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71.
铜(II)在高岭石表面的吸附   总被引:12,自引:2,他引:10  
在天然天体系中,铜、铅、镉等重金属元素的形态分布、归宿和生物有放性强烈取决于重金属元素在水体颗粒物表面的分配趋势,本文对铜(II)在常见的重要粘土矿物-高岭石表面的吸附进行了实难和模式研究,结果表明,在同时考虑自由水合离子Cu^2+和羟基金属郭子CuOH^+与高岭石表面络合的情况下,单一表面基团、无静电表面络合模式能很好地描述酮(II)的吸附行为。拟合得到的CuOH^+的络合常数比Cu^2+的大得  相似文献   
72.
海泡石坡缕石的有机吸附研究   总被引:4,自引:1,他引:3  
本研究采用红外光谱分析、X射线衍射分析和电泳等方法对坡缕石和海泡石吸附有机气体进行了研究。实验表明,这种吸附是因静电力的作用而产生的。矿物表面的吸附水可减弱静电力的作用。坡缕石、海泡石对有机气体的吸附量与气体温度、蒸气压、气体分子偶极矩、样品纯度、矿物结晶有关。温度升高,气体分子热运动将加剧,吸附数量随之减少;若气体分子偶极矩加大,则吸附量增加;增大蒸气压能提高气体分子与矿物微粒间的接触频率,从而  相似文献   
73.
本文利用高表面活性矿物蒙脱石、蛭石、沸石在一定的介质条件下对Zn2 +进行吸附实验研究。蒙脱石和蛭石对Zn2 +的等温吸附线呈双“S”型 ,而沸石对Zn2 +的等温吸附线则呈“Langmuir”型。三种矿物对Zn2 +的吸附容量大小顺序为 :蒙脱石 >蛭石 >沸石。运用粉晶X射线衍射、红外光谱、差热及热重分析等技术对矿物及矿物吸附Zn2 +后的结构特征进行了研究。结果表明 ,蒙脱石吸附锌后其层间域中吸附锌大量水解形成新的物相 ,而蛭石与沸石吸附锌后水解很少。这为利用高表面活性矿物控制和治理环境污染及其可循环利用提供了理论依据。  相似文献   
74.
A new method for solving the transport equation based on the management of a large numbe of particles in a discretized 2-D domain is presented. The method uses numerical variables to represent the number of particles in a given mesh and is more complex than the 1-D problem. The first part of the paper focuses on the specific management of particles in a 2-D problem. The method also would be valid for three dimensions as long as the medium can be modeled similar to a layered system. As the particles are no longer tracked individually, the algorithm is fast and does not depend on the number of particles present. The numerical tests show that the method is nearly numerical dispersion free and permits accurate calculations even for simulations of low-concentration transport. Because each mesh is considered as a closed system between two successive time steps, it is easy to add adsorption phenomenon without any problem of numerical stability. The model is tested under conditions that are extremely demanding for its operating mode and gives a good fit to analytical solutions. The conditions in which it can be used to best advantage are discussed.  相似文献   
75.
斜纤蛇纹石的管道水特征研究   总被引:1,自引:1,他引:1  
河北涞源斜纤蛇纹石为较小的中孔纳米管材料,通过氮吸脱附法、差热和热重曲线分析法、差示扫描量热分析法和红外光谱分析法,主要分析了其纳米管中管道水特征,明确了管道水作为有效加速剂和载体的作用,对以及对抗拉强度和介电常数的影响。研究表明斜纤蛇纹石纳米管中存在管道水(属于吸附水),去除温度在240℃±,内径为2nm~3nm的纳米管中管道水含量最高,管道水含量与纳米管分散度成反比。  相似文献   
76.
DOI: 10.1360/03yd0553 Arsenic, a toxic element, is ubiquitous in the earth’s crust and may lead to health risks for humans. This may come about as a result of oxidative weathering and dissolution of As-containing minerals, use of ar-senical pesticides, excess use of some fertilizers and from mine drainage, smelter wastes and agricultural drainage water from certain arid regions. The dis-solved inorganic arsenic is transported in surface or2156 Science in China Ser. D Earth Sciences groun…  相似文献   
77.
Our understanding on how ash particles in volcanic plumes react with coexisting gases and aerosols is still rudimentary, despite the importance of these reactions in influencing the chemistry and dynamics of a plume. In this study, six samples of fine ash (<100 m) from different volcanoes were measured for their specific surface area, as, porosity and water adsorption properties with the aim to provide insights into the capacity of silicate ash particles to react with gases, including water vapour. To do so, we performed high-resolution nitrogen and water vapour adsorption/desorption experiments at 77 K and 303 K, respectively. The nitrogen data indicated as values in the range 1.1–2.1 m2/g, except in one case where a as of 10 m2/g was measured. This high value is attributed to incorporation of hydrothermal phases, such as clay minerals, in the ash surface composition. The data also revealed that the ash samples are essentially non-porous, or have a porosity dominated by macropores with widths >500 Å. All the specimens had similar pore size distributions, with a small peak centered around 50 Å. These findings suggest that fine ash particles have relatively undifferentiated surface textures, irrespective of the chemical composition and eruption type. Adsorption isotherms for water vapour revealed that the capacity of the ash samples for water adsorption is systematically larger than predicted from the nitrogen adsorption as values. Enhanced reactivity of the ash surface towards water may result from (i) hydration of bulk ash constituents; (ii) hydration of surface compounds; and/or (iii) hydroxylation of the surface of the ash. The later mechanism may lead to irreversible retention of water. Based on these experiments, we predict that volcanic ash is covered by a complete monolayer of water under ambient atmospheric conditions. In addition, capillary condensation within ash pores should allow for deposition of condensed water on to ash particles before water reaches saturation in the plume. The total mass of water vapour retained by 1 g of fine ash at 0.95 relative water vapour pressure is calculated to be ~10–2 g. Some volcanic implications of this study are discussed.Editorial responsibility: J. Gilbert  相似文献   
78.
凹凸棒石粘土吸附铀的性能研究及应用   总被引:34,自引:2,他引:32  
本文研究了凹凸棒石粘土吸铀的酸度,吸附速率、肿附反应热焓吸附容量等性能,确定了吸附铀的最佳条件,并采用动态法片处理了含铀废水,效果良好,钱的去除率在99.95%以上,排放液中的铀的残余浓度达到国家规定的0.05mg/L排放标准。  相似文献   
79.
麦饭石对腐殖酸及重金属离子的吸附作用   总被引:4,自引:0,他引:4  
研究了麦饭石对腐殖酸和重金属离子(Hg2+,Pb2+,Cu2+,Zn2+,Cd2+)的吸附作用,实验结果表明麦饭石对腐殖酸和重金属离子都具有较好的吸附性能,且腐殖酸的存在有利于麦饭石对重金属离子的吸附。pH值是影响吸附的重要因素,当pH值为5.0~6.0时,麦饭石同时吸附腐殖酸和重金属离子的效果最好,麦饭石在吸附腐殖酸和重金属离子的同时能溶出微量元素硒,这对于大骨节病的防治有重要意义。  相似文献   
80.
The effect of coal moisture content and composition upon methane/carbon dioxide mixed gas adsorption characteristics is investigated. Separation factors are used to quantify the relative adsorption of carbon dioxide and methane. Experimental data indicate that carbon dioxide separation factors vary slightly between coal lithotypes, but the effects of variable coal composition and moisture upon selective adsorption are difficult to isolate. Model predictions based upon single-component isotherms show that although some variability in carbon dioxide selectivity exists for different coal types, there is no clear relationship between coal composition and carbon dioxide selectivity. Model predictions also indicate that coal moisture decreases carbon dioxide selectivity. The ideal adsorbed solution (IAS) theory and the extended Langmuir model differ substantially in their ability to predict binary gas adsorption behaviour. Comparison of model predictions to experimental data demonstrates that IAS theory, in conjunction with the Dubinin–Astakhov single-component isotherm equations are more accurate for the prediction of mixed gas desorption isotherms collected in this study than the extended Langmuir. IAS predictions, however, are strongly dependent upon the choice of pure gas isotherm equation.  相似文献   
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