Synergizing photothermal and pyroelectric effects: Coal gangue assisted simultaneous ZnS/CuS for degradation of mineral processing wastewater

Photocatalytic oxidation technology is a green and low carbon approach for degradation of mineral processing wastewater, which is extensively applied to ecological environment restoration. In this research, coal gangue-ZnS/CuS pyroelectric/photothermal composite photocatalyst is constructed by high temperature calcination method. The temperature difference between heat converted from light energy absorbed by CuS and the circulating condensate water provides the impelling force for the pyroelectric effect. The porous structure of coal gangue acts as a “heat capacitor”, which furnishes greater temperature fluctuation for pyroelectric effect. Furthermore, the hydroxyl groups on the surface of coal gangue can availably adsorb oxygen and facilely form superoxide radicals with electrons. The degradation efficiency of xanthate is as high as 99.5 % within 50 min. This research has significant implications for designing and developing highly efficient photocatalysts for the degradation of mining wastewater.