EFFECTS OF CORN COB BIOCHAR ON THE ADSORPTION OF ATRAZINE IN SOIL

Biochar is a stable carbon-rich product which can decrease organic pollutant contaminations in soil. In this study, corn cob carbonized at 400°C (C400) and 700°C (C700) were taken as materials to study the effect of biochar on atrazine adsorption in soil using a batch equilibrium method. The kinetics of atrazine in soils was completed in two steps: a fast adsorption and a slow adsorption, and equilibrium were reached after 24 h of adsorption. The Freundlich model was well fitted to the adsorption process in the biomass carbon in the soil, and the correlation coefficient value was between 0.986–0.999. With addition of 1.0% C400 biochar, the adsorption constant (log Kf) was 1.30 times that of no-biochar soil, and addition of 1.0% C700 biochar produced an adsorption constant (log Kf) that was 6.28 times that of no-biochar soil. At the same addition ratio (1.0%), the adsorption coefficient (Kd) of C700 was 828 mL/g, 229 times that of C400 (3.62 mL/g). Corn cob biochar therefore has a clear ability to adsorb atrazine from trazine-contaminated soil and the adsorption capacity of C700 was significantly higher than C400. C700 was the best sorbent for atrazine removal because of its extremely high specific surface area.