Chem. J. Chinese Universities ›› 2013, Vol. 34 ›› Issue (3): 634.doi: 10.7503/cjcu20120598

• Physical Chemistry • Previous Articles     Next Articles

Thermodynamic Characteristics and Mechanisms of Estrogen Hormones Adsorption on Soil Doped with MnO2

LI Yu, ZHANG Chen, LIU Jian-lin, LI Xiao-Peng, WANG Xia-Jiao   

  1. Research Academy of Energy and Environmental Studies, Key Laboratory of Regional Energy Systems Optimization of Ministry of Education, North China Electric Power University, Beijing 102206, China
  • Received:2012-06-25 Online:2013-03-10 Published:2013-02-18

Abstract:

Adsorption conditions of multiple estrogen compounds on soil doped MnO2 were optimized by factorial experiment design. The thermodynamic characteristics and thermodynamic properties in the course of estrogen hormones adsorption on soil doped MnO2 were investigated by Langmuir adsorption isotherm and Gibbs equation. Finally, the adsorption mechanism of multiple estrogen compounds on soil doped MnO2 was explored by Fourier transform infrared spectroscopy and liquid chromatography-mass spectrometry technology, and the main degradation products were analyzed. The experiment results showed that estrogen concentration and MnO2 had significant positive effects on adsorption capacity of estrogen compounds on soil doped MnO2, and the amount of soil had negative effect. The pH value had positive effect on the adsorption capacity of E2 but negative effect on E3 adsorption. The adsorption behavior of estrogen compounds on soil doped MnO2 could be described by Langmuir adsorption isotherm(R2>0.99). All the calculated ΔG values of estrogen hormones in the course of adsorption were negative, and their absolute values were less than 40 kJ/mol. It demonstrated that the adsorption of the estrogen hormones on soil is a spontaneous physical adsorption process. The adsorption of estrogen hormones on soil doped MnO2 both had physical adsorption and chemical degradation. The degradation reaction was improved which was probably resulted from the enhancement of conductive property of MnO2 through organic carbons in soil. Therefore, MnO2 can be used as a stabilization agent for the soil, which could effectively prevent secondary pollution of estrogen hormones caused by desorption.

Key words: Soil, Estrogen compounds, Manganese dioxide, Thermodynamic adsorption, Immobilization

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