71. Under acidic conditions, QR molecules mainly exist in the molecular state. Due to the principle of similar miscibility, the distribution coefficient in the organic phase of different BC(BMC) surfaces is much larger than that in the water phase. There is no electrostatic repulsion, and it is easier to be adsorbed by BC(BMC), so the adsorption capacity increases. However, when the solution is alkaline, a part of the QR in the solution exists in the form of anions. With the increase of pH value, the hydroxyl, carboxyl, and other groups on the surface of biochar are deprotonated, which increases the electrostatic repulsion between a large number of dissociated QR anions,61 resulting in slow or even inhibition of adsorption efficiency, and the change of adsorption capacity also decreases steadily.

3.2.5. Effect of Humic Acid

Humic acid is ubiquitous in soil and wastewater and affects the adsorption effect. The effect of different concentrations of humic acid on the adsorption of QR by BC(BMC) is shown in Figure 7. The figure illustrates that the adsorption capacity of BC300 and BC500 on QR decreases as the initial humic acid concentration increases. This may be because humic acid itself is a macromolecular organic matter, the adsorption capacity of BC300 and BC500 itself is not high, and its adsorption sites are also less. The macromolecular groups of humic acid also occupy a part of the adsorption sites and block their pores during the adsorption process of BC300 and BC500, resulting in a decrease in the specific surface area of biochar.62 With the increase in the humic acid concentration, this situation will become more obvious. When the concentration is higher than 10 mg/L, this competitive relationship with pollutants is also reflected in the adsorption processes of the other four carbons. However, when the concentration of humic acid was lower than 10 mg/L, the adsorption amount of QR on BC700 and BMC increased slowly, which may be due to the fact that the functional groups, such as −OH and −NH2, on the surface of BC700 and BMC pyrolyzed to 700 °C were more abundant, which could adsorb humic acid through hydrogen bonding or electrostatic attraction.63 These humic acids on the surfaces of BC700 and BMC contain a large number of aromatic benzene rings and oxygen-containing functional groups. Oxygen-containing functional groups can form hydrogen bonds with −OH and other groups in QR molecules, and their benzene ring structure can fix QR molecules through π–π bonds, so that new adsorption sites are formed on the surface of BC700 and BMC.64 Therefore, a low concentration of humic acid has a promoting effect on the adsorption of QR, a trace allelochemical.

3.2.6. Regeneration Adsorption Performance

The potential applications of biochar are determined by its regeneration and adsorption properties. Figure 7c shows the results after desorbing and regenerating the six types of biochar with a 0.5 mol·L–1 NaOH solution. The regeneration adsorption capacity increased after the first few desorptions. Specifically, the adsorption capacity of BC300 increased from 13.06 mg·g–1 to 13.87 mg·g–1, BC500 increased from 37.45 mg·g–1 to 39.71 mg·g–1, and BC700 increased from 69.36 mg·g–1 to 72.25 mg·g–1. The adsorption capacity of BMC300, BMC500, and BMC700 increased from 34.49 mg·g–1 to 37.73 mg·g–1, 61.98 mg·g–1 to 62.85 mg·g–1, and 89.93 mg·g–1 to 91.82 mg·g–1, respectively. This increase in adsorption capacity may be attributed to the reduction of positive charges on the biochar surface during the ultrasonic cleaning process, which weakens the electrostatic repulsion. After conducting five desorption and regeneration performance tests, it was found that the adsorption capacity of BC500, BC700, BMC300, BMC500, and BMC700 for QR remained high, reaching 87.05%, 84.74%, 83.22%, 83.66%, and 86.66%, respectively. However, the adsorption capacity of BC300 reached only 59.96% of the original concentration. These results indicate that these materials have good regeneration and adsorption performances, making them valuable for reuse.

3.2.7. Adsorption Mechanism Analysis

BMC700 has a large specific surface area and developed pore structure, and there are abundant groups, such as −OH, −NH2, and −COOH, on the surface. Figure 8 shows a diagram of the adsorption mechanism hypothesized by BMC700. It can be seen from the adsorption experiment that the adsorption mechanism is complex. First, it can be seen from the intraparticle diffusion model that the QR in the first stage of the solution rapidly diffuses to the surface of BMC700. In the second stage, the QR molecules diffuse to the macropores of BMC700. In the third stage, the adsorption sites of the macropores of biochar decrease, and the QR molecules gradually diffuse to the mesopores and micropores of BMC700. The QR molecule has an −OH group, which can interact with BMC700 as both a hydrogen bond acceptor and a hydrogen bond donor. At the same time, BMC700 has a higher degree of aromatization, and its aromatic ring can undergo π–π conjugation with the benzene ring of QR. In addition, QR molecules exist in different forms at different pHs, while the surface functional groups of BMC700 will absorb or dissociate protons with a certain charge, and the two will have a certain strong electrostatic interaction during the adsorption process.

Figure 8.

Figure 8

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Mechanism of the interaction between BMC700 and QR is proposed.

4. Conclusion

In this study, we prepared the BC material, derived from chrysanthemum traditional Chinese medicine residue, through pyrolysis and ball milling at varying temperatures. The objective of this study was to investigate the adsorption performance of QR. An increase in temperature was found to promote pore formation, decrease oxygen-containing functional groups, increase carbon-containing functional groups, improve aromaticity, and enhance the adsorption performance. The complex pore structure of the BMC is enhanced by ball milling, leading to an increase in oxygen-containing functional groups on the surface. BMC700 exhibits the best adsorption performance, with an equilibrium capacity of 169.7 mg·g–1 at 298 K. The characterization results reveal that in addition to the hydrogen bonds and electrostatic adsorption of oxygen-containing functional groups, pore filling, π–π conjugation, and strong electrostatic interactions contribute significantly to adsorption and removal. These findings are in line with the complex physical and chemical adsorption results from the conducted experiments. The ball-milled, modified biochar material made from traditional Chinese medicine residue, as developed in this study, exhibits excellent adsorption and regeneration capabilities as well as being low-cost and ecofriendly. This study not only pioneered the exploration of the mechanism of biochar adsorbing flavonoid allelopathic substances but also provided a new idea for the management of soil continuous cropping obstacles.

Acknowledgments

This work was supported by the Natural Science Foundation of Anhui Province (No. 2008085MC81), Key R&D Program Projects of Anhui Province (No. 202004a06020003), Graduate Science Research Project of Anhui Science and Technology University (No. YK202107), and Enterprise Horizontal Project Fund (No. 2020QX001).

Supporting Information Available

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsomega.3c09016.

  • Formulas and parameter analysis, such as adsorption capacity equation, removal rate equation, Freundlich, Langmuir, and Temkin adsorption isotherm models, pseudo-first-order, pseudo-second-order adsorption kinetics, and intraparticle diffusion model; quercetin. The liquid-phase detection method, methodology validation, and data (Table S1); intraparticle diffusion fitting data (Table S2), and thermodynamic fitting parameter data (Table S3) (PDF)

Author Contributions

L.L.: Conceptualization, data curation, visualization,writing-original draft. Y.X.: Resources, writing–review, and editing, funding acquisition. K.C.: Writing–review and editing, data curation. J.Z.: Writing–review and editing. M.W.: Writing–review and editing. W.W.: Writing–review and editing, methodology. Z.Z.: Data curation. F.L.: Methodology, data curation, validation. Y.D.: Formal analysis, project administration, investigation. Y.F.: Project administration, writing–review and editing.

The authors declare no competing financial interest.

Supplementary Material

ao3c09016_si_001.pdf (104.6KB, pdf)

References

  1. Ratnadass A.; Fernandes P.; Avelino J.; Habib R. Plant species diversity for sustainable management of crop pests and diseases in agroecosystems: A review. Agron. Sustainable Dev. 2012, 32 (1), 273–303. 10.1007/s13593-011-0022-4. [DOI] [Google Scholar]
  2. Saito K.; Yonekura-Sakakibara K.; Nakabayashi R.; Higashi Y.; Yamazaki M.; Tohge T.; Fernie A. R. The flavonoid biosynthetic pathway in Arabidopsis: Structural and genetic diversity. Plant Physiol. Biochem. 2013, 72, 21–34. 10.1016/j.plaphy.2013.02.001. [DOI] [PubMed] [Google Scholar]
  3. Rice E. L.. Allelopathy, 2nd ed.; Academic press, 1983. [Google Scholar]
  4. Mierziak J.; Kostyn K.; Kulma A. Flavonoids as important molecules of plant interactions with the environment. Molecules 2014, 19 (10), 16240–16265. 10.3390/molecules191016240. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Weston L. A.; Mathesius U. Flavonoids: Their Structure, Biosynthesis and Role in the Rhizosphere, Including Allelopathy. J. Chem. Ecol. 2013, 39 (2), 283–297. 10.1007/s10886-013-0248-5. [DOI] [PubMed] [Google Scholar]
  6. Levizou E.; Karageorgou P.; Petropoulou Y.; Grammatikopoulos G.; Manetas Y. Induction of Ageotropic Response in Lettuce Radicle Growth by Epicuticular Flavonoid Aglycons of Dittrichia viscosa. Biol. Plant. 2004, 48 (2), 305–307. 10.1023/B:BIOP.0000033462.71065.93. [DOI] [Google Scholar]
  7. Feng Q.; Wang B.; Chen M.; Wu P.; Lee X.; Xing Y. Invasive plants as potential sustainable feedstocks for biochar production and multiple applications: A review. Resour., Conserv. Recycl. 2021, 164, 105204. 10.1016/j.resconrec.2020.105204. [DOI] [Google Scholar]
  8. Zhao X.; Elcin E.; He L.; Vithanage M.; Zhang X.; Wang J.; Wang S.; Deng Y.; Niazi N. K.; Shaheen S. M.; Wang H.; Wang Z. Using biochar for the treatment of continuous cropping obstacle of herbal remedies: A review. Appl. Soil Ecol. 2024, 193, 105127. 10.1016/j.apsoil.2023.105127. [DOI] [Google Scholar]
  9. Moore V. M.; Schlautman B.; Fei S.-Z.; Roberts L. M.; Wolfe M.; Ryan M. R.; Wells S.; Lorenz A. J. Plant breeding for intercropping in temperate field crop systems: A review. Front. Plant Sci. 2022, 13, 843065. 10.3389/fpls.2022.843065. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Hao W.-Y.; Ren L.-X.; Ran W.; Shen Q.-R. Allelopathic effects of root exudates from watermelon and rice plants on Fusarium oxysporum f. sp. niveum. Plant Soil 2010, 336 (1–2), 485–497. 10.1007/s11104-010-0505-0. [DOI] [Google Scholar]
  11. McCollum C.; Bergtold J. S.; Williams J.; Al-Sudani A.; Canales E. Perceived Benefit and Cost Perception Gaps between Adopters and Non-Adopters of In-Field Conservation Practices of Agricultural Producers. Sustainability 2022, 14 (19), 11803. 10.3390/su141911803. [DOI] [Google Scholar]
  12. Zhang H.; Zheng X.; Wang X.; Xiang W.; Xiao M.; Wei L.; Zhang Y.; Song K.; Zhao Z.; Lv W.; Chen J.; Ge T. Effect of fertilization regimes on continuous cropping growth constraints in watermelon is associated with abundance of key ecological clusters in the rhizosphere. Agric., Ecosyst. Environ. 2022, 339, 108135. 10.1016/j.agee.2022.108135. [DOI] [Google Scholar]
  13. Chen Y.; Peng Y.; Dai C.-C.; Ju Q. Biodegradation of 4-hydroxybenzoic acid by Phomopsis liquidambari. Appl. Soil Ecol. 2011, 51, 102–110. 10.1016/j.apsoil.2011.09.004. [DOI] [Google Scholar]
  14. Caspersen S.; Alsanius B. W.; Sundin P.; Jensén P. Bacterial amelioration of ferulic acid toxicity to hydroponically grown lettuce (Lactuca sativa L.). Soil Biol. Biochem. 2000, 32 (8–9), 1063–1070. 10.1016/S0038-0717(00)00014-6. [DOI] [Google Scholar]
  15. Adesemoye A. O.; Kloepper J. W. Plant–microbes interactions in enhanced fertilizer-use efficiency. Appl. Microbiol. Biotechnol. 2009, 85 (1), 1–12. 10.1007/s00253-009-2196-0. [DOI] [PubMed] [Google Scholar]
  16. Haider F. U.; Wang X.; Zulfiqar U.; Farooq M.; Hussain S.; Mehmood T.; Naveed M.; Li Y.; Liqun C.; Saeed Q.; Ahmad I.; Mustafa A. Biochar application for remediation of organic toxic pollutants in contaminated soils; An update. Ecotoxicol. Environ. Saf. 2022, 248, 114322. 10.1016/j.ecoenv.2022.114322. [DOI] [PubMed] [Google Scholar]
  17. Danesh P.; Niaparast P.; Ghorbannezhad P.; Ali I. Biochar production: Recent developments, applications, and challenges. Fuel 2023, 337, 126889. 10.1016/j.fuel.2022.126889. [DOI] [Google Scholar]
  18. El-Naggar A.; Lee S. S.; Rinklebe J.; Farooq M.; Song H.; Sarmah A. K.; Zimmerman A. R.; Ahmad M.; Shaheen S. M.; Ok Y. S. Biochar application to low fertility soils: A review of current status, and future prospects. Geoderma 2019, 337, 536–554. 10.1016/j.geoderma.2018.09.034. [DOI] [Google Scholar]
  19. Cho S.-H.; Lee S.; Kim Y.; Song H.; Lee J.; Tsang Y. F.; Chen W.-H.; Park Y.-K.; Lee D.-J.; Jung S.; Kwon E. E. Applications of agricultural residue biochars to removal of toxic gases emitted from chemical plants: A review. Sci. Total Environ. 2023, 868, 161655. 10.1016/j.scitotenv.2023.161655. [DOI] [PubMed] [Google Scholar]
  20. Li D.; Ma J.; Xu H.; Xu X.; Qiu H.; Cao X.; Zhao L. Recycling waste nickel-laden biochar to pseudo-capacitive material by hydrothermal treatment: Roles of nickel-carbon interaction. Carbon Res. 2022, 1 (1), 16. 10.1007/s44246-022-00015-3. [DOI] [Google Scholar]
  21. Ma Z.; Wang Q.; Wang X.; Chen X.; Wang Y.; Mao Z. Effects of biochar on replant disease by amendment soil environment. Commun. Soil Sci. Plant Anal. 2021, 52 (7), 673–685. 10.1080/00103624.2020.1869758. [DOI] [Google Scholar]
  22. Kan T.; Strezov V.; Evans T. J. Lignocellulosic biomass pyrolysis: A review of product properties and effects of pyrolysis parameters. Renewable Sustainable Energy Rev. 2016, 57, 1126–1140. 10.1016/j.rser.2015.12.185. [DOI] [Google Scholar]
  23. Tian L.; Shen B.; Xu H.; Li F.; Wang Y.; Singh S. Thermal behavior of waste tea pyrolysis by TG-FTIR analysis. Energy 2016, 103, 533–542. 10.1016/j.energy.2016.03.022. [DOI] [Google Scholar]
  24. Yuan J.-H.; Xu R.-K.; Zhang H. The forms of alkalis in the biochar produced from crop residues at different temperatures. Bioresour. Technol. 2011, 102 (3), 3488–3497. 10.1016/j.biortech.2010.11.018. [DOI] [PubMed] [Google Scholar]
  25. Yang Y.; Sun K.; Han L.; Jin J.; Sun H.; Yang Y.; Xing B. Effect of minerals on the stability of biochar. Chemosphere 2018, 204, 310–317. 10.1016/j.chemosphere.2018.04.057. [DOI] [PubMed] [Google Scholar]
  26. Lopez-Tenllado F. J.; Motta I. L.; Hill J. M. Modification of biochar with high-energy ball milling: Development of porosity and surface acid functional groups. Bioresour. Technol. Rep. 2021, 15, 100704. 10.1016/j.biteb.2021.100704. [DOI] [Google Scholar]
  27. Glatzel T.; Litterst C.; Cupelli C.; Lindemann T.; Moosmann C.; Niekrawietz R.; Streule W.; Zengerle R.; Koltay P. Computational fluid dynamics (CFD) software tools for microfluidic applications – A case study. Comput. Fluids 2008, 37 (3), 218–235. 10.1016/j.compfluid.2007.07.014. [DOI] [Google Scholar]
  28. Mariana M.; Mistar E. M.; Alfatah T.; Supardan M. D. High-porous activated carbon derived from Myristica fragrans shell using one-step KOH activation for methylene blue adsorption. Bioresour. Technol. Rep. 2021, 16, 100845. 10.1016/j.biteb.2021.100845. [DOI] [Google Scholar]
  29. Liu L.; Li Y.; Fan S. Preparation of KOH and H3PO4 modified biochar and its application in methylene blue removal from aqueous solution. Processes 2019, 7 (12), 891. 10.3390/pr7120891. [DOI] [Google Scholar]
  30. Vakili A.; Zinatizadeh A.; Rahimi Z.; Zinadini S.; Mohammadi P.; Azizi S.; Karami A.; Abdulgader M. The impact of activation temperature and time on the characteristics and performance of agricultural waste-based activated carbons for removing dye and residual COD from wastewater. J. Cleaner Prod. 2023, 382, 134899. 10.1016/j.jclepro.2022.134899. [DOI] [Google Scholar]
  31. Lyu H.; Gao B.; He F.; Zimmerman A. R.; Ding C.; Huang H.; Tang J. Effects of ball milling on the physicochemical and sorptive properties of biochar: Experimental observations and governing mechanisms. Environ. Pollut. 2018, 233, 54–63. 10.1016/j.envpol.2017.10.037. [DOI] [PubMed] [Google Scholar]
  32. Shu Q.; Gao J.; Nawaz Z.; Liao Y.; Wang D.; Wang J. Synthesis of biodiesel from waste vegetable oil with large amounts of free fatty acids using a carbon-based solid acid catalyst. Appl. Energy 2010, 87 (8), 2589–2596. 10.1016/j.apenergy.2010.03.024. [DOI] [Google Scholar]
  33. Liou T.-H.; Wu S.-J. Characteristics of microporous/mesoporous carbons prepared from rice husk under base- and acid-treated conditions. J. Hazard. Mater. 2009, 171 (1–3), 693–703. 10.1016/j.jhazmat.2009.06.056. [DOI] [PubMed] [Google Scholar]
  34. Yang X.; Kwon E. E.; Dou X.; Zhang M.; Kim K.-H.; Tsang D. C.; Ok Y. S. Fabrication of spherical biochar by a two-step thermal process from waste potato peel. Sci. Total Environ. 2018, 626, 478–485. 10.1016/j.scitotenv.2018.01.052. [DOI] [PubMed] [Google Scholar]
  35. Michelsen H. P.; Frandsen F.; Dam-Johansen K.; Larsen O. H. Deposition and high temperature corrosion in a 10 MW straw fired boiler. Fuel Process. Technol. 1998, 54 (1–3), 95–108. 10.1016/S0378-3820(97)00062-3. [DOI] [Google Scholar]
  36. Yao Y.; Gao B.; Inyang M.; Zimmerman A. R.; Cao X.; Pullammanappallil P.; Yang L. Biochar derived from anaerobically digested sugar beet tailings: Characterization and phosphate removal potential. Bioresour. Technol. 2011, 102 (10), 6273–6278. 10.1016/j.biortech.2011.03.006. [DOI] [PubMed] [Google Scholar]
  37. Ertugay N.; Malkoc E. Adsorption isotherm, kinetic, and thermodynamic studies for methylene blue from aqueous solution by needles of Pinus sylvestris L. Pol. J. Environ. Stud. 2014, 23, 6. [Google Scholar]
  38. Schwanninger M.; Rodrigues J.; Pereira H.; Hinterstoisser B. Effects of short-time vibratory ball milling on the shape of FT-IR spectra of wood and cellulose. Vib. Spectrosc. 2004, 36 (1), 23–40. 10.1016/j.vibspec.2004.02.003. [DOI] [Google Scholar]
  39. Li F.; Lin M. Synthesis of biochar-supported K-doped g-C3N4 photocatalyst for enhancing the polycyclic aromatic hydrocarbon degradation activity. Int. J. Environ. Res. Public Health 2020, 17 (6), 2065. 10.3390/ijerph17062065. [DOI] [PMC free article] [PubMed] [Google Scholar]
  40. Chen B.; Zhou D.; Zhu L. Transitional adsorption and partition of nonpolar and polar aromatic contaminants by biochars of pine needles with different pyrolytic temperatures. Environ. Sci. Technol. 2008, 42 (14), 5137–5143. 10.1021/es8002684. [DOI] [PubMed] [Google Scholar]
  41. Pratheeksha P. M.; Rajeshwari J. S.; Daniel P. J.; Rao T. N.; Anandan S. Investigation of in-situ carbon coated LiFePO4 as a superior cathode material for lithium ion batteries. J. Nanosci. Nanotechnol. 2019, 19 (5), 3002–3011. 10.1166/jnn.2019.15881. [DOI] [PubMed] [Google Scholar]
  42. Wang R.; An H.; Zhang H.; Zhang X.; Feng J.; Wei T.; Ren Y. High active radicals induced from peroxymonosulfate by mixed crystal types of CuFeO2 as catalysts in the water. Appl. Surf. Sci. 2019, 484, 1118–1127. 10.1016/j.apsusc.2019.04.182. [DOI] [Google Scholar]
  43. Gao W.; Lin Z.; Chen H.; Yan S.; Zhu H.; Zhang H.; Sun H.; Zhang S.; Zhang S.; Wu Y. Roles of graphitization degree and surface functional groups of N-doped activated biochar for phenol adsorption. J. Anal. Appl. Pyrolysis 2022, 167, 105700. 10.1016/j.jaap.2022.105700. [DOI] [Google Scholar]
  44. Zhang C.; Lai C.; Zeng G.; Huang D.; Yang C.; Wang Y.; Zhou Y.; Cheng M. Efficacy of carbonaceous nanocomposites for sorbing ionizable antibiotic sulfamethazine from aqueous solution. Water Res. 2016, 95, 103–112. 10.1016/j.watres.2016.03.014. [DOI] [PubMed] [Google Scholar]
  45. Zhang S.; Min Z.; Tay H.-L.; Asadullah M.; Li C.-Z. Effects of volatile–char interactions on the evolution of char structure during the gasification of Victorian brown coal in steam. Fuel 2011, 90 (4), 1529–1535. 10.1016/j.fuel.2010.11.010. [DOI] [Google Scholar]
  46. Shrestha D. Efficiency of Wood-Dust of Dalbergia sisooas Low-Cost Adsorbent for Rhodamine-B Dye Removal. Nanomaterials 2021, 11 (9), 9. 10.3390/nano11092217. [DOI] [PMC free article] [PubMed] [Google Scholar]
  47. Zhang P.; Li Y.; Cao Y.; Han L. Characteristics of tetracycline adsorption by cow manure biochar prepared at different pyrolysis temperatures. Bioresour. Technol. 2019, 285, 2019. 10.1016/j.biortech.2019.121348. [DOI] [PubMed] [Google Scholar]
  48. Zimmermann A. C.; Mecabo A.; Fagundes T.; Rodrigues C. A. Adsorption of Cr(VI) using Fe-crosslinked chitosan complex (Ch-Fe). J. Hazard. Mater. 2010, 179 (1–3), 192–196. 10.1016/j.jhazmat.2010.02.078. [DOI] [PubMed] [Google Scholar]
  49. Çelekli A.; İlgün G.; Bozkurt H. Sorption equilibrium, kinetic, thermodynamic, and desorption studies of Reactive Red 120 on Chara contraria. Chem. Eng. J. 2012, 191, 228–235. 10.1016/j.cej.2012.03.007. [DOI] [Google Scholar]
  50. Kalak T.; Kaczmarek M.; Nowicki P.; Pietrzak R.; Tachibana Y.; Cierpiszewski R. Preparation of nitrogen-enriched pine sawdust-based activated carbons and their application for copper removal from the aquatic environment. Wood Sci. Technol. 2022, 56 (6), 1721–1742. 10.1007/s00226-022-01423-9. [DOI] [Google Scholar]
  51. Yao J.; Kong Q.; Zhu H.; Long Y.; Shen D. Adsorption characteristics of nitrite on Friedel’s salt under the landfill circumstance. Chem. Eng. J. 2014, 254, 479–485. 10.1016/j.cej.2014.06.007. [DOI] [Google Scholar]
  52. Xing X.; Zhang Y.; Zhou G.; Zhang Y.; Yue J.; Wang X.; Yang Z.; Chen J.; Wang Q.; Zhang J. Mechanisms of polystyrene nanoplastics adsorption onto activated carbon modified by ZnCl2. Sci. Total Environ. 2023, 876, 162763. 10.1016/j.scitotenv.2023.162763. [DOI] [PubMed] [Google Scholar]
  53. Yang Q.; Wang X.; Luo W.; Sun J.; Xu Q.; Chen F.; Zhao J.; Wang S.; Yao F.; Wang D.; Li X.; Zeng G. Effectiveness and mechanisms of phosphate adsorption on iron-modified biochars derived from waste activated sludge. Bioresour. Technol. 2018, 247, 537–544. 10.1016/j.biortech.2017.09.136. [DOI] [PubMed] [Google Scholar]
  54. Jung K.-W.; Hwang M.-J.; Jeong T.-U.; Ahn K.-H. A novel approach for preparation of modified-biochar derived from marine macroalgae: Dual purpose electro-modification for improvement of surface area and metal impregnation. Bioresour. Technol. 2015, 191, 342–345. 10.1016/j.biortech.2015.05.052. [DOI] [PubMed] [Google Scholar]
  55. Hilber I.; Wyss G. S.; Mäder P.; Bucheli T. D.; Meier I.; Vogt L.; Rainer R. Influence of activated charcoal amendment to contaminated soil on dieldrin and nutrient uptake by cucumbers. Environ. Pollut. 2009, 157 (8–9), 2224–2230. 10.1016/j.envpol.2009.04.009. [DOI] [PubMed] [Google Scholar]
  56. Yang X.; Xu G.; Yu H.; Zhang Z. Preparation of ferric-activated sludge-based adsorbent from biological sludge for tetracycline removal. Bioresour. Technol. 2016, 211, 566–573. 10.1016/j.biortech.2016.03.140. [DOI] [PubMed] [Google Scholar]
  57. Cao D.-Q.; Yang W.-Y.; Wang Z.; Hao X.-D. Role of extracellular polymeric substance in adsorption of quinolone antibiotics by microbial cells in excess sludge. Chem. Eng. J. 2019, 370, 684–694. 10.1016/j.cej.2019.03.230. [DOI] [Google Scholar]
  58. Li X.; Xu J.; Shi J.; Luo X. Rapid and efficient adsorption of tetracycline from aqueous solution in a wide pH range by using iron and aminoacetic acid sequentially modified hierarchical porous biochar. Bioresour. Technol. 2022, 346, 126672. 10.1016/j.biortech.2022.126672. [DOI] [PubMed] [Google Scholar]
  59. Zhou J.; Ma F.; Guo H. Adsorption behavior of tetracycline from aqueous solution on ferroferric oxide nanoparticles assisted powdered activated carbon. Chem. Eng. J. 2020, 384, 123290. 10.1016/j.cej.2019.123290. [DOI] [Google Scholar]
  60. Xu J.; Zhang Y.; Li B.; Fan S.; Xu H.; Guan D.-X. Improved adsorption properties of tetracycline on KOH/KMnO4 modified biochar derived from wheat straw. Chemosphere 2022, 296, 133981. 10.1016/j.chemosphere.2022.133981. [DOI] [PubMed] [Google Scholar]
  61. Sheng X.; Wang J.; Cui Q.; Zhang W.; Zhu X. A feasible biochar derived from biogas residue and its application in the efficient adsorption of tetracycline from an aqueous solution. Environ. Res. 2022, 207, 112175. 10.1016/j.envres.2021.112175. [DOI] [PubMed] [Google Scholar]
  62. Liu Q.; Li D.; Cheng H.; Cheng J.; Du K.; Hu Y.; Chen Y. High mesoporosity phosphorus-containing biochar fabricated from Camellia oleifera shells: Impressive tetracycline adsorption performance and promotion of pyrophosphate-like surface functional groups (C-O-P bond). Bioresour. Technol. 2021, 329, 124922. 10.1016/j.biortech.2021.124922. [DOI] [PubMed] [Google Scholar]
  63. Wang J.; Li H.; Yue D. Enhanced adsorption of humic/fulvic acids onto urea-derived graphitic carbon nitride. J. Hazard. Mater. 2022, 424, 127643. 10.1016/j.jhazmat.2021.127643. [DOI] [PubMed] [Google Scholar]
  64. Kim J. E.; Bhatia S. K.; Song H. J.; Yoo E.; Jeon H. J.; Yoon J.-Y.; Yang Y.; Gurav R.; Yang Y.-H.; Kim H. J.; Choi Y.-K. Adsorptive removal of tetracycline from aqueous solution by maple leaf-derived biochar. Bioresour. Technol. 2020, 306, 123092. 10.1016/j.biortech.2020.123092. [DOI] [PubMed] [Google Scholar]

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