Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, Jiangsu Province, China; University of Chinese Academy of Sciences, Beijing 100049, China; National Engineering Laboratory for Site Remediation Technologies, Beijing 100015, China.
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, Jiangsu Province, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Total Environ. 2020 Jan 1;698:134215. doi: 10.1016/j.scitotenv.2019.134215. Epub 2019 Aug 31.
The application of biochar-supported nanoscale zero-valent iron (biochar-nZVI) was successfully implemented in a field demonstration for the first time. To overcome the significant shortcomings of nZVI agglomeration for in-situ groundwater remediation, biochar-nZVI was injected into groundwater using direct-push and water pressure driven packer techniques for a site impacted by chlorinated solvents in the North China Plain. The field demonstration comprising two-step injections was implemented to demonstrate the effectiveness of nZVI and biochar-nZVI respectively. The outcome of the demonstration revealed a sharp reduction of contaminant concentrations of chlorinated solvents in 24 h following the first injection of nZVI, but the rebound of the concentrations of these contaminants in groundwater has occurred within the next two weeks. However, application of biochar-nZVI greatly enhanced the removal of chlorinated solvents in groundwater over the longer period of 42 days. The enhanced removal of chlorinated solvents in groundwater by biochar-nZVI is mainly attributed to the synergistic effects of adsorption and reduction. The adsorption by biochar significantly reduced the level of chlorinated solvents in groundwater. Overall increases in ferrous iron and chloride concentrations after the injections indicated that the reduction has occurred during the removal of chlorinated solvents in groundwater. In summary, biochar-supported nZVI could be potentially used for the effective remediation of chlorinated solvents in groundwater.
首次成功将生物炭负载纳米零价铁（biochar-nZVI）应用于现场示范。为克服原位地下水修复中纳米零价铁（nZVI）团聚的重大缺陷，采用直接推送和水压驱动封隔器技术，将生物炭负载纳米零价铁注入受华北平原氯化溶剂污染的地下水。该现场示范包括两步注射，以分别证明 nZVI 和 biochar-nZVI 的有效性。示范结果表明，在第一次注入 nZVI 后 24 小时内，污染物浓度急剧下降，但在接下来的两周内，这些污染物在地下水中的浓度又出现反弹。然而，在较长的 42 天内，生物炭负载纳米零价铁的应用大大提高了地下水氯化溶剂的去除率。生物炭负载纳米零价铁增强了地下水氯化溶剂的去除，主要归因于吸附和还原的协同作用。生物炭的吸附显著降低了地下水中氯化溶剂的水平。注入后亚铁和氯离子浓度的总体增加表明，在地下水氯化溶剂去除过程中发生了还原。总之，生物炭负载纳米零价铁可能被用于有效修复地下水中的氯化溶剂。
