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本文研究了Cd(Ⅱ)在三正辛胺-煤油支撑液膜体系中的影响Cd(Ⅱ)迁移的各种因素,并测定了有关条件下Cd(Ⅱ)跨越膜的渗透系数P。结果表明,膜相载体三正辛胺浓度适度增加,Cd(Ⅱ)迁移的渗透系数P增加,三正辛胺增至0.8mol/L时,P值下降,搅拌转速,料液中H^+浓度和Cd(Ⅱ)浓度,温度的影响Cd(Ⅱ)的迁移,反萃剂醋酸铵比氢氧化钠好,煤油比四氧化碳更适宜作膜溶剂,三正辛胺-煤油支撑液膜体系能 相似文献
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Cu2+在支撑液膜中的传质过程 总被引:1,自引:0,他引:1
研究了以疏水性多孔聚丙烯膜(Celgard 2500)为支撑体和LIX984的煤油溶液为膜液的支撑液膜体系萃取Cu2+的传质过程. 采用双膜理论描述Cu2+通过平板支撑液膜的传质过程,建立了其在稳态下的传质动力学方程,且当反萃取侧酸浓度大于2 mol/L时,反萃取侧的传质阻力可以忽略;利用膜内分传质系数km表征支撑液膜膜液的流失行为,在传质过程中,km先增大而后逐渐减小,且载体的流失速率大于稀释剂煤油的流失速率. 考察了操作条件对传质和膜液流失速率的影响,结果表明,Cu2+初始传质通量随载体初始浓度、料液初始pH值和料液初始Cu2+浓度的增大而增大;载体初始浓度越大,膜液流失越快;料液初始Cu2+浓度增大,膜液流失越慢;料液相pH值的改变对膜液流失速率没有影响. 相似文献
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分散支撑液膜中四价铈的传输分离 总被引:1,自引:0,他引:1
研究了以聚偏氟乙烯膜(PVDF)为液膜支撑体,煤油为膜溶剂,2-乙基己基磷酸-单-2-乙基己基酯(PC-88A)为流动载体,煤油和PC-88A的混合溶液作为膜溶液,膜溶液和HCl溶液组成分散相的分散支撑液膜(DSLM)中Ce(IV)的传输行为;考察了料液相酸度、Ce(IV)起始浓度、HCl浓度、膜溶液与HCl溶液体积比、解析剂及载体浓度对Ce(IV)传输的影响,得出其最优传输分离条件为:HCl浓度4.0 mol/L,膜溶液与HCl溶液体积比2:1,载体浓度0.16 mol/L,料液相中HCl浓度0.1 mol/L. 在最优条件下,料液相中Ce(IV)的初始浓度为0.7′10-4 mol/L时,迁移75 min,其迁移率达到96.3%. 提出了Ce(IV)在DSLM中的传质动力学方程,得出Ce(IV)在膜中的扩散系数为6.69′10-8 m2/s,料液-膜边界层厚度为19.3 mm. 对模拟样品Ce(IV)的分离结果表明,在一定条件下,125 min内模拟煤粉灰中Ce(IV)迁移率达到92.8%;105 min内模拟冶金熔渣中其迁移率可达92.6%;215 min内Ce(IV)与Eu(III)的混合液中Ce(IV)迁移率达到83%,其他元素迁移率极低. 相似文献
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以三异辛胺(二甲苯)液从盐酸介质中萃取锌,与大量镍分离。有机相以氢氧化钠液反萃,以盐酸中和反萃水液,直接配成1摩尔氯化钠底液,极谱测定。铬(Ⅵ)及大量铁(Ⅲ)干扰可在萃取时加抗坏血酸消除。含锌为0.1—14微克/毫升 相似文献
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分别应用二(2-乙基己基)二硫代磷酸(D2EHDTPA)和D2EHDTPA-三辛胺(TOA)协萃体系进行了锌、镉分离的研究。D2EHDTPA萃取锌和镉的等摩尔系列法、红外光谱、核磁共振的测试结果表明,萃合物的组成可能为CdA_2和ZnA_2。应用D2EHDTPA-甲苯体系时,镉容易完全萃取,但有机相中的镉很难反萃下来。应用D2EHDTPA和TOA组成的协萃体系时,镉能从硫酸锌溶液中选择性萃取,也能很容易地从有机相中反萃下来,实现镉与锌的分离。萃取速度的控制步骤是界面反应。 相似文献
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以LIX984N为载体,煤油为稀释剂,H2SO4为反萃剂,研究了中空纤维更新液膜过程中铜的传递行为。考察了两相压差、铜离子浓度、两相流速、操作方式以及膜丝有效长度等对传质过程的影响。结果表明:膜丝两侧的操作压差对传质过程几乎没有影响;随着料液相中溶质Cu(Ⅱ)浓度的增大传质通量增大,而反萃相中的Cu(Ⅱ)浓度对传质过程几乎没有影响;传质通量会随着壳程料液流速的增大而增大,但管程侧反萃相的流速对传质过程影响很小;逆流和并流两种操作方式对传质过程的影响可以忽略,而膜丝有效长度的增加会导致单位面积平均传质通量的下降。 相似文献
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《分离科学与技术》2012,47(14):2130-2140
A double strip dispersion hybrid liquid membrane (SDHLM) was successfully used in the simultaneous extraction and separation of Cu(II), Zn(II), and Co(II) from Cu-Zn-Co dilute feed phase. In the double SDHLM system, Acorga M5640-loaded membrane was placed between the 1st and the 2nd compartment, whereas the mono(2-ethylhexyl) 2-ethylhexyl phosphonate [HEH(EHP)]-loaded membrane was placed between the 1st and the 3rd compartment of the transport cell. The feed solution was filled in the central feed compartment(1st compartment) of the transport cell. The effect of the different experimental variables on separation was examined. The optimum separation conditions were summarized. An analysis of mass transfer resistances in the double SDHLM system shows that the mass transfer resistance for the diffusion of Zn(II) ions in the microporous membrane phase is dominant and the mass transfer resistances for the diffusion of copper (II) ions in the aqueous boundary layer and in the microporous membrane phase are dominant in comparison with the overall mass transfer resistance. The experiments verify that the double strip dispersion hybrid liquid membrane (SDHLM) possesses the nonequlibrium mass transfer characteristic. 相似文献
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A liquid membrane system, denoted a strip dispersion hybrid liquid membrane (SDHLM) containing 1‐phenyl‐3‐methyl‐4‐benzoyl‐pyrazolone –5 as carrier in xylene, was reported for the transport and separation of Cu(II) from Zn (II) ions. The effects of various factors on the transport of copper(II) ions through SDHLM were systematically investigated by orthogonal tests. The optimum transport conditions of copper ions were summarized. In the overall mass transfer process the mass transfer resistance due to the aqueous boundary layer diffusion and diffusion in the microporous membrane is dominant. The accumulation of the Cu(II)‐carrier coordination compound in the membrane shows that the transfer in SDHLM possesses the characteristic of nonequlibrium mass transfer in this study. The rheologic experiments verified that the organic phase in the SDHLM system was the non‐Newtonian fluid and the organic phase after transport of 6 hr was a system of thixotropy in our experimental conditions. The lag ring experiments proved that the thixotropy of the organic phase in the SDHLM system was relevant to the composition of the membrane. In the experimental comparison of two types of liquid membrane, SDHLM has superiority over SLM in respect of transport flux, permeability coefficient, recovery percentage or concentration of solute in the stripping solution, efficiency of uphill transport, loss of membrane solution, and the separation efficiency of the membrane. 相似文献
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巯基泥炭吸附重金属离子机理研究 总被引:7,自引:0,他引:7
从热力学、动力学及 XPS三个方面探讨了巯基泥炭对重金属离子的吸附机理。结果表明 :吸附过程以化学吸附为主。外表面、内表面对 Zn2 + 的吸附率分别为 1 6% ,84% ;Cu2 + 为 1 7% ,83% ;Pb2 +为 5 % ,95 % ;且吸附 Cd2 +完全由内扩散所控制 相似文献
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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. 相似文献
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固体支撑液膜的传质速率和应用研究 总被引:3,自引:0,他引:3
固体支撑液膜在湿法冶金和现代环境保护中应用十分广泛,是工业废水处理的一种有效的新技术,尤其对含有金属盐类的废水的处理有其独特的优势。在电镀废水和湿法磷酸除镉等领域中曾试用了支撑液膜系统,该系统具有处理能力大,溶剂损失不,除去有关离子的选择性好等特点。为了推广其应用,进一步进行了用三正十二烷基氯化铵固体支撑液膜处理含有锌和镉等的氯化物工业废水的研究,确定了其过程的传质速率,并讨论了分离废水中锌和镉等金属离子的可能性及基本条件。结果证明本方法适合于回收处理含有金属离子的废水,且分离效果好。 相似文献
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《分离科学与技术》2012,47(12):2825-2847
Abstract The separation and concentration of gallium from acidic leach solutions, containing various other ions such as iron, cobalt, nickel, zinc, cadmium, lead, copper, and aluminium, by an emulsion liquid membrane (ELM) technique using tributyl phosphate (TBP) as carrier has been presented. Liquid membrane consists of a diluent, a surfactant (ECA 4360J), and an extractant (TBP), and 0.1 M HCl or 0.1 M H2SO4 were used as the stripping solution. The important variables governing the permeation of gallium and their effect on the separation process have been studied. These variables were membrane type and composition, mixing speed, diluent type, surfactant concentration, extractant concentration, HCl concentration in the feed, acid type of stripping phase, feed concentration, and treatment ratio. The optimum conditions were determined. It was possible to selectively extract 96.0% of gallium from the acidic leach solutions, containing Fe, Co, Ni, Zn, Cd, Pb, Cu, and Al, at the optimum conditions. 相似文献
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基于电化学理论、膜分离与传质理论,采用非平衡态热力学,建立了熔融盐(43.5% Li2CO2 25%K2CO3 31.5?Na2CO3)(mol.?膜法脱除C02数学模型。首先,根据熔盐体系离子的Hittorf迁移数、比电导、扩散系数等独立实验参数,计算得到体系的Onsager系数和模型参数,然后用计算机求得该模型的数值解。解的结果表明:影响CO2传质通量的因素主要有电流密度及C02在膜两侧的浓度差。在低电流密度下,浓差推动力起主导作用:在较高电流密度下,膜两侧浓差推动力对C02传质影响甚微,电流密度对C02的传质则起着决定性作用。为了进一步验证数学模型,在823K及常压条件下,模拟航天舱中的气体成分,进行了熔融盐膜法脱除CO2的实验研究。实验结果与模型理论解吻合较好。 相似文献