Hydrothermal fabrication of phytic acid decorated chitosan-graphene oxide composites for efficient and selective adsorption of uranium (VI)

An innovative chitosan/graphene oxide composite containing phytic acid (PCG) was fabricated directly by a single hydrothermal reaction using graphene oxide, chitosan, and phytic acid as raw materials for the removal of uranium (VI) from aqueous solutions. The results demonstrated that PCG from the chemical bonding between the hydroxyl group in the phytic acid molecule and the amino group in chitosan possessed flaky surface porous structure, good thermal stability and strong chelating ability to uranium (VI). The adsorption process of PCG for uranium (VI) was consistent with the Langmuir isothermal and pseudo-second-order kinetic models, and its maximum adsorption capacity could reach 325.56 mg/g at pH 5.0. The synthesized PCG exhibited higher adsorption selectivity due to the strong chelating of both the hydroxyl groups and phosphate groups on PCG with uranium (VI). With its easy synthesis, facile solid-liquid separation, good biocompatibility, and negligible toxicity, PCG can effectively recover uranium (VI) from uranium-containing wastewater.