Synergistic promotion effects of MoS2 integrated transition metal sulfides nanoparticles towards efficient tetracycline destruction: Performance, mechanism and toxicity assessment

Construction of effective multi-component composite materials via architecture modulation to destruct antibiotic pollutants through activating peroxymonosulfate (PMS) remains a challenge. In this study, we report a two-step hydrothermal process to construct MoS2 nanosheets integrated with transition metal sulfide (CoS2, Cu2S and MnS) nanoparticles for activating PMS towards degrading emerging tetracycline (TC) antibiotic. Among the samples, CoS2@MoS2 is verified as the best PMS activator for TC destructing with a removal rate of 95.3% in 30 min. The CoS2@MoS2/PMS system also performs well under various reaction conditions. The dominant reactive oxygen species responsible for TC degradation is identified as 1O2. Furthermore, CoS2@MoS2-catalyzed PMS efficiently degrades TC into eleven intermediates via three possible pathways. The toxicity of these intermediates is evaluated, both in terms of acute/chronic toxicity and phytotoxicity. The presence of Mo4+ sites on the catalyst surface facilitates the rapid transfer of electrons from MoS2 to Co3+, promotes the regeneration of Co2+, and facilitates the redox cycle of Co3+/Co2+. Therefore, the synergistic effects between CoS2 and MoS2 are responsible for the efficient degradation of TC over the CoS2@MoS2/PMS system. This study establishes an architecture engineering strategy for preparing dual transition metal sulfides, which synergistically promote PMS activation towards the degradation of organic pollutants. •MoS2 integrated transition metal sulfides are prepared for PMS activation.•CoS2@MoS2 is verified as the best PMS activator for TC destructing.•Synergistic effects between CoS2 and MoS2 are responsible for TC degradation.•Singlet oxygen was the dominant ROS for CoS2@MoS2/PMS system.