High-efficiency detoxification of anticancer drug capecitabine wastewater by non-thermal plasma

Anticancer drugs have raised widespread concerns due to their environmental toxicity and persistence. In this study, dielectric barrier discharge (DBD) plasma was applied for the anticancer drug capecitabine (CPC) specifically, and the degradation results showed excellent performance. The degradation efficiency of this technology reached 99.5% at 30 min, and the total organic carbon (TOC) removal rate reached 68.0% at 120 min. Combining density functional theory (DFT) calculations with liquid chromatography-mass spectrometry (LC-MS) results, possible degradation pathways were inferred. Toxicity assessments further confirmed the superiority of the DBD technology. The biotoxicity of CPC was assessed using the luminescent bacterium strain T3, and it was found that the EC50 value of untreated CPC solution for the T3 strain was 37.4%, whereas samples treated for only 30 min showed no acute toxicity. Combined with ECOSAR analysis, it was indicated that the toxicity of most degradation products is lower than that of the parent compound. This confirms that DBD plasma is currently a highly effective technology for treating CPC, achieving efficient degradation, high mineralization, and effective detoxification.