曝气吹脱技术去除地下水水源地中氯代烃的研究

发布时间：2018-06-07 05:25

  本文选题：氯代烃 + 曝气吹脱　； 参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：地下水中的氯代烃种类多、危害大,对地下水安全和人类健康存在极大隐患。本文以地下水中含量相对较多的四种氯代烃,即四氯化碳、三氯甲烷、三氯乙烯和四氯乙烯为目标污染物,研究如何用曝气吹脱技术快速去除地下水中的氯代烃污染物。本文研究了影响曝气吹脱去除氯代烃的主要影响因素,包括单位面积曝气量,氯代烃初始浓度和温度,并探究了氯代烃共存对去除率的影响。最终建立曝气吹脱去除氯代烃的数学模型,通过模型分别对气水比与氯代烷烃和氯代烯烃的去除效果进行预测,并初步探究了分子连接指数与曝气吹脱速率的关系,以便为该技术的实际应用提供参考,具体结论如下:(1)通过本文的实验探究,表明曝气吹脱技术可以快速有效的去除地下水中的氯代烃污染物,单位面积曝气量越大,氯代烃初始浓度越小,温度越高,达到排放标准需要的时间越短。但是单位面积曝气量增大能耗也会相应增大,因此,用曝气吹脱技术去除5 mg/L的氯代烃最佳条件为单位面积曝气量在0.421~0.631m3/(m2·min)之间,温度高于20℃。(2)同样的实验条件下,四氯化碳、三氯甲烷、三氯乙烯和四氯乙烯的去除速率关系为四氯化碳四氯乙烯三氯乙烯三氯甲烷。多种氯代烃共存可以提高每种氯代烃的去除率。(3)曝气吹脱系统模型可以表示为C/C_0=exp(-G·q),吹脱系数G与亨利常数H有关,q为气水比。利用该模型对氯代烷烃和氯代烯烃在不同气水比下的吹脱效果进行了模拟预测,水温为20℃时,所测氯代烃去除率达50%、70%和90%所需要的气水比分别为:四氯化碳6.48、11.25、21.52,三氯甲烷17.33、30.10、57.56,三氯乙烯13.59、23.61、45.15,四氯乙烯9.90、17.20、32.89。可依次作为曝气吹脱技术去除氯代烃污染地下水的曝气量控制依据。(4)在温度25℃,初始浓度5 mg/L,单位面积曝气量为0.526 m3/(m2·min)的条件下,拟一级反应速率常数k与零级分子连接指数0χ相关性较好,相关方程为k=0.1457×0χ-0.4066,相关指数R~2=0.8401。
[Abstract]:There are many kinds of chlorinated hydrocarbons in groundwater, which are harmful to groundwater safety and human health. In this paper, four kinds of chlorinated hydrocarbons in groundwater, namely carbon tetrachloride, trichloromethane, trichloroethylene and tetrachloroethylene, were used as target pollutants. In this paper, the main factors affecting the removal of chlorinated hydrocarbons by aeration blowing are studied, including aeration amount per unit area, initial concentration and temperature of chlorinated hydrocarbons, and the influence of the coexistence of chlorinated hydrocarbons on the removal rate is discussed. Finally, a mathematical model for removal of chlorinated hydrocarbons by aeration blowing was established. The effects of gas-water ratio on removal of chlorinated alkanes and chlorinated alkenes were predicted by the model, and the relationship between molecular linkage index and aeration blowing rate was preliminarily explored. In order to provide a reference for the practical application of this technology, the concrete conclusion is as follows: 1) through the experimental research in this paper, it is shown that aeration technology can quickly and effectively remove chlorinated hydrocarbon pollutants from groundwater, and the greater the aeration amount per unit area, the greater the amount of aeration per unit area. The lower the initial concentration of chlorinated hydrocarbons, the higher the temperature and the shorter the time required to meet the emission standard. However, the energy consumption per unit area aeration will increase accordingly. Therefore, the best conditions for removal of chlorinated hydrocarbons by aeration blowing technology for 5 mg/L are as follows: the aeration rate per unit area is between 0.421~0.631m3/(m2 and 0.421~0.631m3/(m2, and the temperature is higher than 20 鈩，

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