Solvent Extraction of Cyclohexanecarboxylic Acid From Waste Fluid by Using a Mixture of Toluene and 1-Octanol

Solvent extraction studies have been carried out for the recovery of cyclohexanecarboxylic acid (CCA) from simulated waste fluid. Influences of various parameters including extractant types, pH of the solution, equilibration time, and initial concentrations of CCA, etc., were studied. A mixture of toluene and 1-octanol (90:10, v/v) was found suitable for the extraction. The results showed that solution pH had a great effect on the distribution ratio, and CCA could be efficiently extracted when the pH was lower than 3.5. The extraction was found quite rapidly. The distribution ratio decreased as the initial concentration of CCA increased. The stripping rate of CCA using sodium hydroxide as stripping agent was found to be increased with the increase of alkali concentration. After back extraction once, more than 98% stripping efficiency was achieved with 0.8 mol/L sodium hydroxide solution at aqueous to organic phase (A/O) ratio 1:1 when CCA concentration was lower than 38.3 g/L. The practical extraction process was carried out for the waste fluid (concentration of CCA 36.5 g/L) discharged in the production of caprolactam from toluene. After four extraction stages at A/O ratio 1:1, the cumulative extraction recovery reached 99.3%. The practical stripping efficiency from loaded organic phase reached 98.2% in one single stage.     

EXTRACTION OF NICKEL FROM AQUEOUS SULFATE SOLUTION INTO BIS(2,2,4-TRIMETHYLPENTYL)PHOSPHINIC ACID,CYANEX 272TM -EQUILIBRIUM AND KINETIC STUDIES

ABSTRACT

Equilibrium and kinetic studies have been carried out on the extraction of nickel from sulfate solutions using bis(2,2,4 trimethylpentyl) phosphinic acid HDTMPP, “Cyanex 272tm”- It was found that nickel extraction in HDTMPP was favored by the presence of sodium in the organic phase and that equilibrium nickel concentration could be written in terms of the pre-equilibrated extractant concentration

Kinetic studies were carried out using the rising drop method, reaction orders were determined with respect to the aqueous phase nickel concentration, Ni²⁺, the aqueous phase sodium concentration, Na ⁺ the pH, the organic phase dimer concentration ------ and the organic phase sodium salt concentration ---- In addition, it was found that the extraction kinetics could be explained in terms of an aqueous phase interfacial reaction accompanied by diffusion through the interface. Mass transfer coefficient values were determined indicating extraction rates for metal extraction into HDTMPP were the same order of magnitude as those found for HDEHP.     

Studies Related to the Processing of U–Zr and U–Pu–Zr Metallic Fuels Using Tri-iso-amyl Phosphate (TiAP) as Extractant

Metallic fuel is reprocessed by a compact nonaqueous pyrochemical process. The present study explores the possible uses of an aqueous reprocessing-based method as an alternative to the pyro-processing of metallic fuels. Solvent extraction studies in the batch mode were carried out for both U–Zr- and U–Pu–Zr-based metal alloy systems. Earlier studies carried out in our laboratory have established that Tri-iso-amyl Phosphate (TiAP) is a promising extractant for the reprocessing of spent fuels. In the present study, the distribution data has been generated for the extraction of uranium and zirconium as a function of equilibrium aqueous phase metal ion and nitric acid concentration with TiAP and Tri-n-butyl Phosphate (TBP)-based solvents. These studies indicate the formation of a third phase with zirconium in the presence of uranium with TBP under certain experimental conditions whereas it was not encountered with the TiAP system. Flow sheet for the co-extraction and co-stripping of heavy metal ions by 1.1M TiAP and 1.1M TBP in n-dodecane from U–Zr as well as U–Pu–Zr feed solutions in stage-wise mode has been evaluated. Percentage extraction and stripping of metal ions were calculated stage-wise and the results are discussed.     

Studies on the Development of a Flow-Sheet for AHWR Spent Fuel Reprocessing Using TBP

The present paper describes the results of solvent extraction studies carried out in batch mode to collect data on distribution of uranium, plutonium, and thorium using 5% TBP in n-dodecane. Extraction studies are carried out from feed solutions having bulk thorium containing aluminum and fluoride ions in ～3.00–4.00 M nitric acid at concentration levels anticipated in feed solutions during Advanced Heavy Water Reactor (AHWR) spent fuel reprocessing. Studies are carried out under varied experimental conditions. Parameters such as organic to aqueous phase ratio during extraction, concentration of nitric acid for scrubbing co-extracted thorium from loaded organic phase etc., are studied in detail. Hydroxylamine nitrate is selected for reductive stripping of plutonium in preliminary studies. Reagent mixture containing 0.30 M HAN + 0.60 M HNO₃ and 0.20 M N₂H₄ is found to be optimum for plutonium partitioning. This paper also describes the extraction and stripping of uranium and plutonium in co-current mode. The extraction behavior of relevant fission products is studied from a simulated feed solution. A preliminary study on a few commercially available reducing agents is also included. These data are useful in developing a flow-scheme for the recovery of uranium and plutonium from spent fuel originating from AHWR.     

吡啶从硝酸介质中萃取铀(VI)的研究

研究了新萃取剂吡啶从硝酸介质中萃取铀的机理。考察水相硝酸浓度、萃取剂浓度、盐析剂硝酸钠以及振荡时间和温度对萃取分配比的影响 ,确定了萃合物的组成。求得萃取硝酸铀酰过程的平衡常数及反应的热力学函数。同时研究了相比的影响 ,以及稀释剂的影响。发现吡啶萃取能力在不同稀释剂中由弱到强的顺序为 :四氯化碳、氯仿、苯、甲苯、环己烷、煤油。     

磁性流体固定床萃取分离低浓度金离子

采用一种全新的快速萃取方法--磁性流体固定床萃取分离技术,该方法是将磁性Fe₃O₄纳米颗粒表面包覆油酸,溶于有机溶剂中,加入萃取剂三苯基氧化膦TPPO,制成磁性萃取剂。借助于高梯度磁性分离装置,对目标离子进行萃取分离。萃取完成后通过原子吸收光谱仪测定萃取后金溶液中Au³⁺的浓度。通过对铁磁导线直径、初始金溶液pH值、萃取剂体积分数和协同萃取等影响因素的考察,得出了对Au³⁺浓度为19.128 mg·L^-1的氯金酸溶液进行萃取分离的最佳工艺：采用直径为2.34 mm的铁磁导线作为磁性填充介质时萃取率较其他优越。初始金溶液的pH值和萃取剂的体积分数对萃取率影响较大。在初始金溶液pH=1,萃取剂(TPPO)体积分数达到50%时萃取率最高。使用TPPO和TBP协同萃取也能提高萃取率。采用浓度为1 mol·L^-1的硫脲进行反萃实验,振荡10 min,反萃率在90%以上。     

Reactive Extraction of Levulinic Acid Using TPA in Toluene Solution: LSER Modeling,Kinetic and Equilibrium Studies

Abstract

Levulinic acid, a carboxylic acid containing ketone structure, is a clear to brownish semi‐solid melting at 37°C; soluble in alcohol, ether, and chloroform, levulinic acid can be used as an acidulant in foods and beverages. Organic solutions of amines are being used increasingly to separate organic acids from aqueous mixture solutions by reactive extraction. The design of an amine extraction process requires kinetic data for the acid–amine+solvent system used. Kinetic studies for the extraction of levulinic acid from aqueous solution with tripropylamine (TPA) diluted in toluene were carried out using a stirred cell for kinetic studies. Equilibria for levulinic acid extraction by TPA in toluene as a diluent have been determined. All measurements were carried out at 298.15 K. The equilibrium data were also interpreted by a proposed mechanism of complexation by which (1∶1) and (2∶1) acid‐amine complexes are formed. Kinetics of extraction of levulinic acid by TPA in toluene has also been determined. The results of the liquid‐liquid equilibrium measurements were correlated by a linear solvation energy relationship (LSER).     

Solvent extraction of gold by LIX 79: experimental equilibrium study

The extraction of gold(I) from aurocyanide aqueous solutions using LIX 79 has been studied. Different variables that could affect the extraction system were evaluated: equilibration time, aqueous pH, metal and extractant concentrations, organic phase diluent and aqueous ionic strength. The extraction of the aurocyanide complex with respect to other metal‐cyano complexes has also been studied on both synthetic and real leach solutions. Gold experimental data have been analysed numerically to determine the stoichiometry of extracted species and its equilibrium constant. It was found that gold(I) was extracted into the organic phase by the formation of the species RHAu(CN)₂ (LIX 79=R). Stripping of gold from loaded organic phases was carried out using NaOH or NaCN solutions. © 1999 Society of Chemical Industry     

PERIODIC VARIATIONS OF LANTHANIDES YKERGIC EXTRACTION BY THENOYLTRI-FLUOROACETONE AND TRIPHENYLPHOSPHINE OXIDE MIXTURE∗

Abstract

The synergic extraction of the different lanthani-des, except Pm and Lu, by thenoyltrifluoroacetone (HTTA) and triphenylphosphine oxide (TPPO) mixture in benzene from an aqueous perchlorate medium of constant ionic strength of 0·2 was investigated. It was found that the main adduct extracted contains the lanthanide chelates together with two TPPO molecules. The different extraction and formation constants for the lanthanides investigated have been determined. The variations of the logarithmic values of the chelate extraction constant and the adduct formation constant with the different lanthanides was discussed in the light of the tetrad and the inclined-W effects. The experimental results showed that the nature of coordination by adduct formation for the Yb-Sm group is different than that of the Pr-La group.     

Extraction Behavior of Uranium(VI) with Polyurethane Foam

Abstract

The extraction of uranium(VI) from aqueous solution with polyether-based polyurethane (PU) foam was studied. The effects of the kinds and concentrations of nitrate salts, uranium(VI) concentration, temperature, nitric acid concentration, pH, the content of poly(ethylene oxide) in the polyurethane foam, and the ratio of PU foam weight and solution volume on the extraction of uranium(VI) were investigated. The interferences of fluoride and carbonate ions on the extraction of uranium(VI) were also examined, and methods to overcome both interferences were suggested. It was found that no uranium was extracted in the absence of a nitrate salting-out agent, and the extraction behaviors of uranium(VI) with polyurethane foam could be explained in terms of an etherlike solvent extraction mechanism. In addition, the percentage extraction of a multiple stage was also estimated theoretically.     

Response Surface Modelling and Optimization of Mercury Extraction through Emulsion Liquid Membrane

Mercury(II) is a very harmful metal, highly toxic, and carcinogenic in nature. Experiments were carried out using the emulsion liquid membrane (ELM) technique in order to evaluate the maximum extraction of mercury(II) from aqueous solutions of mercuric chloride using 3³ factorial design. The ELM consisted of di-2-ethylhexylphosphoric acid as a carrier, toluene as an organic solvent, span 80 as a surfactant, and sulphuric acid with thiourea solution as stripping phase. The three factors for the factorial design were mercury(II) concentration in the aqueous solution, that is, feed phase concentration, carrier concentration in the membrane phase, and sulphuric acid concentration in the stripping phase. The study has also highlighted the effects of various other parameters, such as pH of the feed phase and thiourea concentration on mercury(II) extraction. The optimization of the factors to obtain maximum extraction were carried out by incorporating main effect plots, interaction plots, analysis of variance (ANOVA), normal probability plots, residual plots, surface plots, and contour plots. A reduced model developed by regression analysis was suggested in which the experimental data were fitted very well. The results showed that it is possible to extract mercury(II) up to 98% from aqueous solutions at the optimum conditions.     

Studies on the Separation and Recovery of Uranium from Phosphoric Acid Medium Using a Synergistic Mixture of (2-Ethylhexyl)phosphonic Acid Mono 2-Ethyl Hexyl Ester (PC-88A) and Tri-n-octylphosphine Oxide (TOPO)

This paper deals with studies on the extraction of uranium(VI) from phosphoric acid medium using (2-ethylhexyl)phosphonic acid mono 2-ethylhexyl ester and tri-n-octylphosphine oxide individually as well as from their synergistic mixture. Different extraction parameters were investigated. With an increase in phosphoric acid concentration in the aqueous phase, the distribution ratio (Du) was found to decrease in all the cases. Synergism was observed when a mixture of PC-88A and TOPO was used. The synergistic mixture in the mole ratio of 4:1 (1.80 M PC-88A: 0.45 M TOPO) in xylene was found to be most suitable for uranium extraction. Among the various strip liquors used, 5% (w/v) solution of (NH₄)₂CO₃ was found to be the most suitable. Using a mixture of 1.8 M PC-88A and 0.45 M TOPO as the extractant system and 0.5 M ammonium carbonate as the stripping agent, uranium recovery was found to be better than 97% ± 3% in multiple contacts, (n = 2) from actual Davies Gray Waste while in case of wet phosphoric acid more than 52% ± 3% (n = 3) only could be recovered where n is the number of contacts.     

Liquid-Liquid Extraction of Uranium(VI) from Aqueous Solution using 1-Hydroxyalkylidene-1,1-diphosphonic Acids

The extraction of uranium(VI) from aqueous solutions has been investigated using 1-hydroxyhexadecylidene-1,1-diphosphonic acid (HHDPA) and 1-hydroxydodecylidene-1, 1-diphosphonic acid (HDDPA), which were synthesized and characterized by elemental analysis and by FT-IR, ¹H NMR, ³¹P NMR spectroscopy. In this article, we propose a tentative assignment for the shifts of those two ligands and their specific complexes with uranium(VI). We carried out the extraction of uranium(VI) by HHDPA and HDDPA from [carbon tetrachloride?+?2-octanol (v/v: 90%/10%)] solutions. Various factors such as contact time, pH, organic/aqueous phase ratio, and extractant concentration were considered. The optimum conditions obtained were: contact time?=?20 min, organic/aqueous phase ratio?=?1, pH value?=?3.0, and extractant concentration?=?0.3 M. The extraction yields are more significant in the case of the HHDPA which is equipped with a hydrocarbon chain, longer than that of the HDDPA. Logarithmic plots of the uranium(VI) distribution ratio vs. pH_eq and the extractant concentration showed that the ratio of extractant to extracted uranium(VI) (ligand/metal) is 2:1. The formula of the complex of uranium(VI) with the HHDPA and the DHDPA is UO₂(H₃L)₂ (HHDPA and DHDPA are denoted as H₄L). A spectroscopic analysis showed that coordination of uranium(VI) takes place via oxygen atoms.     

氯仿萃取回收己内酰胺的研究

以萃取回收甲苯法生产己内酰胺废液中的己内酰胺为目的,选择氯仿作萃取剂,进行了萃取回收己内酰胺的研究。考察了原料液的pH、萃取温度、萃取时间等因素对氯仿萃取己内酰胺过程的影响。结果表明,在酸性条件下该萃取过程分配比随pH的升高而增大,当pH=7时分配比最大;萃取过程为快速过程,20 min即可达到萃取平衡;水相中硫酸铵和1-磺酸基环己烷羧酸对萃取过程有盐析效应,使分配比增大;萃取过程受温度影响不大,焓变值ΔH=2.86 kJ/mol。实验确定了pH=7时己内酰胺在有机相与水相中的分配平衡关系,当有机相和水相体积比为1时,三级错流萃取的萃取率可达到98%以上。同时,进行了工业废水的萃取验证实验,结果表明,氯仿对废水中己内酰胺的萃取效果良好。     

磷酸三丁酯－煤油从浓酸溶液中萃取Zr的第三相行为

本文研究了磷酸三丁酯（ＴＢＰ）在煤油中从浓硝酸和盐酸溶液中对Ｚｒ（Ⅳ）的萃取，考察了室温了初始Ｚｒ浓度、ＴＢＰ浓度以及水相酸度对萃取的影响，同时确定了体系第二相的形成条件．发现酸同Ｚｒ被—同萃取，酸度越高则萃取率越大，较高的酸度和Ｚｒ（Ⅳ）浓度易使萃取有机相分相．用红外光谱研究了第三相的组成，用Ｋａｒｌ－Ｆｉｓｃｈｅｒ滴定法和电导率仪分别测定了第三相的水含量和比电导，对可能的萃合物结构进行了推测，认为从胶体化学看第三相可能是一种具有双连续相结构的微乳液．     

Extraction of El-Lajjun Oil Shale

Abstract

Extraction of the bitumen fraction of El-Lajjun oil shale was carried out using 17 different solvents, pure and combined. Out of all the solvents used, toluene and chloroform were found to be the most efficient for extraction of the bitumen to perform the major part of the experiments. This selectivity was based on the quality and quantity of the yield and on the quantity of solvent recovered. Extraction was carried out using a Soxhlet extractor. For complete recovery of solvent the extract phase was subjected to two stages of distillation, simple distillation followed by fractional distillation, where different cuts of oil were obtained. It was found that an optimum shale size of 1.0 mm offered better solvent recovery. One hour was the optimum time needed for complete extraction. The yield of oil was determined from the material balance gained from fractional distillation after testing for the existence of any traces of solvent trapped in the different cuts by using a gas chromotography technique. When chloroform was used, it was found that the average amount of bitumen extracted was 0.037 g/g of shale, which corresponds to 98% of the actual bitumen trapped in the oil shale (by assuming the bitumen represents 15% of the organic matter) and 84.1% of solvent recovered. When toluene was used, it was found that the average amount of oil extracted was 0.0293 g/g of shale, which corresponds to 78% of the actual bitumen trapped in the oil shale (by assuming bitumen represents 15% of the organic matter) and 89.9% of solvent for extraction with toluene.     

Extraction of phenols: Ii. distribution data for binary and multicomponent mixtures of phenols,countercurrent extraction performance and model validation

The distribution of binary mixtures of phenol with o-, m- or p-cresol between aqueous solutions of NaOH and toluene or methyl-isobutyl-ketone (MIBK) was investigated. A mathematical model of the distribution was formulated and its parameters were evaluated for each phenol/cresol/solvent combination. The extraction of phenolics from a coal tar fraction with aqueous solutions of sodium phenates was carried out in a countercurrent cascade of four equilibrium stages. The back extraction of phenolics from the aqueous extract was carried out as a triple extraction with pure solvent. A mathematical simulation of the multicomponent, multistage experiments was realized with the DOOM algorithm using an extension of the equilibrium model, formulated for binary mixtures.     

Extraction of toluene,o-xylene from heptane and benzyl alcohol from toluene with aqueous cyclodextrins

The separation of aromatic compounds (toluene and o-xylene) from heptane and of benzyl alcohol from toluene with aqueous solutions of cyclodextrins has been experimentally investigated, because cyclodextrins and its derivatives can selectively incorporate several organic compounds, whereas the separation of the aqueous solution of complexed cyclodextrins from the organic feed is simple. Cyclodextrins are not soluble in organic liquids, but cyclodextrin derivatives are highly soluble in water. Hydroxypropyl-β-cyclodextrins with different degrees of substitution and methylated β-cyclodextrin were selected for the extraction of toluene and o-xylene from heptane. Hydroxypropyl-β-cyclodextrin (two different substitution degrees) and hydroxypropyl-α-cyclodextrin were selected for the extraction of benzyl alcohol from toluene. The liquid–liquid distribution experiments were carried out at room temperature. Toluene and o-xylene form 1:1 complexes with different cyclodextrins and heptane can form 1:1 to 1:3 complexes. Benzyl alcohol forms 1:3 complexes with hydroxypropylated cyclodextrins. The models developed describe the experimental data reasonably well, considering the large deviations in the analyses.Aqueous cyclodextrin solutions are not feasible for the separation of aromatic components from aliphatic hydrocarbons, due to low distribution ratios of toluene (0.05) and o-xylene (0.023) between the aqueous and organic phase. With high distribution ratios of benzyl alcohol, between 0.3 and 2.2 depending on the CD concentration (at a solvent-to-feed ratio of 1) and a benzyl alcohol/toluene selectivity of at least 100, aqueous hydroxypropylated cyclodextrin solutions have sufficient potential for extracting benzyl alcohol from toluene.