One Step Interface Activation of ZnS Using Cupric Ions for Mercury Recovery from Nonferrous Smelting Flue Gas.

The flue gases with high concentration of mercury are often encountered in the nonferrous smelting industries and the treatment of mercury-containing wastes. To recover mercury from such flue gases, sorbents with enough large adsorption capacity are required to capture and enrich mercury. ZnS is a cheap and readily prepared material, and even can be obtained from its natural ores. In this work, a simple controllable oxidation method-soaking in cupric solution-was developed to improve the interfacial activity of ZnS and its natural ores for Hg adsorption. The gaseous Hg adsorption capacity of ZnS was enhanced from 0.3 to 3.6 mg·g after such treatment. Further analysis indicated that a new interface rich in S ions was formed and provided sufficient active sites for the chemical adsorption of Hg. In addition, the cyclic Hg adsorption and recovery experiments demonstrated that the adsorption performance of spent activated-ZnS was recovered after reactivating sorbents with Cu, indicating the recovery of activated interface. Meanwhile, the high concentration of adsorbed mercury at the surface can be collected using a thermal treatment method. Utilization of raw materials from a zinc production process provides a promising and cost-effective method for removing and recovering mercury from nonferrous smelting flue gas.