{"title":"热增强土壤蒸气萃取法结合混砂法修复受石油碳氢化合物污染的低渗透性土壤的机制","authors":"Ying Yu, Wenhui Kang, Jianan Song, Zhenli He, Jianguo Wang, Yu Liu, Zhiyu Yan","doi":"10.1007/s41742-024-00639-w","DOIUrl":null,"url":null,"abstract":"<p>Thermally-enhanced soil vapor extraction (T-SVE) combined with sand mixing is an alternative technology for remediating low-permeable soil polluted by organic contaminants. In this study, a T-SVE apparatus with a large heating cylinder was constructed for exploring removal mechanisms of typical petroleum hydrocarbons of <i>n</i>-C<sub>11</sub> and C<sub>13−16</sub> alkanes, and dynamics of heat propagation within soils during T-SVE operation was simulated by CMG-STARS software. After 6 days of T-SVE, most of the soil concentration-gradient curves of <i>n</i>-alkanes almost coincided with their isothermal contours, suggesting the crucial role of heat conductivity on T-SVE remediation efficiency. The instantaneous concentration of <i>n</i>-alkanes in extracted gas showed great fluctuations, and higher than 90% of spiked <i>n</i>-alkanes was removed from soils. <i>n</i>-alkanes were more easily eliminated from soil with lower organic matter due to the less retention ratio despite the trivial impact of organic matter on heat transfer. By contrast, the higher soil moisture adopted in the study retarded heat transfer in the initial 2 days due to thermal consumption induced by water evaporation. During the last 4 days, however, the average temperature of more humid soil was obviously elevated, especially in the zones receiving less energy input. It was attributed to the fact that soil temperature was mainly determined by heat conduction, and soil pores still occupied by water were more beneficial for heat conduction, leading to the promoted evaporation of <i>n</i>-alkane and therefore eventual remediation efficiency. Suitable original soil moisture is important for T-SVE remediating low-permeable soil combined with sand mixing.</p>","PeriodicalId":14121,"journal":{"name":"International Journal of Environmental Research","volume":null,"pages":null},"PeriodicalIF":2.6000,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"The Mechanism for Remediation of Low-Permeable Soil Contaminated with Petroleum Hydrocarbons by Thermally-Enhanced Soil Vapor Extraction Combined with Sand Mixing\",\"authors\":\"Ying Yu, Wenhui Kang, Jianan Song, Zhenli He, Jianguo Wang, Yu Liu, Zhiyu Yan\",\"doi\":\"10.1007/s41742-024-00639-w\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>Thermally-enhanced soil vapor extraction (T-SVE) combined with sand mixing is an alternative technology for remediating low-permeable soil polluted by organic contaminants. In this study, a T-SVE apparatus with a large heating cylinder was constructed for exploring removal mechanisms of typical petroleum hydrocarbons of <i>n</i>-C<sub>11</sub> and C<sub>13−16</sub> alkanes, and dynamics of heat propagation within soils during T-SVE operation was simulated by CMG-STARS software. After 6 days of T-SVE, most of the soil concentration-gradient curves of <i>n</i>-alkanes almost coincided with their isothermal contours, suggesting the crucial role of heat conductivity on T-SVE remediation efficiency. The instantaneous concentration of <i>n</i>-alkanes in extracted gas showed great fluctuations, and higher than 90% of spiked <i>n</i>-alkanes was removed from soils. <i>n</i>-alkanes were more easily eliminated from soil with lower organic matter due to the less retention ratio despite the trivial impact of organic matter on heat transfer. By contrast, the higher soil moisture adopted in the study retarded heat transfer in the initial 2 days due to thermal consumption induced by water evaporation. During the last 4 days, however, the average temperature of more humid soil was obviously elevated, especially in the zones receiving less energy input. It was attributed to the fact that soil temperature was mainly determined by heat conduction, and soil pores still occupied by water were more beneficial for heat conduction, leading to the promoted evaporation of <i>n</i>-alkane and therefore eventual remediation efficiency. Suitable original soil moisture is important for T-SVE remediating low-permeable soil combined with sand mixing.</p>\",\"PeriodicalId\":14121,\"journal\":{\"name\":\"International Journal of Environmental Research\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.6000,\"publicationDate\":\"2024-07-24\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"International Journal of Environmental Research\",\"FirstCategoryId\":\"93\",\"ListUrlMain\":\"https://doi.org/10.1007/s41742-024-00639-w\",\"RegionNum\":4,\"RegionCategory\":\"环境科学与生态学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"ENVIRONMENTAL SCIENCES\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Journal of Environmental Research","FirstCategoryId":"93","ListUrlMain":"https://doi.org/10.1007/s41742-024-00639-w","RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ENVIRONMENTAL SCIENCES","Score":null,"Total":0}
The Mechanism for Remediation of Low-Permeable Soil Contaminated with Petroleum Hydrocarbons by Thermally-Enhanced Soil Vapor Extraction Combined with Sand Mixing
Thermally-enhanced soil vapor extraction (T-SVE) combined with sand mixing is an alternative technology for remediating low-permeable soil polluted by organic contaminants. In this study, a T-SVE apparatus with a large heating cylinder was constructed for exploring removal mechanisms of typical petroleum hydrocarbons of n-C11 and C13−16 alkanes, and dynamics of heat propagation within soils during T-SVE operation was simulated by CMG-STARS software. After 6 days of T-SVE, most of the soil concentration-gradient curves of n-alkanes almost coincided with their isothermal contours, suggesting the crucial role of heat conductivity on T-SVE remediation efficiency. The instantaneous concentration of n-alkanes in extracted gas showed great fluctuations, and higher than 90% of spiked n-alkanes was removed from soils. n-alkanes were more easily eliminated from soil with lower organic matter due to the less retention ratio despite the trivial impact of organic matter on heat transfer. By contrast, the higher soil moisture adopted in the study retarded heat transfer in the initial 2 days due to thermal consumption induced by water evaporation. During the last 4 days, however, the average temperature of more humid soil was obviously elevated, especially in the zones receiving less energy input. It was attributed to the fact that soil temperature was mainly determined by heat conduction, and soil pores still occupied by water were more beneficial for heat conduction, leading to the promoted evaporation of n-alkane and therefore eventual remediation efficiency. Suitable original soil moisture is important for T-SVE remediating low-permeable soil combined with sand mixing.
期刊介绍:
International Journal of Environmental Research is a multidisciplinary journal concerned with all aspects of environment. In pursuit of these, environmentalist disciplines are invited to contribute their knowledge and experience. International Journal of Environmental Research publishes original research papers, research notes and reviews across the broad field of environment. These include but are not limited to environmental science, environmental engineering, environmental management and planning and environmental design, urban and regional landscape design and natural disaster management. Thus high quality research papers or reviews dealing with any aspect of environment are welcomed. Papers may be theoretical, interpretative or experimental.