Efficient Separation of Zn2+ and Cd2+ Ions in Solution by the Mechanochemically Activated Talc

Natural silicate clay minerals are widely used in the purification of heavy metal polluted wastewater and resource recovery. In this case, mechanochemical activation technology has been used to effectively improve the chemical reaction activity of natural clay mineral talc, and enable the efficient separation and recovery of Zn2+ and Cd2+ ions in mixed solution. A large number of Mg2+ and OH- were released from the structure of talc, after mechanochemical activation, and Zn2+ can be selectively precipitated in the form of bechererite, in the presence of SO42-. By adjusting the mechanochemical activation intensity, reaction temperature, talc dosage and metal salt type, etc., a considerable separation effect with 112.01 mg/g of Zn2+ removal and 16.92 mg/g of Cd2+ removal was obtained, at the optimum conditions. The mechanochemical activation of clay minerals in nature shows a favorable application potential in the disposal of heavy metal wastewater as well as the separation and utilization of renewable polymetallic resources.