title: Two-compartment sorption of phenanthrene on eight soils with various organic carbon contents.
abstract: Sorption characteristics of phenanthrene (PHE) were studied on eight soils with organic carbon contents spanning over an order of magnitude using phase distribution relationships (PDRs) at 1 h, 48 h, and 720 h contact times. A new algebraic method was employed to describe the sorption characteristics at different time intervals (between 1 h and 48 h, and 1 h and 720 h). It was found that nonlinearity increased with increasing contact time and sorption that occurred in the subsequent time interval following the initial 1 h exhibited stronger isotherm nonlinearity. Sorption coefficients were positively correlated with the organic carbon contents of the soils. Detailed sorption dynamics were also examined on these soils. A two-compartment, first-order model was used to describe the sorption dynamics. The rate constants of the two compartments differed 18-170 times, suggesting the dissimilar sorption behaviors of the mathematically separated compartments. These two compartments were labeled fast and slow sorption compartment according to the rate constants. Calculation showed that the fast compartment accounted for over 80% of the overall sorption at the initial 1 h, while the slow compartment predominated the total sorption in the following 47 h. By combining the discussion of PDRs and sorption dynamics, the contributions of the two compartments to linear and nonlinear sorption were differentiated. The slow sorption compartment made a major contribution to nonlinear sorption and possibly to sequestration of organic pollutants by these soils.
authors.affiliation: Laboratory for Earth Surface Processes, College of Environmental Sciences, Peking University, Beijing 100871, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Pan
authors.forename: Baoshan
authors.initials: B
authors.lastname: Xing
authors.forename: Wenxin
authors.initials: W
authors.lastname: Liu
authors.forename: Shu
authors.initials: S
authors.lastname: Tao
authors.forename: Xiumei
authors.initials: X
authors.lastname: Lin
authors.forename: Yanxv
authors.initials: Y
authors.lastname: Zhang
authors.forename: Huishi
authors.initials: H
authors.lastname: Yuan
authors.forename: Hancheng
authors.initials: H
authors.lastname: Dai
authors.forename: Xianming
authors.initials: X
authors.lastname: Zhang
authors.forename: Yang
authors.initials: Y
authors.lastname: Xiao
mesh_terms: D000327:Adsorption; D007700:Kinetics; D008433:Mathematics; D008956:Models, Chemical; D009930:Organic Chemicals / Q000032:analysis / Q000737:chemistry*; D010616:Phenanthrenes / Q000737:chemistry*; D012987:Soil / Q000032:analysis*; D012989:Soil Pollutants / Q000737:chemistry*; D013997:Time Factors
chemical_list: D009930:Organic Chemicals; D010616:Phenanthrenes; D012987:Soil; D012989:Soil Pollutants; C031181:phenanthrene