Adsorption of uranium onto amidoxime-group mesoporous biomass carbon: kinetics, isotherm and thermodynamics

Biomass is one of the most important carbon raw due to high availability and low cost. In this study mesoporous biomass carbon adsorbent derived from Luffa chemically modified with task-specific amidoxime group (Luffa-AO for short) was prepared. Luffa-AO was verified using SEM, TEM, FT-IR, N-2 adsorption-desorption isotherm and X-ray photoelectron spectroscopy (XPS). The effects of operational parameters such as pH, mixing time, initial uranium concentration, temperature and recycle time on the adsorption of U(VI) with Luffa-AO were studied. The results showed that the saturation adsorption amount q(max) reached 247.58 mg g(-1), a competitive adsorption ability compared with the values reported in the previous references. Kinetics, isotherm and thermodynamics were investigated. The variation in binding energy elucidated with XPS indicated nitrogen and oxygen atoms involved in the process of complexing uranium. The study expanded the application fields of Luffa biomass and enriched the list of uranium adsorbents.