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

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-PO 4 ) 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-PO 4 , indicating that the phosphorylation process is mainly the reaction of C–O bonds on the surface of the material with –PO 4 . The results of the batch experiments showed that the uptake equilibrium of HLPC-PO 4 to U(VI) occurred within 20 min, and the kinetic simulation showed that the process was monolayer chemical adsorption . Interestingly, the maximum U(VI) uptake capacity of HLPC-PO 4 at T = 298.15 K and pH = 6.0 was 552.6 mg/g, which was more than 3 times that of HLPC. In addition, HLPC-PO 4 showed an adsorption selectivity of 70.1% for U(VI). After 5 cycles, HLPC-PO 4 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 –PO 4 to U(VI).