title: Synergistic role of different soil components in slow sorption kinetics of polar organic contaminants.
abstract: We observed that the sorption kinetics of nitrobenzene and 2,4-dinitrotoluene (two model polar compounds) was significantly slower than that of 1,4-dichlorobenzene and phenanthrene (two model apolar compounds). The difference was attributable to the strong non-hydrophobic interactions between the polar molecules and soil. Interestingly, sorption kinetics of the polar sorbates to the soil organic matter-free soil, humic/fulvic acid-free soil, and extracted humic acids was very fast, indicating that different soil components played a synergetic role in the observed slow kinetics. We propose that slow sorption kinetics of highly polar sorbates stems mainly from the strong specific interactions (H-bonding, electron donor-acceptor interactions, etc.) with humic/fulvic acids; such specific interactions occur when sorbate molecules diffuse through humic/fulvic acids coiled, in relatively compressed confirmations, within the complex, tortuous, and porous soil matrices formed by mineral grains/particles and soil organic matter.
authors.affiliation: College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin 300071, China; School of Environment, Northeast Normal University, Jilin, China.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Zhang
authors.forename: Lei
authors.initials: L
authors.lastname: Hou
authors.forename: Dongqiang
authors.initials: D
authors.lastname: Zhu
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
mesh_terms: D000327:Adsorption; D001578:Benzopyrans / Q000737:chemistry; D002722:Chlorobenzenes / Q000737:chemistry*; D004136:Dinitrobenzenes / Q000737:chemistry; D006812:Humic Substances; D007700:Kinetics; D008903:Minerals / Q000737:chemistry; D008956:Models, Chemical; D009578:Nitrobenzenes / Q000737:chemistry; D010616:Phenanthrenes / Q000737:chemistry*; D016062:Porosity; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry*
chemical_list: D001578:Benzopyrans; D002722:Chlorobenzenes; D004136:Dinitrobenzenes; D006812:Humic Substances; D008903:Minerals; D009578:Nitrobenzenes; D010616:Phenanthrenes; D012987:Soil; D012989:Soil Pollutants; C031181:phenanthrene; C016403:2,4-dinitrotoluene; C018511:4-dichlorobenzene; C036077:nitrobenzene; C005023:fulvic acid
keywords: Non-hydrophobic interactions; Polar organic contaminants; Slow sorption kinetics; Soil components