地学前缘 ›› 2008, Vol. 15 ›› Issue (6): 142-150.

• 论文 • 上一篇    下一篇

苯、甲苯对粒状铁去除四氯乙烯影响的柱实验研究

  

  1. 中国地质大学(北京) 水资源与环境工程北京市重点实验室, 北京 100083

  • 出版日期:2008-06-20 发布日期:2008-06-20
  • 通讯作者: 刘菲(1969—),女,副教授。E-mail:feiliu@cugb.edu.cn
  • 作者简介:夏凡(1984—),女,硕士研究生，环境工程专业,研究方向:地下水污染防治与控制。
  • 基金资助:

    国家自然科学基金项目(40572146)

Column experimental studies on effects of benzene, toluene on reductive dechlorination of PCE by granular iron.

  1. Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences (Beijing)， Beijing 100083, China

  • Online:2008-06-20 Published:2008-06-20

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摘要：

挥发性氯代烃和石油烃类污染是地下水中最常见的混合污染类型,而且这两类污染物毒性极强,对人类危害非常严重。文中选取具有代表性的四氯乙烯、苯和甲苯为研究对象,采用柱实验的方法研究苯和甲苯在粒状铁反应系统中吸附平衡后,对粒状铁去除四氯乙烯的机理及反应动力学的影响。在实验装置运行的过程中,苯、甲苯和四氯乙烯的浓度始终控制在2 mg/L左右的水平。实验结果表明:苯或甲苯的存在对被还原的产物组成没有影响,主要氯代中间产物均为TCE、1,1DCE、cis1, 2DCE和VC,但组成比例略有不同。苯和甲苯的存在对去除速率有影响,即苯对四氯乙烯的去除有促进作用,去除速率平均提高135％;而甲苯则抑制四氯乙烯的去除,去除速率平均降低138％。对比控制柱,苯和甲苯存在时对出水水化学变化的影响没有明显差异。

关键词: 粒状铁; 苯; 甲苯; 四氯乙烯(PCE); 渗透反应格栅(PRB); 地下水修复; 反应动力学

Abstract:

Multicomponent plume in groundwater which blends chlorinated solvents with petroleum hydrocarbons has recently attracted great attention because of its wellknown carcinogenicity in humans and exceptional difficulty to be remedied simultaneously. This paper presents some column experiments which were conducted to evaluate the effects of benzene, toluene on reductive dechlorination of perchloroethene (PCE) by granular iron. The results showed that the kinetics of PCE (at the initial concentration of 2 mg/L more or less) reduction accorded with pseudo firstorder even in the presence of benzene or toluene (at about 2 mg/L, respectively). The presence of benzene increased PCE degradation by 135％ averagely; nevertheless, in the existence of toluene, PCE reduction rates averagely decreased by 138％. These data suggested that benzene would be a potential promoter, but toluene suppressed the removal of PCE. Furthermore, the dechlorinated daughter products in the presence/absence of benzene or toluene were identical. Trichloroethylene (TCE), cis1, 2dichloroethene (cis1, 2DCE), 1, 1dichloroethene (1, 1DCE) and vinyl chloride (VC) except for trans1, 2dichloroethene (trans1, 2DCE), were observed as the chlorinated intermediates, and cis1, 2DCE was the majority. Otherwise, ethyne, ethylene and ethane were observed as the major nonchlorinated end products. The accumulation of chlorinated intermediates was consistent with the removal ratios of PCE. In addition, the investigated changing of groundwater chemistry showed a noticeable disappearance of calcium (II), bicarbonate and sulfate. However, in the presence of benzene or toluene, there were slight variations in these changes. The results indicated that the effects of such copollutants should be considered in designing the sequential permeable reactive barriers (PRBs) combined iron walls with biotreated zones for groundwater remediation.

Key words:

granular iron; benzene; toluene; perchloroethylene (PCE); permeable reactive barrier (PRB); groundwater remediation; kinetics

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