• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Influence of nonionic surfactants on the bioavailability and microbial reductive dechlorination of hexachlorobenzene.
【24h】

Influence of nonionic surfactants on the bioavailability and microbial reductive dechlorination of hexachlorobenzene.

机译：非离子表面活性剂对六氯苯的生物利用度和微生物还原脱氯的影响。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Research was conducted to investigate the effect of nonionic surfactants on the microbial reductive dechlorination of hexachlorobenzene (HCB) and to evaluate the potential for surfactant-enhanced bioavailability of sorbed-phase HCB in contaminated sediments. The biological compatibility of sixteen surfactants for both methanogenesis and reductive dechlorination was evaluated using HCB-dechlorinating, mixed, enrichment cultures developed with a contaminated estuarine sediment sample. Polyoxyethylene sorbitan fatty acid esters (Tween surfactants) were the least inhibitory. Increasing surfactant concentration generally inhibited reductive dechlorination, but not necessarily methanogenesis. The anaerobic biodegradability of three similar surfactants (Tween 60, 61, and 65) was assessed and compared to their structural features. Subcultures were successfully developed in which these Tween surfactants were utilized as the sole carbon source for methanogenesis and served as a stable source of electrons to sustain the reductive dechlorination of HCB for over eighteen months. The equilibrium phase distribution of HCB and surfactant in a suspended-growth culture system was measured through batch sorption assays and depicted with a mathematical model accounting for the distribution of HCB to the micellar-, accumulated surfactant-, and biomass-phases. Assays were conducted to determine the effect of HCB availability on its dechlorination rate. Mathematical models utilizing Michaelis-Menten type kinetics, based on either the concepts of bioavailability-limitation or enzyme-inhibition, were developed and reasonably simulated HCB dechlorination in the presence of a biodegradable surfactant. The effect of surfactants on the concurrent desorption and biotransformation of sorbed-phase HCB was evaluated using a field-contaminated (over 40 years) sediment containing HCB and other polychlorinated organic compounds which are resistant to desorption. Anaerobic sediment slurry microcosms, fed with glucose or Tween surfactants, were established. Although the Tween surfactants served as electron donors and supported the microbial reductive dechlorination and desorption of HCB, they did not enhance the bioavailability of sediment-bound HCB compared to the glucose-fed system over 119 d. This outcome is attributed to both the high degree of HCB sequestration in the high organic content, historically-contaminated sediment as well as surfactant losses from the solution phase due to sorption/precipitation and biodegradation. These findings illustrate the inherent difficulties in remediating environmental systems containing long-term, strongly-sequestered and recalcitrant contaminants.
机译：进行了研究，以研究非离子表面活性剂对六氯苯（HCB）微生物还原脱氯的影响，并评估吸附相HCB在受污染沉积物中提高表面活性剂生物利用度的潜力。使用由受污染的河口沉积物样品开发的HCB脱氯，混合，浓缩培养物评估了16种表面活性剂在甲烷生成和还原性脱氯反应中的生物相容性。聚氧乙烯失水山梨糖醇脂肪酸酯（吐温表面活性剂）的抑制作用最小。表面活性剂浓度的增加通常会抑制还原性脱氯，但不一定能抑制甲烷生成。评估了三种类似表面活性剂（吐温60、61和65）的厌氧生物降解能力，并将其与结构特征进行了比较。成功开发了亚文化，其中将这些Tween表面活性剂用作甲烷生成的唯一碳源，并用作稳定的电子源，以维持HCB还原脱氯18个月以上。 HCB和表面活性剂在悬浮培养系统中的平衡相分布是通过分批吸附测定法测量的，并用数学模型描述了HCB在胶束相，表面活性剂相和生物质相中的分布。进行测定以确定六氯代苯的可用性对其脱氯速率的影响。基于生物利用度限制或酶抑制的概念，开发了利用Michaelis-Menten型动力学的数学模型，并在可生物降解的表面活性剂存在下合理模拟了HCB脱氯。表面活性剂对吸附相六氯代苯并发脱附和生物转化的影响是使用含有六氯苯和其他多氯代有机化合物的经现场污染（超过40年）的沉积物评估的，这些沉积物具有抗脱附性。建立了以葡萄糖或吐温表面活性剂为食的厌氧沉积物泥浆微观世界。尽管吐温表面活性剂充当了电子供体并支持了六氯代苯的微生物还原性脱氯和解吸，但与葡萄糖喂养系统相比，它们在119 d内并未提高沉积物结合型六氯代苯的生物利用度。该结果归因于高有机物含量的高度HCB隔离，历史上受污染的沉积物以及由于吸附/沉淀和生物降解作用导致溶液相中表面活性剂的损失。这些发现说明了补救环境系统中固有的困难，这些环境系统包含长期的，强烈隔离的和顽固的污染物。

著录项

  • 作者

    Yeh, Daniel H.;

  • 作者单位

    Georgia Institute of Technology.;

  • 授予单位 Georgia Institute of Technology.;
  • 学科 Engineering Environmental.; Biology Microbiology.
  • 学位 Ph.D.
  • 年度 2000
  • 页码 420 p.
  • 总页数 420
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 环境污染及其防治;微生物学;
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号