Unveiling the hidden photocatalytic potential of sediment: Engineering sediment-derived S-scheme heterojunction boost water decontamination via peroxymonosulfate activation

The design of green and low-cost S-scheme heterojunctions with strong interface interactions is key to their photocatalytic performance and practical application. Here, novel S-scheme heterojunctions of self-grown CuO/ sediment (CUS) were successfully fabricated using a calcination method with sediment derived from nature. Various methods were employed to evaluate the micromorphology, crystal structure, chemical composition, and optical characteristics of the photocatalysts. Supported by ultra-violet photoelectron spectroscopy (UPS) analyses, an S-scheme charge migration path was revealed in the CUS during the photocatalytic reaction. The CUS3:7 S-scheme heterojunction exhibited optimal photocatalytic activity at 4.08 times and 1.57 times higher than those of pure CuO and SM-300, respectively, and excellent photocatalytic activity was detected in the peroxymonosulfate (PMS) system. Notably, metal and nonmetal ions in sediment themselves and 1O2 generated in PMS system are resistant to anionic and cationic interferences in water decontamination. In addition, the photocatalytic mechanism, possible intermediates, and degradation pathways were elucidated using theoretical calculations and experimental results. Moreover, mung bean sprout cultivation experiments confirmed the non-toxicity of the developed heterojunction and degraded tetracycline solution. These findings offer new insights to aid in synthesizing photocatalysts for wastewater treatment.