采用高级氧化技术,以Co2+为催化剂分解单过氧硫酸氢钾(PMS)所产生的强氧化性硫酸根自由基(SO4·-)降解水中的二氯喹啉酸(QC).考察了PMS用量、Co(Ⅱ)/PMS比值和Cl-浓度以及QC初始浓度对该均相Co(Ⅱ)/PMS体系降解QC的影响.结果表明,QC的降解遵循准一级动力学过程.当QC初始浓度在0.02~0.2mmol/L时,QC的降解速率随着QC/PMS比值的降低而增大,但当QC/PMS比值小于1/100时,则相反.QC的降解速率随着PMS浓度升高而线性增大,当PMS浓度为32mmol/L时,4h内QC的降解率可达94%.增大Co(Ⅱ)/PMS的摩尔比能够促进QC的降解,而Cl-对QC的降解有一定的抑制作用.LC/MS分析结果表明,3,7-二氯-8-羟基喹啉和7-氯-8-喹啉甲醛为QC降解过程中两种主要的中间产物.%An effective advanced oxidation process for the degradation of quinclorac (QC) in water is reported. This method is based on the oxidation of quinclorac by sulfate radicals generated from the decomposition of peroxymonosulfate (PMS) mediated by Co (Ⅱ) ion in the aqueous phase. The effects of the concentration of PMS and Cl-, molar ratio of Co (Ⅱ)/PMS as well as the initial concentration of QC on the degradation efficiency of QC were examined. The results showed that the degradation of QC in the homogeneous Co (Ⅱ)/PMS system fitted well to the pseudo-first-order kinetic model. The degradation rate of QC increased with the decreasing of molar ratio of QC/PMS, but declined as the ratio of QC/PMS lower than 1/100 when the initial concentration of QC was in the range of 0.02~0.2mmol/L. The reaction rates linearly increased with the increase of PMS concentration with a QC decomposition as high as 94% within 4 hours at an initial concentration of 32mmol/L PMS. The ratio of Co (Ⅱ)/PMS had positive effect on the degradation of QC, while Cl- had negative impact. The results of LC/MS analysis indicated that 3,7-dichloro-8-hydroxy quinoline and 7-chloro-8-quinoline carboxaldehyde were the two major intermediates of QC degradation.
展开▼
