挥发性有机污染物水中亨利常数的简易测定方法

开发了挥发性有机物亨利常数的简易实验测定方法,并以此方法测定了5种汽油成分(甲基叔丁基醚(MTBE)、苯、甲苯、乙苯、邻二甲苯)的亨利常数,相对标准偏差基本上在5%以内.使用此方法测定的汽油成分、硝基苯、2,4-二氯酚、苯酚和三氯乙烯(TCE)的亨利常数数值比估算值更接近文献值.在不同温度下,使用本方法对MTBE、苯、甲苯、TCE溶液进行测定,结果表明亨利常数随着温度的升高而变大,符合亨利常数随温度变化趋势的一般规律.两种挥发性有机物在混合条件下的亨利常数比单独存在时的亨利常数大.

Methods for Estimating Henry's Law Constants of Volatile Organic Water Pollutants

A simple and fast experimental method for estimating the Henry's law constant (HLC) of a volatile organic compound (VOC) in water samples was developed; it required only the equilibrium liquid phase concentration of a close system partially filled with the VOC solution for calculating its HLC of the test conditions. The simple experimental method was highly reproducible; its relative standard derivations(RSDs) for 5 minor gasoline constituents (MTBE, benzene, toluene, ethyl benzene, o-xylene) were less than 5%. Compared with the HENRYWIN calculations, the experimental HLCs of those VOCs,nitrobenzene, and trichloro ethylene (TCE) were all in better agreements with most experimental values reported in the two USEPA databases and the literature. The method was utilized for estimating HCL of different solution temperatures and composition. HLC of MTBE, benzene, toluene and TCE increased as the temperature went up and that they were higher in the bisolute solutions with greater effect noted due to presence of a more soluble coexisting VOC.