Photocatalytic membrane treatment of antibiotics: combined chemical and toxicological evaluation of effectiveness

Abstract

Antibiotic residues in wastewater promote the emergence of resistant bacteria, posing a serious potential threat to human health and ecosystems. Effective degradation strategies are crucial for removing antibiotics from wastewater. In this study, a photocatalytic polymer membrane was used to treat three antibiotics, i.e., sulfamethoxazole, chloramphenicol, and ofloxacin. In parallel with chemical analysis, the acute and chronic toxicity of the antibiotics and their degradation mixtures to the freshwater green alga Scenedesmus vacuolatus was assessed. Photocatalytic membrane treatment of 10 mg/L aqueous solutions (and 1100 mg/L for ofloxacin) achieved complete parent-compound removal, with half-lives ranging from 6.2–102.3 min. Toxicity measured at successive irradiation times revealed initial detoxification followed by increased toxicity due to transformation products and by-products caused by membrane photoaging, limiting the total detoxification effectiveness. The results underscore the promise of photocatalytic membranes for antibiotic removal while highlighting the critical importance of photostable polymer–photocatalyst materials to prevent secondary ecotoxicological effects in water treatment applications. These results further demonstrate the need to combine chemical and toxicological methods to validate new technologies for wastewater treatment.

Graphical abstract

Keywords

Micropollutant degradation / Polymer membrane / Photocatalysis / Ecotoxicology / Microalgae / WWTP

Highlight

	● Photocatalytic polymer membrane effectively removed three antibiotics from water.
	● Degradation process was monitored by combined chemical and toxicological approach.
	● Initial detoxification is followed by resurgence of algal photosynthetic inhibition.
	● Membrane photoaging products limiting the overall detoxification effectiveness.

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