Novel heterojunction catalyst for the sustainable degradation of amoxicillin and propyl-2-thiourea: Ecotoxicity evaluation and mechanistic insights

초록

The occurrence of pharmaceutical and agrochemical residues such as amoxicillin (AMX) and propyl-2-thiourea (PTU) in aquatic environments poses significant environmental and health risks. The present study introduces a green route to synthesize a non-ferrous Fenton-like (NFFL) catalyst, ZY@C1C2, by incorporating cerium and copper nanoparticles into zeolite Y using Carica papaya leaf extract. Comprehensive characterization confirmed well-dispersed nanoparticles, enhanced surface properties, reduced band gap, and superior electron transfer capability. The catalyst demonstrated outstanding performance in degrading AMX and PTU under light irradiation, with efficiencies exceeding 90% within 120 min at near-neutral pH. Kinetic evaluation followed pseudo-first-order behavior, while LC-MS and DFT analyses elucidated radical-mediated oxidative pathways involving center dot OH radical attacks, stepwise bond cleavage, and progressive mineralization into CO2 and H2O. Total organic carbon removal further confirmed substantial mineralization of the contaminants. Furthermore, the experimental toxicity test using D. magna and prediction using ECOSAR, revealed that both the catalyst and intermediates exhibited low environmental toxicity. The ZY@C1C2 retained high activity after multiple reuse cycles, and its performance in natural spring water validated real-world applicability. The work highlights the promising utilization of the nanocatalysts as eco-friendly and scalable alternatives to conventional iron-based systems for the sustainable elimination of micropollutants from wastewater.

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