Wang, Song, et al (2024) Volatile Organic Compounds (VOCs) in Soil: Transport Mechanisms, Monitoring, and Removal by Biochar-Modified Capping Layer. Coatings. https://doi.org/10.3390/coatings14030270

Industrialization and urbanization have led to a surge in industrial legacy contamination sites, posing a significant threat to soil health. Organic compounds, particularly volatile organic compounds (VOCs), contribute to soil pollution, demanding urgent attention. This comprehensive review explores the historical development, monitoring techniques, and removal methods of VOCs within soil, with a focus on biochar-modified capping layers.

The migration of VOCs in soil is governed by complex interactions, primarily convection-diffusion. To effectively address this issue, in situ monitoring techniques, including gas chromatography–mass spectrometry (GC-MS) and laser spectroscopy, are essential for identifying and quantifying VOCs. Current remediation technologies, such as thermal desorption and soil vapor extraction, are costly and carry risks of secondary contamination. The paper advocates for in situ treatment technologies, highlighting soil vapor extraction (SVE) as a commonly used method, albeit with limitations.

Recognizing the shortcomings of SVE, the review introduces the concept of a capping layer as an in situ remediation technique to control VOC emissions. BiocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More, a green and economically friendly material, emerges as a promising candidate for modifying the capping layer. Its unique attributes, including porosityPorosity of biochar is a key factor in its effectiveness as a soil amendment and its ability to retain water and nutrients. Biochar’s porosity is influenced by feedstock type and pyrolysis temperature, and it plays a crucial role in microbial activity and overall soil health. Biochar More and high surface area, make it effective for VOC adsorption and environmental remediation.

Despite extensive research on capping layers, the paper identifies a gap in systematic reviews. The goal is to provide researchers with a foundational understanding of VOCs, their transport mechanisms, monitoring technologies, and removal approaches. By emphasizing the potential of biochar-modified capping layers, the review aims to inspire advancements in environmental protection and soil pollution control, offering a sustainable solution to the global issue of VOC contamination.