叔胺萃取分离钴(II)、铁(II)

研究了不必预先氧化二价铁,直接用叔胺从氯化物溶液中萃取分离钴(II)、铁(II)的新方法. 考察了不同改性剂对叔胺萃取钴(II)、铁(II)的影响以及各种因素对钴(II)、铁(II)萃取、洗涤及反萃的影响. 提出了用叔胺萃取分离钴(II)、铁(II)的最佳工艺参数.     

高氯酸介质中2-羟基-5-仲辛基-二苯甲酮肟萃取钯的机理

报道了２－羟基－５－仲辛基－二苯甲酮肟（Ｎ５１０）从高氯酸体系中萃取钯的机理．结果表明,钯的萃取率随ｐＨ的增大而增加,而与高氯酸根离子浓度无关．采用斜率法测得萃合物组成为Ｐｄ·Ｎ５１０．萃取反应方程式为：Ｈ２Ｎ５１０（Ｏ）＋Ｐｄ２＋（Ａ）＝ＰｄＮ５１０（Ｏ）＋２Ｈ＋（Ａ     

仲辛醇与仲辛酮萃取苯酚稀溶液性能研究

为了给工业含酚废水处理提供萃取剂选择和过程设计的指导,以中性含氧类萃取剂仲辛醇、仲辛酮为溶剂进行了苯酚稀溶液萃取性能的实验研究,测定了不同水相pH值、苯酚初始质量浓度条件下2种溶剂的萃取平衡分配系数,并研究了混合溶剂的萃取性能以及盐效应对于萃取平衡的影响.结果表明:在酸性和中性条件下,仲辛醇和仲辛酮对苯酚均有良好的萃取...     

Pd(Ⅱ)、Zn(Ⅱ)、Cu(Ⅱ)、原卟啉的非有机溶剂液-固萃取分离

难溶于水的原卟啉在1.0%的吐温80水溶液中因氢键作用力变为可溶。研究了Pd(Ⅱ)、Zn(Ⅱ)、Cu(Ⅱ)、原卟啉在吐温80存在下的吸收光谱,并以原卟啉为萃取剂,考察了金属原卟啉在非有机溶剂液-固萃取体系中的分配行为,讨论了分相盐、成相聚合物、萃取剂、萃取酸度等对金属原卟啉在两相分配的影响。结果表明,(NH4)2SO4浓度1.51 mol/L,吐温80质量浓度9.0%,原卟啉浓度6.0×10-5mol/L,萃取酸度分别为5.0与pH 9.0,沸水浴加热15 min的条件下可分别实现Pd(Ⅱ)~Zn(Ⅱ),Cu(Ⅱ)~Pd(Ⅱ)的定量分离;体系萃取容量为0.020 mg/mL。该法不用有毒溶剂,仅控制萃取酸度分离性质相近的元素。其萃取机理是:金属原卟啉分子上的羰基质子受体与吐温分子上的羟基质子供体形成氢键。     

硝酸体系中Cyanex923萃取La(Ⅲ)性能研究

研究了硝酸体系中中性萃取剂Cyanex923(三烷基氧膦混合物)对轻稀土元素La(Ⅲ)的萃取性能.考察了金属离子、Cyanex923及硝酸根的浓度对La(Ⅲ)萃取的影响,由斜率分析法确定了反应机理,得出萃取平衡方程.探讨了温度对Cyanex923萃取La(Ⅲ)的影响,由Van't Hoff方程计算出温度范围在298～3...     

离子液体对Cd(Ⅱ)的萃取性能的研究

研究了2种离子液体[Omim]PF6(1-辛基-3-甲基咪唑六氟磷酸盐)和Aliquat 336(甲基三辛基季铵盐)对Cd(Ⅱ)的萃取性能,考察了离子液体种类、初始浓度、萃取时间、离子液体相与水相体积比(相比)及酸浓度对萃取率的影响。实验结果表明,[Omim]PF6对Cd(Ⅱ)的萃取率很低,而Aliquat 336对Cd(Ⅱ)的萃取率可以高达97%。随着废水中Cd(Ⅱ)初始浓度的增大,萃取率呈先略微升高,然后急剧下降的变化趋势。以Aliquat 336作为萃取剂,优化萃取时间为10 min,相比为1∶5,酸浓度为0.5 mol/L。     

N,N-二辛基甘氨酸萃取铑的机理

报道了Ｎ，Ｎ－二辛基甘氨酸从盐酸体系中萃取铑的机理．结果表明：铑的萃取率随酸度、氯离子浓度、铑离子浓度的增大而降低．采用斜率法测得萃合物组成为：Ｒ２ＮＣＨ２ＣＯＯＨＨＲｈ（Ｈ２Ｏ）２Ｃｌ４．萃取反应方程式为：Ｒ２ＮＣＨ２ＣＯＯＨ．ＨＣｌ（Ｏ）＋Ｒｈ（Ｈ２Ｏ）２Ｃｌ－４（Ａ）＝Ｒ２ＮＣＨ２ＣＯＯＨ．ＨＲｈ（Ｈ２Ｏ）２Ｃｌ４（Ｏ）＋Ｃｌ     

人工神经网络光度法同时测定水中Fe(II)、Fe(III)

应用径向基函数人工神经网络(RBF)和误差反向传播神经网络(BP),采用磺基水杨酸-邻菲罗啉双显色剂光度法同时分析了水中Fe(II)和Fe(III)。实验证明,RBF算法在所需神经元个数、训练时间、预测准确度等方面均明显优于BP网络算法。该技术和光度法结合有望成为多组分分析的有效选择方法之一。     

正辛基-对叔丁基苯基亚砜萃取钯(Ⅱ)的动力学研究

采用恒界面池搅拌法测定了正辛基－对叔丁基苯基亚砜萃取钯（Ⅱ）的反应速率常数（kf)和反应的表观活化能（Ea),初步探讨了亚砜类萃取剂结构对其萃取性能的影响。     

聚(3-辛基噻吩)的溶致变色、热致变色及发光性能

采用三氯化铁法合成了聚(3 辛基噻吩)(P3OT),利用核磁共振氢谱确定产物中含有摩尔分数为60%的头尾(HT)结构。通过改变良溶剂三氯甲烷与不良溶剂甲醇的体积配比,研究了P3OT的溶致变色行为,P3OT的紫外吸收峰随着甲醇用量的增加发生红移,在φ(CH3OH)=70%时,吸收峰从纯三氯甲烷溶液的435nm红移至490nm。在室温和0℃下,研究了紫外-可见吸收光谱随温度的变化,温度降低,P3OT的吸收峰发生蓝移。以400nm的光激发P3OT的三氯甲烷溶液,在573nm处得到了稳定的发射峰。     

萃取、共沸精馏技术联用回收废液中的醋酸

针对化工生产过程中产生的稀醋酸溶液难以回收高纯度醋酸的问题,首先采用乙酸乙酯和苯的混合溶剂萃取浓缩稀醋酸溶液;再通过精馏蒸出溶液中的萃取剂和部分水;最后采用乙酸丁酯作为挟带剂,用共沸精馏法分离得到醋酸。得到的醋酸质量分数达96.84%,回收率达84.97%。对工业化回收稀醋酸溶液中的醋酸有一定的实用价值。     

Highly selective solvent extraction of Zn(II) and Cr(III) with trioctylmethylammonium chloride ionic liquid

This study investigates the recovery of Zn(II) and Cr(III) from aqueous solutions based on solvent extraction with trioctylmethylammonium chloride [TOMA⁺][Cl-], commercialy named Aliquat 336. Single metal solutions and binary mixtures of both metals were considered. The effect of relevant operating conditions such as pH, contact time, initial concentration, O/A phase volumetric ratio, and temperature were evaluated. Additionally, loading capacity and stripping studies were performed. Results showed that [TOMA⁺][Cl^?] is an effective extracting agent for Zn(II), reaching maximum removal capacity at pH 1.8 and demonstrating fast extraction kinetics. Extraction efficiencies above 99% were achieved at 0.5, 0.75, and 1.00 O/A volumetric phase ratios for 0.1 g/L initial Zn(II) concentration. At 1 g/L and 10 g/L concentration, for the same O/A ratios, approximately 88% of the initial Zn(II) was extracted. In contrast, it was found that negligible amounts of Cr(III) were transferred to the [TOMA⁺][Cl^?] phase at the 1-5 pH range. Selectivity studies showed that Zn(II) removal is boosted in the presence of Cr(III), although no Cr(III) is extracted. [TOMA⁺][Cl^?] exhibited a high Zn(II) storage capacity, since after 25 loading cycles with 1 g/L, the loading capacity reached approximately 13.5 g/L, and after five loading cycles with 5 g/L, the capacity reached 19.4 g/L. Stripping tests revealed that NaOH is an efficient agent for the removal of Zn(II) from the ionic liquids, reaching 98.5% removal after two cycles, whereas HNO₃ is not a suitable agent, reaching less than 40% removal after three cycles. [TOMA⁺][Cl^?] revealed high potential for separating Zn(II) from Cr(III).     

Extraction of bismuth with mixing systems of sec-octylphenoxy acetic acid and 1,10-phenanthroline

sec-Octylphenoxy acetic acid and 1,10-phenanthroline were employed for the extraction of bismuth from chloride medium, showing evident synergistic effects on bismuth extraction. Stoichiometry of the synergistic extraction was determined, giving a logarithm value of equilibrium constant of 6.75, which was much higher than those obtained by single sec-octylphenoxy acetic acid or 1,10-phenanthroline. Thermodynamic studies indicated that the synergistic extraction was an endothermic and spontaneous process. Moreover, antagonistic effects were found when the mixture was employed for lead extraction, demonstrating its potential to be applied to the separation of bismuth and lead at low mole fractions of sec-octylphenoxy acetic acid.     

Sorption of Pb(II), Cd(II) and Zn(II) by iminodiacetate chelating resins in non-competitive and competitive conditions

Two chelating resins (CRs) bearing iminodiacetate (IDA) groups derived from acrylonitrile - divinylbenzene (AN-DVB) copolymers having 10 and 15 wt.% nominal cross-linking degrees and a high mobility of the functional groups caused by the presence of a longer spacer between the matrix and the IDA groups were synthesized and tested as sorbents for heavy metal ions like: Pb(II), Cd(II) and Zn(II) from aqueous solutions by batch and column techniques. Experimental data obtained from batch equilibrium tests have been analyzed by two isotherm models: Freundlich and Langmuir. The overall adsorption tendency of CRs toward Pb(II), Cd(II) and Zn(II), under non-competitive conditions, followed the order: Cd(II) > Pb(II) > Zn(II). Selectivity studies were performed in ternary mixture of Pb(II), Cd(II) and Zn(II) to check if the synthesized CRs can be useful for selective separation of heavy metal cations. The results revealed that the CRs with IDA groups exhibited high selectivity toward Pb(II), both in batch and column techniques. Regeneration of the resins was achieved using 0.1 M HCl solution.     

Evaluation of Annular Centrifugal Contactors for the Extraction of Acetic Acid from Aqueous Streams

This study investigates the use of annular centrifugal contactors for the liquid-liquid extraction of acetic acid from an acidic aqueous phase into an organic phase consisting of 1.5 M Tributyl Phosphate in n-Dodecane. Initial break time tests were performed in order to investigate the mixing/separation viability of the organic/aqueous system, and after determining that centrifugal contactors could be used to perform the liquid-liquid extraction, hydraulic tests established the combination of rotation rate and throughput which should be used to ensure proper separation of the two outlet phases. Finally, extraction efficiency data was collected to examine the system conditions that provided the most efficient removal of acetic acid.     

Dodecylhydroxydiphosphonic Acid for Solvent Extraction

Abstract

The extraction behavior of Zn(II) and Cu(II) in acetate media has been investigated using dodecylhydroxydiphosphonic acid, DHDPA, which was previously synthesized and characterized. The extraction of both cations was carried out in different media with the addition of CH₃COOH, HCl or H₂SO₄ at different pH. The maximum extraction yield of 80% for zinc, was obtained in one step after the addition of sulfuric acid at pH_i=5.5 and for copper after the addition of 10 mg of sodium acetate. The authors plan additional tests using polar solvents.     

Removal of Cu(II) and Zn(II) Using Lignocellulosic Fiber Derived from Citrus reticulata (Kinnow) Waste Biomass

Abstract

The biosorption of Cu(II) and Zn(II) using dried untreated and pretreated Citrus reticulata waste biomass were evaluated. The Cu(II) and Zn(II) sorption were found to be dependent on the solution pH, the biosorbent dose, the biosorbent particle size, the shaking speed, the temperature, the initial metal ions (800 mg/L), and the contact time. Twenty-eight physical and chemical pretreatments of Citrus reticulata waste biomass were evaluated for the sorption of Cu(II) and Zn(II) from aqueous solutions. The results indicated that biomass pretreated with sulphuric acid and EDTA had maximum Cu(II) and Zn(II) uptake capacity of 87.14 mg/g and 86.4 mg/g respectively. Moreover, the Langmuir isotherm model fitted well than the Freundlich model with R ² > 0.95 for both metal ions. The sorption of Cu(II) and Zn(II) occurred rapidly in the first 120 min and the equilibrium was reached in 240 min. FTIR and SEM studies were also carried out to investigate functional groups present in the biomass and the surface morphological changes of biomass.     

Synergistic Solvent Extraction and Transport of Zn(II) and Cu(II) across Polymer Inclusion Membranes with a Mixture of TOPO and Aliquat 336

Separation of zinc(II) and copper(II) ions from aqueous solutions by synergistic extraction and transport through polymer inclusion membranes (PIMs) has been investigated. A mixture of trioctylphosphine oxide (TOPO) and trioctymethylammonium chloride (Aliquat 336) was used as a selective extractant as well as an ion carrier in polymer membranes. The effects of hydrochloric acid concentration in the aqueous phase and extractants concentration in the organic phase on the separation process of zinc(II) and copper(II) ions have been studied. Zn(II) ions were successfully separated from Cu(II) ions in solvent extraction process using 0.025 M TOPO and 0.06 M Aliquat 336 in kerosene. Polymer inclusion membranes (PIMs) containing a mixture of TOPO and Aliquat 336 as the ion carrier have been prepared and the facilitated transport of Zn(II) and Cu(II) ions has been studied. The influence of membrane composition on the transport kinetic of Zn(II) and Cu(II) has been evaluated. Zn(II) ions were preferably transported from the aqueous solutions containing Cu(II) and above 87% of Zn(II) ions were effectively recovered from the 0.5 M HCl solution as the source phase through PIM into 0.5 M H₂SO₄ as the stripping phase.