title: Effect of heat treatment on sorption of polar and nonpolar compounds to montmorillonites and soils.
abstract: Batch sorption isotherms of 1,3,5-trichlorobenzene, 1,3,5-trinitrobenzene, and tetracycline to organic-free montmorillonites and soils receiving heat treatment (375°C for 24 h) were compared with those to unheated sorbents. Sorption of the nonpolar 1,3,5-trichlorobenzene to soil was lowered after the removal of humus by heating, consistent with the mechanism of hydrophobic partition into organic matter. For 1,3,5-trinitrobenzene, the enhanced sorption to heated soils was attributed to specific interactions with exchangeable cations facilitated by heating-induced irreversible partial dehydration of the clay interlayer. For tetracycline, an additional mechanism for sorption enhancement could be due to increased exposure of strong complexation sites on clay minerals after removal of the humic coating. These hypotheses were supported by the sorption data to heated and unheated Na-, K-, and Cs-saturated montmorillonites. The combustion method is commonly adopted to measure the content of black carbon in soils and sediments. However, findings from the present study indicate that combustion may greatly modify the structural properties of clay minerals, leading to misinterpreted sorption contributions of different soil components to sorption of polar or ionic compounds.
authors: Nanjing University, Jiangsu, China.
authors: Dan
authors: D
authors: Lv
authors: Yuqiu
authors: Y
authors: Wan
authors: Xin
authors: X
authors: Shi
authors: Huaizhou
authors: H
authors: Xu
authors: Wei
authors: W
authors: Chen
authors: Dongqiang
authors: D
authors: Zhu
mesh_terms: D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D002722:Chlorobenzenes / Q000737:chemistry; D004785:Environmental Pollutants / Q000737:chemistry*; D006358:Hot Temperature; D012987:Soil / Q000737:chemistry*; D013752:Tetracycline / Q000737:chemistry; D014301:Trinitrobenzenes / Q000737:chemistry
chemical_list: D002722:Chlorobenzenes; D004785:Environmental Pollutants; D012987:Soil; D014301:Trinitrobenzenes; D001546:Bentonite; C029222:sym-trinitrobenzene; C500273:1,3,5-trichlorobenzene; D013752:Tetracycline