| 苯或甲苯对粒状铁还原三氯乙烯及其中间产物顺式二氯乙烯的影响 |
| 摘要点击 2138 全文点击 1088 投稿时间：2009-08-07 修订日期：2009-09-27 |
| 查看HTML全文
查看全文 查看/发表评论 下载PDF阅读器 |
| 中文关键词 粒状铁 苯 甲苯 三氯乙烯 顺式二氯乙烯 连续渗透反应格栅 |
| 英文关键词 granular iron benzene toluene trichloroethylene (TCE) cis-1,2-dichloroethylene (-1,2-DCE) sequential permeable reactive barrier (SPRB) |
|
| 中文摘要 |
| 地下水中挥发性氯代烃和石油烃类（主要为苯、甲苯、乙苯和二甲苯，总称为BTEX）混合污染羽可用铁渗透反应格栅（Fe0-PRB）联合厌氧生物降解技术修复；在设计上游Fe0-PRB时，需考虑BTEX存在下是否需增加其厚度.采用柱实验方法研究了苯和甲苯在粒状铁反应系统中吸附平衡后，对粒状铁去除三氯乙烯（TCE）长期运行的影响.结果表明，苯或甲苯（浓度各1～2 mg·L-1左右）存在时，TCE（2 mg·L-1左右）的去除仍符合准一级反应动力学；苯和甲苯的存在分别使TCE的去除速率平均降低约15.1%和18.5%，而使cis-1,2-DCE的去除速率各提高约4.5%和42.8%.在Fe0-PRB的长期运行中，矿物沉淀的积累仍是影响TCE还原脱氯的主要因素，苯或甲苯对TCE还原脱氯的抑制仅表现在运行初期；无论有无苯和甲苯，TCE的氯代中间产物种类皆相同，其中以顺式二氯乙烯（cis-1,2-DCE）为主，并且各柱中cis-1,2-DCE均首先穿透，出水浓度为2～75 μg·L-1，需以cis-1,2-DCE的水力停留时间来确定Fe0-PRB的厚度，因此在设计上游Fe0-PRB时，若仅考虑TCE的修复目标，不考虑cis-1,2-DCE对下游BTEX生物降解的影响，则不需增加Fe0-PRB厚度. |
| 英文摘要 |
| Mixed plumes contained chlorinated solvents and petroleum hydrocarbons which mainly refers to BTEX (benzene, toluene, ethylbenzene and xylenes) in groundwater can be remediated by sequential units combined an iron permeable reactive barrier (Fe0-PRB) with an anoxic wall. In design of the Fe0-PRB it should be taken into account the necessity of altering the width of the iron cell in the presence of BTEX. Three column experiments were conducted to evaluate the effects of benzene, toluene on the long-term performance of reductive dechlorination of trichloroethylene (TCE) by granular iron. The results showed that the kinetics of TCE (at the initial concentration of 2 mg·L-1 more or less) reduction was accorded with pseudo first-order even in the presence of benzene or toluene (at about 1-2 mg·L-1, respectively). The existence of benzene and toluene inhibited the removal of TCE by 15.1% and 18.5%, respectively; however, the presence of benzene slightly increased cis-1,2-DCE reduction rate by 4.5%, and the presence of toluene increased cis-1,2-DCE reduction rate by 42.8%. The inhibition of benzene and toluene other than mineral precipitates was not one of the decisive factors in the long-term performance of an Fe0-PRB; in addition, the kinds of chlorinated daughter products of TCE in the presence/absence of benzene or toluene were identical and cis-1,2-dichloroethylene (cis-1,2-DCE), the major intermediate, firstly broke through from all the 3 columns at concentrations about 2-75 μg·L-1, indicating that designing the width of an Fe0-PRB should be based on the hydraulic residence time of cis-1,2-DCE. In conclusion, if only considering the TCE remedial goals and disregarding the effects of cis-1,2-DCE on BTEX biodegradation downgradient the Fe0-PRB, the results suggested that it should be not necessary to increase the width of the iron cell for constructing sequential permeable reactive barriers (SPRBs) to rescue TCE- and BTEX-contaminated aquifers. |
|
|
|
