Multi-chamber membrane capacitive deionization coupled with peroxymonosulfate to achieve simultaneous removal of tetracycline and peroxymonosulfate reaction byproducts

Advanced oxidation technologies based on peroxymonosulfate (PMS) have been extensively applied for the degradation of antibiotics. However, the degradation process inevitably introduces SO 4 2- and other sulfur-containing anions, these pollutants pose a huge threat to the water and soil environment. Addressing these concerns, this study introduced PMS oxidation into a multi-chamber membrane capacitive deionization (MC-MCDI) device to achieve simultaneous tetracycline (TC) degradation and removal of PMS reaction byproduct ions. The experimental results demonstrated that when the TC solution (40 mg L −1 ) was pre-adsorbed for 10 min, the voltage was 1.2 V and the concentration of PMS solution added was 4 mg mL −1 , the removal efficiency of TC and ion can reach 77.4 % and 46.5 % respectively. Furthermore, the activation process of PMS in MC-MCDI/PMS system and the reactive oxygen (ROS) that mainly produce degradation were deeply investigated. Finally, liquid chromatography-mass spectrometry (LC-MS) was employed to identify intermediates of TC degradation, propose potential degradation pathways, and analyze the toxicities of the intermediates. In addition, in five cycles, the MC-MCDI/PMS system demonstrated excellent stability. This study provides an effective strategy for treating TC wastewater and a novel approach for simultaneous TC degradation and desalination.