Crystal phase tailored TiO2 for photocatalytic ciprofloxacin (CIP) elimination: Performances, degradation pathways, and toxicity assessment

Abstract

Environmental residues of antibiotic molecules adversely affecting human health and ecological safety. TiO₂-intervened photocatalytic technology had been praised as a common method for green and efficient degradation of antibiotics. In this work, TiO₂ with different ratios of anatase/rutile crystal phases were synthesized by calcining as-prepared H₂Ti₅O₁₁ at different temperatures. The degradation experiments showed that complete removal of ciprofloxacin (CIP) solution was achieved upon the heterophase TiO₂ with anatase/rutile=92:8. The degradation intermediates and possible degradation pathways of ciprofloxacin were determined by high resolution liquid mass spectrometry (HRMS). The toxic effects of CIP on aquatic organisms during the degradation process was predicted by the ECOSAR program. The monitored pea seedlings growth process showed that the degradation of CIP by heterophase TiO₂ was a friendly process and had almost no negative impact on the environment. This work provided a reference for the tailoring of crystal phase TiO₂ and the toxicity assessment of the degradation process of the ciprofloxacin antibiotic.