Effect of forestry-waste biochars on adsorption of Pb(II) and antibiotic florfenicol in red soil.

Biochars derived from Pinus massoniana and Cunninghamia lanceolata trunks (abbreviated as PB and CB, respectively) were used to investigate their potential capabilities to improve lead (Pb(II)) and antibiotic florfenicol (FLO) immobilization in soil. Results shows that, after incubation for 60 days, the maximum adsorption capacities (Q ) of biochar-treated soils (soil-PB and soil-CB) for Pb(II) was increased by 27 and 14 %, respectively, compared with pristine soil sample. In the case of FLO, however, the Q of biochar-treated soils were enhanced by 266 and 206 % for soil-PB and soil-CB, respectively. The increased Pb(II) adsorption was mainly due to the enhanced interactions between Pb(II) and oxygen-containing functional groups and aromatic structures in biochars. Whereas, the improvement of FLO adsorption was achieved through electrostatic interaction, hydrogen bonding, and van der Waals forces interactions between FLO molecule and biochars. Regardless of the similarities in chemical compositions between two biochars, significantly higher surface area and total pore volume of PB than CB biochar may be the key factors accounting for the differences in adsorption efficiencies for Pb(II) and FLO between Soil-PB and Soil-CB.