紫外光活化亚硫酸盐降解水中卡马西平

Degradation of Carbamazepine in Water by UV-activated Sulfite Process

研究了紫外光活化亚硫酸盐高级氧化工艺降解水中典型新污染物——卡马西平(CBZ)的效能和降解机制.探究了不同溶解氧浓度[ρ(DO)]对紫外光活化亚硫酸盐降解CBZ的影响,并在模拟自然水体环境控制初始ρ(DO)为(8.0±0.2) mg·L^(-1)条件下,考察了不同工艺参数(亚硫酸盐投加量、反应pH)与水环境要素(碳酸氢根离子、氯离子、腐殖酸)对CBZ降解效能的影响.结果表明,紫外光活化亚硫酸盐工艺可在30 min内降解85.3%的CBZ,降解过程遵循拟一级动力学,动力学常数为0.055 7 min^(-1).并采用电子顺磁共振波谱技术、活性物质淬灭实验和竞争反应动力学实验发现,CBZ的降解主要来自紫外光活化亚硫酸盐工艺中硫酸根自由基(SO_(4)^(-)·)与羟基自由基(·OH)等活性物质,且降解贡献率分别为43.9%和56.1%.而且CBZ降解率随HCO_(3)^(-)浓度升高而降低,但Cl-浓度变化对CBZ降解率影响不大,水中存在的腐殖酸可显著抑制CBZ的降解.反应过程中硫酸盐的积累量显著低于《生活饮用水卫生标准》(GB 5749-2022)限值,且亚硫酸盐消耗速率(0.004 4 min^(-1))显著低于CBZ的降解速率,说明亚硫酸盐可被紫外光高效活化用于降解水中存在的CBZ.

In this study,the degradation efficiency and mechanism of carbamazepine(CBZ),a typical emerging contaminant in water,in the UV/sulfite process were investigated.The effects of different concentrations of dissolved oxygen[ρ(DO)]on the degradation of CBZ by UV-activated sulfite were investigated.Additionally,under a simulated natural water environment-controlled initialρ(DO)of(8.0±0.2)mg·L^(−1),the effects of different process parameters(sulfite dosages and reaction pH)and water environmental factors(the presence of HCO_(3)^(−),Cl^(−),and humic acids)on the degradation of CBZ were comprehensively analyzed.The results showed that the UV/sulfite process efficiently degraded CBZ with a degradation rate of 85.3%during the 30 min reaction time and followed the pseudo-first order kinetic model with the constant of 0.0557 min−1.Using the electron spin resonance detection,reactive species quenching tests,and the competition kinetics,the sulfate radicals(SO_(4)^(−)·)and hydroxyl radicals(·OH)in the UV/sulfite process were determined to be the main reactive species and were responsible for the degradation of CBZ with contribution rates of 43.9%and 56.1%,respectively.In addition,the degradation efficiency of CBZ decreased with the increasing concentration of HCO_(3)^(-),and the presence of Cl^(-)had little effect on the degradation of CBZ,whereas the presence of humic acids significantly inhibited the degradation of CBZ.Moreover,the accumulation of sulfate during the reaction was significantly lower than the limit of the Standard for Drinking Water(GB5749-2022).Additionally,the sulfite consumption rate constant was 0.0044 min−1,which was significantly lower than the degradation rate constant of CBZ,indicating that sulfite could be activated efficiently by UV light to degrade CBZ in water.