Highly efficient removal of U(VI) by a novel biochar supported with FeS nanoparticles and chitosan composites

The new biochar supported with FeS nanoparticles and chitosan composites (chitosan-FeS@biochar) was prepared and its performance to remove U(VI) ions in aqueous solution was investigated. The results showed that chitosan-FeS@biochar as an efficient adsorbent for treating the environmental pollution was high stability and effective uptake capacity of U(VI). The equilibrium uptake capacity of the chitosan-FeS@biochar at pH 4.16, 100 mg/L of U(VI) and 308 K for U(VI) reached 92.45 mg/g. The superior adsorption performance could be attributed to: (1) a lot of functional groups were observed on the surface of chitosan-FeS@biochar; (2) FeS nanoparticles could react with U(VI); (3) chitosan prevented FeS nanoparticles aggregation and enhanced their stability and removal efficiency. The suggested reaction mechanism mainly was electrostatic attractive, surface complexation, chemical precipitation and reductive reaction. The chemical stability of chitosan-FeS@biochar was very well. It was also environmentally friendly materials with good reusability in wastewater treatment with low replacement costs. • The chitosan-FeS@biochar exhibited highly efficient uptake capacities for U(VI). • It was a good reusability material in wastewater treatment. • Chitosan prevented aggregation and enhanced stability and removal efficiency. • The reaction mechanism was suggested.