Table 4.
Adsorbed heavy metals, maximum adsorption capacity, pH and temperature for adsorption of heavy metals by organic-inorganic core/shell and hierarchically structured nanocomposites.
| Adsorbent (interacting group) | Heavy metal (qmax, pH and t (°C)) | Isotherm | Reference |
|---|---|---|---|
| Core/shell nanocomposites
| |||
| SiO2/salicyclic acid functionalized polystyrene (O atom of –COOH and N atom of –N=N–) | Cu2+ (1.29 mmol/g, 5, room) | Langmuir | [233] |
| Ag+ (1.85 mmol/g, 5, room) | Langmuir | ||
| Au3+ (1.61 mmol/g, 2.7, room) | Langmuir | ||
| SiO2/amino functionalized polystyrene (–NH2) | Cu2+ (0.17 mmol/g, neutral, room) | Experimental | [234] |
| Ag+ (0.47 mmol/g, neutral, room) | Experimental | ||
| Au3+ (0.59 mmol/g, neutral, room) | Experimental | ||
| SiO2/imidazole-functionalized polystyrene (–N=N– and imidazole) | Au3+ (1.7 mmol/g, 2.7, room) | Langmuir | [235] |
| SiO2/aniline formaldehyde condensate (–NH2) | Cu2+ (76.33 mg/g, 5.4–5.7, room) | Langmuir | [236] |
| SiO2/polyacrylamide (–NH2) | Hg2+ (26.5 mg/g, acidic, 40) | Experimental | [237] |
| SiO2/Chetoceros sp microalgae | Pb2+ (0.19 mmol/g, 5, 27) | Langmuir | [238] |
| SiO2/chitosan imprinted by sucrose (amino groups) | Cu2+ (3.2 mg/g, 6, 25) | Langmuir | [239] |
| SiO2/chitosan imprinted by polyethylene glycol 4000 (amino groups) | Cu2+ (9.1 mg/g, 6, 25) | Langmuir | – |
| SiO2/chitosan imprinted by sucrose and polyethylene glycol 4000 (amino groups) | Cu2+ (10.5 mg/g, 6, 25) | Langmuir | – |
| SiO2/Cd2+-imprinted chitosan (amino groups) | Cd2+ (1.14 mmol/g, 6, room) | Experimental | [240] |
| SiO2/chitosan (amino groups) | Cd2+ (0.58 mmol/g, 6, room) | – | – |
| SiO2/chitosan (–NH2 and –OH) | Cu2+ (0.2 mmol/g, 5.5, 25) | Experimental | [241] |
| SiO2/chitosan (amino groups) | Ni2+ (182 mg/g, 7, 25) | Langmuir | [242] |
| SiO2(CO2H)/chitosan (amino groups) | Ni2+ (210 mg/g, 7, 25) | Langmuir | – |
| Fe3O4/poly(3,4-ethylenedioxythiophene) (–O–) | Ag+ (27.96 mmol/g, neutral, room) | Experimental | [243] |
| Hg2+ (16.02 mmol/g, neutral, room) | Experimental | ||
| Pb2+ (14.99 mmol/g, neutral, room) | Experimental | ||
| γ-Fe2O3/polyrhodanine (oxygen, nitrogen and sulfur atoms of polyrhodanine) | Hg2+ (179 mg/g, 4, 25) | Langmuir | [244] |
| Fe3O4 nanoparticle/chitosan (amino groups) | Cu2+ (21.5 mg/g, 5, 27) | Langmuir | [245] |
| Fe3O4 nanoparticle/chitosan (amino groups) | Au3+ (59.52 mg/g, 2, 25) | Langmuir | [246] |
| Fe3O4 nanoparticle/thiol-functionalized mesoporous microsphere (–SH) | Hg2+ (185.19 mg/g, 5, 20) | Langmuir | [247] |
| Pb2+ (114.7 mg/g, 5, 20) | Langmuir | ||
| Chitosan/zerovalent iron nanoparticles (complexation between Fe and Arsenic) | As3+ (94 mg/g, 7, 25) | Langmuir | [248] |
| Arsenate (119 mg/g, 7, 25) | Langmuir | ||
| Polystyrene/nano-Fe3O4 (Fe3O4) | Arsenate (139.3 mg/g, 6, 25) | Langmuir | [249] |
| Nanosized hydrous MnO2/porous polystyrene cation exchanger resin (–SO3−, –Mn(OH) and –Mn(OH)2 groups) | Cd2+ (1.96 mmol/g, 4.7, 25) | Langmuir | [250] |
| Zn2+ (1.67 mmol/g, 4.7, 25) | Langmuir | ||
| Fe3O4/SiO2/poly(1,2-diaminobenzene) (–NH2, –NH– and –N=) | As3+ (84.5 mg/g, 6, 25) | Langmuir | [251] |
| Cr3+ (77 mg/g, 5.3, 25) | Langmuir | ||
| Cu2+ (65 mg/g, 6, 25) | Langmuir | ||
| SiO2/Fe3O4/ion-imprinted polymer (–NH –CH2 –CH2 –NH2) | Pb2+ (19.61 mg/g, 7.5, room) | Langmuir | [252] |
| SiO2/Fe3O4/non-imprinted polymer (–NH –CH2 –CH2 –NH2) | Pb2+ (6.57 mg/g, 7.5, room) | Experimental | – |
| Polyaniline nanorods on graphene oxide nanosheets (amine group) | Cr(VI) (1149.4 mg/g, 3, 25) | Langmuir | [253] |
| Silica/polystyrene (–SH) | Cu2+ (11.33 mg/g, 5, 15) | Langmuir | [254] |
| CaCO3-pepsin (CaCO3 and adsorption occurs through formation of PbCO3 and CuCO3) | Pb2+ (1167 mg/g, neutral, room) | Experimental | [255] |
| Cu2+ (611 mg/g, neutral, room) | Experimental | ||
| CaCO3-maltose (CaCO3 and adsorption occurs through formation of PbCO3, CuCO3, NiCO3 and CdCO3) | Pb2+ (3242.48 mg/g, 7, 25) | Langmuir | [256] |
| Cd2+ (487.8 mg/g, 7, 25) | Langmuir | ||
| Cu2+ (628.93 mg/g, 7, 25) | Langmuir | ||
| Ni2+ (769.23 mg/g, 7, 25) | Langmuir | ||