Table 3.
Adsorbed heavy metals, maximum adsorption capacity, pH and temperature for adsorption of heavy metals by organic polymer/layered compound hybrids.
| Adsorbent (interacting group) | Heavy metal (qmax, pH and t (°C)) | Isotherm | Reference |
|---|---|---|---|
| Chitosan/cloisite 10 A (protonated –NH2) | Cr(VI) (357.14 mg/g, 3, 35) | Langmuir | [199] |
| Chitosan/bentonite (ion exchange property of bentonite and –OH and –NH2 groups of chitosan) | Pb2+ (15 mg/g, 4, 25) | Langmuir | [200] |
| Cu2+ (12.6 mg/g, 4, 25) | Langmuir | ||
| Ni2+ (6.1 mg/g, 4, 25) | Langmuir | ||
| Chitosan/perlite (protonated –NH2) | Cr(VI) (153.8 mg/g, 4, 25) | Experimental | [201] |
| Chitosan/perlite (–NH2 and –OH) | Cu2+ (196.08 mg/g, 5, room) | Langmuir | [202] |
| Ni2+ (114.95 mg/g, 5, room) | Langmuir | ||
| Chitosan/perlite (–NH2) | Cd2+ (178.6 mg/g, 6, 25) | Experimental | [203] |
| Chitosan/perlite (–NH2 and –OH) | Cu2+ (1.59 mmol/g, 4.5, 25) | Langmuir | [204] |
| Chitosan/clinoptilolite (–NH2) | Cu2+ (11.32 mmol/g, 5, 25) | Langmuir | [205] |
| Co2+ (7.94 mmol/g, 5, 25) | Langmuir | ||
| Ni2+ (4.21 mmol/g, 5, 25) | Langmuir | ||
| Chitosan/alumina (protonated amino groups) | Cr(VI) (9.71 mg/g, 4, 40) | Langmuir | [206] |
| Chitosan/alumina (protonated –NH2) | Cr(VI) (153.85 mg/g, 4, 25) | Langmuir | [207] |
| Chitosan/montmorillonite (protonated –NH2) | Cr(VI) (40.65 mg/g, 4, 35) | Langmuir | [208] |
| Chitosan/montmorillonite (protonated –NH2 group of chitosan) | Selenate (18.4 mg/g, 4, room) | Langmuir | [209] |
| Chitosan/calcium alginate (–NH2 and –OH) | Ni2+ (222.2 mg/g, 5, room) | Langmuir | [210] |
| Cellulose/hydroxyapatite (ion exchange property of hydroxyapatite) | Pb2+ (16.32 mg/g, neutral, 25) | Langmuir | [211] |
| Chitosan/bentonite (–NH2) | Cu2+ (9.85 mg/g, 4, 25) | Langmuir | [212] |
| Epichlorohydrin-crosslinked chitosan/bentonite (–NH2) | Cu2+ (11.75 mg/g, 4, 25) | Langmuir | – |
| Ethylene glycol diglycidyl ether-crosslinked chitosan/bentonite (–NH2) | Cu2+ (10.52 mg/g, 4, 25) | Langmuir | – |
| Glutaraldehyde-crosslinked chitosan/bentonite (–NH2) | Cu2+ (4.17 mg/g, 4, 25) | Langmuir | – |
| Chitosan-g-poly(acrylic acid)/attapulgite/sodium humate (–COO−, –COOH, –NH2 and –O−) | Pb2+ (809.5 mg/g, 5.5, 35) | Langmuir | [213] |
| Chitosan-g-poly(acrylic acid)/attapulgite (–COO−) | Cu2+ (303.03 mg/g, 5.5, 30) | Langmuir | [214] |
| Chitosan-g-poly(acrylic acid)/attapulgite (–COOH, –NH2 and –OH) | Hg2+ (785.2 mg/g, 5, 30) | Langmuir | [215] |
| Poly(methacrylic acid) grafted chitosan/bentonite (–COOH) | U(VI) (117.2 mg/g, 5.5, 30) | Langmuir | [216] |
| Poly-methacrylic acid grafted chitosan/bentonite (amino and hydroxyl groups of chitosan) | Hg2+ (125 mg/g, 6, room) | Langmuir | [217] |
| Pb2+ (111 mg/g, 6, room) | Langmuir | ||
| Cd2+ (83 mg/g, 6, room) | Langmuir | ||
| Chitosan-g-poly(acrylic acid)/vermiculite (–COOH, –NH2 and –OH) | Pb2+ (3.08 mmol/g, neutral, 30) | Langmuir | [218] |
| Cd2+ (2.94 mmol/g, neutral, 30) | Langmuir | ||
| Humic acid-immobilized-amine modified polyacrylamide/bentonite (–COOH) | Cu2+ (106.2 mg/g, 5, 30) | Langmuir | [219] |
| Zn2+ (96.1 mg/g, 9, 30) | Langmuir | ||
| Co2+ (52.9 mg/g, 8, 30) | Langmuir | ||
| Polyethylenimine800/magnetite-montmorillonite (protonated –NH2) | Cr(VI) (8.77 mg/g, 3, 25) | Langmuir | [220] |
| Polyacrylic acid crossliked by N,N′-methylenebisacrylamide/montmorillonite (–CONH– and –COOH) | Ni2+ (270.3 mg/g, neutral, 25) | Langmuir | [221] |
| Pb2+ (1666.7 mg/g, neutral, 25) | Langmuir | ||
| Poly[N-(4-vinylbenzyl)-N-methyl-D-glucamine]/montmorillonite (protonated tertiary amine) | As(V) (72.26 mg/g, 6, 30) | Langmuir | [222] |
| As(V) (72.99 mg/g, 6, 40) | Langmuir | ||
| As(V) (82.64 mg/g, 6, 50) | Langmuir | ||
| Polyacrylamide/bentonite (–NH2) | Cu2+ (32.81 mg/g, 6.2, 20) | Langmuir | [223] |
| Polyacrylamide-bentonite composite (negatively charged sites of bentonite) | Pb2+ (0.16 mmol/g, 4.5–5, room) | Langmuir | [224] |
| Phytic acid-modified polyacrylamide-bentonite composite (negatively charged sites of bentonite) | Pb2+ (0.18 mmol/g, 4.5–5, room) | Langmuir | – |
| Polyaniline/attapulgite (–NH– and –N=) | Hg2+ (909.1 mg/g, 6, 25) | Langmuir | [225] |
| Polyacrylamide/attapulgite (–NH2) | Hg2+ (192.5 mg/g, 4.4, 30) | Langmuir | [226] |
| Polyvinyl alcohol/attapulgite (–OH) | Pb2+ (169.5 mg/g, 5, 30) | Langmuir | [227] |
| Acrylamide-2-acrylamido-sodium 2-methylpropane sulfonate copolymer/clay (–SO3−) | Cu2+ (1.07 mmol/g, 4.5, 25) | Experimental | [228] |
| Cd2+ (1.28 mmol/g, 4.5, 25) | Experimental | ||
| Pb2+ (1.03 mmol/g, 4.5, 25) | Experimental | ||
| Poly(methoxyethyl)acrylamide/clay (–NH–) | Pb2+ (0.385 mmol/g, 5, 30) | Langmuir | [229] |
| 3-Aminopropyltriethoxysilane/sepiolite (–NH2) | Fe2+ (0.44 mmol/g, 3, 25) | Langmuir | [230] |
| Cu2+ (0.14 mmol/g, 4, 25) | Langmuir | ||
| Triethoxy-3-(2-imidazolin-1-yl)propylsilane/sepiolite (negatively charged sites of sepiolite and N atoms of imidazolin) | Mn2+ (0.085 mmol/g, 4, 25) | Langmuir | [231] |
| Cu2+ (0.13 mmol/g, 4, 25) | Langmuir | ||
| Fe3+ (0.05 mmol/g, 2.5, 25) | Langmuir | ||
| Zn2+ (0.035 mmol/g, 4, 25) | Langmuir | ||
| Co2+ (0.28 mmol/g, 4, 25) | Langmuir | ||
| Cd2+ (0.09 mmol/g, 4, 25) | Langmuir | ||
| Iodine-modified chitosan/bentonite (I2 and I−) | Gas-phase Hg0 at 110 °C | Experimental | [232] |