Persimmon tannin-modified graphene oxide/chitosan microsphere for removing U(VI) in rare earth wastewater

A new persimmon tannin-modified graphene oxide/chitosan microsphere (PGC) was prepared by the mixed crosslinking method, and the effective adsorption behavior of U(VI) in an aqueous solution was discussed. The study shows that at the temperature of 30 °C, pH of 5, time of 120 min, and the an initial uranium concentration of 10.00 mg/L, the maximum adsorption capacity of PGC microspheres for U(VI) reached 199.13 mg/g, with a removal rate of 98.2%. The adsorption process of U(VI) by PGC microspheres conforms to the pseudo-second-order kinetic model and the Freundlich isothermal adsorption model. The adsorption mechanism of U(VI) by PGC microspheres is electrostatic interaction and chelation reaction. Meanwhile, PGC microspheres have excellent adsorption selectivity and recycling, and they have a good adsorption effect in the uranium treatment of rare earth real wastewater. Therefore, PGC microspheres can be used as a promising material to treat uranium-containing rare earth wastewater.