褐煤自氨性溶液中吸附铜、镍、钴的物理化学研究

本文讨论了褐煤对单独或共存于氨性溶液中的铜、镍、钴吸附时,各因素对Me、NH_3及CO_2吸附的影响,并对吸附机理进行了初步探讨.褐煤的吸附作用主要是其腐植酸中的羧基及酚羟基的化学吸附和其表面的物理吸附.达到吸附平衡的先后次序为NH_3、Ni、Co、Cu;吸附量的大小次序为Cu>Co>Ni>NH_3;洗脱先后次序为NH_3、Ni及Co、Cu.金属的洗脱近于完全.褐煤自金属-氨溶液中所吸附的氨易于挥损,在120℃仅有少部分尚保留于褐煤体中.对溶液中CO_2的吸附系物理性的,在通常湿法冶金条件下,其吸附量<1%.     

Adsorption of Uranium(VI) and Zirconium(IV) from Acid Solutions on Silica Gel

Abstract

Adsorption of uranium(VI) and zirconium(IV) from aqueous solutions on silica gel was investigated by the batch equilibration method. The influence of shaking time and concentrations of nitric acid (i.e., pH of solution) and metal ions in solution were studied. Adsorption of uranium(VI) and zirconium(IV) increases with an increase of pH (decrease of nitric acid concentration) and ion concentrations. The adsorption mechanism of uranium(VI) and zirconium(IV) from aqueous solutions on silica gel is proposed. It is shown that zirconium(IV) and uranium(VI) can be separated if the concentration of nitric acid in solution is higher than 0.01 mol/dm³.     

Adsorption of Chlorinated Hydrocarbon Pollutants on Silica Gel

Abstract

A survey of indoor air pollutants was conducted. The removal of six chlorinated hydrocarbons, including methyl chloride, methylene chloride, chloroform, carbon tetrachloride, 1,1,1-trichloroethane, and tetrachloroethylene was performed using adsorption methods. The equilibrium uptakes of the six indoor pollutants on silica gel were determined gravimetrically at 25°C and at pressures up to saturation. The modified potential theory proposed by Dubinin and coworkers was used to correlate the adsorption data.     

Separation of Copper and Nickel from Ammoniacal/Ammonium Carbonate Solutions Using ACORGA PT5050

ABSTRACT

ACORGA PT5050 diluted with iberfluid (kerosene-type diluent, mostly aliphatic) was used to coextract copper and nickel from ammoniacal carbonate solutions. The influence of kinetics, temperature, equilibrium pH, and extractant concentration on the extraction of both metals has been studied. It was observed that nickel extraction is very sensitive to aqueous pH and that the extraction falls beyond an equilibrium pH of 9. For a typical solution containing near 3 g/L each of copper and nickel and 60 g/L ammonium carbonate, conditions were established for the coextraction and selective stripping of nickel and copper.     

Sol–Gel Synthesis of Cadmium Telluride-Microcrystal-Doped Silica Glasses

The sol–gel process has been applied to the preparation of small-sized CdTe-doped silica glasses. Gels synthesized by the hydrolysis of a complex solution of Si(OC₂H₅)₄, Cd(CH₃COO)₂· 2H₂O, and Te were heated from 350° to 600°C in a H₂─N₂ atmosphere to form fine cubic CdTe crystals. The size of CdTe crystals, determined from the line broadening of X-ray diffraction pattern, increases from 4 to 9 nm in diameter with increasing heat-treatment temperature. The optical absorption edge shifts to the higher-energy side as the size of the CdTe crystals decreases. This phenomenon is interpreted in terms of a quantum confinement effect of electron and hole in the CdTe microcrystals.     

Adsorption of Acetaldehyde,Propionaldehyde, and Butyraldehyde on Silica Gel

Abstract

Adsorption isotherms of acetaldehyde, propionaldehyde, and butyraldehyde on Davison silica gel were determined gravimetrically at three temperatures. The isoteric heat of adsorption initially increased at low loading and then decreased monotonically with an increase in loading. The equilibrium adsorption data were successfully correlated by Polanyi's potential theory. The equilibrium data were also correlated with the Langmuir, BET, Freundlich, and the Hines et al. models. The Freundlich and the Hines et al. models provided the best fit to the data, while the BET equation was found to be applicable only for a relative pressure range of 0.05 to 0.2. The monolayer surface coverages of silica gel by all of the aldehydes estimated by the Langmuir equation were found to be consistently higher than those calculated from the BET equation, except for acetaldehyde at 306.5 K.     

Ammonium Removal from Aqueous Solutions Using Sulfonated Polystyrene Grafted Silica Gel Sorbent

Abstract

A novel non‐swelling sulfonated polystyrene grafted silica gel sorbent was synthesized for use in ammonium removal from aqueous solutions. The ammonium sorption equilibrium isotherm was determined at 298 K by batch experiments, and the effects of flow rate and initial solution pH on the sorption were measured by breakthrough experiments in a laboratory scale fixed bed column. The equilibrium data were fitted to the Langmuir, Freundlich, Langmuir‐Freundlich, and Toth isotherm models. The breakthrough data were fitted to a dynamic isothermal mathematical model with an axial dispersion term to obtain the effective diffusion coefficient. The sorption rate of the sulfonated polystyrene grafted silica gel is higher than that of ion‐exchange resins, which enables shorter cycle times in column processes for the grafted silica gel.     

从铜镉渣中回收铜

对不同的金属还原剂从铜镉渣中置换铜进行了研究,提出了用新制海绵镉置换铜的新方法,减少了共存离子的置换,有效地防止了有毒气体的生成. 用含铜2%的铜镉渣制得了纯度高达95%的海绵铜,铜的回收率达到99%以上.     

硫化锌纳米微粒在溶液中吸附镉离子的行为研究

在25℃条件下,将微乳液法合成的ZnS纳米微粒用于吸附废水中的镉离子,研究溶液pH、纳米粒子尺寸及初始Cd(II)浓度等因素对吸附镉离子的影响。结果表明,镉离子的去除率在pH=2.5~6.5范围内随溶液pH的升高而增加,不同粒径的纳米ZnS对Cd(II)表现出了不同的吸附能力,粒径小的微粒其吸附能力更强,当其他条件一定的情况下,到达吸附平衡所需的时间将随着Cd(II)初始浓度的增大而增加。     

Modeling of the Extraction Equilibrium of Copper from Sulfate Solutions with Acorga M5640

The extraction equilibrium of copper from sulfate media with the aldoxime Acorga M5640 in ShellSol D70 has been investigated. The distribution results were interpreted by taking into account the nonideality of the aqueous phase. The activity of copper and hydrogen ions in the target systems CuSO₄/H₂SO₄/Na₂SO₄ and CuSO₄/H₂SO₄/Fe₂(SO₄)₃/ZnSO₄ were calculated through the speciation of the aqueous solutions and by applying the Pitzer model. The experimental pH values were found in good agreement with the predicted pH values. A model considering the dimerization of the aldoxime extractant was proposed to predict the distribution ratio and the copper loading isotherms. The extraction constant at infinite dilution and the apparent dimerization constant were evaluated from the experimental data and were found to be 10^{3.06 ± 0.07} and 51 ± 9 M^?1, respectively, at 25°C.     

Anodic Reaction of Arsenopyrite in Ammoniacal Solutions

Anodic dissolution of arsenopyrite in ammoniacal solution has been investigated by electrochemical methods. The process is an irreversible reaction with formation of a ferric oxidized film and is retarded by the film. The process rate is controlled by the electrochemical reaction on the electrode surface in the lower temperature range, or alternatively by the diffusion through the film in the higher temperature range. The overall reaction has 14 electron transferred and can be expressed by     

活性炭硅胶吸附法油气回收技术及其应用

油库在运行过程中,其油气排放过程主要发生在发油阶段。基于此对油库发油阶段实施油气回收。吸附法油气回收技术,采用吸附剂活性炭加硅胶进行填充,降低吸附床层的吸附热,提高安全性,延长活性炭的寿命。     

Liquid-Liquid Extraction of Copper from Ammoniacal Solution with 4-Acylpyrazol-5-ones

Abstract

The extraction of copper from ammoniacal solution with different 4-acylpyrazol-5-ones was studied. Depending on the nature of aliphatic acyl groups, the influence of pH and of the concentrations of ammonia and copper were evaluated. The extraction parameters are given and compared with those of the commercially available extractant LIX 54. The best results were obtained for 1-phenyl-3-methyl-4(2-ethylhexanoyl)-pyrazol-5-one.     

混合铜矿的高压氨浸工艺

对新疆某地混合铜矿采用高压氨浸工艺, 考了NH3·H2O浓度、NH4+盐用量、氧压、浸出温度、浸出时间及固液比等因素对浸出过程的影响. 结果表明, 在适宜的工艺条件下,铜浸出率可达98%以上.     

Phosphate and Silica Adsorption and Desorption from Soils

Phosphate adsorption and desorption in conjunction with silica desorption, were studied on soils of two field experiments. The soil samples were taken from control plots and plots that had received a total of 14 ton/ha superphosphate over a three-year period. Initially, silica desorption was increased by P added in the past as fertilizer and that added in equilibration solutions. Subsequently, after repeated washings, the rate of silica desorption was independent of the previous phosphate treatment. The adsorbed P was completely leached from the high P fertilized samples but not from those of the control. The slow reaction of phosphate with the soil was accompanied by a release of silica to the equilibrium solution. Most of the slow reaction product was not isotopically exchangeable in 48 hr.     

Equilibrium Parameters for the Sorption of Copper,Cadmium and Zinc Ions onto Peat

This paper details a study into the sorption of three divalent metal ions—namely cadmium, copper and zinc—onto peat, in single component, binary and ternary systems. The Langmuir Freundlich and Redlich–Peterson equilibrium isotherms for each metal ion in each system have been determined and correlated. The Langmuir isotherms have been found to have the highest regression correlation coefficients. © 1997 SCI.     

气相二氧化硅和胶体电池

通过对气相二氧化硅本身的特性和气相二氧化硅成胶性能的分析,提出优异的触变性能是气相二氧化硅用于胶体电池的关键因素,也是未来胶体发展的方向。使用优质气相二氧化硅,配合完善的电池组件设计和选择,可以保证较高的胶体电池气体再化合效率,也使得胶体电解液不易干涸,这样的胶体电池才会有着较长的循环寿命。     

Adsorption of Colloidal Silica on Alumina and of Colloidal Alumina on Silica

The mutual adsorption of colloidal silica on alumina and of colloidal alumina on silica and silicate materials occurs in aqueous suspension at about pH 4. It is shown that the adsorption of colloidal particles on the surface of opposite charge is limited to essentially a monoparticle layer. An adsorbed layer of fibrils of colloidal alumina on the surfaces of silica, asbestos, graphite, and finely divided clay is shown in electron micrographs. The effect of the adsorbed colloid on dispersibility of the substrate materials is discussed.     

Correlation of Methyl Chloride,Methylene Chloride,Chloroform, and Carbon Tetrachloride Adsorption Data on Silica Gel

Abstract

Adsorption data of the homologous series methyl chloride, methylene chloride, chloroform, and carbon tetrachloride on silica gel were measured gravimetrically at 288, 293, and 298 K. For all the chlorinated hydrocarbons examined, the isotherms were Type I, showing no apparent hysteresis between the adsorption and desorption cycles. Experimental data were compared with the calculated equilibrium uptake as predicted by a synthetic heterogeneous isotherm model in which the local isotherm on a site is given by the Jovanovic equation and the distribution of energetically different sites is represented by a Morse-type energy distribution function. The absolute errors between the values calculated by the heterogeneous isotherm model and the experimental data ranged from 1.17 to 2.67%. Energy distribution functions showed that silica gel exhibits the same degree of heterogeneity for all of the adsorbates in the homologous series.