Simultaneous adsorption and degradation of γ-HCH by nZVI/Cu bimetallic nanoparticles with activated carbon support

Cu amended zero valent iron bimetallic nanoparticles were synthesized by doping Cu on the surface of iron. They were incorporated with granular activated carbon (AC) to prepare supported particles (AC–Fe0–Cu), which were used to remove γ-HCH. Cu on the surface of iron enhanced the dechlorination activity of Fe0. The dechlorination rate constant (kobs) increased with the Cu loading on the surface of iron and the maximum was achieved with 6.073% Cu. AC as a support was effective for increasing the dispersion of the nanoparticles and avoiding the agglomeration of the metallic nanoparticles. The simultaneous adsorption of γ-HCH on AC accelerated the degradation rate of γ-HCH by the bimetals. After reaction for 165 min, around 99% of γ-HCH was removed by the solids of AC–Fe0–Cu. In addition, AC could adsorb the degradation products. The degradation of γ-HCH was mainly through dehydrochlorination and dichloroelmination based on the intermediate products detected by GC/MS. ► Deposition of Cu on the surface of Fe enhances its dechlorination efficiency toward γ-HCH. ► Incorporation of the bimetallic nanoparticles with activated carbon (AC) reduces their agglomeration. ► AC support increases the contact of γ-HCH with the nanoparticles and enhances the degradation efficiency. ► The AC support adsorbs γ-HCH and its degradation products, reducing their ecological risks in water. Impregnation of Cu amended iron on AC enhances the removal efficiency of γ-HCH and reduces the concentrations of its intermediates in aqueous solution.