UV/H_2O_2降解羟苯甲酮反应动力学及影响因素

Degradation of Organic Sunscreens 2-hydroxy-4-methoxybenzophenone by UV/H_2O_2 Process: Kinetics and Factors

有机防晒剂随着日常使用不断进入环境中,成为一类新兴污染物.考察了UV/H2O2工艺对典型有机防晒剂羟苯甲酮(BP-3)的水相光化学降解特征,并对BP-3降解反应的影响因素包括初始BP-3浓度、H2O2浓度、UV光强、共存阳离子和阴离子、叔丁醇和腐殖酸投加量等进行了研究.结果表明,BP-3的降解速率常数随初始BP-3浓度升高而降低,随着H2O2浓度增大而增高,随着UV光强增强而增大;阴离子会在一定程度上降低反应速率,阳离子中Fe3+会产生类芬顿反应,促进生成·OH,对降解反应有显著的促进作用,投加叔丁醇和腐殖酸皆会抑制降解反应进行.采用每一对数减小级电能输入(EEo)指标对UV/H2O2工艺的电能利用效率进行了评价,Fe3+的加入显著减小了EEo.研究不同因素对UV/H2O2工艺降解效果的影响,可对实际工程中采用UV/H2O2去除苯甲酮类有机防晒剂提供参考.

Organic sunscreens continue to enter the environment through people’s daily consumption,and become a kind of emerging contaminants. The photochemical degradation of benzophenone-3( BP-3) in water by UV / H2O2 process was investigated. Several factors,including the initial BP-3 concentration,H2O2 concentration,UV light intensity,coexisting cations and anions,humic acid and tert-butyl alcohol,were also discussed. The results showed that BP-3 degradation rate constant decreased with increasing initial BP-3 concentration,while increased with increasing H2O2 dosage and UV intensity. Coexisting anions could reduce the degradation rate,while coexisting ferric ions could stimulate the production of ·OH through Fenton-like reaction,further significantly accelerated BP-3 degradation process. The BP-3 degradation would be inhibited by humic acid or tert-butyl alcohol. The electrical energy per order( EEo) values were also calculated to evaluate the cost of BP-3 degradation by UV/H2O2 process. The addition of ferric ions significantly reduced the value of EEo. The investigation of processing parameter could provide a reference for the practical engineering applications of benzophenone compounds removal by UV / H2O2 process.