Fabrication of pyrite-zero nickel composites for efficient removal of Se(IV) from aqueous solution

${}^{79}$Se is one of the important radionuclides in the safety evaluation of high-level radioactive waste repository due to its long half-life and highly fissionable radioactivity. Nanoscale pyrite-zero nickel composites (FeS${}_2$/Ni${}^0$) were fabricated by ball milling method for selenium(IV) (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 FeS${}_2$/Ni${}^0$ were investigated. FeS${}_2$/Ni${}^0$ 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 FeS${}_2$/Ni${}^0$ had a good removal effect on Se(IV). When pH was 5.5, the solid-liquid ratio was 0.1 g L${}^{-1}$, the reaction time was 40 min, the maximum adsorption capacity of Se(IV) by FeS${}_2$/Ni${}^0$ could reach 259 mg g${}^{-1}$. The research results can provide a theoretical basis for the treatment of wastewater containing Se(IV).