Efficiency And Mechanism Of Metal Complex/Membrane Activated PMS For Removal Of Carbamazepine Wastewater

Carbamazepine（CBZ）is a non-biodegradable pharmaceutical residue that has become an emerging contaminant in various aquatic environments.Trace amounts of CBZ exposure in the environment can cause incalculable harm to both humans and the environment.Advanced oxidation processes based on sulfate radicals（SR-AOPs）are considered a reliable strategy for removing common pharmaceutical pollutants from water.Sulfate radicals can be produced by activating persulfate（PMS）through heterogeneous catalysts of transition metals.However,in the catalytic process,transition metal catalysts are prone to defects such as decreased catalytic performance and difficult recovery,thus limiting their widespread application.To address these issues,this paper modified bimetallic sulfides in different ways and prepared semi-coke powder/nickel-iron sulfide（SC/Ni Fe₂S₄,SCNF）and copper-cobalt sulfide/nano-microporous composite membranes（Cu Co₂S₄/Microporous Composite Membrane,CCSM）,and activated them with PMS to remove CBZ from water and elucidate the degradation mechanism of CBZ in water.This study mainly carried out the following work:（1）SCNF-x nanocomposites were prepared by a hydrothermal method,and various characterization methods were used to analyze that Ni Fe₂S₄ is a block structure nanomaterial and semi-coke powder（SC）is a spherical structure loaded on the surface of Ni F₂S₄.The composite catalyst has abundant functional groups on the surface,which can effectively activate PMS.In addition,the prepared catalysts have good magnetism and can be easily recovered,reducing catalyst waste.SCNF-0.5,SCNF-1,and SCNF-2 were prepared by changing the mass ratio of SC and Ni Fe₂S₄.Subsequently,they were used to activate PMS to remove CBZ from water,and SCNF-0.5 was found to have excellent catalytic performance.When the catalyst dosage was 0.35 g·L^-1,PMS dosage was 0.20g·L^-1,and the initial p H of the solution was 6.95,the SCNF-0.5/PMS system could degrade 67.3%of CBZ within 140 min.The effects of inorganic salt ions（Cl^-,NO₃^-）and natural organic matter humic acid（HA）on CBZ can be ignored,while HCO₃^-in the system inhibits the degradation of CBZ.In addition,free radical scavenging experiments and electron paramagnetic resonance（EPR）showed that free radical（SO₄·^-,·OH and O₂·^-）and non-free radical（¹O₂ and O_v）pathways coexist in the system,but non-free radical¹O₂ plays a major role.Moreover,SC surface can adsorb PMS and directly decompose pollutants through electron transfer,indicating that SC/Ni Fe₂S₄ synergistically catalyzes the degradation of CBZ by PMS.After 4 cycles of experiments,the catalytic performance of SCNF-0.5 decreased significantly,but it can be regenerated by ultrasound and heat treatment.CCSM composite membranes were prepared by a hydrothermal and filtration method.Cu Co₂S₄ was found to be a typical nanoflower structure that covered well on the surface of polyvinylidene fluoride（PVDF）films.When the catalyst dosage was 0.05 g·L^-1,PMS dosage was 0.30 g·L^-1,and the initial solution p H was 6.95,the CCSM/PMS system could degrade 91.3%of CBZ within 3 min.After ten cycles,the catalytic efficiency of CCSM decreased by only about 10%.In addition,the CCSM composite membrane that had been placed for three months was activated with PMS,and the catalytic efficiency remained almost unchanged,indicating its outstanding and stable activation performance.Meanwhile,CCSM/PMS was applied to the degradation of four common types of antibiotics（sulfamethoxazole,metronidazole,tetracycline hydrochloride,and ciprofloxacin hydrochloride）,and the degradation rates of these antibiotics within 3 minutes were 72.6%,99.6%,98.6%,and 97.3%,respectively,indicating that CCSM has a wide range of applicability.Furthermore,based on free radical scavenging experiments,EPR experiments,and high-performance liquid chromatography-mass spectrometry（HPLC-MS）analysis of the possible mechanism and pathways for CBZ degradation,the results show that the removal of CBZ is mainly due to the action of SO₄·^-in the system,and CBZ has four degradation pathways.This work proposes a new approach for modifying transition metal heterogeneous catalysts and regenerating their catalytic performance.The prepared composite catalyst enhances the efficiency and purification effect of treating pharmaceutical wastewater.This study has significant potential for academic and practical applications and provides important opportunities for theoretical exploration and engineering innovation in the field of water treatment.