Effect of bamboo biochar on pentachlorophenol leachability and bioavailability in agricultural soil

Abstract

In this study, bamboo biochar (BBC) was proposed as a practical carbonaceous material for the in situ remediation of organic pollutants. Column leaching experiments were used to evaluate the leachability of pentachlorophenol (PCP) in soil amended with BBC (0, 1, 2, and 5%; w/w). After leaching, the residual bioavailability of PCP in the soil column was determined by chemical extraction methods (methanol and distilled water). The results showed that compared to the control, the addition of 5% BBC decreased the cumulative leach-loss content of PCP by 42%, and also reduced PCP concentrations by 56 and 65% in methanol and distilled water extracts, respectively. Moreover, the linear leaching curves for the 10-h leaching time indicated that the rapid release process may be dependent on the continuous diffusion and partition mechanism. Regression analyses showed a significant (p<0.001) relationship between the BBC percentage and cumulative content of leached PCP, in addition, a significant relationship between BBC percentage and the chemical extraction of PCP with correlation coefficients (R(2)) greater than 0.9. Therefore, adding BBC to soil could prevent PCP further contamination such as bioavailability, surface or groundwater contamination through leaching.