An experimental study on the dynamic removal of heavy metallic multi-pollutants using composite mineral media

Aiming at the in-situ remediation of groundwater pollution caused by the leachate from the tailings reservoir of a polymetallic mine in Guangxi Zhuang Autonomous Region, experiments of the dynamic adsorption of multi-pollutants Cu²⁺, Zn²⁺, Mn²⁺ and CrO₄²– have been conducted by using composite PRB medium materials of vermiculite, CTAB-modified vermiculite and hematite for investigating the removal behaviors of multi-pollutants by different assemblies of three mineral materials. The results of dynamic adsorption experiments show that different assembly methods of media have affected pH values of the systems and removal efficiencies of their multi-pollutants by the adsorption column. The pollutants removal mechanisms of composite mineral medium materials have been discussed based on the measurement and characterization of phases and morphologies of composite mineral media before and after the dynamic adsorption. The removal of pollutants by hematite is mainly in form of the surface adsorption, while removals of pollutants by vermiculite and the CTAB modified vermiculite are mainly in form of the ion exchange, and littlely in form of the surface adsorption. The above results have laid an important foundation for the practical application of these composite mineral media into the in-situ remediation of heavy metal polluted groundwater.