Interaction mechanisms of organic contaminants with burnedstraw ash charcoal
Wenhai Huang , Baoliang Chen
DOI:
Received October 05, 2009,Revised May 28, 2010, Accepted , Available online
Volume 22,2010,Pages 1586-1594
- Summary
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Black carbons (e.g., charcoal) have a great impact on the transport of organic contaminants in soil and water because of its
strong a nity and ubiquity in the environment. To further elucidate their interaction mechanism, sorption of polar (p-nitrotoluene,
m-dinitrobenzene and nitrobenzene) and nonpolar (naphthalene) aromatic contaminants to burned straw ash charcoal under di erent
de-ashed treatments were investigated. The sorption isotherms fitted well with Freundlich equation, and the Freundlich N values
were all around 0.31–0.38, being independent of the sorbate properties and sorbent types. After sequential removal of ashes by acid
treatments (HCl and HCl-HF), both adsorption and partition were enhanced due to the enrichment of charcoal component. The separated
contribution of adsorption and partition to total sorption were quantified. The e ective carbon content in ash charcoal functioned as
adsorption sites, partition phases, and hybrid regions with adsorption and partition were conceptualized and calculated. The hybrid
regions increased obviously after de-ashed treatment. The linear relationships of Freundlich N values with the charring-temperature of
charcoal or biochar (the charred byproduct in biomass pyrolysis) were observed based on the current study and the cited publications
which included 15 di erent temperatures (100–850°C), 10 kinds of precursors of charcoal/biochar, and 10 organic sorbates.
