Thermal desorption provides an efficient solution to remediate soil contaminated with chlorinated organic pollutants. However, enhanced desorption efficiency is desired to facilitate easier and less costly remediation. Hence, nanoscale zero-valent iron (nZVI) was combined with thermal desorption to remove trichloroethene (TCE) and trichlorobenzene (TCB) from soil in a laboratory-scale study. The addition of nZVI greatly improved the desorption efficiency, especially at low temperature with 99.6% of TCE and 98.8% of TCB removed at 300 °C for 2 h. Characterization results revealed that the addition of nZVI loosened the structure of soil, preventing the soil from agglomerating during the thermal treatment. Besides, the analyses of dechlorination intermediates and the variation of Fe species proved the in situ dechlorination effect of nZVI and the redox cycle of Fe was revealed. Moreover, the influences of nZVI dosage and treatment time on thermal treatment were assessed. This study not only offers new perspectives for contaminated soil remediation, but also provides mechanistic insights into the dechlorination effect of nZVI in the thermal desorption.

中文翻译：

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纳米零价铁增强氯化烃热解吸：原位脱氯效果

热解吸为修复被氯化有机污染物污染的土壤提供了有效的解决方案。然而，需要提高解吸效率以促进更容易且成本更低的修复。因此，在实验室规模的研究中，纳米级零价铁（nZVI）与热解吸相结合，从土壤中去除三氯乙烯（TCE）和三氯苯（TCB）。 nZVI的添加极大地提高了解吸效率，特别是在低温下，300℃2小时去除了99.6%的TCE和98.8%的TCB。表征结果表明，nZVI 的添加疏松了土壤结构，防止了土壤在热处理过程中结块。此外，脱氯中间体的分析和Fe形态的变化证明了nZVI的原位脱氯效果，并揭示了Fe的氧化还原循环。此外，还评估了 nZVI 剂量和处理时间对热处理的影响。该研究不仅为污染土壤修复提供了新的视角，而且为nZVI在热解吸中的脱氯效应提供了机理见解。