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41.
Seunghun KANG Saikat Ghosh Baoshan XING 《中国地球化学学报》2006,25(B08):263-264
Soils are the largest carbon reservoir in the terrestrial system. Soils contain about three times more carbon than vegetation and twice as much as that present in the atmosphere. Soil organic matter (SOM) is very complex in composition and structure, formed of heterogeneous substances and generally associated with minerals in soils. SOM is classified as labile and stable fractions on the basis of residence time, determined not only by the chemical composition of SOM, but also by types of protection or bonds within soils. The stable carbon fraction is protected either physically or chemically. To understand the process of SOM stabilization, physicochemical properties of organic-mineral complexes were determined by Fourier transformed infrared (FTIR) with attenuated total reflectance (ATR) and diffuse reflectance (DRIFT), atomic force microscopy (AFM), and nuclear magnetic spectroscopy (NMR). Humic acids and carboxylic acids with relatively short carbon chains were used as sorbates, and goethite, kaolinite, and montmorillonite as adsorbents. Humic acid was fractionated during adsorption on the minerals, which was highly influenced by the characteristics of minerals. For instance, long-chain aliphatic carbon was likely to be adsorbed onto the surface of kaolinite and montmorillonite, while goethite surface attracted carboxylic functional groups of humic acid. 相似文献
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Yu LIU Huanyan XU 《中国地球化学学报》2006,25(B08):104-105
The sorption of aqueous cadmium on carbonate-hydroxyapatite (CHap) is a complicated non-homogeneous solid/water reaction, From kinetic point of view, it can be described by two stages: at the earlier stage, reaction rate is so fast that its kinetic course is intricate, and at the later stage, the rate of reaction becomes slow and the process of reaction accords with one order reaction kinetic equation. Experimental results show that the relationship between reaction rate constant kl and temperature T accords to Arrhenius Equation, and the activation energy of sorption (Ea) is 6.075 J/mol and frequency factor (A) is 220 s^-1. At the same time, reaction rate constant kl increases with decreasing Cd^2+ initial concentration, on the contrary, with increasing pH and CHap dosage. 相似文献
44.
Xia JIANG Xiangcan JIN Dongmei LIU 《中国地球化学学报》2006,25(B08):164-165
Seasonal variations of adsorption/desorption equilibrium were investigated by collecting overlying water and seasonal sediment from the Meiliang Bay, Taihu Lake, China. At the same time, seasonal variations of TP and P fractions' concentrations in the initial and end of adsorption experiment were also carried out. In addition, the effects of temperature on the P translocation process were also conducted and discussed. The following conclusions were obtained: The sequence of adsorption/desorption equilibrium concentrations of P at water-sediment interface was spring〈winter〈autumn. In sediment the concentrations of TP decline. Concentration P decreased with temperature. 相似文献
45.
矿物界面作用与环境工程材料 总被引:17,自引:1,他引:16
矿物水界面作用是环境地球化学研究的基础,它控制着世界淡水质量、土壤发生与发展、表生地质作用中元素迁移与富集等过程,是矿物环境工程材料的理论基础[1]。这是因为矿物水界面作用发生于矿物表面,许多环境工程材料是通过材料表面吸附(或共沉淀)作用去清除水... 相似文献
46.
几种粘土矿物对Pb^2+的吸附作用及其主要影响因素的探讨 总被引:10,自引:0,他引:10
对土壤中常见的三种粘土矿物对Pb^2+的附作用及其主要影响因素进行了探讨。结果表明,三种粘土矿物对Pb62+的吸附能力顺序为:蒙脱石-伊利石-高岭石.蒙脱石对Pv^2+的吸附受PH的强烈影响,PH高有利于Pb^2+的吸附。与蒙脱石形成复合体形式的有机化合物的存在不利于蒙脱石对Pb^2+的吸附。 相似文献
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SHI Hebin ZHONG Hong LIU Yu DENG Jinyang 《《地质学报》英文版》2007,81(3):517-522
This article reports a preliminary research on silicate-incorporated hydroxyapatite as a new environmental mineral used to remove cadmium ions from aqueous solutions. The silicate-incorporated hydroxyapatite was prepared by coprecipitation and calcining, and silicate was incorporated into the crystal lattice of hydroxyapatite by partial substitution of phosphate. The amount of cadmium ions removed by silicate-incorporated hydroxyapatite was significantly elevated, which was 76% higher than that of pure hydroxyapatite. But the sorption behavior of cadmium ions on silicate-incorporated hydroxyapatite was similar to that of pure hydroxyapatite. Morphological study revealed that silicate incorporation confined the crystal growth and increased the specific surface area of hydroxyapatite, which were in favor of enhancing the cadmium ion sorption capacity of the samples. Incorporation of silicate into hydroxyapatite seems to be an effective approach to improve the environmental property of hydroxyapatite on removal of aqueous cadmium ions. 相似文献
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50.
土壤对可溶性油的吸附作用及其影响因素分析 总被引:21,自引:0,他引:21
在沈(阳) 抚(顺) 灌区土-水-作物系统石油污染调查的基础上, 根据土壤非饱和带的结构和组成, 选择代表性的土壤剖面分别采集表土和底土, 分析土样的主要物理和化学性质, 系统测定不同土样对可溶性油吸附的动力学曲线和吸附等温线, 并分析了有机质、粘粒含量和含盐量对吸附作用的影响.结果表明, 土壤对可溶性油的吸附平衡时间为20~24h, 而且不同土样的吸附等温线均为直线型理想吸附.另外, 通过试验发现, 当水相中可溶性油低于一定浓度时, 不但不产生吸附, 反而使土壤中的残留油分释放出来. 相似文献