Enhanced and irreversible sorption of pesticide pyrimethanilby soil amended with biochars
Xiangyang Yu , Ligang Pan , Guangguo Ying , Rai S. Kookana
DOI:
Received June 14, 2009,Revised September 21, 2009, Accepted , Available online
Volume 22,2010,Pages 615-620
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Biochar derived from partial combustion of vegetation is ubiquitous and potentially e ective in sequestration of environmental
contaminants. Biochars were prepared by burning of red gum (Eucalyptus spp.) woodchips at 450 and 850°C (labeled as BC450 and
BC850). These two biochars were found to possess markedly di erent properties in terms of surface area and porosity. Short-term
equilibration tests (24 hr) were conducted to assess the sorption-desorption behavior of pyrimethanil in the soil amended with various
amounts of biochar of each type, with a special focus on the desorption behavior of the sorbed pesticide through four times successive
desorption by dilution. Sorption coe cient and isotherm nonlinearity of the amended soils progressively increased with the content of
biochar in the soil. Biochar BC850 with higher surface area and microporosity showed a stronger e ect on the reversibility of sorption
pesticide. The soils amended with 5% BC450 and 1% BC850 had nearly the same sorption capacity for pyrimethanil; however, their
desorption processes were very di erent with 13.65% and 1.49% of the sorbed pesticide being released, respectively. This study
suggested that biochar in soil could be an important factor for immobilization of a pesticide and thus a ecting its environment fate in
soil.
