State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541006, China.
Environ Pollut. 2019 Oct;253:488-496. doi: 10.1016/j.envpol.2019.07.044. Epub 2019 Jul 12.
Electron transfer capacities (ETC) of humic-like acids (HLA) and their effects on dechlorination are dependent on their redox-active properties. Aging and minerals can affect the chemical compositions and structures of HLA. However, the underlying mechanism and the impacts on the dechlorination capacities of HLA are poorly understood. We investigated how redox properties change in association with the intrinsic chemical natures and exterior minerals of the HLA extracted from landfilled solid wastes. Furthermore, the ETC of the landfill-derived HLA could be strengthened by increasing landfill age and demineralization, thereby facilitating the dechlorination of pentachlorophenol (PCP). The HLA molecules started to polymerize aromatic macromolecules during landfilling, leading to an increase in ETC and dechlorination capacities. Macromolecular HLA were dissociated to smaller molecules and exposed more aromatic and carboxyl groups when separated from minerals, which enhanced the ETC and the dechlorination abilities of the HLA. Microbial-mediated dechlorination was an effective way to degrade PCP, and almost 80% of the PCP was transformed after 40 days of demineralized HLA and Shewanella oneidensis MR-1 incubation. The demineralization and aging further facilitated the microbial-mediated PCP dechlorination. The findings provide a scientific base for improving in-situ bioremediation of chlorinated compound-contaminated soils using freshly synthesized HLA.
类腐殖酸（HLA）的电子转移能力（ETC）及其对脱氯的影响取决于其氧化还原活性。老化和矿物质会影响 HLA 的化学成分和结构。然而，其潜在机制以及对 HLA 脱氯能力的影响仍知之甚少。我们研究了与从垃圾填埋场固体废弃物中提取的 HLA 的内在化学性质和外部矿物质相关的氧化还原性质如何发生变化。此外，通过增加填埋年龄和去矿物质化，可以增强源自垃圾填埋场的 HLA 的 ETC，从而促进五氯苯酚（PCP）的脱氯。在填埋过程中，HLA 分子开始聚合芳香大分子，导致 ETC 和脱氯能力增加。当从矿物质中分离出来时，大分子 HLA 会解离成较小的分子，并暴露出更多的芳香族和羧基，从而增强了 HLA 的 ETC 和脱氯能力。微生物介导的脱氯是降解 PCP 的有效途径，在经过 40 天的去矿物质化 HLA 和希瓦氏菌属 MR-1 孵育后，几乎有 80%的 PCP 被转化。去矿物质化和老化进一步促进了微生物介导的 PCP 脱氯。这些发现为使用新合成的 HLA 改善原位生物修复氯化物污染土壤提供了科学依据。
