Biochar Production, Modification, and Its Uses in Soil Remediation: A Review

Abstract

Soil remediation is the act of removing or reducing the availability of contaminants from soil. In the case of agriculture, soil remediation targets the removal of pollutants, including residual pesticides/herbicides, hydrocarbons, and toxic heavy metals. This is often done by chemical treatments with multiple washes or excavation of soils, which are costly and time-consuming. Therefore, finding cheaper, less time-consuming remediation methods is highly desirable. In this review, we will examine the addition of biochar as an effective method of soil remediation. Biochar is a carbon-rich material derived from burning biomass in an oxygen-limited environment with benefits such as high cation exchange capacity, large surface area, neutral to alkaline pH, and some nutritional content. Biochar can also be a sanctuary for naturally occurring microbes and can be inoculated with specific microbes for contaminant breakdown. The physical and chemical characteristics of biochar combined with biological activity can help bind and promote the degradation process of these contaminants without the need to use hazardous chemicals or remove a large amount of soil. Biochar, and the microbes they house, can bind these contaminants through electrostatic attraction, sorption, precipitation, and bioaccumulation, reducing their availability to the surrounding environment. However, the characteristics of biochar and its biological activity can vary depending on the feedstock, pyrolysis temperature, and time the mass is heated. Therefore, some of these traits can be modified through pre or post-treatments to suit their intended use, allowing for biochar to be made for specific contaminants. This review hopes to increase interest in biochar research to fill in missing gaps of information that could make biochar production cheaper and more consistent, as it offers a greener way to clean up contaminants in soil.

Emerging contaminants: A One Health perspective

“… 533 Biochar, recognized as an environmentally friendly material, not only plays a pivotal role in alleviating soil contamination but also enhances the properties of degraded soil, serving as an ideal habitat for beneficial microbes. 534 , 535 Ultrasonic waves are effective in destroying the structure of algae cells through the mechanical vibration effect. 536 Additionally, physical methods such as manual salvage or mechanical algae removal equipment can be used to prevent the accumulation of cyanobacteria.…”

Biochar as an Environment-Friendly Alternative for Multiple Applications

“…This complexity poses a barrier to large-scale private investments in biochar production. To advance biochar production and deployment, careful consideration of these conditions is imperative [112,113]. To navigate these complexities, collaborative efforts between scientists and environmentalists and a comprehensive evaluation of the economic costs of biochar production focusing on both costs and benefits are required.…”

Management of a contaminated mine soil: Effect of soil water content on antimony and arsenic immobilisation by iron‐based amendments and biochar composites

“…Because BC has generally a negative surface charge, it alone tends to increase Sb/As leaching from soil because of, for example, direct electrostatic surface repulsion of the negatively charged Sb/As molecules (Ahmad et al, 2017), or because of its indirect effect of increasing soil pH (Lomaglio et al, 2017). To overcome the disadvantages of pure BC, specific designer BC composite sorbents are being developed with specific properties for the removal of target pollutants (Blenis et al, 2023; Rajapaksha et al, 2016; Thapar Kapoor & P. Shah, 2022). For example, (nanoscale) iron loaded BC composites (i.e.…”