In Situ Remediation of DNAPLs by coupling cosolvent flushing and hydrogen peroxide: contribution of reductive reactions on contaminant transformation

通过耦合共溶剂冲洗和过氧化氢对 DNAPL 进行原位修复：还原反应对污染物转化的贡献

• 批准号: RGPIN-2015-04850
• 负责人: Pham, Anh
• 金额: $ 1.68万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=679285
• 关键词: Situ; Remediation; DNAPLs; coupling; cosolvent

In a report released in 2014, the Parliamentary Budget Officer of Canada estimated that, despite two decades of investment in remediation efforts, Canada still has over 22,000 federal hazardous waste sites that will require an additional $4.9 billion of remediation cost. The report also indicated that Dense Non-Aqueous Phase Liquids (DNAPLs), such as chlorinated solvents and polychlorinated biphenyls, were among the most prevalent contaminants at those sites. To date, however, the remediation of DNAPLs has been challenging because these compounds are often located far below the surface, sparingly soluble in water, and relatively recalcitrant. Thus, our research program aims to develop an innovative approach that can expedite DNAPLs removal and reduce remediation cost.***The proposed research investigates the efficiency and practicality of a technology that combines cosolvent flushing with hydrogen peroxide (H2O2)-based remediation. In the past, although these two technologies have been used separately for DNAPLs remediation, the idea of combining them into a single treatment technology has received little attention as it was often assumed that they are incompatible (i.e., the oxidant produced from H2O2 will not oxidize the contaminants but will react with the cosolvent instead). However, our kinetics model, built based on a careful review of organic and radical chemistry literature, suggested that in a combined cosolvent/H2O2 system DNAPLs could be effectively removed through unexpected reductive transformation processes. In particular, the model indicated that these transformation processes could be initiated by a series of radical chain reactions whose importance were overlooked in the past. Thus, we propose laboratory experiments to examine whether this is truly the case, and if so, to find ways to make the combined technology more effective and robust for field application. The outcome of this research will be an innovative technology capable of effectively removing DNAPLs, which would reduce remediation cost and human exposure to DNAPLs.

加拿大议会预算官员在2014年发布的一份报告中估计，尽管加拿大在修复工作上进行了二十年的投资，但加拿大仍然有超过22,000个联邦危险废物场，需要额外的修复费用49亿加元。该报告还指出，氯化溶剂和多氯联苯等浓非水相液体（DNAPL）是这些地点最普遍的污染物之一。然而，迄今为止，DNAPL 的修复一直具有挑战性，因为这些化合物通常位于地表以下很远的地方，微溶于水，而且相对难降解。因此，我们的研究计划旨在开发一种创新方法，可以加速 DNAPL 去除并降低修复成本。***拟议的研究调查了将共溶剂冲洗与基于过氧化氢 (H2O2) 的修复相结合的技术的效率和实用性。过去，尽管这两种技术已分别用于 DNAPL 修复，但将它们组合成单一处理技术的想法很少受到关注，因为人们通常认为它们是不相容的（即，由 H2O2 产生的氧化剂不会氧化污染物，但会与助溶剂发生反应）。然而，我们的动力学模型是基于对有机和自由基化学文献的仔细审查而建立的，表明在组合的共溶剂/H2O2 系统中，DNAPL 可以通过意想不到的还原转化过程被有效去除。特别是，该模型表明，这些转化过程可能是由一系列自由基链式反应引发的，而这些反应的重要性在过去被忽视了。因此，我们建议进行实验室实验来检验情况是否属实，如果是，则找到使组合技术在现场应用中更加有效和稳健的方法。这项研究的成果将是一种能够有效去除 DNAPL 的创新技术，从而降低修复成本和人类对 DNAPL 的接触。