Facile Synthesis of Polypyrrole/Reduced Graphene Oxide Composite Hydrogel for Cr(VI) Removal

Polymeric-inorganic composites are promising for the efficient treatment of contaminated water. In this work, the recyclable composite hydrogel with three-dimensional network composed of polypyrrole and reduced graphene oxide are synthesized through a hydrothermal process using polypyrrole nanotubes and graphene oxide as the precursors. Due to the synergic effect between graphene nanosheets and polypyrrole nanotubes, the composite hydrogel exhibits excellent removal capability of 395 mg g(-1) for Cr(VI) removal through the simultaneous adsorption and chemical reduction. The adsorption equilibrium isotherm is well fitted with the Langmuir adsorption model. The result of adsorption kinetics is simulated by the pseudosecond-order model. The composite hydrogel still possesses Cr(VI) removal capacity without a significant decrease in the presence of coexisting cations. Moreover, because of the stable network in the composite hydrogel, it can be easily separated from the contaminated water after adsorption and can be regenerated and reused efficiency after six adsorption-desorption cycles. Thus, polypyrrole/reduced graphene oxide composite hydrogel provides a potential platform as a cost-effective material for Cr(VI) removal applications. [GRAPHICS] .