Adsorption of Cr (VI) ion from aqueous solution on acrylamide – grafted starch (Coccinia abyssinicca) – PVA/PVP/chitosan/graphene oxide blended hydrogel: isotherms, kinetics, and thermodynamics studies

Adsorption of Pb2+ and Cd2+ on the l‐cysteine‐functionalized graphene oxide/chitosan/polyvinyl alcohol hydrogel: Kinetic, isotherm, and thermodynamic study

“…The polyvinyl alcohol‐chitosan‐cysteine‐functionalized graphene oxide (PCCFG) hydrogel was synthesized according to the method reported elsewhere (Lemma et al, 2022; T. Li et al, 2019) with some modification (Figure 2a). Briefly: 2 g of PVA and 0.25 g of sodium alginate powder were added to 60 mL of hot (90°C) ultrapure water and mixed vigorously (350 rpm) for 2 h in water bath.…”

“…The polyvinyl alcohol-chitosan-cysteine-functionalized graphene oxide (PCCFG) hydrogel was synthesized according to the method reported elsewhere (Lemma et al, 2022;T. Li et al, 2019) with some modification (Figure 2a).…”

“…The restacking and agglomeration problem of pristine GO in aqueous solutions can be improved by covalent functionalization with electron-rich atoms-bearing materials or noncovalent modification/blending with polymers, such as chitosan and PVA. Blending GO with chitosan-PVA (Lemma et al, 2022;L. Li et al, 2015;T.…”

“…The restacking and agglomeration problem of pristine GO in aqueous solutions can be improved by covalent functionalization with electron‐rich atoms‐bearing materials or noncovalent modification/blending with polymers, such as chitosan and PVA. Blending GO with chitosan–PVA (Lemma et al, 2022; L. Li et al, 2015; T. Li et al, 2019), and surface modification through functionalization with electron reach atom‐bearing materials (Daneshmand et al, 2018; Madadrang et al, 2012) improves the adsorption capacity as well as the selectivity of GO. However, monofunctional group (amine or thiol) surface modification limits the application in wastewater treatment due to the presence of the multivalent oxidation state of heavy metal ions in wastewater.…”