Removal of Molybdenum (VI) from Mine Tailing Effluents with the Aid of Loessial Soil and Slag Waste

摘要

Removal of heavy metals from mine tailing effluent has been a long-standing environmental management issuenin the mining industry. This article aims to investigate molybdenum [Mo(VI)] removal by waste slag, which hasnnot been fully tested. In this study, the removal efficiencies of Mo(VI) from aqueous solutions by desulfurizationnsteel slag (DSS), converter steel slag (CSS), and cinder (CI) were examined and compared against that of loessialnsoil (LS). Results showed that the sorption isotherms fitted the Langmuir model well, and the Langmuir adsorptionncapacity (Q0) of the four sorption media generally complied with the following order: DSS > CSS >nCI > LS. Adsorption reaction was found to follow the pseudo–second-order rate, and the adsorption of Mo(VI)nwas sensitive to pH values. The four adsorbents exhibited a significant Mo(VI) removal at low pH values (e.g.,npH 3–4.5), but such adsorption decreased rapidly when pH was > 5; little adsorption occurred when the pHnvalue was > 8. The competitive effect of PO4n3 - and SO4n2 - with Mo(VI) for adsorption associated with the fournsorption media followed the order LS > CI > CSS > DSS, and moreover, the effect of PO4n3 - on the adsorption ofnMo(VI) was observed to be stronger than that of SO4n2 - . Desorption capacity of the four sorption media generallyncomplied with the following order: LS > CI > CSS > DSS.