砂柱中铁锰的淋溶淀积及其对Pb（Ⅱ）和Cd（Ⅱ）的吸附特征

夏 彪; 尹兰果; 陈 斌; 黄 丽

文章摘要

夏彪,尹兰果,陈斌,黄丽.砂柱中铁锰的淋溶淀积及其对Pb（Ⅱ）和Cd（Ⅱ）的吸附特征[J].农业环境科学学报,2014,33(2):345-351.

砂柱中铁锰的淋溶淀积及其对Pb（Ⅱ）和Cd（Ⅱ）的吸附特征

Leaching and Deposition of Fe and Mn in Sand Column and Their Adsorption Characteristics of Pb（Ⅱ） and Cd（Ⅱ）

DOI：10.11654/jaes.2014.02.020

中文关键词: 砂柱铁锰淀积淋溶 Pb（Ⅱ） Cd（Ⅱ）等温吸附

英文关键词: sand column iron-manganese deposition leaching Pb（Ⅱ） Cd（Ⅱ） isothermal adsorption

基金项目:

作者	单位
夏彪	华中农业大学农业部长江中下游耕地保育重点实验室，武汉 430070
尹兰果	华中农业大学农业部长江中下游耕地保育重点实验室，武汉 430070
陈斌	华中农业大学农业部长江中下游耕地保育重点实验室，武汉 430070
黄丽	华中农业大学农业部长江中下游耕地保育重点实验室，武汉 430070

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中文摘要:

以不同浓度（0~0.04 mol·L-1）的FeSO4和MnCl2溶液淋溶白云石砂柱50次，形成砂粒表面铁锰氧化物胶膜，分析其中铁锰氧化物的淀积以及胶膜对Pb（Ⅱ）、Cd（Ⅱ）的等温吸附特征。研究结果表明：（1）当淋溶液的铁浓度为0.04 mol·L-1时，随着淋溶液中锰浓度的增加，砂粒表面胶膜的游离锰和非晶形锰含量呈增加趋势，而游离铁和非晶形铁含量的变化规律不明显；原子吸收光谱（AAS）和能谱（EDS）分析表明，砂粒表面游离铁和非晶形铁的淀积量均显著高于锰氧化物的。（2）扫描电镜（SEM）图像表明，铁锰在砂粒表面呈球形或板状淀积，分布不规则。（3）砂粒表面铁锰胶膜对Pb（Ⅱ）拟合的最大吸附量远大于对Cd（Ⅱ）的，最大时为Cd（Ⅱ）的8.43倍。（4）Cd（Ⅱ）的最大吸附量与砂粒表面游离铁和非晶形铁的含量呈显著正相关，说明铁的淀积对重金属Cd（Ⅱ）的吸附起了重要作用；但Pb（Ⅱ）的最大吸附量与游离和非晶形铁锰都没有显著的相关性。

英文摘要:

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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