钙钛矿LaBO_(3)催化过氧乙酸降解水中双酚A机制研究

MECHANISM OF PEROVSKITE LaBO_(3)CATALYZED PEROXYACETIC ACID DEGRADATION OF BISPHENOL A IN WATER

为高效去除水中内分泌干扰物类污染物,采用溶胶-凝胶法合成钙钛矿LaBO_(3)(B=Fe、Cr、Co)催化剂,用于催化过氧乙酸(PAA)降解水中双酚A(BPA)。采用TG-DSC、SEM、TEM、XRD等方法对钙钛矿LaBO_(3)催化剂形貌及微观结构进行表征,研究其在不同条件下催化PAA去除BPA的效果,并提出催化PAA反应机制。结果表明:LaBO_(3)(B=Fe、Cr、Co)为大小不一、表面光滑、团聚的不规则球体,比表面积为11.89 m^(2)/g。研究条件下,LaCoO_(3)/PAA体系对BPA的降解率高达85%,显著高于LaCrO_(3)/PAA(14%)和LaFeO_(3)/PAA(14%)体系。此外,LaCoO_(3)/PAA体系对其他污染物(金橙Ⅰ、磺胺甲噁唑、4-氯苯酚)亦展现出良好的降解效果,并且对水中常见的无机阴离子和腐殖酸具有较强的抗干扰能力,使LaCoO_(3)成为一种有发展前景的环境友好型催化剂。采用淬灭实验和电子自旋共振光谱揭示了有机自由基是LaCoO_(3)/PAA体系导致BPA降解的主要活性物种。直接电子转移途径为LaCoO_(3)/PAA体系催化降解BPA的次要氧化途径。此外,CoⅢ/CoⅡ的氧化还原对与PAA之间的氧化还原反应确保了自由基的连续生成和较高的降解效能。该研究工作可为水中内分泌干扰物污染治理提供新的思路。

To remove endocrine disruptors in water efficiently,perovskite LaBO_(3)(B=Fe,Cr,Co)catalyst was synthesized by sol-gel method to catalyze the degradation of bisphenol A(BPA)in water by peracetic acid(PAA).The morphology and microstructure of the catalyst were characterized using TG-DSC,SEM,TEM,XRD,etc.The effect of catalytic PAA removal of BPA under different conditions was studied,and the catalytic PAA reaction mechanism was proposed.The results indicated that LaBO_(3)(B=Fe,Cr,Co)was an irregular sphere with varying sizes,smooth surfaces,and aggregation.The specific surface area of LaCoO_(3)was 11.89 m^(2)/g.BPA degradation could reach 85%in the LaCoO_(3)/PAA system,significantly higher than that of LaCrO_(3)/PAA(14%)and LaFeO3/PAA(14%)systems.In addition,the LaCoO_(3)/PAA system also exhibited good degradation efficiency on other pollutants(orange I,sulfamethoxazole,4-chlorophenol),and had strong anti-interference ability with common inorganic anions and humic acids in water,making LaCoO_(3)an environmentally friendly catalyst with promising development prospects.The quenching experiment combined with electron spin resonance spectroscopy revealed that organic radicals were the main active species causing BPA degradation in the LaCoO_(3)/PAA system.The electron transfer pathway was the secondary oxidation pathway for the catalytic degradation of BPA in the LaCoO_(3)/PAA system.In addition,the oxidation-reduction reaction between CoⅢ/CoⅡand PAA ensured the continuous generation of radicals and high degradation efficiency.This work can provide new insight into the treatment of endocrine disruptors in water pollution.