Preparation Of CoCo-PBA@CuFe-LDH And Activation Of Peroxymonosulfate For Atrazine Degradation

The advanced oxidation method,which was based on the activation of peroxymonosulfate（PMS）to generate sulfate radicals(SO₄^·-)for the degradation of contaminants,had been a focus in wastewater treatment research due to its high performance and environmental friendliness.In this paper,a novel CoCo-PBA@CuFe-LDH composite was prepared by in-situ growth method to load Cobalt-based Prussian blue analogue（CoCo-PBA）on the layered double hydroxides CuFe-LDH,which was used to activate PMS for atrazine（ATZ）degradation.This paper mainly studied the activation performance of PMS before and after CoCo-PBA loading,and the factors influencing ATZ degradation with PMS activated by CoCo-PBA@CuFe-LDH composite were investigated.The oxidative active substances in CoCo-PBA@CuFe-LDH/PMS system were investigated,and the possible degradation paths of ATZ were proposed.The catalyst CoCo-PBA@CuFe-LDH composite was prepared by in situ growth method by loading CoCo-PBA on layered double hydroxide CuFe-LDH.The results showed that CoCo-PBA was successfully loaded on CuFe-LDH.Co,Cu,Fe,N,O elements were uniformly distributed in CoCo-PBA@CuFe-LDH composite,Cu,Co and Fe existed in the forms of Cu（Ⅱ）,Co（Ⅱ）/Co（Ⅲ）and Fe（Ⅲ）respectively;The layered structure of CoCo-PBA@CuFe-LDH composite was not obvious,but it had a larger specific surface area and pore volume than the single CoCo-PBA,and the pore volume of mesopores increased significantly,which was conducive to the adsorption and migration of ATZ molecules.The main influencing factors on ATZ degradation by CoCo-PBA@CuFe-LDH composite activated PMS were investigated.It was shown that the increase of CoCo-PBA@CuFe-LDH dosage and temperature were all favorable to ATZ degradation;Excessive dosage of PMS has a slight inhibitory effect on ATZ degradation;Over-acidic and over-alkaline environments were not beneficial to ATZ degradation;The presence of HCO₃^-,H₂PO₄^-,and Cl^-ions in the system all showed inhibitory effects on ATZ degradation.The optimal reaction conditions for the degradation of ATZ in CoCo-PBA@CuFe-LDH/PMS system were as follows:15 mg·L^-1 ATZ,300 mg·L^-1PMS,50 mg·L^-1 CoCo-PBA@CuFe-LDH,initial p H 6.3,and temperature 298 K,and the degradation rate of ATZ was up to 99.5%after 15 min.After 4 times of recycling,the degradation rate of ATZ still reached 83.4%,which indicated that as-prepared CoCo-PBA@CuFe-LDH had great catalytic performance and reusability.Finally,the results of the EPR experiment and the quenching experiment revealed that SO₄^·-and hydroxyl radicals were generated simultaneously in the CoCo-PBA@CuFe-LDH/PMS system,and SO₄^·-played a more critical role in the degradation of ATZ.In addition,the possible degradation paths of ATZ were proposed based on the detected intermediates.