Containment of emerging VOC pollutants by biochar

Air pollutants are known to be responsible for up to 8.9 million premature deaths per year across the world. Among the pollutions are, emerging organic pollutants such as volatile organic compounds (VOC) that pose significant global risk to human health and the environment. Contaminated lands by crude oil and petrochemical products are major source for the emission of VOCs in the world. Long-term solutions for remediation of VOC contaminations in soil and water are expensive and require advanced technologies. The challenge of access to affordable and practical solutions is particularly highlighted in the case of vast contaminated lands. Hence, the provision of a simple, affordable, easy-to-localise and environmentally sustainable solution is critical to contain the emission of harmful gases or contamination of the groundwater resources. This paper presents the results of a series of experimental investigations on efficiency and sustainability of biochar-based containment systems for VOC contaminated lands. A bespoke experimental setup was developed to study the kinetics of VOC sorption in biochar manufactured from a range of feedstock and pyrolysis temperatures. Sorption behaviour of pure and mixed VOC gases in biochar was investigated, and the effects of various parameters on the sorption capacity including material characteristics and environmental conditions were evaluated and dominant sorption mechanisms were identified. The results show that the uptake of VOC by biochar is mainly controlled by factors such as porous structure, surface chemistry and pore size distribution of adsorbents along with molecular properties of adsorbates.