Degradation of representative perfluorinated and hydrocarbon surfactants by electron beam irradiation

Perfluorinated and hydrocarbon surfactants are important contaminants in wastewater. In this study, degradation of surfactants including PFOS, LAS, and CTAB under electron beam irradiation is investigated under different irradiation conditions (0-10 kGy absorbed dose, pH 3-11). Fulvic acid and H2O2 are used as active species inhibitors to study the effect of OH and e(aq)(-) on surfactants degradation. Irradiation degradation products of surfactants are analyzed by liquid chromatography-mass spectrometry. The degradation mechanisms of surfactants are summarized according to the experimental results. It shows that surfactants degradation is promoted at a high absorbed dose and pH value. The degradation rate of PFOS, LAS, and CTAB is 93.8%, 89.1%, and 80.6% maximum, respectively. The e(aq)(-) plays a dominant role in the breakage of C-C bonds in surfactants. The bonds of C-F, C-S, and C-N are mainly destroyed by OH. The degradation of surfactants follows pseudo-first-order kinetics. Degradation products of surfactants include various long and short-chain molecules. Furthermore, concentrations of short-chain products increase with absorbed dose because of further degradation of long-chain products. This study shows the potential application for electron beam irradiation technology to remove perfluorinated and hydrocarbon surfactants from wastewater.