Remediation of toluene-contaminated soils by sequential treatment: Soil vapor extraction systems and internal combustion engine units

IF 3.5 3区环境科学与生态学 Q2 ENVIRONMENTAL SCIENCES

Journal of contaminant hydrology Pub Date : 2025-03-08 DOI:10.1016/j.jconhyd.2025.104532

Zhengju Lyu, Weilong Zhou, Xiaolong Gao, Haowei Zheng, Jianli Jia

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引用次数: 0

Abstract

This paper reports soil vapor extraction (SVE) systems and internal combustion engine (ICE) units to remediate soils contaminated with toluene. Response surface methodology (RSM) was used to evaluate the influence of toluene concentration, air flow rate and soil water content on SVE systems, thus to identify the optimal conditions for SVE systems. ICE units were used to treat the SVE off-gas extracted from toluene-contaminated soils, and the performance in removing toluene was effectively evaluated. Furthermore, the pulsed operation of SVE systems and the thermal enhancement with ICE off-gas were explored, and the positive effects on remediation efficiency were analyzed. The remediation experiments performed in toluene-contaminated soils allowed concluding that the optimal desorption time of toluene was 615 min with the toluene concentration of 0.3 g/kg, air flow rate of 10 L/min and soil water content of 9 %. The ICE units showed that the main components of ICE off-gas were CO, CO₂ and hydrocarbon (HC). After 25 min, the concentration of HC decreased to 140 ppm, and the volume fractions of CO and CO₂ were 0.3 % and 9.5 % respectively. ICE units had consistently achieved toluene destruction and removal efficiencies (DREs) of 100 %. Moreover, the pulsed operation and thermal enhancement promoted equilibrium partitioning of toluene between the soil matrix and the gas phase, thereby facilitating the desorption of toluene, which decreased the required time and energy needed for the remediation. This study provides theoretical support for system design and applicability assessment of SVE systems and ICE units in the remediation of contaminated soils.

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通过序贯处理来修复受甲苯污染的土壤：土壤蒸气萃取系统和内燃机装置

本文报道了土壤蒸汽萃取（SVE）系统和内燃机（ICE）装置修复被甲苯污染的土壤。采用响应面法（RSM）评价了甲苯浓度、空气流速和土壤含水量对SVE系统的影响，从而确定了SVE系统的最佳条件。采用ICE装置处理甲苯污染土壤的SVE废气，并对其去除甲苯的效果进行了有效评价。在此基础上，探讨了SVE系统的脉冲操作和ICE废气的热强化，并分析了其对修复效率的积极影响。通过对甲苯污染土壤的修复实验得出，在甲苯浓度为0.3 g/kg、空气流速为10 L/min、土壤含水量为9%的条件下，甲苯的最佳解吸时间为615 min。内燃机装置研究表明，内燃机废气主要成分为CO、CO2和碳氢化合物（HC）。25 min后，HC的浓度降至140 ppm， CO和CO2的体积分数分别为0.3%和9.5%。ICE装置一直实现100%的甲苯破坏和去除效率（DREs）。此外，脉冲操作和热增强促进了甲苯在土壤基质和气相之间的平衡分配，从而促进了甲苯的解吸，从而减少了修复所需的时间和能量。本研究为SVE系统和ICE单元在污染土壤修复中的系统设计和适用性评估提供了理论支持。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of contaminant hydrology 环境科学-地球科学综合

CiteScore

6.80

自引率

2.80%

发文量

129

审稿时长

68 days

期刊介绍： The Journal of Contaminant Hydrology is an international journal publishing scientific articles pertaining to the contamination of subsurface water resources. Emphasis is placed on investigations of the physical, chemical, and biological processes influencing the behavior and fate of organic and inorganic contaminants in the unsaturated (vadose) and saturated (groundwater) zones, as well as at groundwater-surface water interfaces. The ecological impacts of contaminants transported both from and to aquifers are of interest. Articles on contamination of surface water only, without a link to groundwater, are out of the scope. Broad latitude is allowed in identifying contaminants of interest, and include legacy and emerging pollutants, nutrients, nanoparticles, pathogenic microorganisms (e.g., bacteria, viruses, protozoa), microplastics, and various constituents associated with energy production (e.g., methane, carbon dioxide, hydrogen sulfide). The journal''s scope embraces a wide range of topics including: experimental investigations of contaminant sorption, diffusion, transformation, volatilization and transport in the surface and subsurface; characterization of soil and aquifer properties only as they influence contaminant behavior; development and testing of mathematical models of contaminant behaviour; innovative techniques for restoration of contaminated sites; development of new tools or techniques for monitoring the extent of soil and groundwater contamination; transformation of contaminants in the hyporheic zone; effects of contaminants traversing the hyporheic zone on surface water and groundwater ecosystems; subsurface carbon sequestration and/or turnover; and migration of fluids associated with energy production into groundwater.