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| Leaching and Deposition of Fe and Mn in Sand Column and Their Adsorption Characteristics of Pb（Ⅱ） and Cd（Ⅱ） |
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| KeyWord:sand column; iron-manganese deposition; leaching; Pb（Ⅱ）; Cd（Ⅱ）; isothermal adsorption |
| Author Name | Affiliation | | XIA Biao | Key Laboratory of Arable Land Conservation（Middle and Lower Reaches of Yangtze River）, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China | | YIN Lan-guo | Key Laboratory of Arable Land Conservation（Middle and Lower Reaches of Yangtze River）, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China | | CHEN Bin | Key Laboratory of Arable Land Conservation（Middle and Lower Reaches of Yangtze River）, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China | | HUANG Li | Key Laboratory of Arable Land Conservation（Middle and Lower Reaches of Yangtze River）, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China |
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| Abstract: |
| Dynamics of Fe and Mn oxides have important impacts on the behaviors of Pb and Cd in soils. In this paper, deposition of iron-manganese oxides and their isothermal adsorption of Pb（Ⅱ） and Cd（Ⅱ） were studied using Dolomite sand column. Cutans of iron-manganese oxides were generated by leaching different concentrations（0~0.04 mol·L-1） of FeSO4 and MnCl2 solution through the column for 50 times. At 0.04 mol·L-1 of Fe concentration in the leaching solution, free and amorphous manganese contents in the cutans on the sand surface increased with Mn concentrations in the leaching solution, but free and amorphous iron contents in the cutans had no obvious changes. Atomic absorption spectroscopy（AAS） and Energy Dispersive Spectrometer（EDS） analysis showed that the amounts of free and amorphous iron in the cutans were higher than free and amorphous Mn oxides. Scanning electron microscopy（SEM） images showed that the forms of iron and manganese oxides deposited on the surface of the sand appeared spherical or platy shapes and their distributions were irregular. The maximum adsorption of Pb（Ⅱ） and Cd（Ⅱ） generally increased with iron and manganese concentrations in the leached solution, with the maximum adsorbed Pb（Ⅱ） higher than that of Cd（Ⅱ）, with the greatest difference of 8.43 times. The maximum adsorption of Cd（Ⅱ）had significant positive correlation with free and amorphous iron oxides on the sand surfaces, indicating an important role of iron deposited in the cutans in the adsorption of Cd（Ⅱ）, but the maximum adsorption of Pb（Ⅱ） had no correlation with free and amorphous iron-manganese oxides. |
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