二（2-乙基己基）磷酸/磷酸三丁酯复合萃取剂协萃对氨基苯甲酸

为强化两性官能团化合物的萃取分离性能,以对氨基苯甲酸（PABA）为被分离溶质,二（2-乙基己基）磷酸（D2EHPA）/磷酸三丁酯（TBP）/正庚烷的混合物为萃取剂进行了萃取平衡特性的研究,考察了溶液的pH值、D2EHPA浓度、TBP浓度对于萃取平衡的影响,建立了复合萃取剂协同萃取PABA的萃取平衡分配系数的表达式.结果表明,D2EHPA/TBP/正庚烷复合萃取剂萃取PABA具有明显的协萃效应,协萃机理为D2EHPA及TBP分别与PABA的Lewis碱性官能团（—NH2）和Lewis酸性官能团（—COOH）缔合形成亲油性更强的萃合物,且D2EHPA与TBP的浓度差异越小,协萃效应越明显.根据萃取平衡分配系数表达式拟合求取了表观萃取平衡常数,复合萃取剂的值远大于D2EHPA、TBP单独作为萃取剂的值,进一步证明了本文提出的协萃机理.     

D2EHPA萃取回收Cr(Ⅲ)的研究

以回收废水中Cr(Ⅲ)为目的,选择2-乙基己基磷酸(D2EHPA)为萃取剂,煤油为稀释剂,进行了萃取回收Cr(Ⅲ)的实验研究.考察了皂化剂种类、溶液pH值、助溶剂种类、萃取剂浓度等因素对于萃取平衡影响以及三种无机酸、两种有机酸对于负载Cr(Ⅲ)的D2EHPA反萃效果的影响.结果表明,pH值是影响D2EHPA/煤油萃取Cr(Ⅲ)的重要因素, 在pH＜2时,D2EHPA几乎不萃取Cr(Ⅲ),通过萃取剂的皂化,提高水相pH值,可以实现D2EHPA萃取Cr(Ⅲ).随平衡水相pH值的升高,D2EHPA显示出良好的萃取效果.NaOH溶液作为皂化剂比氨水的分相效果好.加入助溶剂后萃取效率提高,其中10%～20%正辛醇是适宜的助溶剂选择.D2EHPA/正辛醇/煤油萃取Cr(Ⅲ)后立即用无机酸或有机酸反萃,其中硫酸、盐酸或草酸的反萃率能够达到90%以上.     

三烷基氧磷萃取对氨基苯酚的性能

以三烷基氧磷(TRPO)为反应萃取剂,研究了稀释剂种类、溶液pH值等因素对对氨基苯酚稀溶液反应萃取分配系数(D)的影响,提出了同时考虑反应萃取和物理萃取作用的分配系数的表达式.结果表明：TRPO对对氨基苯酚的萃取主要通过与其中性分子的氢键缔合和溶剂化效应实现,D值的变化与中性分子的摩尔分数有关;稀释剂的极性对对氨基苯酚的萃取影响较小;除20%TRPO/正庚烷体系外,拟合实验数据得到的表观萃取平衡常数变化较小;体系的物理萃取分配常数则随TRPO浓度的增大而增大,且符合稀释剂和TRPO的物理萃取能力的简单加和;酸性、碱性和中性的反应萃取剂都可有效地萃取对氨基苯酚,萃取能力为二(2-乙基己基)磷酸＞ TRPO ＞ 三烷基胺,相应的操作pH值为2～3、4～5和6.5～7.5,应用时可根据体系的pH值范围选用相应的萃取剂,而不必调节溶液的pH值.     

酸性有机磷萃取剂对镓的萃取研究

水相初始pH值=2. 0时,0. 3 mol/L的酸性有机磷萃取剂基本可以实现对盐酸溶液中镓的完全萃取,且萃取能力遵循萃取剂的酸度顺序:D2EHPA(99. 2%) PC88A(98. 3%) Cyanex 272(76. 9%)。随着水相初始pH值升高,越来越多的镓被萃取到有机相,且由于氢离子的释放导致较高的平衡pH值。通过FT-IR分析了D2EHPA的P=O及P-O的吸收峰明显大于PC88A、Cyanex 272。另外,3mol/L的盐酸溶液作为反萃剂对D2EHPA、PC88A、Cyanex 272的负载有机相进行反萃时,镓的反萃率达到最高,分别为81. 7%、85. 5%、93. 5%。最后,利用斜率分析法推导出三种酸性含磷萃取剂的萃取机理方程式:Ga(OH)_(2,org)~++(HA)_(2,org)=Ga(OH)_2A·(HA)_(org)+H_(aq)~+。     

萘磺酸类有机废水的络合萃取研究

采用络合萃取法对萘磺酸类有机废水进行预处理。选用了三烷基胺(7301)、三辛胺作萃取剂,用NaOH、KOH、NH3.H2O作反萃剂,分别进行萃取与反萃实验,确定了最优良的萃取与反萃体系。同时,研究了萃取剂与稀释剂比例、废水pH、油水比以及萃取温度对废水萃取效果的影响及反萃时碱液的最佳质量分数和油碱比。     

D2EHPA对高浓度盐酸介质中钛的萃取

研究了D2EHPA对盐酸介质中钛的萃取和反萃性能。研究结果表明:萃取液中钛以TiOCl2.2D2EHPA的形式存在。钛萃取率随无机相中氯离子浓度和有机相中萃取剂浓度的增加而增加。D2EHPA对钛的饱和承载量为8.98 g/100 g D2EHPA。红外光谱研究进一步表明了Ti-D2EHPA螯合物的性质。在0.5～12 mol/dm3的盐酸介质中,D2EHPA对钛的萃取率随盐酸介质浓度的增加而增加,而对铁、铝、钙、镁无萃取性能。以7%H2O2+3 mol/dm3H2SO4为反萃剂,有机相中的钛可实现一次完全反萃。     

萃取剂相对酸(碱)度对极性有机物络合萃取平衡的影响

选择萃取剂的相对酸（碱）度为萃取剂的特征参数,以三种常用的络合萃取剂,TOA／正辛醇、TRPO/煤油、D2EHPA/煤油为研究对象,测定TOA和TRPO相对于HCI的pKa.Bs,D2EHPA相对于NaOH的相对酸度（pkAs）物性参数,分别结合萃取有机羧酸、有机胺的平衡特性,进一步研究萃取剂的相对酸（碱）度与络合萃取平衡的关系。结果表明,萃取剂的相对酸（碱）度与萃取剂的浓度有关,并由此直接影响络合萃取平衡的结果,是影响络合萃取平衡的重要因素：提出了影响萃取平衡的三个重要因素：溶质的亲油性、溶质的电性参数、络合剂的相对碱（酸）度,并在不同体系下建立了表观络合萃取平衡常数与这三参数的关联式,关联精度是相当满意的,可以很好地预测络合萃取平衡的特性。     

乙醇酸与乙醛酸的萃取分离

以乙醇酸和乙醛酸的稀溶液为分离对象,采用三烷基氧磷 (TRPO)为萃取剂、甲基异丁基酮 (MiBK)为稀释剂,研究了单、双溶质有机酸的萃取分离特性,测定了TRPO、有机酸的浓度等因素对单、双溶质有机酸萃取平衡的影响,在适当假定的基础上,建立了描述TRPO萃取乙醇酸、乙醛酸单、双溶质特性的数学模型.结果表明,随TRPO浓度的增大,分离系数β_{（glycolic /glyoxylic）}由小于1逐渐增大至大于1,乙醇酸与TRPO的萃合物有1∶1和1∶2两种形式,采用单溶质萃取反应平衡常数预测双溶质萃取的结果,预测值与实验值相当接近.同时,还对三烷基胺、磷酸三丁酯等萃取剂分离乙醇酸和乙醛酸的特性进行了讨论.     

乳化萃取法脱除Mg2+制备工业级磷酸二氢钠的研究

本文以高效的二(2-乙基己基磷酸)(D2EHPA)为萃取剂,采用乳化萃取技术来提取NaH2PO4溶液中的Mg2+杂质,通过考察萃取剂浓度,水相溶液pH值,相比(水相:有机相),乳化速度等对萃取Mg2+萃取率的影响,求得适宜工艺条件:D2EHPA体积分数:75%,相比(A/O):2∶1,起始NaH2PO4溶液pH值为4,搅拌速度:3000r.min-1;实验结果表明,在适宜工艺条件下,经过三级萃取,可制取工业级NaH2PO4。     

二(2-乙基己基)磷酸萃取L-苯丙氨酸

以二（2-乙基己基）磷酸（D2EHPA）-正辛烷萃取L-苯丙氨酸为对象,研究了D2EHPA浓度、L-苯丙氨酸初始浓度以及pH值对萃取平衡分配系数的影响。不同pH值下负载有机相的红外谱图分析表明,D2EHPA与L-苯丙氨酸形成的萃合物结构与pH值无关。提出了在萃取过程中同时存在着离子交换反应和质子转移反应的观点。1个氨基酸分子与2个二（2-乙基己基）磷酸二聚体相结合。本文建立的萃取平衡分配系数关联式,拟合精度令人满意。     

三烷基胺与二（2-乙基己基）磷酸协同萃取对氨基苯酚

引　言随着现代工业的发展及环境保护标准的严格实施 ,对极性有机物稀溶液的分离和工业废水的治理提出了更高的要求 ,而萃取技术在该领域已进行了较为广泛的研究 ,并进行了工业应用 .由于废水体系的复杂性 ,尤其是含多官能团的极性有机物废水 ,在采用萃取方法进行废水预处理时强化萃取能力是十分必要的 .自 195 6年Blake[1] 提出协同萃取以来 ,由于它兼具物理萃取和化学萃取的优点 ,具有更高的选择性和高效性 ,已成功地用于金属的萃取分离中 .协同萃取用于极性有机物稀溶液的分离多见于物理萃取 ,例如乙酸丁酯与苯乙酮协萃苯酚[2 ] 、乙酸…     

Study on Mg<Superscript>2+</Superscript> removal from ammonium dihydrogen phosphate solution by solvent extraction with di-2-ethylhexyl phosphoric acid

The extraction of Mg²⁺ from ammonium dihydrogen phosphate (MAP) solution by extractant (D2EHPA) and its mixture, including acidic extractant (HEHPEHE), alkaline extractant (TOA) and neutral extractant (TBP) respectively, is investigated. The good extraction selectivity of Mg²⁺ with D2EHPA from ammonium dihydrogen phosphate solution is verified, which is found to be associated with the cation exchange and chelation capability of D2EHPA on the basis of its molecular structure. The related thermodynamic data are also obtained in terms of experimental results as follows: the extraction enthalpy is 2.659×10⁻² (J·mol⁻¹·K⁻¹), the free energy is 1.501×10³ (J·mol⁻¹) and the entropy is 4.441 (J·mol⁻¹). Meanwhile, the major influencing factors, such as the initial pH, the initial concentration of extractant, phase ratio and the extraction temperature on the extraction ratios of Mg²⁺, are studied, and the optimal process conditions are obtained. As shown in the extraction experiments for practical MAP solution, superior grade MAP can be obtained by three levels of extraction under optimal condition.     

N-癸酰吗啡啉(DMPHL)萃取苯酚水溶液

通过吗啡啉与癸酰氯反应生成了酰胺类萃取剂N-癸酰吗啡啉(DMPHL),并用苯为稀释剂考察DMPHL萃取苯酚的性能。研究了萃取剂浓度、苯酚浓度、酸度和温度对萃取苯酚的影响,计算出萃取反应的平衡常数以及有关的热力学函数,实验结果表明,DMPHL对于苯酚有良好的萃取性能。     

三烷基氧膦反应萃取一元羧酸的规律

化学萃取法对有机羧酸稀溶液的分离具有高效性和高选择性.萃取剂的相对碱性是表征萃取剂性质的重要参数.选取三烷基氧膦（TRPO）为萃取剂,煤油为稀释剂,甲酸、乙酸、丙酸、丁酸、己酸、一氯乙酸、二氯乙酸、三氯乙酸、乳酸9种一元羧酸为被萃溶质,研究了溶质种类、TRPO浓度对萃取剂相对溶质的相对碱度（pK_a,BS）的影响,探索了从化学反应基本理论出发研究络合萃取平衡规律的可行性.实验结果表明,对于TRPO/煤油萃取剂体系,pK_a,BS值不随TRPO的浓度而变化;而溶质的亲油性和酸性对pKa,BS值影响显著;从基本理论出发推证的只包含溶质的pK_a以及萃取剂的pK_a,BS的描述反应萃取平衡规律的数学表达式可以预测TRPO萃取有机羧酸的平衡规律,并对水溶性较小或萃取平衡分配系数较小体系的pK_a,BS值测定提出了简单、易行的修正方法.     

Investigating the Synergistic Effect of D2EHPA and Cyanex 302 on Zinc and Manganese Separation

The synergistic effect of Cyanex 302 on the extraction of zinc and manganese with D2EHPA in sulfate media was investigated. Experiments were carried out in the pH range of 1.0–5.0, temperature of 23, 40, and 60°C with sole D2EHPA and Cyanex 302 as extractant and D2EHPA to Cyanex 302 ratios of 1:3, 1:1, and 3:1. The experimental results showed that the co-extraction of zinc and manganese increased with increasing equilibrium pH and temperature. Increasing the D2EHPA to Cyanex 302 ratio in the organic phase, caused a left shifting of the extraction isotherm of zinc and a right shifting of the extraction isotherm of manganese. Thus, a better separation of zinc over manganese was achieved. At low pHs, the separation factor is low when pure D2EHPA is used as an extractant; however, using Cyanex 302 as a synergist, the separation factor increases and results in a better separation of zinc from manganese. Stoichiometric coefficient of zinc for single D2EHPA and Cyanex 302 and their mixture was calculated to be close to 6.     

Selective and Synergistic Extraction of Nickel from Simulated Cr-Ni Electroplating Bath Solutions using LIX 63 and D2EHPA as Carriers

The main goal of the present study is to explain synergistic extraction of nickel from simulated Cr-Ni electroplating bath solutions (SEBS) using 5,8-diethyl-7-hydroxydodecane-6-one oxime (LIX 63) and di-(2-ethylhexyl) phosphoric acid (D2EHPA) as extractants by emulsion liquid membrane (ELM) technique. The importance of membrane composition and aqueous phase properties on nickel extraction percentage has been highlighted for the selective extraction of nickel. Some important parameters like acid concentration, stripping solution type and concentration, mixing speed, extractant concentrations, phase ratio, and surfactant concentration was studied to improve the extraction and stripping efficiencies. Higher than > 99% of nickel was recovered at optimum conditions within 6 min. The higher separation factors (β_Ni/Cr) were obtained as 580. As a result, the nickel extraction kinetic with D2EHPA has been defined as faster than LIX63. So, the kinetic transport of nickel mainly depends on LIX63 than D2EHPA. According to these results, D2EHPA behaves as a synergistic extractant in the present extraction mechanism.     

Synergistic extraction and separation of Fe(III) and Zn(II) using TBP and D2EHPA

Waste chloride pickle liquors from hot-dip galvanizing plants, steel plants and flue dust contain reasonable amounts of heavy metals such as Zn, Cr, Ni, etc. Iron is invariably associated with most of these materials and comes into solution during leaching. Thus, the synergistic extraction of zinc(II) and iron(III) from leach solutions in tri-n-butyl phosphate (TBP)–di(2-ethylhexyl) phosphoric acid (D2EHPA) system diluted in kerosene was investigated. The Zn and Fe concentrations in the leach liquor used in the present study were 2 g/L. Experiments were carried out in the pH range of 0.5–4.0, temperature of 25°C, using sole D2EHPA, sole TBP and D2EHPA–TBP mixtures at different ratios. Results showed that the co-extraction of zinc(II) and iron(III) increased with increasing equilibrium pH using D2EHPA. It is demonstrated that the mixtures of TBP and D2EHPA are more efficient and selective than D2EHPA alone. At low pH values, the separation factor is low when pure D2EHPA is used as an extractant; however, using TBP as a synergist, the separation factor increases and results in a better separation of zinc from iron. Increasing TBP to D2EHPA ratios in the organic phase caused a slight shift to the right in the extraction isotherm of iron and a marked shift to the right in the extraction isotherm of zinc, and the maximum separation factor of 13.3 × 10³ was achieved at a TBP to D2EHPA volume ratio of 4:1 (0.58 M TBP: 0.12 M D2EHPA). Furthermore, the effect of equilibrium pH, organic to aqueous phase ratio and Cl^? concentration on the selective extraction was investigated. Using two extraction stages at the O/A ratio of 2:1 and pH_e (equilibrium pH) of 3 and 1 for zinc and iron, respectively, 99% of zinc(II) and 96.25% of iron(III) were extracted.     

Reactive solvent extraction of amino acids with cationic extractants

A mixture of amino acids (arginine, phenylalanine, alanine, glycine and aspartic acid) in solution was extracted by four acidic extractants (dinonylnaphthalenesulphonic acid (DNNSA), di(2-ethylhexyl)monothiophosphoric acid (D2EHPA(S)), di(2-ethylhexyl)phosphoric acid (D2EHPA) and Versatic 10) in toluene. The extractive capacity of the organic phase for the amino acids, using DNNSA, D2EHPA(S) and D2EHPA was found to decrease in the order arginine>phenylalanine>alanine>glycine>aspartic acid, although at low pH values phenylalanine>arginine occurred for D2EHPA(S) and D2EHPA. Separation factors derived for pairs of amino acids were in the range 2·0 (glycine–aspartic acid) to 20·1 (alanine–glycine). The extractive and loading capability of the extractants for the amino acids was found to decrease in the order DNNSA>D2EHPA(S)>D2EHPA>Versatic 10, which follows the reverse order of their respective acid dissociation constants. DNNSA was shown to be a promising extractant for the extraction and fractionation of amino acids. © 1998 SCI