FeMn-layered double hydroxide-modified carbon cloth combined with ion exchange membrane enhanced the degradation of ionic organic pollutants in the capacitive desalination/peroxymonosulfate system

FeMn-layered double hydroxide (FeMn-LDH)-modified carbon cloth (CC) and ion exchange membranes were used to enhance adsorption of ionic organic pollutants (IOPs) by the hybrid capacitive deionization (HCDI) system. This system was then coupled with peroxymonosulfate (PMS) activation to efficiently degrade common IOPs, such as Acid Orange 7 (AO7). The FeMn-LDH-HCDI/PMS system achieves efficient removal of AO7 in saline wastewater by adding 1.0 mM PMS at a low voltage of 1.2 V, with a removal efficiency of approximately 94.9%. The system can effectively remove AO7 from saline water across a wide pH range (3-8) and is less affected by common coexisting anions. The presence of the cation exchange membrane enhances the system's electrosorption of AO7, while FeMn-LDH boosts PMS activation through the valence changes of metal elements. The degradation of AO7 is primarily due to the generation of • OH, SO 4 •− and 1 O 2 through PMS activation, while the toxicity of the intermediate products is reduced during the treatment process. Additionally, the system can achieve a removal efficiency of 83.1% for Cu(II)- ethylenediaminetetraacetic acid (EDTA) after 60 min of treatment, highlighting its potential for treating various IOPs.