紫外活化过硫酸钠降解水中三唑酮的效能

Degradation of triadimefon in water by UV irradiation-activated sodium persulfate process

针对常规水处理工艺难以去除原水中低浓度有机氯农药的问题,采用新型高级氧化技术——紫外(UV)活化过硫酸钠(PS)去除水中有机氯农药三唑酮(triadimefon,TDF),分别研究了TDF初始浓度、PS浓度、初始pH、氯离子浓度以及腐殖酸(HA)浓度对TDF降解效果的影响。结果表明:随着TDF浓度的增加,其去除率逐渐降低;PS浓度从100μmol·L^(-1)增到250μmol·L^(-1),TDF去除率可以提高6.83%;初始pH为5时,TDF的去除率最大;氯离子的存在会抑制TDF降解;存在HA时会降低TDF去除效果。当TDF浓度为200μg·L-1、PS投加量为250μmol·L^(-1)、pH为5、温度为(25±2)℃和反应时间为600 s的反应条件下,TDF的去除率达到99.83%。相比于单独采用UV辐照和PS氧化技术,UV/PS技术对TDF的去除率分别提高了64.2%和86.22%。TDF的降解机制是紫外直接光解和以硫酸根自由基(SO4·-)为主的自由基氧化的共同作用。

Conventional technologies were ineffective in removing organochlorine pesticides with low content in raw water,a new advanced oxidation technology,ultraviolet(UV)activated sodium persulfate(PS)process,was therefore introduced to degrade the typical organochlorine pesticide of triadimefon(TDF).The effects of initial TDF concentration,PS dosage,initial pH,concentrations of chloride ion and humic acid(HA)on TDF degradation were studied.The results showed that TDF removal rate gradually decreased with the increase of its concentration.When PS dosage increased from 100μmol·L-1 to 250μmol·L-1,TDF removal rate could increase by 6.83%.And the maximum TDF removal rate occurred at the initial pH of 5.TDF degradation by UV/PS was inhibited by chloride ions or HA.TDF removal rate could reach 99.83%at TDF concentration of 200μg·L-1,PS dosage of 250μmol·L-1,pH 5,(25±2)℃and reaction time of 600 s.Compared with UV irradiation or PS oxidation alone,TDF removal rate of UV/PS technology increased by 64.2%and 86.22%,respectively.The mechanism for TDF degradation with UV/PS system is a combination of direct photo-degradation by UV and radical oxidation mainly based on sulfate radical(SO4·-).