Adsorptive Removal of Selenium(IV) from Aqueous Solution by Ferrous Hydroxide Complex-Zero Nickel Composites

ABSTRACT Nanoscale ferrous hydroxide complex-zero nickel composites (FHC/Ni0) were fabricated by ball milling method for Se(IV) adsorption from aqueous solution. The effects of pH, solid-liquid ratio, time, temperature, initial concentration of Se(IV) on the adsorption of Se(IV) by FHC/Ni0 were investigated. FHC/Ni0 was characterized by SEM, XPS, XRD, FT-IR, BET and Zeta potential, and the mechanism of removing Se(IV) was analyzed. The results showed that FHC/Ni0 had a good removal effect on Se(IV). When pH was 5.0, the solid-liquid ratio was 0.15 g L−1, the reaction time was 40 min, the maximum adsorption capacity of Se(IV) by FHC/Ni0 could reach 216 mg g−1. The pseudo-second-order kinetic model and Langmuir had a good fit for the Se(IV) adsorption process of FHC/Ni0, indicating that the monolayer and chemical adsorption played a leading role in the adsorption process. XPS analysis further confirmed that the adsorption of Se on FHC/Ni0 was mainly due to the formation of stable complexes with a large number of functional groups containing Fe, Ni and S, meanwhile, the removal of Se(IV) by the material is achieved through a combination of chemical adsorption and reduction reactions. The research results can demonstrate the feasibility of FHC/Ni0 in Se(IV) removal and provide a theoretical basis for the treatment of wastewater containing Se(IV).