Synergistic interfacial chemical bonds and internal electric field promote antibiotic degradation and algal inactivation: DFT calculations, ecological risks and microbiomics evidence

To tackle the dual water environment issues of emerging contaminants and algal blooms in social development, this study employed photocatalytic technology to degrade tetracycline (TC) and inactivate Microcystis aeruginosa (M. aeruginosa) , focusing on the underlying mechanisms and ecological risks.   The ZnIn 2 S 4 /Zn 2 SnO 4 heterojunction facilitated efficient charge separation via a Z -scheme transfer mechanism. Under optimal conditions, the system achieved 91.1% TC degradation and 89.6% M. aeruginosa inactivation in single-pollutant systems, while in a coexisting system, it maintained high efficiencies of 87.9% and 83.2%, respectively. Furthermore, Excitation-Emission Matrix (EEM) spectra revealed that protein-like substances released during the inactivation of M. aeruginosa transformed into humic-like substances and the possible degradation processes of TC and Microcystin-leucine arginine (MC-LR), were analyzed. Ecological Structure-Activity Relationship Model (ECOSAR) combining microbial diversity analysis based on 16S rRNA gene high-throughput sequencing results confirmed a significant reduction in ecological toxicity after treatment. This study offers potential tech and theoretical support for composite water issues of emerging contaminants and algal blooms.