研究报告

  • 周妮,乔文静,叶淑君.1,2,4-三氯苯厌氧还原脱氯过程及荧光增白剂PF对脱氯过程影响研究[J].环境科学学报,2018,38(10):3954-3963

  • 1,2,4-三氯苯厌氧还原脱氯过程及荧光增白剂PF对脱氯过程影响研究
  • Reductive dechlorination of 1,2,4 -trichlorobenzene and the effect of fluorescent whitening agent PF on dechlorination process
  • 基金项目:国家自然科学基金(No.41472212)
  • 作者
  • 单位
  • 周妮
  • 南京大学地球科学与工程学院, 表生地球化学教育部重点实验室, 南京 210023
  • 乔文静
  • 南京大学地球科学与工程学院, 表生地球化学教育部重点实验室, 南京 210023
  • 叶淑君
  • 南京大学地球科学与工程学院, 表生地球化学教育部重点实验室, 南京 210023
  • 摘要:南京某化工厂生产荧光增白剂PF(1,2-双(5-甲基-2-苯并唑基)-乙烯,调查发现其地下水中存在多种污染物:1,2,4-三氯苯(TCB)、二氯苯同分异构体(DCB)、一氯苯(MCB)、苯和PF.场地多年监测结果显示很可能存在厌氧条件下氯苯类污染物的自然降解.为了探索污染物降解机制并确定荧光增白剂PF对该脱氯过程的影响,笔者通过室内实验发现1,2,4-TCB被脱氯为1,2-DCB、1,3-DCB和1,4-DCB,摩尔比率约为10%、35%、55%.随着1,2,4-TCB投喂次数的增加,降解菌的脱氯速度越来越快,最高可达到7 μmol·d-1.1,2-DCB和1,3-DCB先脱氯产生MCB,1,4-DCB滞后约两周开始降解,脱氯速度从第14周的0.19 μmol·d-1增加到第17周的0.88 μmol·d-1,并在第108 d左右消耗完全.虽然1,2-DCB和1,3-DCB比1,4-DCB先开始脱氯,但脱氯速度相对缓慢,1,2-DCB的脱氯速度从第12周的0.001 μmol·d-1增加到第15周的0.21 μmol·d-1,1,3-DCB的脱氯速度从第12周的0.06 μmol·d-1增加到第17周的0.14 μmol·d-1.DCBs降解产生的MCB在第160 d左右开始脱氯生成苯,脱氯速度从第23周的0.296 μmol·d-1到第25周的1.94 μmol·d-1再到第28周的0.007 μmol·d-1.同时,实验结果表明荧光增白剂PF不会改变1,2,4-TCB的脱氯过程,但在MCB脱氯到苯的过程中具有一定的抑制作用.
  • Abstract:Site investigations were conducted at a former chemical plant located in Nanjing, China, which manufactured fluorescent whitening agent PF. The results delineate the groundwater was contaminated with 1,2,4-trichlorobenzene (TCB), dichlorobenzene (DCB) isomers, monochlorobenzene (MCB), benzene and PF. The five-year groundwater monitoring results reveal that the chlorobenzenes were likely naturally attenuated to benzene under anaerobic conditions. To explore the degradation mechanisms of chlorobenzenes and to confirm the effect of PF on dechlorination processes, a laboratory microcosm study was conducted to demonstrate that 1,2,4-TCB was dechlorinated to 1,2-DCB, 1,3-DCB and 1,4-DCB in approximately 10%, 35% and 55% molar proportions, respectively. The dechlorination rate increased substantially along with the feeding events, reaching up to 7 μmol·d-1. 1,2-DCB, 1,3-DCB were dechlorinated to MCB first, while 1,4-DCB began to degrade after approximately 2 weeks. The dechlorination rate of 1,4-DCB increased from 0.19 μmol·d-1 in the 14th week to 0.88 μmol·d-1 in the 17th week, and it was completely consumed after 108 days of incubation. Although 1,2-DCB and 1,3-DCB were dechlorinated earlier than 1,4-DCB, their dechlorination rates were relatively slow. The dechlorination rate of 1, 2-DCB increased from 0.001 μmol·d-1 in the 12th week to 0.21 μmol·d-1 in the 15th week, and the dechlorination rate of 1,3-DCB increased from 0.06 μmol·d-1 in the 12th week to 0.14 μmol·d-1 in the 17th weeks. The dechlorination of MCB produced by DCBs started on the 140th day. The MCB dechlorination rate increased from 0.296 μmol·d-1 in the 23th week to 1.94 μmol·d-1 in the 25th week, then decreased to 0.007 μmol·d-1 in the 28th week. The addition of PF did not change the dechlorination processes of 1,2,4-TCB and DCB isomers, but inhibited the further dechlorination of MCB to benzene.

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