Removal of Cr(VI) by a simply prepared biochar-supported nanoscale zero-valent iron

BACKGROUND Cr(VI) is highly migratory and toxic, and long-term exposure to Cr(VI) is likely to cause cancer, teratogenesis and mutagenicity. Therefore, the removal of Cr(VI) in polluted wastewater is the key to ensure the safety of water quality. In this study, a composite material consisting of nanoscale zero-valent iron (NZVI) particles supported on biochar derived from starch (NZVI/BC) was prepared via carbonizing the mixture of starch and ferric nitrate in inert gas and used for removal of Cr(VI) from solution. The effects of NZVI/BC dosage, initial pH and reaction temperature on the removal efficiency of Cr(VI) were investigated. RESULTS The results revealed that H-2 and CH4 originating from the decomposition of starch acted as reducing agents for in situ generation of NZVI from Fe precursors. The removal efficiency of Cr(VI) was strongly dependent on dosage, pH and reaction temperature. Higher dosage, lower pH value and higher temperature led to an increase in Cr(VI) removal efficiency. Pseudo-second-order kinetics was suitable to describe the process of Cr(VI) removal by NZVI/BC. CONCLUSIONS NZVI/BC could be a potential and effective material for removal of Cr(VI) from solution. (c) 2022 Society of Chemical Industry (SCI).