Cyanex 923从硫酸体系中萃取钪及其与P507和环烷酸的比较

稀土元素钪(Sc)在相关原料中含量低,伴生杂质元素多,回收困难。针对这一问题,本文系统对比了直链三烷基氧化膦(Cyanex 923)、2-乙基己基磷酸单-2-乙基己基酯(P507)、环烷酸在硫酸体系中对Sc的萃取、分离和反萃。Cyanex 923在高酸度下能完全萃取Sc,而环烷酸和P507则在低酸度下有较高萃取率。Cyanex 923分离Sc与锆(Zr)、钛(Ti)的最佳水相酸度为1 mol/L,分离系数分别为5. 6和10. 6。P507在水相H~+浓度为2 mol/L时对Sc/Zr、Sc/Ti有最大分离系数,分别是21和59. 7。虽然P507有更好的分离效果,但难以反萃。3种萃取剂中仅有Cyanex 923能被有效反萃,在反酸H+浓度为0. 4 mol/L时有最大反萃率。因此,Cyanex 923更适合从含Sc二次资源浸出液中分离回收Sc。     

分散支撑液膜体系中Pb2+离子的传输

在现有支撑液膜分离技术的理论研究基础上,探索合适的液膜分离体系,研究了Pb(Ⅱ)在PC-88A-煤油-HCl分散支撑液膜体系中的传输行为;考察了料液pH值、膜溶液与解析剂体积比、解析相中HCl浓度以及Pb(Ⅱ)的起始浓度对Pb(Ⅱ)传输的影响。 结果表明,以HCl为解析剂,料液相pH=5.25、膜溶液与解析剂体积比为160∶40、解析相中HCl浓度为5.00 mol/L时,该分散支撑液膜体系对金属Pb(Ⅱ)具有良好的传输作用。 在选取的最佳传输条件下,料液相中Pb(Ⅱ)的初始浓度为3.00×10-4 mol/L时,传输190 min,传输率可达88.9％,而传统支撑液膜只有72.3％。 分散支撑液膜不仅具有较高的传输效率,而且膜体系稳定,膜的使用寿命长。     

含P507微胶囊萃取水相中稀土的迁移行为

分别用乙基纤维素和海藻酸钙作为膜材，将Ｐ５０７（２－乙基己基鳞酸单２－乙基己基酯）微胶囊化。将这两种含萃取剂的微胶囊用于萃取Ｌａ３＋、Ｎｄ３＋和Ｌｕ３＋，可以将这些离子富集于微胶囊内。由于固体膜对芯材固定化和对离子的阻障作用，使萃取的传质过程发生了变化。以渗透系数来比较三种离子的传质速度，改变原料液的ｐＨ，可使离子的渗透系数改变，从而增大离子间渗透系数的差值。用６ｍｏｌＬ－１的ＨＣｌ对微胶囊内稀土离子进行反萃取，可以定量地富集稀土。     

二(2,4,4-三甲基戊基)膦酸在中空纤维膜器中萃取镱、铒及传质研究

中空纤维膜萃取技术是将液液萃取过程与膜过程相结合的新型分离技术．二（２,４,４三甲基戊基）膦酸（ＨＢＴＭＰＰ,ＨＬ）萃取稀土及其它高价金属离子时所需水相酸度低,反萃容易,加之空间位阻等因素,很可能成为优于２乙基己基膦酸单２乙基己基酯（ＨＥＨ／...     

二-(2-乙基己基)磷酸-煤油液膜萃取锌(Ⅱ)的动力学分析

锌离子;二乙基己基磷酸;迁移动力学;二-(2-乙基己基)磷酸-煤油液膜萃取锌(Ⅱ)的动力学分析     

乳状液-中空纤维膜萃取钕及其传质性能研究

采用非分散的萃取方式,将乳状液膜体系Span80/皂化D2EHPA/煤油/液体石蜡/盐酸通过中空纤维膜对钕进行了逆流萃取,研究了乳化剂浓度、乳状液与水相流量比、内相盐酸浓度、萃取时间等因素对萃取率的影响。结果表明,乳状液和水相流量越小、乳状液内相盐酸浓度越大,萃取率越高,内相富集倍数越大。将乳液循环萃取70次后,内相富集倍数达50.2,表明乳状液在中空纤维膜萃取器中对稀土有很好的萃取和富集效果。与乳状液膜的分散萃取方式相比,非分散萃取方式的萃取速率更快,而且萃余水相澄清,液膜稳定性好,泄漏少,膜溶胀小。同时还计算了非分散萃取过程基于水相的总传质系数实验值和理论值,当调节参数Kf(络合反应传质系数)的取值为3.5×10-9m.s-1,水相流量大于10×10-6m3.s-1时,实验值与理论预测值相吻合。     

含载体D2EHPA的更新型支撑液膜体系对三价钆的分离

研究了以聚偏氟乙烯膜为支撑体, 二-(2-乙基己基)磷酸(D2EHPA)为流动载体, 煤油和D2EHPA的混合溶液作为膜溶液, 膜溶液和解析剂HCl溶液组成更新相的更新型支撑液膜(RSLM)中Gd(III)的分离行为|考察了料液pH、更新相HCl浓度、膜溶液与HCl溶液体积比、不同载体浓度对Gd(III)分离的影响, 得出了Gd(III)最优分离条件为: 更新相HCl溶液浓度4.00 mol/L, 膜溶液与HCl溶液体积比4∶3, 载体浓度控制在0.160 mol/L, 料液相中pH为4.80. 在最优分离条件下, 当Gd(III)的初始浓度为1.00×10^－4 mol/L时, 35 min Gd(III)分离率达到95.7%. 最后根据传质定律和界面化学理论提出了Gd(III)在RSLM中的传质动力学方程.     

聚偏氟乙烯中空纤维膜器对钐传质性能的影响

以Ｐ５０７－煤油ＨＣｌ－Ｓｍ为实验体系,在两种聚偏氟乙烯中空纤维膜器中研究了溶胀性能、反萃酸度对基于水相的总传质系数及中空纤维膜孔径的影响,考察了料液酸度、萃取剂浓度、钐离子浓度与萃取速率的关系。获得了相应的反应级数。根据界面反应动力学,得到了速率常数值和动力学方程。     

2-乙基己基膦酸单2-乙基己基酯与钕的萃合物在正己烷溶液中的结构研究

2-乙基己基膦酸单2-乙基己基酯[HEH(EHP)]是一种良好的萃取剂, 已被广泛地应用于稀土和钴和镍的分离[1,2]。对于它的萃取性能和机理已作过大量的研究。本文针对用HEH(EHP)萃取分离稀土时必须保证萃取剂与有机相稀土含量的摩尔比大于6, 否则即发生乳化现象, 利用蒸气压渗透法及红外光谱为手段, 研究了HEH(EHP)与钕所生成的萃合物在溶液中的存在形式及结构, 阐明发生乳化及破乳过程的实质。     

在线液液液微萃取-电动流动分析系统测定水中挥发酚类化合物总量

采用在线液液液微萃取(LLLME)富集净化和电动流动分析(EFA)系统测定水中挥发酚类化合物折合苯酚总量.EFA系统由一台自制电渗泵和4个电磁切换阀组成,计算机控制泵运作和阀切换.结果表明:在聚丙烯中空纤维膜壁上涂十二醇液膜,管内充10 μL 0.25 mol/L NaOH反萃液,试样以2.0 mL/min流量流经萃取通道7.5次循环,1.0 mL样品体积的富集倍数为53,分析时间为 9 min,挥发酚类化合物折合浓度线性范围为9.4×10-3～5.7 mg/L苯酚,检出限为3 μg/L苯酚,远低于一和二级污水排放中挥发酚类化合物的最大允许量;6.0 mL样品体积的富集倍数为300,挥发酚类化合物折合浓度线性范围为1.7×10-3～1.0 mg/L苯酚,检出限为0.6 μg/L苯酚,低于Ⅰ和Ⅱ类地面水中挥发酚类化合物的最大允许量.     

Separation of Trivalent Samarium through Facilitated Stripping Dispersion Hollow Fiber Liquid Membrane Using p204 as Mobile Carrier

The separation of Sm(III) through stripping dispersion hollow fiber liquid membrane system (SDHFLM) containing feed phase adding acetate buffer solution and dispersion solution with HCl solution as the stripping solution and membrane solution of di(2‐ethylhexyl) phosphoric acid (p204) dissolved in kerosene, has been studied. A set of factors were studied, including pH value, initial concentration of Sm(III) and different ionic strength of feed phase, volume ratio of membrane solution and stripping solution (O/W), HCl concentration, carrier concentration, different stripping agents of dispersion phase on Sm(III) separation. Experimental results indicate that the optimum separation conditions of Sm(III) were obtained as that HCl concentration was 4.00 mol/L, p204 concentration was 0.150 mol/L, and volume ratio of membrane solution and stripping solution (O/W) was 1.00 in the dispersion phase, and pH value was 4.60 in the feed phase. Ionic strength had no obvious effect on separation of Sm(III). When initial Sm(III) concentration was 1.00×10^?4 mol/L, the separation rate of Sm(III) was up to 93.5% in 85 min. The kinetic equation was developed in terms of the law of mass diffusion and the theory of interface chemistry. The modeled results were in good agreement with the experiment data.     

Simultaneous reactive extraction separation of amino acids from water with D2EHPA in hollow fiber contactors

Reactive extraction separation of binary amino acids from water using a microporous hollow fiber has been studied, in which the acidic extractant di(2-ethylhexyl)phosphoric acid (D2EHPA) was selected as an active carrier dissolved in kerosene. l-Phenylalanine (Phe) was extracted from an aqueous solution through the shell side of module to the organic phase through the lumen of fiber in the extraction module, in which l-Phe was then back-extracted to stripping phase in stripping module. Experiments were conducted as a function of the initial feed concentration of equimolar Phe and l-aspartic acid (l-Asp) (5 mol/m³), feed pH (3–5), the carrier concentration (0.1–0.5 mol/dm³), and stripping acidity (0.1–2 mol/dm³). The effect of process variables on the separation factor of Phe/Asp and the possible transport resistances including aqueous-layer diffusion, membrane diffusion, organic-layer, and interfacial chemical reaction were quantitatively studied and discussed. The high separation factor (β) of Phe/Asp was obtained to be 18.5 at feed pH 5 and 2 mol/dm³ of strip solution (HCl). The extraction and stripping processes appear to rely on pH dependence of the distribution coefficient of amino acids in reactive extraction system. The separation factor (β) was enhanced in hollow fiber membrane (HFM) process compared with conventional solvent process, which was a result of the counter transport of hydrogen ions.     

Stripping dispersion hollow fiber liquid membrane containing carrier PC-88A and HNO3 for the extraction of Sm3+

Stripping dispersion hollow fiber liquid membrane system（SDHFLM） containing feed phase adding acetate buffer solution and dispersion solution with HNO₃ solution as the stripping solution and membrane solution of 2-ethyl hexyl phosphoric acid-mono-2-ethylhexyl ester（PC-88A） dissolved in kerosene,has been studied for the extraction of Sm³⁺.Many factors including pH value, volume ratio of membrane solution to stripping solution（OAV） and carrier concentration on Sm³⁺ extraction were investigated. Experimental results indicate that the optimum extraction conditions of Sm³⁺ were obtained as that PC-88A concentration was 0.120 mol/L,and OAV was 1.00 in the dispersion phase,and pH value was 4.80 in the feed phase.When initial Sm³⁺ concentration was 1.20×10^-4 mol/L,the extraction percentage of Sm³⁺ was up to 92.8%in 160 min.     

Transport of Tb3+in Dispersion Supported Liquid Membrane System with Carrier P507

The Tb³⁺ transport in dispersion supported liquid membrane (DSLM) consisting of polyvinylidene fluoride membrane (PVDF) as the liquid membrane support and dispersion solution including HCl solution as the stripping solution and 2‐ethyl hexyl phosphonic acid‐mono‐2‐ethyl hexyl ester (P507) dissolved in kerosene as the membrane solution, has been studied. The effects of pH value, initial concentration of Tb³⁺ and different ionic strength in the feed phase, volume ratio of membrane solution and stripping solution, concentration of HCl solution, concentration of carrier, different stripping agents in the dispersion phase on transport of Tb³⁺ has also been investigated, respectively. As a result, the optimum transport conditon of Tb³⁺ was that concentration of HCl solution was 4.0 mol/L, concentration of P507 was 0.10 mol/L, and volume ratio of membrane solution and stripping solution was 1.0 in the dispersion phase, and pH value was 5.2 in the feed phase. Ionic strength had no obvious effect on transport of Tb³⁺. Under the optimum condition studied, when initial concentration of Tb³⁺ was 1.0×10^?4 mol/L, the transport rate of Tb³⁺ was up to 95.2% during the transport time of 95 min. The kinetic equation was developed in terms of the law of mass diffusion and the theory of interface chemistry. The results were in good agreement with the literature data.     

双功能离子液体[A336][P507]在盐酸和硝酸介质中对Sc(Ⅲ)的萃取

利用双功能离子液体萃取剂三辛基甲基氯化铵2-乙基己基磷酸2-乙基己基酯盐([A336][P507])在HCl和HNO₃介质中对Sc(Ⅲ)的萃取和分离。 研究表明,萃取剂在低酸度条件下,对Sc(Ⅲ)有较好的萃取能力;但是当水相酸度从0.5 mol/L增加到4 mol/L,Sc(Ⅲ)的萃取率有较大程度的下降。 并且讨论了在HCl介质和HNO₃介质中,[A336][P507]萃取Sc(Ⅲ)的机理,由于Sc(Ⅲ)的半径最小,而且在萃取过程中存在P=O与P-O的竞争作用,使得其萃合物结构与轻稀土不同。 水相中加入盐析剂NaCl或NaNO₃对Sc(Ⅲ)的萃取有一定的促进作用;萃取过程的热力学参数的结果表明,萃取反应是放热反应。 还研究了混合稀土中Sc(Ⅲ)和其它稀土离子的分离,在较低酸度的条件下萃取剂[A336][P507]对其它稀土离子的萃取可以忽略不计,因此该萃取体系对Sc(Ⅲ)和其它稀土离子有较好的分离效果,显示了本研究潜在的应用价值。     

Studies on extraction of chromium (VI) from acidic solutions containing various metal ions by emulsion liquid membrane using Alamine 336 as extractant

The extraction of chromium (VI) ions from acidic solutions containing various metal ions by emulsion liquid membrane (ELM) was studied. Liquid membrane consists of a diluent, a surfactant, and an extractant. 0.5 M ammonium carbonate solution was used as stripping solution. Effects of acid concentration in feed solution, type and concentration of stripping solution, mixing speed, surfactant concentration, phase ratio and the influence of membrane characteristics were studied and optimum conditions were determined. Under the optimum conditions, extraction of chromium (VI) was tested and it was possible to selectively extract 99% of chromium from the acidic feed solution. This study also examined the effect of extractant concentration and acid type in the feed solution on the extraction of Cr (VI) ions and almost all of Cr (VI) from the acidic feed solution containing 500 mg/L from each of Co (II), Ni (II), Cd (II), Zn (II), and Cu (II) ions, and 100–500 mg/L Cr (VI) was extracted within 5–10 min.     

三正辛胺-二甲苯液膜迁移Cd(Ⅱ)的研究

研究了三正辛胺-二甲苯支撑液膜体系中搅拌速率、反萃剂、三正辛胺浓度、料液中H+浓度等因素对Cd(Ⅱ)离子迁移的影响.用大块液膜测定了不同温度时Cd(Ⅱ)离子跨膜迁移的萃取及反萃取的表观速率常数k₁和k_2.实验表明,温度升高,k₁和k₂均增大(k₁>k₂),且达到膜相最大镉离子浓度时所需的时间逐渐减少.膜相积累的镉离子浓度达最大时,Cd(Ⅱ)离子跨膜传输为稳态传输.根据Arrhenious关系得到膜相萃取反应和反萃取反应的活化能分别为23.8和19.3kJ/mol.     

Tb(III) Transport in Dispersion Supported Liquid Membrane System with D2EHPA as Carrier in Kerosene

The transport of Tb(III) in dispersion supported liquid membrane(DSLM) with polyvinylidene fluoride membrane(PVDF) as the support and dispersion solution including HCl solution as the stripping solution and di(2-ethylhexyl) phosphoric acid(D2EHPA) dissolved in kerosene as the membrane solution, has been studied. The effects of pH value, initial concentration of Tb(III) and different ionic strength in the feed phase, volume ratio of membrane solution to stripping solution, concentration of HCl solution, conc...     

Selective separation of trace nickel(II) and gold(I) ions via hollow fiber supported liquid membrane enhanced by synergistic extractants D2EHPA/TBP

This work presents the selective and simultaneous separation of nickel (Ni²⁺) and gold ([Au(CN)₂]⁻) ions, in trace amounts, from alkaline solution via hollow fiber supported liquid membrane (HFSLM) technique. HFSLM is challengingly carried out in real rinse wastewater generated by the ENIG plating process. The influence of various chemical parameters, including the type of extractant and their concentrations, molar ratios of mixed extractant as well as type of strippant, are also studied. The organophosphorus extractant mixtures of D2EHPA and TBP provide a synergistic effect for target Ni²⁺ ions but has an antagonistic effect as regards the extraction of non-target [Au(CN)₂]⁻ ions. Compared to other inorganic acids, HCl is seen to be the most suitable strippant for the selective stripping. Results demonstrate that percentages of extraction and stripping of Ni²⁺ ions achieved 85.7 and 83.2%, respectively. In contrast, percentages of extraction and stripping of non-target [Au(CN)₂]⁻ ions attained 15.6 and 1.94%.