Dual Z-scheme Pr2Sn2O7/P@g-C3N4/SnS2 heterojunctions for the removal of tetracycline antibiotic by persulfate activation: Kinetics, thermodynamic parameters, density functional theory, and toxicity studies

In this study, a Pr2Sn2O7/P@g-C3N4/SnS2 ternary nanocomposite photocatalyst is obtained by hydrothermal synthesis, followed by mechanical grinding. By separating electrons and holes (e−/h+) effectively through the dual Z-scheme heterojunction and activating persulfate (PS), the heterojunction demonstrated superior visible light-driven catalytic activity. Tetracycline (TC) was degraded (89.48 %) in 60 min using 30 mg/L of ternary composite and 30 mg/L of PS. This system displayed the highest pseudo-first-order kinetic constant (0.0989 min−1 and R2 = 0.969). The electron paramagnetic resonance analysis showed that SO4−, OH, O2−, and 1O2 were involved in TC degradation. TC's vulnerability positions and degradation pathways were analyzed using DFT and gas chromatography-mass spectrometry analysis, while toxicity assessment software was used to determine the toxicity of intermediate products. Thus, Pr2Sn2O7/P@g-C3N4/SnS2 was established to be a promising photocatalyst template for pollutant remediation.