Equilibrium Analysis of Aggregation Behavior in the Solvent Extraction of Cu(II) from Sulfuric Acid by Didodecylnaphthalene Sulfonic Acid

Abstract

By use of the principles of equilibrium analysis, the liquid-liquid cation exchange of Cu(II) from aqueous sulfuric acid at 25°C by didodecylnaphthalenesulfonic acid (HDDNS) in toluene may be understood in terms of small hydrated aggregated species in the organic phase. Extraction data have been measured as a function of organic-phase HDDNS molarity (1.0 × 10^?4 to 1.0 × 10^?1), aqueous copper(II) sulfate molarity (1.2 × 10^?8 to 1.3 × 10^?2), and aqueous sulfuric acid molarity (0.03 to 6.0). Graphical analysis of linear regions of the data support a model in which organic-phase aggregates of HDDNS function by cation exchange to incorporate Cu(II) ions with no apparent change in aggregation number at low loading. Supporting FTIR spectra and water-content measurements of HDDNS solutions in toluene show that the HDDNS aggregates are highly hydrated. By use of the computer program SXLSQA, a comprehensive equilibrium model was developed with inclusion of activity effects. Aqueous-phase activity coefficients and degree of aqueous bisulfate formation were estimated by use of the Pitzer treatment. Organic-phase nonideality was estimated by the Hildebrand-Scott treatment and was shown to be a negligible effect under the conditions tested. Excluding aqueous sulfuric acid molarities greater than 1, it was possible to model the data to within experimental error by assuming only the equilibrium extraction of Cu²⁺ ion by the aggregate (HDDNS)₄(H₂O)₂₂ and the equilibrium dissociation of (HDDNS)₄(H₂O)₂₂ to the monomer. The dependence of Cu(II) distribution on aqueous sulfuric acid molarity was shown to be quantitatively consistent with a cation-exchange process. In comparison with the graphical approach, the computer analysis allows comprehensive model testing over large, nonlinear data sets and eliminates the need to make limiting assumptions. Overall, the results provide useful insight toward the development of selective synergistic extraction systems in which HDDNS provides a nonselective cation-exchange vehicle in combination with a selective second extractant.     

P204-C5-7 氧肟酸协同萃取Ge4+的机理

研究了从硫酸介质中用二-(2-乙基己基)-磷酸(P204)与C5-7氧肟酸协同萃取Ge4+的机理, 经斜率法确定了其萃取Ge4+的机理和萃合物的组成.基于红外光谱的研究,探讨了协萃配合物的结构.     

Removal of Cu2+ Ions from Aqueous Solutions by Starch-Graft-Acrylic Acid Hydrogels

Gelatinized starch was prepared by constantly stirring a mixture of starch and water at 95°C for 1 hour. Starch-graft-acrylic acid (S-g-AA) hydrogels were prepared by grafting acrylic acid (AA) [monomer/starch (w/w) 0.5–1.5] onto gelatinized starch with ceric ammonium nitrate as initiator under nitrogen atmosphere. The surface morphology of samples was studied using a scanning electron microscope (SEM). The hydrogels were evaluated for the removal of Cu²⁺ ion from aqueous solutions at different pH. The concentration of Cu²⁺ ion in aqueous solution was kept constant at 4 mmol/L. The metal ion removal capacities changed depending on treatment time, initial pH of the solution, and monomer/starch (w/w) ratio of the S-g-AA hydrogels. Cu²⁺ ion removal capacities were determined by atomic absorption spectrometer (AAS).     

硫酸介质中D2EHPA萃取In~(3+)与Fe~(3+)的动力学

采用恒界面池法研究了从硫酸介质中萃取In3+和Fe3+的动力学,考察了搅拌速度、界面面积、温度、萃取剂浓度、氢离子活度及硫酸根浓度对In3+,Fe3+萃取速率的影响.结果表明,在温度25℃、搅拌转速70～240 r/min条件下,In3+以三价离子形式被萃取,萃取活化能为17.54 k J/mol,萃取过程为扩散控制;Fe3+以Fe SO4+形式被萃取,萃取活化能为52.87 k J/mol,萃取过程为界面化学反应控制.增加D2EHPA浓度可增大正向反应动力,提高萃取速率.萃取过程为阳离子交换,氢离子活度增加会导致萃取速率降低,硫酸根与金属离子的络合效应会降低萃取速率.通过动力学研究得到In3+萃取的正向速率方程为-d CIn3+/dt=10-0.378[In3+](aq)[H+](aq)-0.376[H2A2](org)0.158,Fe3+萃取的正向速率方程为-d CFe3+/dt=10-2.413[Fe3+](aq)[H+](aq)-1.526[H2A2](org)0.600.     

季铵盐(Aliquat 336)萃取对氨基苯磺酸的特性研究

利用季铵盐(Aliquat 336)为反应剂,在较宽的pH值条件下,研究了对氨基苯磺酸稀溶液的萃取相平衡特性;测定了反应剂浓度、稀释剂种类、盐的存在以及溶液pH值对反应萃取平衡分配系数的影响;提出了反应剂与对氨基苯磺酸负离子的阴离子交换反应机理,建立了平衡分配系数D值的表达式。结果表明,极性稀释剂不利于对氨基苯磺酸的萃取,惰性稀释剂能提供较大的萃取平衡分配系数,其顺序为:苯>四氯化碳>氯仿>正辛醇;盐的存在会降低Aliquat 336的萃取效率;与三烷基胺(Alamine 336)相比,Aliquat 336具有更宽的pH值适用范围。     

用P507从硫酸体系中萃取分离镓与铁锌离子

采用P507萃取剂对硫酸体系中的Ga3+与Fe2+, Zn2+进行萃取分离,考察了料液酸度、萃取剂浓度、时间、温度对萃取的影响,绘制萃取等温线;通过比较负载有机相中3种离子用不同浓度HCl和H2SO4反萃的效果及规律,提出用HCl洗脱Fe2+和Zn2+后,再用H2SO4反萃Ga3+的分离方案,并绘制反萃等温线. 结果表明,以40%(j) P507+磺化煤油为有机相,在相比O/A=1:1、温度25℃、时间20 min条件下,经过4级逆流萃取,Ga3+萃取率可达98.48%,同时19.56%的Fe2+和38.42%的Zn2+共萃进入有机相. 负载有机相用6 mol/L HCl洗涤3次可完全洗脱Fe2+和Zn2+而不损失Ga3+,除Fe2+和Zn2+后的负载有机相用100 g/L H2SO4按O/A=4:1、25℃、10 min,经过4级逆流反萃,Ga3+反萃率达97.64%.     

乳状液膜法从铀矿的硫酸浸出液中提取铀的研究

本文研究了以双丁二酰亚胺为表面活性剂,三正辛胺为载体,磺化煤油为溶剂,碳酸钠为膜内相组成的乳状液膜体系,从矿石硫酸浸出液中提取铀.考察了各种因素对膜稳定性和铀提取率的影响,提出了适宜的工艺条件.结果表明,此乳状液膜体系对铀具有迁移速度快,提取效率高,选择性和稳定性好的优点.铀的提取率可达99.4%.     

Selective Transport of Cu2+ Ions through Bulk Liquid Membrane System Mediated by Erythromycin Ethyl Succinate

The carrier mediated transport of Cu²⁺ ions from an aqueous medium has been examined. The ability of Erythromycin Ethyl Succinate (EES) as a carrier to form a complex with Cu²⁺ ions and transport them to the receiving phase is reported. The fundamental parameters influencing the transport of Cu²⁺ ions such as the pH in the source and receiving phases and concentration of the stripping agent in the receiving phase have been optimized and accordingly, the amount of Cu²⁺ transported across the liquid membrane after 5 h was 94.3 ± 1.8% in the presence of L-histidine as a suitable stripping agent. Moreover, the selectivity and efficiency of Cu²⁺ ions transport from aqueous solution over other cations in ternary and quaternary mixtures have been investigated. The results indicate that our fabricated membrane is very sensitive toward Cu⁺² ions in the presence of heavy metal ions.     

Comprehensive Equilibrium Analysis of the Complexation of Cu(II) by Tetrathia-14-crown-4 in a Synergistic Extraction System Employing Didodecylnaphthalene Sulfonic Acid

Abstract

Liquid-liquid extraction experiments, UV/vis spectra, and equilibrium modeling by use of the program SXLSQA have been employed to reveal the origin of synergism in the extraction of Cu(II) from sulfuric acid by the tetradentate macrocycle tetrathia-14-crown-4 (TT14C4) combined with the cation exchanger didodecylnaphthalene sulfonic acid (HDDNS) in toluene. The key feature of the system is the 1:1 complexation of Cu(II) by TT14C4. HDDNS functions both as a source of exchangeable protons and as a solvating agent that promotes the formation of small, hydrated aggregates. In the absence of the cation-exchange vehicle provided by HDDNS, the macrocycle does not extract Cu(II) detectably. Combined with HDDNS, however, TT14C4 significantly enhances the extraction of the metal by HDDNS. Comparative UV/vis spectrophotometry indicates the formation of the deep-blue chromophore attributed to the complex ion Cu(TT14C4)²⁺, wherein the planar set of four endo sulfur donor atoms of TT14C4 circumscribes the metal cation. Modeling of the extraction and spectral absorbance data by use of the program SXLSQA supports the conclusion that this 1:1 complex accounts for essentially all of the extracted Cu(II) in excess of that extracted by HDDNS alone. The best model includes HDDNS aggregates incorporating Cu(TT14C4)²⁺ or Cu²⁺ ions. In the analysis, activity effects in both aqueous and organic phases have been taken into account by the Pitzer and Hildebrand-Scott treatments, respectively, with explicit inclusion of the formation of aqueous hydrogen sulfate ion. The model accounts for the effect of variation of the solute components CuSO⁴, H²SO⁴, HDDNS, and TT14C4.     

Extraction of Alumina from Coal Fly Ash with Sulfuric Acid Leaching Method

Coarse g-Al2O3 powder was prepared through acid leaching, solid-liquid separation, crystallizing and aluminum sulfate decomposing processes using coal fly ash and concentrated sulfuric acid as raw materials. The metallurgy level Al2O3 can be obtained by disposing coarse g-Al2O3 powder with Bayer process. The optimum conditions of acid leaching process were determined by experiments. The extraction rate of Al2O3 can be stabilized at about 87% under these conditions. The thermodynamics and kinetics of sulfuric acid leaching process were studied with irreversible thermodynamics.     

硫酸改性甘草废渣生物吸附剂对Pb~(2+)离子的吸附

以甘草废渣为原料,经硫酸处理得到了改性甘草废渣生物吸附剂,并将其用于对水溶液中重金属离子Pb2+的吸附。通过扫描电镜、红外光谱、比表面积和表面官能团的测定等方法对改性前后甘草废渣进行了表征。采用静态吸附实验,考察了Pb2+初始浓度、吸附时间、溶液p H值及投入量对吸附剂吸附性能的影响。经硫酸改性后,甘草废渣表面结构发生了变化,表面活性基团的数目增加。在p H=5.5,对浓度为1 mmol·L-1的含Pb2+离子溶液,经90 min吸附后,吸附率达97.43%。等温吸附符合Langmuir模式,根据Langmuir方程计算,25℃时饱和吸附量为1.12 mmol·L-1,高于改性前(0.8 mmol·L·-1)。甘草废渣吸附剂对Pb2+离子的吸附符合二级动力学方程。解吸再生实验表明改性后的甘草废渣吸附剂可以再生重复使用5次以上,是性能良好的重金属离子吸附剂。     

铝土矿硫酸焙烧与水浸提取铝铁

通过单因素实验和正交实验研究了铝土矿硫酸焙烧与水浸提铝铁过程中焙烧温度、焙烧时间和酸/矿摩尔比对铝和铁提取率的影响. 结果表明,在酸/矿摩尔比3.75:1、焙烧温度325℃,焙烧时间2.5 h的条件下,Al提取率达98%, Fe提取率达80%,各因素对铝铁提取率的影响顺序为：酸/矿摩尔比>焙烧温度>焙烧时间. 该工艺具有焙烧温度低、金属提取率高等特点,对铝土矿的开发利用具有重要的意义.     

三烷基胺萃取氨基磺酸及其废水的特性研究

p-Amino benzene sulfonic acid (PABSA) is selected as the solute with amphoteric functional group, Lewis acid and Lewis base, to be separated from its dilute solutions. An aliphatic, straight chain amine, Alamine 336, is used as the extractant, and kerosene, 1-octanol, chloroform, butyl acetate and benzene as the diluent. The effects of pH value of solution, extractant concentration, salt and types of diluent on the distribution coefficient, D, are studied. There is a peak of D value with pH value of solution, the polar diluents are favorable for extracting PABSA, and the salt in aqueous phase reduces values of D apparently. The extraction equilibrium is described using the mass action law, and the calculated data according to the proposed model agree with the experimental data well. Further, the extraction behavior for other amino benzene sulfonic acids, 1-amino-8-naphtol-3,6-disulfonic acid (H acid) and 4,4′-diaminostilbene-2,2′-disulfonic acid (DSD acid), is investigated in a wide pH value region. Finally. H acid and DSD acid are successfully removed from wastewater by the extraction with Alamine 336.     

离子选择电极法测定硫酸生产用冷却水中氟化物

采用离子选择电极法对硫酸生产用冷却水中氟化物进行测定,加入离子强度缓冲溶液以调节试样的p H,稳定和活化试液中氟离子的浓度,减少其对测定结果的影响。测定的线性范围为0.10~3.0 mg/L,检出限为0.05 mg/L,加标回收率为97%~102%,相对标准偏差(n=5)为0.04%~1.12%。方法简单快捷,重现性和加标回收率好,能用于硫酸生产用冷却水中氟化物的测定。     

Amorphization of SiO2 Thin Films by Using 200 MeV Ag15+ Ions

Silicon - Effect of swift heavy ions (SHI) on low-k SiO2 thin films has been investigated. SiO2 thin films were deposited on pre-cleaned p-Si substrate by using sol-gel spin coating technique....     

Removal of Cu2+ from Water Using Liquid-Liquid Microchannel Extraction

The very good extraction selectivity of Cu²⁺ from water was demonstrated with a new microchannel equipment, by employing di-(2-ethylhexyl)phosphoric acid (D2EHPA) as an extractant and kerosene as a solvent. The effects of different experimental parameters on the extraction efficiency E, the volumetric mass transfer coefficient K_La, and the entrainment were experimentally investigated. The results showed that the extraction efficiency increased with increasing temperature, extractant concentration, phase ratio (organic/aqueous), and pH. The total flow rate, phase ratio, and pH were found to have a great effect on the mass transfer, whereas the temperature and the extractant concentration showed little effect.     

Synergistic Extraction of U(VI), Th(IV), and Lanthanides(III) from Nitric Acid Solutions Using Mixtures of TODGA and Dinonylnaphthalene Sulfonic Acid

The extraction of U(VI), Th(IV), and lanthanides(III) from aqueous nitric acid solutions with mixtures of N,N,N′,N′-tetra(n-octyl)diglycolamide (TODGA) and dinonylnaphtalene sulfonic acid (HDNNS) in n-decane has been investigated. The extraction efficiency of U(VI), Th(IV), and Ln(III) ions is greatly enhanced by addition of HDNNS to an organic phase containing TODGA. The synergistic effect arises from the higher hydrophobicity of U(VI), Th(IV), and Ln(III) extracted species formed by TODGA and DNNS^? anions as compared to those formed by TODGA and NO₃^? ions as counter anions. The synergistic effect for U(VI), Th(IV), and Ln(III) extraction from aqueous nitric acid solutions with mixtures of TODGA and HDNNS becomes weaker when the acidity of the aqueous phase increases. A high synergistic enhancement is accompanied with a high selectivity of Ln(III) extraction from nitric acid solutions.     

聚甲基丙烯酸十二酯-丙烯酸共聚物对乳状液膜中Cu2+迁移的影响

将两亲共聚物聚甲基丙烯酸十二酯-丙烯酸[P(DM-AA)]作为膜稳定剂加到由Span-80作表面活性剂、二-(2-乙基己基)磷酸(HDEHP)作流动载体、煤油和液体石蜡作膜溶剂及硫酸稀溶液作内相而组成的W/O型乳状液膜中,研究了此体系对Cu2+的迁移作用. 结果表明,由于两亲高分子的空间稳定作用而导致乳液膜对Cu2+具有较好的迁移效果. 最优条件为：在膜相中P(DM-AA)含量 3.0%, Span-80 4.0%, HDEHP 3.0%, 石蜡6.0%(w), 膜相:料相=1:10(j), [H+]=1.0 mol/L,接触时间6 min,搅拌速率200~300 r/min. 此外,还探讨了乳状液膜的结构和Cu2+迁移的机理,认为其迁移属于异向耦合传输机理.     

Solvent Extraction of Alkaline Earth Metal Ions by Diglycolic Amides from Nitric Acid Solutions

Abstract

N,N,N′,N′‐Tetraoctyl‐3‐oxapentane diamide (TODGA) and its homologues were shown to be usefully applied to the extraction of divalent alkaline earth metal: M(II) ions from aqueous solutions of high nitric acid concentration, specifically around 3 M. The stoichiometry of the extracted Sr(II)‐DGA species was found to depend mainly on the concentration of nitric acid and molecular structure of DGA. The degree of extraction of M(II) by TODGA decreases in the order of Ca(II) > Sr(II) > Ba(II).