Using Biochar for Remediation of Contaminated Soils

Abstract

In recent years, soil contamination has become a global environmental problem. Biochar is a porous and carbon-rich material produced from pyrolysis of biomass residues from agricultural and forestry production. It can be used to immobilize heavy metals and organic pollutants in soil through adsorption. Here we report results obtained from our recent studies focusing on the interactions between biochar and soil contaminants. Incubation and pot experiments were carried out to investigate the effect of biochar type, application rate, and particle size on soil properties, bioavailability, mobility, and redistribution of the heavy metals in soil and the accumulation of heavy metals in the plants. Batch equilibration method was used to explore the effect of biochar type, aging process, dosage, and soil organic carbon content on adsorption and desorption of organic pollutants (e.g., phthalic acid esters, or PAEs) in soil. Incubation and pot trials were conducted to evaluate the impact of biochar on the degradation and bioavailability of PAEs in soils. Our results demonstrate that biochar can potentially be used as soil amendment for remediation of soils contaminated with heavy metals and organic pollutants. The efficacy of biochar application on immobilization of contaminants varies with the type, application rate, and particle size of biochars, soil properties, and contaminant types.