Phosphorylated biomass-derived porous carbon material for efficient removal of U(VI) in wastewater.

Abstract

A simple strategy to prepare cost-effective adsorbent materials for the removal of U(VI) in radioactive wastewater is of great significance to environmental protection. Here, activated orange peel was used as a precursor for the synthesis of biomass charcoal, and then a phosphorylated honeycomb-like porous carbon (HLPC-PO4) material was prepared through simple phosphorylation modification. FT-IR and XPS showed that P-O-C, P-C, and P˭O bonds appeared in HLPC-PO4, indicating that the phosphorylation process is mainly the reaction of C-O bonds on the surface of the material with -PO4. The results of the batch experiments showed that the uptake equilibrium of HLPC-PO4 to U(VI) occurred within 20\xa0min, and the kinetic simulation showed that the process was monolayer chemical adsorption. Interestingly, the maximum U(VI) uptake capacity of HLPC-PO4 at T\xa0=\xa0298.15\xa0K and pH\xa0=\xa06.0 was 552.6\xa0mg/g, which was more than 3 times that of HLPC. In addition, HLPC-PO4 showed an adsorption selectivity of 70.1% for U(VI). After 5 cycles, HLPC-PO4 maintained its original adsorption capacity of 90.5%. The adsorption mechanism can be explained as the complexation of U(VI) with P-O and P˭O on the surface of the adsorbent, confirming the strong bonding ability of -PO4 to U(VI).