Synergistic piezo-catalytic degradation of organic pollutants and Cr (VI) by co-metallene/SnS nanorods: Mechanistic insights

Abstract

Organic pollutants and Cr(VI) were primary water contaminants that form stable chelate complexes, making them more difficult to remove. Herein, a series of Co-ene/SnS nanorods with high piezoelectric and carrier migration performance were synthesized by in-situ modification of SnS with Co-metallene. The introduction of Co-metallene significantly enhanced the piezoelectric effect of SnS, and the d₃₃ value of the optimized Co-ene/SnS nanorods was 1.43 times that of SnS. Therefore, within 25 min of ultrasonic treatment, Co-ene/SnS nanorods can simultaneously remove 99.2 % of Cr(VI) (5 ppm) and 98.4 % of MO (5 ppm). Compared with the degradation of a single pollutant, the synergistic degradation effect was 1.6 times and 1.3 times that of Cr(VI) and MO alone. Meanwhile, Co-ene/SnS nanorods also showed good synergistic degradation of tetracycline, norfloxacin, chlortetracycline hydrochloride, and Cr(VI), with degradation rates of 71.12 %, 91.86 %, and 89.69 %, respectively. The reduction rates of Cr(VI) in different synergistic systems were 75.78 %, 77.94 %, and 95.7 %, respectively. Characterization and experimental results showed superoxide radicals (·O₂⁻) and electrons (e⁻) were demonstrated as the most important active species in the synergistic degradation system. This study provided new insights into effective organic pollutant degradation and Cr(VI) elimination in wastewater treatment.