Effects of solution chemistry on dielectric barrier atmospheric non-thermal plasma for operative degradation of antiretroviral drug nevirapine

Abstract

The global prevalence of human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) has been an environmental menace. Tons of drug wastes from antiretroviral therapy are released into the environment annually. We, for the first time, employed the novel dielectric barrier atmospheric non-thermal plasma (DBANP) discharge, to mitigate the inadvertent pollution arising from the antiretroviral therapy. A 40-min treatment of nevirapine achieved >94 % (0.075 min−1) removal efficiency at discharge power of 63.5 W and plasma working gas of atmospheric air. Chemical probes confirmed •OH, ONOO− and eaq− as the dominant reactive species whilst further revealing the reaction acceleration role of NaNO3 and CCl4 which are known reaction terminators. The commonly coexisting inorganic anions potentiated nevirapine removal with over 98 % efficiency, achieving the highest rate constant of 0.148 min−1 in this study. Moreover, the initial solution pH (1.5–11.1) was no limiting factor either. The insensitivity of the DBANP discharge to actual water matrices was an eminent inference of its potential applicability in practical conditions. With reference to data obtained from the liquid chromatography-mass spectrometer analysis, nevirapine degradation pathway was proposed. A nucleophilic attack by ONOO− at the cyclopropyl group and •OH attack at the carbonyl carbon of the amide group, respectively, initiated nevirapine degradation process. It is anticipated that the findings herein, will provide new insights into antiretroviral drug waste management in environmental waters using the innovative and green non-thermal plasma process.