Molybdenum disulfide (MoS2) promoted sulfamethoxazole degradation in the Fe(III)/peracetic acid process

Abstract Activation of peracetic acid (PAA) for pollutants degradation has been a hotspot recently. In this study, molybdenum disulfide (MoS2) was first employed to enhance sulfamethoxazole (SMX) degradation in the Fe(III)/PAA process at pH 3.0. The addition of MoS2 can not only accelerate the transformation from Fe(III) to Fe(II), but also can directly activate PAA. A series of reactive species including Fe(IV), 1O2, HO●, CH3C(O)O● and CH3C(O)OO● were generated in this Fe(III)/MoS2/PAA process, which was responsible for SMX degradation except 1O2. The increase of MoS2 dosage (0.025–0.2 g/L) accelerated SMX degradation, and the optimum pH was 3.0. The increase of either PAA (0.075–0.45 mM) or Fe(III) concentration (0.025–0.2 mM) also accelerated SMX degradation. However, the higher concentration of SMX, the addition of humic acid, and extra adding H2O2 lowered the removal efficiency of SMX. Based on the identified products, possible pathways of SMX degradation initiated by electron transfer reaction were proposed. Furthermore, a continuous flow reactor configuration was employed to recycle the used MoS2, and the stable removal efficiency of SMX during 6 h reaction brings a new strategy for this process in practical use. This study developed an efficient method to remove SMX and provided a new idea for the PAA activation in water treatment.