Structure of polyvinyl alcohol-g-acrylic acid-2-acrylamido-2-methyl-1-propanesulfonic acid hydrogel and adsorption mechanism for advanced Pb(II) removal

Polyvinyl alcohol-g-acrylic acid-2-acrylamido-2-methyl-1-propanesulfonic acid hydrogel (PVA-g-AA-AMPS) with varying AMPS/AA molar ratio was synthesized. The shear storage modulus and effective network density of the hydrogel increased with AMPS dosage, and more uniform and dense porous network structure formed. Pb2+ adsorption capacity of the hydrogel increased with AMPS/AA molar ratio, while Langmuir isotherm fitted well with the experimental data, indicating homogeneous nature of monolayer adsorption of Pb2+. The adsorption was rapid and spontaneous, favorable at high temperature, and belonged to the second-order kinetic model, indicating chemical adsorption with ion-exchange mechanism. Good reusability of the hydrogel was achieved.

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