UV-Fenton法降解对硫磷的机理及动力学

采用UV-Fenton法对对硫磷的氧化消除及动力学规律进行研究,利用气相色谱法测定对硫磷的浓度,以半衰期的大小来表示降解效果;并考察了Fe2+浓度、H2O2浓度以及pH对光解对硫磷的影响.结果表明,UV-Fenton对对硫磷的氧化降解过程符合一级反应动力学;溶液中Fe2+与H2O2浓度对降解反应影响较大,随着浓度的增加对硫磷的降解效果增大,一定程度后呈下降趋势;在pH=3时,对硫磷的降解效果最好,其半衰期可达到0.256 h,一级动力学方程可表示为Ct=4.9652e-2.7 066t.     

Improved method for analyzing the degradation of estrogens in water by solid-phase extraction coupled with ultra performance liquid chromatography-ultraviolet detection

We established an improved method for the determination of four estrogens including estriol (E3), 17 -estradiol (E2), 17 -ethynylestrodiol (EE2) and estrone (E1) in water. The method consisted of solid-phase extraction (0.5 L water) and subsequent analysis of analytes by ultra-performance liquid chromatography (UPLC) with an ultraviolet detector (UVD). Base-line separation was achieved for all studied estrogens using a column (50 mm 2.1 mm) packed with 1.7 m particle size stationary phase. Recovery was higher than 88% and detection limits ranged between 12.5–23.7 ng/L for the four estrogens, with the RSD ranging from 7% to 11%. The method was successfully applied to determine E2 and EE2 in simulated natural water, which found that about 70% of E2 was degraded (with a half-life of about 30 hr) within 48 hr and about 55% of EE2 was degraded (with a half-life of about 36 hr). Low levels of E1 were found, however E3 was undetectable during the process.     

紫外驱动高级氧化法降解水体中的磷酸三苯酯

有机磷酸酯（OPEs）作为备受关注的一类新污染物,已对偏远的南极地区水环境引发了中等风险.磷酸三苯酯（TPHP）是水体中常见的OPEs,已被证实具有毒性效应、生物富集和放大效应,对环境和人体健康威胁较大.利用傅里叶红外光谱仪（FT-IR）和液相色谱-串联质谱联用仪（LC-MS/MS）探究TPHP在紫外-过氧化氢（UV-H₂ O₂）、紫外-二氧化钛（UV-TiO₂）和紫外-过硫酸盐（UV-PS）这3种高级氧化体系（UV-AOPs）中的降解过程,创新性地利用FT-IR实现了TPHP降解过程中红外特征峰变化的在线观测,并对其降解反应动力学、光降解产物和降解路径进行了分析.结果表明,TPHP在UV-H₂ O₂、UV-TiO₂和UV-PS体系下均能得到有效降解,其光降解半衰期分别为74、150和89 min.其中,UV-H₂ O₂体系对TPHP的降解效果最好.TPHP在3种体系下的降解反应均符合一级动力学.当H₂ O₂浓度为0~0.097 mol ·L^-1时,H₂ O₂浓度升高会促进TPHP降解;当TiO₂浓度为0~0.013 mol ·L^-1时,TiO₂浓度升高会促进TPHP降解.TPHP的光降解路径主要是P—O—C键断裂、苯环结构的C—H键断裂和水解反应.利用UV-H₂ O₂体系对成都市环境水体中OPEs进行降解实验,发现对公园景观水体的水样进行降解反应60 min时,TPHP的去除率为66%.