Table 5. Different bio-adsorbents for As removal.
| Bio-adsorbents | pH | Isotherm model fit | Capacity (mg g−1) | Reference | |
|---|---|---|---|---|---|
| AsIII | AsV | ||||
| Chitosan gel beads modified with molybdate | 2–3 | Langmuir | 70 | 230 | 161 |
| Coating natural biopolymer, chitosan, on ceramic alumina, using a dip-coating process | 4 | Langmuir, Freundlich | 56.50 | 96.46 | 158 |
| Alumina nanoparticles and immobilized them in chitosan-grafted polyacrylamide matrix | 7.2 | Freundlich | — | 6.56 | 165 |
| Chitosan zerovalent iron nanoparticles (CIN) | 7 | Langmuir | 94 | 119 | 166 |
| Xanthated chitosan granules (XCB) | 7.5 | Langmuir, Freundlich | 48 | 36 | 166 |
| Chitosan-graphene oxide-gadolinium oxide | 3–7 | Langmuir, Freundlich | — | 252.12 | 167 |
| Ultrafine nanobiosorbent of cerium modified chitosan | 8 | Langmuir | 57.5 | — | 168 |
| Iron–chitosan composites | 7 | Langmuir | 16.15 | 22.47 | 169 |
| α-Fe2O3 impregnated chitosan | 5 | Langmuir | 9.36 | — | 170 |
| TiO2-impregnated chitosan bead without exposure to UV light | 6.61–7.02 | Langmuir | 2.2 | 2.05 | 171 |
| TiO2-impregnated chitosan bead without exposure to UV light | 6.61–7.02 | Langmuir | 6.4 | 4.93 | 171 |
| Granular chitosan-titanium | 8 | Langmuir | — | 165.6 a | 172 |
| Magnetic chitosan-based composite microparticles | — | — | 33.68 | 34.61 | 173 |
a
μg L−1.