Vacancy and impurity synergy in natural sphalerite: mechanistic insights into photocatalytic arsenic removal

초록

Natural sphalerite, containing Fe impurities, develops lattice defects during crystallization, enhancing its photocatalytic activity. These defects create vacancy sites that broaden light absorption and expose surface-active metal sites, critical for activating H2O2 to generate reactive oxygen species (ROS). In Fenton-like systems, ZnS acts as a co-catalyst, accelerating the Fe3+/Fe2+ redox cycle via exposed Zn+ sites, thereby improving As(III) removal efficiency. Spectroscopic and computational analyses confirm that vacancy defects optimize surface atom activation, directly linking ROS generation to defect-mediated mechanisms. Fe elution, driven by surface oxidation, further sustains the catalytic process. This study demonstrates ZnS's dual role: (1) structural defects enhance light absorption and active site exposure, and (2) synergistic interaction with Fe promotes H2O2 activation and ROS production. The optimized system achieves efficient As(III) degradation, highlighting ZnS's potential as a sustainable heterogeneous catalyst for water treatment.

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