MODEL OF CHEMICAL REACTION EQUILIBRIUM OF SULFURIC ACID SALTS OF TRIOCTYLAMINE

The chemical reaction of trioctylamine (TOA) and sulfuric acid in organic solvent/aqueous solution was carried out. TOA salt products of various kinds were obtained based on different conditions of operation and organic solvents. An equilibrium model, based on the chemical reaction of sulfuric acid and trioctylamine, is proposed. The equilibrium constants of various reactions of trioctylamine and sulfuric acid were searched by means of the modified LETAGROP-DISTR computer program, from which the sum of the least-square error of the extraction of sulfuric acid per unit concentration of TOA salts was minimized. The corresponding concentration profiles of the various main products as a function of the activity of sulfuric acid in the aqueous solution were also obtained. The activity coefficient of the sulfuric acid in the aqueous phase and the density of the aqueous solution of sulfuric acid were considered in order to evaluate the activity of the sulfuric acid in the aqueous solution more accurately. The results obtained from the proposed model are consistent with that of Wilson's published model.     

KINETICS OF PHENOL EXTRACTION FROM AQUEOUS PHASE BY SULFURIC ACID SALTS OF TRIOCTYLAMINE

The kinetics of the extraction of phenol from the aqueous phase by sulfuric acid salts of trioctylamine (TOA salts) in kerosene and the stripping of phenol from the organic phase by sodium hydroxide solution were studied using a constant interfacial area cell. Measurements of the extraction and stripping rates were made by measuring the time-dependent phenol concentrations in the aqueous phase. It is found that the extraction rate of phenol is strongly dependent on the initial concentration of phenol in the aqueous phase and on the initial concentration of TOA salts in the organic solvent. However, the effect of the total sulfate concentration and the acidic concentration on the extraction rate are not significant. The stripping rate is only a function of the initial concentration of phenol in the TOA salt-organic phase. By analyzing the experimental data, it was recognized that the extraction of phenol occurs at the interface, rather than in the bulk of the solution. The diffusion resistance, rather than the resistance of chemical reaction, is the rate-controlling step for the phenol extraction. Based on the experimental data, simple expressions of the extraction rate and stripping rate of phenol were obtained.     

EXTRACTION MECHANISM OF PHENOL BY SULFURIC ACID SALTS OF TRIOCTYLAMINE

In the present study, the extraction mechanism of phenol from an aqueous solution by sulfuric acid salts of trioctylamine (TOA salts) was investigated. Based on the experimental evidence that the affinity of sulfuric acid and amine is greater than that of phenol and amine, the procedure of the extraction mechanism is assumed to involve two independent steps, i.e., trioctylamine (TOA) is first reacted with sulfuric acid to form TOA salts and phenol is extracted from the aqueous phase by TOA salts. The Wilson model, which accounts for the reaction of trioctylamine and sulfuric acid to form different kinds of TOA-salts, is employed to predict the extraction of phenol in the present study. The number of water molecules in the neighborhood of the different TOA-salts, which directly reflects the extraction capability of phenol, was determined. This prediction from the Wilson model is fairly consistent with the experimental data.     

MASS TRANSFER OF SULFURIC ACID BY TRIOCTYLAMINE THROUGH A SUPPORTED LIQUID MEMBRANE

The extraction of sulfuric acid in a supported-liquid membrane (SLM) process, and the kinetics of extraction and stripping of sulfuric acid in a cell of constant interfacial area by trioctylamine (TOA)/kerosene solvent were investigated. The kinetics of extraction and stripping were determined by examining the effects of the operating variables. The extraction rate is a function of the activity of sulfuric acid and the concentration of TOA; the stripping rate is a function of the concentration of trioctylamine sulfate salts in the organic solution. A generalized transport model, which included the film diffusion of sulfuric acid in the aqueous phase, the membrane diffusion within the SLM, and the interfacial chemical reaction, was built. The permeability of sulfuric acid through the SLM using TOA as a mobile carrier was determined. The rate-determining step of the extraction of sulfuric acid through a SLM was analyzed using the data obtained from the experiments of extraction kinetics and the mass transfer in the aqueous phase. Diffusion within the membrane dominates the process of extraction process of sulfuric acid by TOA through a SLM.     

发酵液中丁酸络合萃取分离条件的研究

研究了络合萃取-反萃法从发酵液中分离丁酸的工艺条件.比较了不同萃取体系,在以三辛胺为萃取剂、正辛醇为稀释剂的萃取体系,三辛胺体积分数为40％,发酵液初始pH值为2-3,萃取相比(体积比)为0.3时,分配系数和萃取率均达到较高值,分别为t3.91和80.67％.增大相比能进一步提高萃取率,但萃取剂使用量将增大.2级萃取能...     

Extraction equilibrium of m-cresol by tri-n-octylamine sulfate salts

The influence of the extraction conditions on the distribution coefficient of m-cresol were investigated. The equilibria of m-cresol extraction from an aqueous solution by the tri-n-octylamine sulfate salts (TOA salts) in an organic solvent were examined. Sulfuric acid first reacted with tri-n-octylamine (TOA) to form TOA salts; then m-cresol was extracted into the organic phase from the aqueous phase by the TOA salts. The model of the equilibrium of the chemical reaction of TOA and sulfuric acid to form the TOA salts was constructed by modifying the Wilson model (Wilson, 1967). The predictions of the developed model were fairly consistent with the experimental data, and it was applied to the reaction systems in benzene at various temperatures to predict the extraction of m-cresol. The number of water molecules associated with the various TOA salts, which reflect the extraction capability of m-cresol, was determined.     

Extraction of Chloride Ions from Zinc-Bearing Waste Lixivium by Trioctyl Amine (TOA)

This paper presents research on separating Cl^? from zinc-bearing waste lixivium by using trioctylamine as an extractant, 2-octanol as a solvent, and sulfonated kerosene as a diluent. The effects of trioctylamine concentration, organic/aqueous phase ratio, extracting stages, and waste lixivium pH were investigated, and the process of stripping was also discussed. The optimal conditions were achieved. The extraction efficiency, separation factor, and stripping efficiency were calculated with optimal values of 99.47%, 595, and 99.99%, respectively. Besides, the extractant regenerated after stripping was observed without the emulsifying phenomenon. The mechanism of extraction and stripping was also discussed.     

溶剂萃取法从褐藻浸提液中分离提取褐藻糖胶

用溶剂萃取法分离提取了实际海藻浸提液中的褐藻糖胶. 考察了接触时间、溶剂加入量及萃取剂浓度等对萃取的影响，并与从多糖配制液中的萃取情况进行比较. 考察了无机盐水溶液反萃褐藻糖胶的性能及在溶剂中加入TOA(三正辛胺)对萃取和反萃的影响，结果表明，季铵盐从实际鼠尾藻浸提液中萃取褐藻糖胶受溶剂加入量的影响很大，溶剂加入量越大，萃取率越低；而萃取时间对萃取的影响不大. 海带浸提液的萃取优于鼠尾藻浸提液，而超声破碎法有利于萃取. TOA的加入既有利于褐藻糖胶的萃取也有利于无机盐水溶液反萃褐藻糖胶. 采用溶剂萃取法制备的固体褐藻糖胶的纯度优于乙醇分步沉淀法制备的固体褐藻糖胶的纯度.     

三辛胺络合萃取分离一氯乙酸和二氯乙酸

以三辛胺(TOA)工业品为萃取剂、正己烷为稀释剂,研究了一氯乙酸和二氯乙酸(质量比为322:1)水溶液的萃取分离特性,考察了温度和初始萃取剂浓度对萃取平衡的影响,建立了TOA萃取一氯乙酸和二氯乙酸的数学模型。结果表明,两酸分配系数随温度升高而增大,但影响有限;随萃取剂初始浓度的增大,一氯乙酸分配系数随之增大,二氯乙酸分配系数先升后降。基于TOA的表观碱度,建立了二氯乙酸单溶质模型,解释了其分配系数随萃取剂浓度增大先升后降的特殊规律;在此基础上,考虑协同萃取的影响,建立了双溶质萃取模型。上述研究为一氯乙酸工业品的进一步提纯分离提供了指导。     

Simultaneous solvent extraction of cobalt and magnesium in the presence of nickel from sulfate solutions by Ionquest 801

The simultaneous extraction of Co(II) and Mg(II) from nickel sulfate solutions has been carried out using the organophosphonic extractant Ionquest 801 diluted in Exxsol D‐80. Statistical design and analysis of experiments were used in order to determine the main effects and interactions of the solvent extraction parameters, which were the extraction pH at equilibrium, the temperature, the extractant concentration and the organic/aqueous phase ratio. A statistically designed experiment was also carried out to study the stripping of the Ionquest 801 organic phase loaded with cobalt and magnesium by sulfuric acid solution. The number of stages required for both extraction and stripping processes of cobalt and magnesium was evaluated. The results of continuous counter‐current mini‐plant tests demonstrated the simultaneous recovery of cobalt and magnesium from nickel sulfate solution. Copyright © 2005 Society of Chemical Industry     

三辛胺萃取酸性染料玫红BB的平衡特性研究

络合萃取技术是一种非常有前途的可用于印染废水中染料回收的技术。本文以酸性染料玫红BB为研究对象,探讨了三辛胺萃取回收酸性染料的萃取平衡特性。水相中染料的浓度用分光光度法测定,油相中染料浓度由物料衡算求得。获得了初始染料浓度对萃取率、分配系数的影响,并获得了相平衡曲线,进一步就平衡曲线的工程应用做了详细的讨论。给出工程应用时的计算机方法和程序。     

Experimental,equilibrium modelling,and column design for the reactive separation of biomass-derived 2-furoic acid

Electrochemical conversion of biomass to value-added chemicals has gained impetus in recent years. Herein, we present a methodology for recovering biomass-derived 2-furoic acid from the dilute aqueous stream by reactive extraction. The reactive extraction was performed using a chemical extractant, trioctylamine (TOA), with diluents (octanol, chloroform, and diethyl ether). Equilibrium parameters influencing the recovery of 2-furoic acid were evaluated. Using TOA in various diluents, the 2-furoic acid was recovered with 85%–99% efficiency. A 1:1 complex of the 2-furoic acid—TOA was formed in the organic phase, and the experimental equilibrium complexation constant was compared with that obtained from the relative basicity and Langmuir models. The equilibrium parameters were used for column design to estimate the solvent to feed ratio (S/F) and the number of theoretical stages (NTS). The NTS required is 12 to attain 99% recovery of 2-furoic acid in counter-current extraction. The present study sheds light on the reactive extraction process adopted for process intensification with electrochemical conversion, paving the way for the commercialization of valuable products obtained from biomass.     

Extraction of 2-chloroethanol from aqueous solutions by trioctylamine

The trioctylamine (TOA) with kerosene as a diluent was used to separate 2-chloroethanol from aqueous hydrochloride acid solution. The stoichiometry of complex data was studied with infrared spectroscopic and the result shows that the ratio of 2-chloroethanol to amine in the complex was 1:2. The equilibrium constant was assumed to be 4.05 × 10⁵. Effects of temperature, equilibrium pH, TOA concentration, organic phase to aqueous (O/A) phase ratio and contact time on extraction yield of 2-chloroethanol were investigated. The results show that extraction yield can reach 58.2% under the optimum conditions.     

Salt Effects on the Recovery of Phenol by Liquid‐Liquid Extraction with Cyanex 923

Abstract

In this work, the effect of salt addition on the recovery of phenol from a 46 g/L aqueous solution simulating a phenolic resin plant effluent by liquid‐liquid extraction at 298 K has been studied by using an organic phase containing 0.6 M Cyanex 923 extractant in ShellSol T. Addition of sodium sulfate, potassium nitrate, and sodium chloride to the aqueous phase was tested and sodium chloride was selected. Based on the obtained results, a study of phenol recovery process was undergone by taking advantage of the salting‐out effect. Equilibrium curves are presented for liquid‐liquid extraction with and without salt addition to the aqueous phase. An integrated process involving salting‐out and liquid‐liquid extraction was proposed. The stripping concentrates can be reused for phenolic resin production.     

对羟基三甲基苯磺酸氧化废水萃取研究

三甲基氢醌是合成维生素E的重要中间体，国内企业主要采用对羟基三甲基苯磺酸，经MnO2氧化为三甲基苯醌，再加氢还原而得。本文采用三辛胺作萃取剂，在不同稀释剂作用下对氧化废水萃取回收磺化物和降低COD的研究。结果表明，萃取可有效地回收磺化物在废水相的残留并大大降低COD。     

生物油中络合萃取乙酸的研究

采用三正辛胺（TOA）作为络合剂,异辛醇和煤油分别作为助溶剂和稀释剂,对生物油中的乙酸进行了络合萃取研究。考察了TOA体积分数、异辛醇浓度、萃取剂与生物油轻馏分体积比以及温度对乙酸萃取率的影响,结果表明：温度为0 ℃,萃取体系为40%TOA+40%异辛醇+20%煤油(各组分浓度均为体积分数,下同),萃取剂与生物油轻馏分体积比为3∶1时,乙酸的一次萃取率较高,可达74.6%。     

EXTRACTION OF COPPER SALTS WITH A MIXED EXTRACTANT

Equilibrium distribution measurements and spectroscopic studies were undertaken in order to investigate the extraction of copper salts into a mixed extractant consisting of 2-ethyl hexanoic acid and trioctylamine in toluene. The predominant species in the organic phase was found to be a large ion pair of the type [R₃NH⁺]₂[CuX₂(R'COO-)₂]A By contacting the copper-loaded organic phase with water, an aqueous salt solution, or dilute HCI, copper can easily be back-extracted into the aqueous phase.     

Phenol Removal from Aqueous System by Bis(2-ethylhexyl) Sulfoxide Extraction

Solvent extraction is generally considered as one of the important and effective techniques to remove toxic phenol from wastewater. This paper explores the solvent extraction of phenol from wastewater using bis(2-ethylhexyl) sulfoxide (BESO) as extractant. Various parameters such as equilibrium time, the volume percentage of BESO, pH value, and ionic strength of the aqueous solution on the phenol extraction were investigated. The results indicated that BESO exhibited excellent performance of phenol extraction. The extraction percentage increased from 97.26% to 99.47%, varying the BESO concentration from 10% (v/v) to 30% (v/v). The extraction percentage decreased with increasing temperature in the range of 298-343 K. FTIR spectra of fresh and phenol loaded BESO organic phase indicated the existence of the hydrogen bonding interactions between S=O groups and phenol molecules. The relationship between log D and log [BESO] suggested the stoichiometry of the extracted species was a 1:1 complex, namely, [PhOH]·[BESO]. Phenol stripping from the loaded organic phase by sodium hydroxide was feasible, and more than 99% of phenol could be stripped when the NaOH concentration was 0.5 mol L^?1. The results obtained established that BESO/kerosene extraction system has potential for practical application in the phenol removal and recovery.     

SOLVENT EXTRACTION OF PHENOL WITH MINERAL ACID SALTS OF HIGH-MOLECULAR-WEIGHT AMINES

Distribution equilibria in the solvent extractions of phenol with various mineral acid salts of high-molecular-amines were measured at 30°C to examine the effects of types of amines and mineral acids on the distribution equilibria.

It was found that the extraction is greatly enhanced by converting the free base amines into their hydrochloric acid salts in the cases of secondary and tertiary amines while it is decreased in the case of a primary amine. On the effect of types of mineral acids, sulfuric acid and hydrochloric acid salts of trioctylamine can much more effectively extract phenol than the free base amine and the order of the efficiency for phenol extraction was found to be as follows: Aliquat 336 > sulfuric acid salt of trioctylamine i its hydrochloric acid salt ≥ its nitric acid salt > its perchloric acid salt ? free base amine.     

盐酸介质中三辛胺对钴的萃取行为研究

研究了在盐酸介质中三辛胺对钴的萃取行为，通过考察水相盐酸浓度、温度、调相剂浓度、不同稀释剂下萃取剂浓度对萃取率的影响以及反萃时间等因素，得出在盐酸浓度为2mol·L^-1、35％的温度下振荡30min、萃取剂体积分数为25％、加入10％的调相剂，用200#芳烃溶剂油作稀释剂时，萃取效果较好，萃取的综合效益较高，具有较高的实际应用价值。