Pedosphere 20(1): 104--110, 2010
ISSN 1002-0160/CN 32-1315/P
©2010 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Effect of initial concentration on adsorption-desorption characteristics and desorption hysteresis of hexachlorobenzene in soils |
GAO Hong-Jian1,2 and JIANG Xin2 |
1 School of Resources and Environmental Science, Anhui Agricultural University, Hefei 230036 (China)
2 State Key Lab of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China)v |
| ABSTRACT |
| Adsorption and desorption are important processes that influence the transport, transformation, and bioavailability of hexachlorobenzene (HCB) in soils. To examine the adsorption-desorption characteristics of HCB, equilibrium batch experiments were carried out using two soils (red soil and paddy soil) with different initial HCB concentrations (0.25, 0.50, 0.75, 1.00, 1.50, 2.50, 3.50, and 5.00 mg L-1) by using 0.01 mol L-1 calcium chloride as the background solution. The successive desorption experiments (48, 96, 144, 192, and 240 h) were conducted after each adsorption equilibrium experiment. The results revealed that adsorption and desorption isotherms of HCB on two soils were nonlinear, which can be best described by the Freundlich equation with the square of the correlation coefficient (r2) ranging from 0.97 to 0.99. Desorption of HCB from the two soils exhibited hysteresis at all HCB concentrations because the Freundlich desorption coefficients were always higher than the Freundlich adsorption coefficients. The hysteretic effect was enhanced with increasing initial HCB concentration, and positive hysteresis was observed at different concentrations. |
| Key Words: Freundlich equation, sorption coefficients, sorption isotherms |
| Citation: Gao, H. J. and Jiang, X. 2010. Effect of initial concentration on adsorption-desorption characteristics and desorption hysteresis of hexachlorobenzene in soils. Pedosphere. 20(1): 104-110. |
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