• 关键词：土壤  铁锰结核  氧化锰矿物  氧化还原  铬

• 基金项目：国家自然科学基金资助项目(批准号:49771049);华中农业大学科技创新基金

• 谭文峰
• 华中农业大学农业部亚热带土壤资源与环境重点实验室,武汉 430070

• 刘凡
• 华中农业大学农业部亚热带土壤资源与环境重点实验室,武汉 430070

• 李学垣
• 华中农业大学农业部亚热带土壤资源与环境重点实验室,武汉 430070

• 贺纪正
• 华中农业大学农业部亚热带土壤资源与环境重点实验室,武汉 430070

• 胡红青
• 华中农业大学农业部亚热带土壤资源与环境重点实验室,武汉 430070

• 摘要：用X射线光电子能谱、氧化还原平衡等技术,研究了我国几种土壤铁锰结核对Cr(Ⅲ)的氧化特性.结果表明:供试土壤铁锰结核中的锰为+3、+4价态.黄棕壤(N2-1)、黄褐土(N4-1)、砂姜黑土(N5-1)铁锰结核中氧化锰矿物对Cr(Ⅲ)的最大氧化量分别为627.1、723.6、478.6mmolkg(MnO₂),其中水钠锰矿锂硬锰矿组合对Cr(Ⅲ)的氧化量比钙锰矿锂硬锰矿组合的大;对Cr(Ⅲ)的氧化百分率随Pb吸附量的增加而降低至稳定,随Cd、P离子吸附量增大的变幅较小.土壤铁锰结核中的氧化锰矿物对Cr(Ⅲ)的氧化量与氧化锰矿物类型、锰的价态、吸附态阳离子种类及表面位点亲和性等因素有关.

• Abstract：X ray photoelectron spectroscopy (XPS) and equilibrium technique of redox were used to investigate redox characteristics between several Fe Mn nodules in soils and Cr(Ⅲ). The results are:the valence states of Mn in Fe-Mn nodules are +3 and +4. Maximum amounts of Cr(Ⅲ) oxidized by Mn oxide minerals of Fe-Mn nodules in yellow-brown soil (N2-1), yellow-cinnamon soil (N4-1) and Shajiang black soil (N5-1) are 627.1, 723.6 and 478.6mmol/kg(MnO₂), respectively. The amounts of Cr(Ⅲ) oxidized by association of birnesite and lithiophorite are higher than those by association of todorokite and lithiophorite in Fe-Mn nodules. The differences are related to structural characteristics of Mn oxide minerals and valance of Mn in Fe Mn nodules. The ratio of Cr(Ⅲ) oxidized by Fe Mn nodule decreases slightly as the amounts of Cd and P ions adsorbed on Fe Mn nodules increases, however, the ratio decreases remarkably as the amount of Pb ion adsorbed on Fe Mn nodules increases. Redox characteristics between Fe Mn nodules and Cr(Ⅲ)are affected by type of adsorbed ion and Mn oxide mineral, valance of Mn and affinity of surface site.

• Key words：soil  Fe-Mn nodule  Mn oxide mineral  redox  Cr

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