Table 3.
Different hydrogel-based functionalized adsorbent materials for the removal of heavy metals.
| Hydrogel | Active Functional Group | Heavy Metals Removed | References |
|---|---|---|---|
| Graphene oxide-chitosan-poly(acrylic acid) (GO-CS-AA) hydrogel nanocomposite | R-COOH | Pb2+ | [84] |
| Hydrous ferric oxide-Poly(trans-aconitic acid/2-hydroxyethyl acrylate (HFO-P(TAA/HEA)) hydrogel | R-OH | Cu2+, Cd2+, Pb2+ and Ni2+ | [85] |
| Chitosan-sodium lignosulfonate-acrylic acid (CS-SLS-AA) hydrogel | R-NH2 | Co2+ and Cu2+ | [86] |
| Poly(3-acrylamidopropyl) trimethyl ammonium chloride/ɤ-Fe2O3 | R-N+(CH3)3 | Cr4+ | [87] |
| Sulfathiazole-based novel UV-curved hydrogel | R-SH | Hg2+, Cd2+ and Zn2+ | [88] |
| Magnetic anionic hydrogel (nFeMAH) | R-SO3Na | Cu2+ and Ni2+ | [64] |
| Poly(2-acrylamido-2-methyl-1-propane sulfonic acid) magnetic hydrogel | R-SO3H | Cd2+, Co2+, Fe2+, Pb2+,Cu2+, Cr2+ and Ni2+ | [39] |
| Acrylamide/crotonic acid (AAm/CA) hydrogel | R-COOH, and R-CONH2 | Hg2+ | [89] |
| Glucan/chitosan hydrogel | R-OH and R-NH2 | Co2+, Cu2+, Cd2+, Ni2+ and Pb2+ | [90] |
| Malic acid enhanced chitosan hydrogel beads (mCHBs) | R-COOH and R-NH2 | Cu2+ | [91] |
| Carboxymethyl cellulose/polyacrylamide (CMC/PAM) composite hydrogel | R-OH, R-COOH and R-NH2 | Cd2+, Pb2+ and Cu2+ | [92] |
| Chitosan poly(acrylic acid) supermacroporous hydrogel | R-OH, R-COOH and R-NH2 | Cu2+ and Pb2+ | [93] |
| Lignosulfonate-modified graphene hydrogel | R-C=O, R-OH and R-COOH | Pb2+ | [94] |
| Polyacrylonitrile-chitosan-graphene oxide (PCG) hydrogel composite | R-C(NH2)=N-OH | U6+ | [73] |