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Extraction of acetate from simulated waste solutions in chloromycetin production
Abstract
Four extractants including Alamine 336 (tri-n-octyl/decyl amines), Aliquat 336 (tri-n-octylmethylammonium chloride), TOPO (tri-n-octylphosphine oxide), and TBP (tri-n-butylphosphate) in xylene were used to evaluate the possibility of recovering acetate from simulated waste streams in chloromycetin production (typically, 15.4% acetic acid, 8.8% sodium acetate, and 4.7% w/w NaCl). Different stripping agents including water, NaOH, Na2CO3, HCl, and H2SO4 were tested. The optimal recovery conditions were determined according to the extractability, economy, and stripping efficiency. It was shown that the Aliquat 336/Na2CO3 was the best choice, although it had problems with phase separation due to emulsion formation. The second alternative was the TBP/Na2CO3; although it gave a worse performance, it was less expensive and had no problems with phase separation.
... A number of separation techniques have been proposed for the removal of acids. These include adsorption (da Silva and Miranda, 2013;Suescún-Mathieu et al., 2014), electrodialysis (Lopez and Hestekin, 2013;Meynial-Salles et al., 2008), and liquid-liquid extraction (LLE) (Buttranon et al., 2022;Juang and Wu, 1999;Kaur et al., 2020). LLE has major advantages of high selectivity, mild conditions, and simple equipment setup. ...
... The reactive extraction improves a percent extraction as extractants can form complexation with acids, resulting in a higher partition coefficient. Quaternary ammonium salts such as aliquat 336 are common extractants (Juang and Wu, 1999;Kaur et al., 2020;Keshav et al., 2009). The extraction system containing aliquat 336 as an extractant and 1-octanol as a diluent was effective for recovering acids that are relevant to this work (i.e., propionic and lactic acids) (Keshav et al., 2008;Kyuchoukov et al., 2004). ...
... Acetic acid is extensively utilized in various industrial applications like printing, dyeing, food and pharmaceutical industries and also in the synthesis of acetyl cellulose and plastics [1][2][3]. Chemical processes such as petrochemical and wood pulping mills produce acetic acid in aqueous solutions [1,4]. Carboxylic acids are mainly produced by the fermentation processes and are acquired together with by-products in the aqueous solutions. ...
... The molar flux values for FCCCD experiments were calculated by using Eqs. (4) and (5). The results are given in Table 10. ...
In this research, the removal of acetic acid from aqueous solutions using bulk ionic liquid membrane (BILM)containing tributyl phosphate (TBP)was investigated. The effects of various parameters in BILM like the stirring, the initial acetic acid concentration in feed phase, the extractant (TBP)concentration and the selectivity of different ionic liquids in the membrane phase and the stripping phase type and concentration were investigated. For this purpose, a statistical experimental design study was applied. Face-centered central composite design (FCCCD)was utilized as the experimental design. The values of extraction and stripping removal efficiencies of different BILM systems were determined, and compared. Also, the optimal conditions to acquire the higher removal efficiency were determined. The higher removal efficiency values were obtained in systems where the TBP concentration in the membrane phase was 2 mol/L and NaOH concentration in the stripping phase was 4 N. The removal study shows that BILM can be used as an effective method for the removal of acetic acid from its aqueous solutions.
... Separation of metal ions or acids at low concentrations from aqueous streams is an important operation. Processing in food, pharmaceutical, petroleum and chemical industries often generates the effluent aqueous streams containing carboxylic acids having concentration in the range 0.1-5% [1][2][3]. Separation and subsequent recovery of carboxylic acids from such waste streams is essential as well as economically desirable. Most of the carboxylic acids, such as citric acid [4], lactic acid [5], etc., are produced from the fermentation processes. ...
... (a) Extraction profiles for feed and strip (feed phase, 0.5 g/l Nd 3+ and 2 g/l UO 2þ 2 at 3 M HNO3 (1,000 ml); carrier, 0.1 M TODGA + 5% (v/v) 1-decanol in n-dodecane; strip phase, distilled water (1,000 ml); feed/strip phase flow rates, 50 ml/min). (b) Separation factor profile. ...
Process intensification using hollow fibre-supported liquid membranes (HFSLMs) has been studied in the present work. The importance of use of HFSLM is highlighted over the other conventional available methods for separation. The present study focuses mainly on the recovery of acids and metal ions from dilute aqueous waste streams. The solute (acids or metal ions) flux through hollow fibre contactor measured under different operating conditions. The HFSLMs have been compared with conventional separation techniques, such as solvent extraction, ion exchange, etc., to highlight the process intensification potential.
... Senol [16] deduced a molar loading of greater than one for carboxylic acids removal from water by alamine 336 in halogenated hydrocarbon diluents. The use of tri-n-ctylphosphine oxide (TOPO) as an extractant for the removal of fatty acids from aqueous solutions has been discussed in several papers [15,[18][19][20][21][22][23][24][25]. Because of its high hydrogen-bonding acceptor basicity, TOPO complexes strongly with a carboxylic acid in an organic phase, enhancing the transfer of the carboxylic acid to the extract phase. ...
Liquid-liquid extraction (LLE) can be used for the recovery of acetic acid from black liquor prior to bioethanol fermentation. Recovery of value-added chemicals such as acetic-, formic- and lactic acid using LLE from Kraft black liquor was studied. Acetic acid and formic acid have been reported to be strong inhibitors in fermentation. The study elucidates the effect of three reaction parameters: pH (0.5∼3.5), temperature (25∼65 °C), and reaction time (24∼48 min). Extraction performance using tri-n-octylphosphine oxide as the extractant was evaluated. The maximum acetic acid concentration achieved from hydrolyzates was 69.87% at 25°C, pH= 0.5, and 36 min. Factorial design was used to study the effects of pH, temperature, and reaction time on the maximum inhibitor extraction yield after LLE. The maximum potential extraction yield of acetic acid was 70.4% at 25.8°C, pH=0.6 and 37.2 min residence time.
... There are several appropriate solvents for the removal of organic acids from hydrolyzates. The use of trioctylphosphine oxide (TOPO) as an extractant for fatty acids from aqueous solutions is discussed in several papers (Helsel, 1977;Niitsu and Sekine, 1978;Wardell and King, 1978;Ricker et al., 1979;Hano et al., 1990;Reisinger and King, 1995;Juang and Wu, 1999;Al-Mudhaf et al., 2002;Wisniewski and Pierzchalska, 2005). Because of its high hydrogen bond accepting ability, TOPO complexes strongly with carboxylic acids in the organic phase, thereby enhancing the transfer of the carboxylic acid into the extract phase. ...
Most modern commodity chemicals are synthesized from fossil resources. Organic acids are attractive targets in process development for the emerging renewable resources based biorefinery industry. Liquid-liquid extraction (LLE) is a common separation method for the recovery of a solute from a solution and can be applied to the recovery of acetic acid from the black liquor of Typha latifolia pulp prior to the bioethanol fermentation process. LLE of acetic acid was studied using alkanes containing 37% (w/w) concentrations of trioctylphosphine oxide. The extraction yield has also been evaluated with a four-level factorial design. Four independent variables, pH (1–3), temperature (25–65 °C), residence time (24–48 min), and concentrated hydrolyzates (1–10 times), were screened. The results showed that a lower pH and temperature gave the highest yield for the extraction of the organic acid. The yield also increased with less concentrated hydrolyzates. However, the residence time did not affect the yield. The maximum extraction yield of acetic acid achieved 71.7% at pH 1.02, 31.4 °C, 46.8 min, and 1.07 times. And the maximum extraction yield of formic acid and lactic acid was 75.1% (obtained at pH 1.46, 25.0 °C, 44.5 min, and 1.04 times) and 65.0% (obtained at pH 1.71, 35.9 °C, 44.6 min, and 1.11 times), respectively. It appears that the stabilities of the extracted acids are highly affected by the initial feed concentration of the organic acid.
... A molar loading of greater than one was deduced by Senol [19] for the removal of carboxylic acids from water using alamine 336 in halogenated hydrocarbon diluents. The use of trioctylphosphine oxide (TOPO) as an extractant for the removal of fatty acids from aqueous solutions is discussed in several papers [18,[22][23][24][25][26][27][28][29]. Due to its high hydrogen bonding acceptor basicity, TOPO undergoes strong complexation with carboxylic acids in the organic phase, thereby enhancing the transfer of the carboxylic acid into the extract phase. ...
Liquid-liquid extraction (LLE) using various solvents was studied for recovery of acetic acid from a synthetic ethanol fermentation broth. The microbial fermentation of sugars presented in hydrolyzate gives rise to acetic acid as a byproduct. In order to obtain pure ethanol for use as a biofuel, fermentation broth should be subjected to acetic acid removal step and the recovered acetic acid can be put to industrial use. Herein, batch LLE experiments were carried out at 25°C using a synthetic fermentation broth comprising 20.0 g l-1 acetic acid and 5.0 g l-1 ethanol. Ethyl acetate (EtOAc), tri-n-octylphosphine oxide (TOPO), tri-n-octylamine (TOA), and tri-n-alkylphosphine oxide (TAPO) were utilized as solvents, and the extraction potential of each solvent was evaluated by varying the organic phase-to-aqueous phase ratios as 0.2, 0.5, 1.0, 2.0, and 4.0. The highest acetic acid extraction yield was achieved with TAPO; however, the lowest ethanol-to-acetic acid extraction ratio was obtained using TOPO. In a single-stage batch extraction, 97.0 % and 92.4 % of acetic acid could be extracted using TAPO and TOPO when the ratio of organic-to-aqueous phases is 4:1 respectively. A higher solvent-to-feed ratio resulted in an increase in the ethanol-to-acetic acid ratio, which decreased both acetic acid purity and acetic acid extraction yield.
... In other words, the substance from one liquid phase will move to the other phase which has higher solubility for the transferred substance. For example, acetic acid is partially extracted from an aqueous solution by mass-transfer equilibration between the aqueous and a second, immiscible phase [4,15,16]. ...
Pre-pulping extraction is a means of deriving a hemicellulose-rich process stream from the front end of a kraft pulp mill. When the extraction is carried out using green liquor, pulp quality and quantity can be retained while still releasing hemicellulose and acetic acid for recovery as bioprocessing feedstock or chemical products. The acetic acid that is present in the wood extraction is inhibitory to microorganisms and can inhibit fermentation. It is also a commodity chemical that may provide sufficient value to justify recovery and purification.
In this study, a liquid-liquid extraction method is applied to extract acetic acid from a green liquor pre-pulping hardwood extract. The acetic acid removal process takes place as an initial step prior to the fermentation process. A solution of trioctylphosphine oxide (TOPO) and un-decane is prepared and mixed with wood extract. TOPO has strong hydrogen bonding acceptor properties that induce the carboxylic acid to transfer to the extract phase. Next the extract phase is centrifuged in order to separate the aqueous and organic phases. The aqueous phase is sent on to fermentation. Distillation is used to separate acetic acid from the organic phase. The acetic acid is recovered and the organic solvents are recycled back to the extraction. Results present the extraction and recovery efficiencies. Preliminary comparisons are made with other potential separation technologies.
... The composition of the stripping solution, e.g. stripping reagent type [123,126] and its concentration in the stripping solution [90,95,123] may considerably influence the performance of the stripper. The most important is to have an excess of reagent and to avoid the formation of a boundary layer depleted in the reagent. ...
Various possibilities of the application of membrane-based solvent extraction (MBSE) and pertraction in recovery and separation of organic acids, and in biotransformations are discussed. A short overview of the subject literature is presented. Factors, which have to be considered in the development of MBSE application, will be discussed. Hybrid processes employing MBSE will be covered as well. Mass-transfer characteristics of hollow fiber contactors for MBSE of organic acids are presented. The kinetics of formation and decomposition of the permeant–extractant complex may influence greatly the mass-transfer rate and should be taken into account in modelling. A case study on recovery of 5-methyl-2-pyrazinecarboxylic acid (MPCA) by simultaneous MBSE and membrane-based solvent stripping shows potential of this process. Optimised process parameters for MPCA are suggested on bases of simulations. Outlook for future applications of HF contactors in extraction separations is discussed and potential for progress is envisaged, especially for higher value acids and integrated or hybrid reaction-separation systems.
... Calcium and potassium salts of propionic acid are used in the food industry as preservatives (Cai et. al. 2001, Jaung andWu, 1999). Processing in petrochemical plants, and wood pulping mills often generate aqueous effluent streams containing carboxylic acids, particularly acetic acid (Technical Bulletin, 1999). ...
The separation (or removal) of organic residues from aqueous waste streams released from industries is important and essential from the points of view of pollution control and recovery of useful materials. The disposal of waste waters containing most widely-used industrial organic acids such as acetic acid, formic acid and propionic acid has been recognized as a significant expense to the industry and environment. This paper presents a state-of-the-art review on the development of techniques for the separation of carboxylic acids from waste water. Available conventional techniques including fractional distillation, liquid extraction, adsorption, precipitation, ion exchange, etc. have been discussed emphasizing the major drawbacks of these methods. A new method – reactive extraction -for extracting carboxylic acids from dilute aqueous solutions using a chemical extractant is described and compared with the other conventional techniques. Reactive extraction is an efficient, economical, and environmental friendly method for separation of acids from waste water streams.
3-Hydroxy-2-naphthoic acid (BON acid) is an important intermediate in the dyestuff and pigments industry. The BON acid produced in conventional way from the Kolbe-Schmitt reaction usually contains 2-5% 2-naphthol impurity. The objective of the work was to selectively remove 2-naphthol from BON acid using tributyl phosphate (TBP). The solubility of 2-naphthol and BON acid in water was modeled using the non random two liquid (NRTL) equation. The hollow fiber supported liquid membrane (HFSLM) was used for the purification. A mathematical model was developed to explain the results. The distribution coefficient of 2-naphthol was significantly higher than BON acid. The distribution coefficient decreased with increase in pH. In HFSLM experiments optimal separation was obtained in the pH range of 7-9. The stability of HFSLM module was investigated. During HFSLM runs separation factors in excess of 200 were obtained. HFSLM studies showed that it was possible to selectively remove 2-naphthol from the mixture, resulting in a significantly higher purity BON acid. Experimental data was adequately correlated using a developed mathematical model. Based on the experiments, a modified purification scheme is proposed.
The unique electrocoagulator proposed in this study is highly efficient at removing Ni-EDTA, providing a potential remediation option for wastewater containing lower concentrations of Ni-EDTA (Ni ≤ 10 mg L⁻¹). In the electrocoagulation (EC) system, cylindrical graphite was used as a cathode, and a packed-bed formed from iron scraps was used as an anode. The results showed that the removal of Ni-EDTA increased with the application of current and favoured acidic conditions. We also found that the iron scrap packed-bed anode was superior in its treatment ability and specific energy consumption (SECS) compared with the iron rod anode. In addition, the packed density and temperature had a large influence on the energy consumption (ECS). Over 94.3% of Ni and 95.8% of TOC were removed when conducting the EC treatment at an applied current of 0.5 A, initial pH of 3, air-purged rate 0.2 L min⁻¹, anode packed density of 400 kg m⁻³ temperature of 313 K and time of 30 min. SEM analysis of the iron scraps indicated that the specific area of the anode increased after the EC. The XRD analysis of flocs produced during EC revealed that hematite (α-Fe2O3) and magnetite (Fe3O4) were the main by-products under aerobic and anoxic conditions, respectively. A kinetic study demonstrated that the removal of Ni-EDTA followed a first-order model with the current parameters. Moreover, the removal efficiency of real wastewater was essentially consistent with that of synthetic wastewater.
Trialkyl (Cyanex 923) and trioctylphosphine oxides (Cyanex 921) dild. in toluene, octane or in low-aromatic naphtha b. 222-234°C (Exxsol D 220/230) were studied as extractants of propionic (I), crotonic (II) and oxalic (III) acids from 0.01-0.1 M solns. at 20-70°C. The extd. acids were stripped with water or aq. NaOH. Extn. and stripping isotherms were detd. I and II could be fully stripped with 4M NaOH from the loaded org. phase. Multistage extn. and stripping were also examd. Equil. was always established in 5 min. At lower acid concns. and temps., the yields of extn. were higher. Extractant/acid 1:1, 2:1 and 3:2 complexes were formed in the org, phase. The apparent enthalpy and entropy data for the complex formation with Cyanex 921 dild. in octane at 20°C were: I, -21.11, -40.6; II, -24.19, -44.4; III, -27.47 kJ/mol, -81.4 J/mol-K, resp.
Novel semi-interpenetrating polymer network (semi-IPN) anion-permselective membranes are prepared via a facile monomer sorption method. The base membrane is prepared by in-situ copolymerization of N,N'-dimethylaminoethyl methacrylate (DMAEMA) and divinylbenzene (DVB) in a non-porous poly(vinyl chloride) (PVC) substrate film (i.e. poly(DMAEMA-co-DVB)/PVC). The successive quaternization reaction along with di-functional p-xylylene dichloride forms the structurally stable anion-exchange groups that are fused with one another. Various characterizations (measurements of the transport number, electrical resistance, I-V curves, and chronopotentiometry etc.) reveal that the electrochemical properties of the prepared membranes are almost comparable with those of a commercial anion-exchange membrane (AMX, Astom Corp., Japan). In addition, the structural stability of the anion-exchange sites is confirmed through the water-splitting experiments at a high applied current condition.
Extractions of hard- and softwood chips were carried out using green liquor with varying alkali charges (1%, 3%, and 5% on dry wood weight). The pulp yield of a mill was sustained while producing a by-product stream of extracted hemicellulose. The extractions were performed at 180 °C for 18 min and the pre-pulping extracts contained mostly xmg (= xylose + mannose + galactose), acetic acid, and formic acid. We investigated the use of a liquid extractive agent in removing fermentation inhibitors. The extraction potential of each solvent was examined at an organic to aqueous phase ratio of 1:1. The liquid-liquid extractions were performed at different temperatures (25-65 °C) and pH values (0.5-3.5) for 36 min. The extraction potentials of trioctylphosphine oxide (TOPO) and trialkylphosphine oxide (TAPO) were compared to determine their application in industrial-scale extraction. It was determined that the acetic acid extraction efficiency of TAPO was higher than that of TOPO. The maximum acetic acid extraction yields for the extracts derived from hard- and softwood were 83.1% and 82.1%, respectively, using TAPO as an extractant at 25 °C and pH 0.5.
Extraction characteristics are shown for trioctylphosphine oxide (TOPO) dissolved in alkane for recovery of acetic acid from dilute water solution and hardwood-derived hemicellulose extracts. The recovery of acetic acid with TOPO is significantly influenced by the pH in the aqueous phase and lightly affected by temperature. In a one-stage extraction, 76.0% of the acetic acid could be extracted below pH 3. The yield of fractional extractions increase with increasing TOPO concentration in alkane and with increasing acetic acid concentration in the aqueous phase. It was found that for dilute extractions carried out at 70°C and pH 1, the solvent extraction is effective at 37% TOPO in alkane (w/w) and that little improvement is realized by further increases in TOPO concentration. Partition coefficients for green liquor and hot water extracts ranged between 2.0 and 2.5 at the tested conditions. Fermentation of hemicellulose extracts that had been treated with TOPO for removal of acetic acid was tested to determine whether TOPO processing resulted in any positive or adverse affects on the microbial activity. Fermentation of TOPO-treated green liquor hemicellulose extract with Pichia stipitis resulted in improved ethanol production relative to untreated extract. Accordingly, placement of TOPO extraction after hydrolysis and prior to fermentation is optimal for acetic acid recovery and maintenance of fermentation rates.
An indirect CO2 mineral sequestration involving two separated steps with acetic acid as a recycling medium provides a promising method for CO2 sequestration as well as the minimum CO2 emission for calcium carbonate production. In such an indirect route, the calcium carbonate production in the second gas-liquid reactive crystallization step has been challenged by low carbonation efficiency. This paper describes significant enhancement of the second step by coupling reactive crystallization and solvent extraction with the introduction of the organic solvent, tributyl phosphate (TBP), to the process. Based on the reaction mechanism of this enhanced carbonation process, many influencing factors including stirring speed, phase ratio, reaction time, reaction temperature, CO2 partial pressure, and the composition of the initial aqueous solution, were studied. Given the operating conditions of 60 min reaction time, 500 rpm stirring speed, organic-to-aqueous phase volume ratio of 1, 80 °C reaction temperature, 4.0 MPa CO2 partial pressure, and initial pH of 7, the obtained crystallization conversion in the second step was found to increase from 20% to above 50%, with the incorporation of TBP and the addition of magnesium acetate.© 2014 Society of Chemical Industry and John Wiley & Sons, Ltd
Posidonia oceanica leaves have been pre-treated with HCl solutions to elaborate a biosorbent that was carried out for Pb(II) sorption at pH 4 and pH 5. The sorption of Pb(II) was characterized using SEM-EDAX, XPS spectrometry and FT-IR spectroscopy. Maximum sorption capacity reached up to 140mgPb g−1 at pH 5. The uptake kinetics were controlled by chemisorption reaction rate. This was correlated to the lamellar structure observed using SEM analysis. The influence of sorbent dosage, particle size and metal concentration on uptake kinetics was also investigated. Sorption performances are compared to other biosorbents and to previous studies on P. oceanica for binding of mineral and organic compounds.
Electrolytic recovery of binary Cu(II) and Pb(II) from solutions containing strong complexing agent EDTA (ethylenediaminetetraacetic acid) was studied in a two-chamber cell separating with a cation exchange membrane Neosepta CM-1. An equimolar solution of EDTA and total metals was focused. The iridium oxide coated on titanium (Ti/IrO2) and stainless steel were used as the anode and cathode, respectively. Experiments were carried out at different current densities (18.5–185 A/m2), initial catholyte pH (1.47–6), the total metal concentrations (5–20 mM) and their concentration ratios. It was shown that the deposition recovery of Cu(II) was faster and more efficient than that of Pb(II). Compared to single metal–EDTA solutions, lower metal recovery and current efficiency were obtained in binary solutions regardless of what metal concentration ratios. This was probably related to the deposit structure of binary metals onto the cathode.
Treatment of arsenic ions from produced water coming along with a gas separation plant in the Gulf of Thailand by hollow fiber supported liquid membrane (HFSLM) was studied. Cyanex® 923 (a mixture of phosphine oxide), tri-n-butylphosphate (TBP), bis(2, 4, 4-trimethylpentyl) dithiophosphinic acid (Cyanex® 301), tri-n-octylamine (TOA) and methyltrioctylammonium chloride (Aliquat 336) were used as the extractants. The stripping solution was sodium hydroxide. The concentration of the extractant in liquid membrane and concentration of sodium hydroxide were examined. In addition, the influence of various numbers of runs of the stripping solution through the HFSLM on the concentration of arsenic ions in the outlet stripping solution was observed. Of all the extractants used, 35% (v/v) Aliquat 336 attained high percentages of extraction and recovery of arsenic ions because it reacted with both undissociated arsenic (H3AsO3) and dissociated arsenics (H2AsO4− and HAsO42−). Cyanex® 923, TBP and TOA had low extractability since Cyanex® 923 and TBP reacted only with undissociated forms while TOA reacted only with dissociated forms. In case of Cyanex® 301, although it offered a relatively high percentage of extraction but very poor recovery due to this extractant formed very strong complex species with arsenic ions, which slowed down and made the stripping difficult. It was found that the percentage of arsenic recovery increased with the concentration of sodium hydroxide and was almost constant after 0.5M due to the limitation of mass transfer area of the hollow fibers. After 3-cycle separation, the extraction and recovery of arsenic ions from produced water were 91% and 72%, respectively. Accordingly, the concentration of arsenic ions of 0.1201ppm in produced water was observed, which was in accordance with the legislation discharge of industrial effluent in Thailand. More arsenic ions were recovered by increasing the numbers of runs of the recycling stripping solution through the HFSLM.
The kinetics for extraction recovery of acetate ions from simulated waste streams in chloromycetin production by Aliquat 336 (a quaternary amine) and tri-n-butylphosphate (TBP) in xylene were examined using a microporous membrane-based stirred cell. The waste stream typically contained 15.4% acetic acid, 8.8% sodium acetate, and 4.7% (w/w) NaCl. The stirred cell could give intrinsic rates for formation of the complex occurring at or near the organic–aqueous interface. It was shown that the extraction rate with TBP was higher than that with Aliquat 336. The effect of temperature (288–318 K) on the reaction rate with TBP was also examined and the activation energy (54.5 kJ mol−1) was obtained.© 1999 Society of Chemical Industry
To explore electrodialysis for purification of negatively charged large organic molecules (e.g., amino acids and medicine), water-swollen formyl methyl pyridinium-immobilized polyvinyl alcohol (PVA-FP) anion-exchange membranes were prepared and characterized in terms of their electrochemical properties. The PVA-FP membranes exhibited low electrical resistance (1.0–3.0Ωcm2), high swelling properties (water content ratio, 0.62–0.73), and reasonable transport number (t¯−>0.96 for Cl−). For glutamic acid solutions, the electrical resistance of the PVA-FP membrane was low (1.0–3.0Ωcm2) in a wide pH range, with no membrane fouling. Since the resonance effect of quaternary aromatic ammonium contributed to the structural stability of the PVA-FP membrane, the water-splitting with the PVA-FP membrane was approximately one order of magnitude lower than that with a commercial ion-exchange membrane at a same current density.
Low-density polyethylene (LDPE)/polystyrene (PS) cation exchange membranes were prepared using the monomer sorption method and UV radiation polymerization. In the preparation method, reaction behaviors during polymerization and sulfonation were investigated. The prepared membranes were characterized in terms of physical and electrochemical properties, exhibiting reasonable mechanical properties for an ion exchange membrane with weight gain (Wr) of above 0.3. DSC studies and FE-SEM image revealed the formation of a homogeneous membrane. The resulting membrane showed membrane electrical resistance (MER) of below 1.0Ωcm2 and ion exchange capacity of 1.8meq./g dry membrane. Both the current–voltage and the chronopotentiometric curves of the membranes suggest that LDPE/polystyrene membranes can be properly used at a high current density, and that the surface homogeneity of cation exchange sites in the membranes was comparable to that in commercial membranes.
Electrolytic recovery of metals from aqueous solutions containing complexing chelating agents such as EDTA, NTA, and citrate was studied in a two-chamber cell separating with a commercial cation-exchange membrane (CEM). Equimolar solutions of metal and a chelating agent as a catholyte and NaNO3 as an anolyte were used; the effect of current densities, initial catholyte and anolyte pH, metal concentration and the type of the CEM, chelating agent and metal on the recovery of metals was determined. The recovery of metal increased with higher initial anolyte pH, concentration and current density, whereas it decreased with lower initial catholyte pH. The results show that electrodeposition seems to be an applicable method for the recovery of metals under appropriate conditions.
Indium is a rare metal that is mostly consumed as indium tin oxide (ITO) in the fabrication process of liquid-crystal display (LCD) panels. The spent LCD panels, termed as LCD-waste hereafter, is an increasing contributor of electronic waste burden worldwide and can be an impending secondary source of indium. The present work reports a new technique for the reclamation of indium from the unground LCD-waste using aminopolycarboxylate chelants (APCs) as the solvent in a hyperbaric environment and at a high-temperature. Microwave irradiation was used to create the desired system conditions, and a substantial abstraction of indium (≥ 80%) from the LCD-waste with the APCs (EDTA or NTA) was attained in the acidic pH region (up to pH 5) at the temperature of ≥ 120 °C and the pressure of ∼ 50 bars. The unique point of the reported process is the almost quantitative recovery of indium from the LCD-waste that ensured via the combination of the reaction facilitatory effect of microwave exposure and the metal extraction capability of APCs. A method for the selective isolation of indium from the extractant solution and recycle of the chelant in solution is also described.
A new acetic acid separation method was developed through a successful combination of cloud point extraction and complex extraction technology (CPE-SE), where an acetic acid complex compound formed and was solubilized in a surfactant micelle solution, instead of an organic solvent, and then concentrated into one phase by a phase separation process of the CPE technology. Since no organic solvent diluents were used, the new process was environmentally friendly and with a lower cost; meanwhile, the high selectivity of the complex extraction based on chemical complexation and high efficiency of CPE were also inherited as advantages over conventional solvent extraction process. In consideration of the compatibility and the related CPE characteristics, tributyl phosphate and PEG/PPG-18/18 Dimethicone were selected as complexing agent and surfactant of the CPE-SE system, respectively, and the extraction system was optimized by studying the effect of the main process parameters, including surfactant and complexing agent concentration, temperatures for the stirring and incubation steps, on the recovery and the distribution coefficient. A relative high recovery of 71.4% and a distribution coefficient of 1.4 were achieved simultaneously with the optimized process in the treatment of 0.1 M acetic acid solution. Based on its competitive extractability, high efficiency, low-cost, and environment friendlyness, the CPE-SE process was expected to be a potential separation method for a dilute acetic acid solution.
Low-density polyethylene (LDPE)/polyvinylbenzyl trimethyl ammonium salts (PVBTMA) anion-exchange membranes were prepared by a monomer-sorption method and UV radiation polymerization. Morphology of the membrane was controlled by variation of monomer composition. FT-IR–ATR/TR and DSC analyses were carried out for the membranes prepared. Due to swelling effect of styrene in LDPE network, the increasing styrene content in monomer solution led to formation of homogeneous membrane. The membranes were also characterized in terms of electrochemical properties, i.e. ion-exchange capacity (IEC), membrane electrical resistance (MER), transport number (t−), current–voltage (I–V) and chronopotentiometric curves. The permselectivity and MER of the membrane were depending strongly on the surface-homogeneity and the cross-sectional homogeneity, respectively.
Electrokinetic extraction was tested to remove lead from an Algerian contaminated soil ([Pb] = 4432 ± 275 µg.g !1) located near a battery plant. The enhancement of pollutant removal was achieved by introducing a chelating reagent (disodium salt of ethylendiaminetetraacetic acid, EDTA 0.1 M) in the catholyte. In order to avoid ligand loss, the cell was also modified by adding extra compartments and inserting cation-exchange membranes. Results of contaminant distribution across the soil column showed efficient transport of lead toward the anode, despite a large amount of calcite (25%) and a high acid/base buffer capacity of the sample. Simultaneous recovery of EDTA and lead from their chelated solutions was made possible using the same set-up and by monitoring pH in the circulating fluids.
This study was aimed at examining the use of the organophosphine oxides Cyanex®921 and Cyanex®923 for the extraction of formic, acetic and propionic acids from aqueous solutions. The stripping of monocarboxylic acids with water from the loaded extractants was also examined. The studies were aimed at determining the equilibrium conditions for extraction and stripping. Overall, the effect of the kind of extractant was not significant although Cyanex®921 extracted carboxylic acids slightly better than Cyanex®923 with 1:1 complexes being formed by both extractants with the acids during extraction. The efficiency of extraction depended on temperature, acid concentration and solvent, with toluene a better diluent for the extractants than octane or Exxsol®D 220/230. Extraction efficiency increased as the concentration of acid in the feed decreased and, also, as the temperature increased, the amount of acid extracted decreased. The extraction and stripping isotherms were determined. The apparent enthalpy and entropy of the extraction reaction were determined. Distribution data for the transfer of carboxylic acids from aqueous (NaCl) solutions to organic solvents in the presence of trialkylphosphine oxide were determined at 293 K with the distribution ratios increasing as the concentration of NaCl increased. Copyright © 2005 Society of Chemical Industry
The recovery of EDTA (ethylenediaminetetraacetic acid) and metals such as CuII, PbII, CdII, and ZnII from simulated washing effluents of metal-contaminated soils was investigated using a two-chamber electrolytic cell, which was separated by a cation exchange membrane Neosepta CM-1. The iridium oxide coated on titanium electrode and stainless steel were used as the anode and cathode, respectively. An equimolar solution of EDTA and total metals was selected. All experiments were carried out at a fixed current density (185 A/m2) and concentration ratio among metals, but at different initial catholyte pH values (1.47–6.0) and total metal concentrations (10.4–31.1 mM). It was shown that the initial catholyte pH played the most important role in metal recovery. Metal recovery generally decreased in the order CuII>PbII>CdII>ZnII, which was related to the reduction tendency of free metal ions. The effect of added supporting electrolytes such as NaCl and Na2SO4 on electrolytic recovery was also investigated.
A water-swollen type of poly(vinyl alcohol) (PVA)/poly(styrene sulfonic acid-co-maleic acid) (PSSA-MA) cation-exchange membrane was prepared and characterized in terms of its electrochemical properties including ion-exchange capacity (IEC), electrical resistance, and transport number, etc. PVA/PSSA-MA membranes exhibited low electrical resistance and highly swelling property. In spite of 2–4 times higher water swelling ratio (WSR) than that of CMX (Tokuyama Corp., Japan), the transport number of the prepared membrane was comparable to that of the commercial membrane (tn>0.93). Moreover, the electric resistance of PVA/PSSA-MA membrane was measured as low as 1.0–1.5 Ω cm2. Further, in this study, interrelation between the membrane characteristics and crosslinking was investigated, and the result exhibited that the crosslinking degree is one of major factors affecting the ion transport through a water-swollen ion-exchange membrane (IEM).
Aminopolycarboxylate chelants (APCs) are extremely useful for a variety of industrial applications, including the treatment of toxic metal-contaminated solid waste materials. Because non-toxic matrix elements compete with toxic metals for the binding sites of APCs, an excess of chelant is commonly added to ensure the adequate sequestration of toxic metal contaminants during waste treatment operations. The major environmental impacts of APCs are related to their ability to solubilize toxic heavy metals. If APCs are not sufficiently eliminated from the effluent, the aqueous transport of metals can occur through the introduction of APCs into the natural environment, increasing the magnitude of associated toxicity. Although several techniques that focus primarily on the degradation of APCs at the pre-release step have been proposed, methods that recycle not only the processed water, but also provide the option to recover and reuse the metals, might be economically feasible, considering the high costs involved due to the chelants used in metal ion sequestration. In this paper, we propose a separation process for the recovery of metals from effluents that contain an excess of APCs. Additionally, the option of recycling the processed water using a solid phase extraction (SPE) system with an ion-selective immobilized macrocyclic material, commonly known as a molecular recognition technology (MRT) gel, is presented. Simulated effluents containing As(V), Cd(II), Cr(III), Pb(II) or Se(IV) in the presence of APCs at molar ratios of 1:50 in H2O were studied with a flow rate of 0.2 mL min(-1). The 'captured' ions in the SPE system were quantitatively eluted with HNO3. The effects of solution pH, metal-chelant stability constants and matrix elements were assessed. Better separation performance for the metals was achieved with the MRT-SPE compared to other SPE materials. Our proposed technique offers the advantage of a non-destructive separation of both metal ions and chelants compared to conventional treatment options for such effluents.
Electrokinetic extraction has been tested to remove lead from an Algerian contaminated soil ([Pb] = 4.432 +/- 0.275 mg g(-1)) sited near a battery plant. The effect of EDTA at various concentrations (0.05-0.20 M) on the enhancement of lead transport has been studied by applying a constant voltage corresponding to a nominal electric field strength of 1 V cm(-1) (duration: 240 h). Results of contaminant distribution across the experimental cell have shown efficient transport of lead toward the anode despite the presence of calcite (25%) and the high acid/base buffer capacity of the soil. To avoid ligand loss, which would be anodically oxidized, the cell was modified by adding extra compartments and inserting cation exchange membranes (Neosepta CMX). Thus, simultaneous recovery of EDTA and lead from their chelated solutions has been made possible using the same set-up and by controlling fluids chemistry.
A membrane contactor is a device that achieves gas/liquid or liquid/liquid mass transfer without dispersion of one phase within another. This is accomplished by passing the fluids on opposite sides of a microporous membrane. By careful control of the pressure difference between the fluids, one of the fluids is immobilized in the pores of the membrane so that the fluid/fluid interface is located at the mouth of each pore. This approach offers a number of important advantages over conventional dispersed phase contactors, including absence of emulsions, no flooding at high flow rates, no unloading at low flow rates, no density difference between fluids required, and surprisingly high interfacial area. Indeed, membrane contactors typically offer 30 times more area than what is achievable in gas absorbers and 500 times what is obtainable in liquid/liquid extraction columns, leading to remarkably low HTU values.Although a number of membrane module geometries are possible, hollow fiber modules have received the most attention. In general, tube side mass transfer coefficients can be predicted with reasonable accuracy; on the other hand, shell side coefficients are more difficult to determine, and several research groups are currently addressing this problem.Membrane contactor technology has been demonstrated in a range of liquid/liquid and gas/liquid applications in fermentation, pharmaceuticals, wastewater treatment, chiral separations, semiconductor manufacturing, carbonation of beverages, metal ion extraction, protein extraction, VOC removal from waste gas, and osmotic distillation. This paper provides a general review of hollow fiber membrane contactors, including operating principles, relevant mathematics, and applications.
Hexane solutions of long-chain alkyl secondary amine were equilibrated with aqueous solutions of carboxylic acid. Chemical species formed were estimated and equilibrium constants for these reactions were evaluated. It was found that these extraction equilibria could be interpreted by use of the following reaction mechanisms: 1) Mono-carboxylic acids (HA) react with amine (B) to form ion-pairs such as (BH)⁺A_. 2) The ion-pairs further bind to acid-forming (BH)⁺A_(HA)n_1 type species. Values of n are 2, 3, 4 for propionic acid and acetic acid and 2, 3 for formic acid. 3) In the case of the reaction with formic acid, (BH)⁺A_B, (BH)2⁺A2A_ and ((BH)⁺A_(HA))2 type species are formed in addition to the above-mentioned ones. 4) Aqueous oxalic acid (H2A) forms ion-pairs such as (BH)2⁺A2_ reacting with amine. © 1982, The Society of Chemical Engineers, Japan. All rights reserved.
The extraction of acetic acid with TBP in different, diluents was studied. The decreasing order of extraction ability of TBP is as follows; toluene, benzene, cyclohexane, kerosene, tetrachloride, chloroform and methyl isobutylketone. The effect of temperature on the extraction equilibrium was also investigated and the enthalpy of the extraction was obtained. The relationship between the extraction equilibrium constants Kex, and the physical parameters of diluents can be derived. The extraction mechanism and equilibrium were examined by measurements of IR spectrophotometry.
Solvent extraction is a common industrially used equilibrium-based separation process. In such a process, a solute (or solutes) in a solution, aqueous or organic, is extracted into an immiscible solvent, organic or aqueous, by dispersing one of the immiscible phases as drops in the other phase. This creates a large interfacial area and increases the extraction rate considerably. After the extraction is over, the phases are separated and the dispersed phase coalesced. There are two general categories of equipment for solvent extraction. A mixer-settler arrangement provides a single equilibrium stage; a number of them connected together provide multistage extraction. Continuous countercurrent contacting equipment whether in the form of columns or centrifugal devices can generate the equivalent of many stages in one device (Treybal 1963).
Organic solutions of a tertiary amine are being used increasingly to separate organic acids from aqueous solutions by reactive extraction. The present paper deals with experimental investigations and the modeling of the liquid-liquid equilibria encountered when toluene, chloroform or methyl isobutyl ketone are used as solvents for the tertiary amine tri-n-octylamine. Acetic acid was used as an example of a carboxylic acid. All measurements were carried out at 298.15 K. Experimental results for the compositions of the coexisting phases are reported. Infrared spectroscopic investigations were carried out to determine the equilibrium constants of some of the chemical reactions observed in the organic solvents toluene and chloroform. The results of the liquid-liquid equilibrium measurements were correlated by a model which takes into account chemical reactions as well as physical interactions. Some of the model parameters were deduced from the spectroscopic investigations and others were determined from literature data on binary subsystems. The remaining parameters (chemical equilibrium constants and physical interaction parameters) were fitted to the liquid-liquid equilibrium data. The final correlation gives a good description of the distribution of acetic acid between the coexisting phases over a wide concentration range. The model also describes reliably the solubility of water in the acetic-acid-containing organic phases and the influence of acetic acid on the solubility of the organic solvents in the aqueous phase.
The extraction equilibrium of organic acids (acetic, glycolic, propionic, lactic, pyruvic, butyric, succinic, fumaric, maleic, malic, itaconic, tartaric, citric and isocitric) with tri-n-octylphosphine oxide (TOPO) was measured. The solvation numbers of the acids were the same as the numbers of the carboxyl groups on each acid molecule. The extraction equilibrium constant was controlled by the hydrophobicity of the acid when hexane was used as a diluent. © 1990, The Society of Chemical Engineers, Japan. All rights reserved.
Several carboxylic acids are prominent commercial products, and their number and importance will probably grow. Getting these acids out of aqueous solution is necessary in petrochemical manufacture, fermentation, and the environmentally and economically important recovery from waste streams. In this paper, the authors discuss the methods possible to extract acids such as citric, lactic, and succinic from complex mixtures. Carboxylic acids are also readily made by fermentation and are among the most attractive substances that could be manufactured from biomass. Branches of this cycle lead to acetic, lactic, propionic, and formic acids, among others. Carboxylic acids are promising intermediates in a bioprocessing complex, because the oxygen of the biomass is placed in a form that is useful for further reaction with many other products. Citric acid is manufactured on a large scale by fermentation, and lactic and fumaric acids, among others, were manufactured that way in the past.
This work examines the chemistry of solvent extraction by long-chain amines for recovery of carboxylic acids from dilute aqueous solution. Long-chain amines act as complexing agents with the acid, which facilitates distribution of the acid into the organic phase. The complexation is reversible, allowing for recovery of the acid from the organic phase and regeneration of the extractant. Batch extraction experiments were performed to study the complexation of acetic, lactic, succinic, malonic, fumaric, and maleic acids with Alamine 336, an aliphatic, tertiary amine extractant, dissolved in various diluents. Results were interpreted by a ''chemical'' model, in which stoichiometric ratios of acid and amine molecules are assumed to form complexes in the solvent phase. From fitting of the extraction data, the stoichiometry of complexes formed and the corresponding equilibrium constants were obtained. The results of the model were combined with infrared spectroscopic experiments and results of past studies to analyze the chemical interactions that are responsible for extraction behavior. The information from the equilibrium studies was used to develop guidelines for large-scale staged extraction and regeneration schemes. A novel scheme, in which the diluent composition is shifted between extraction and regeneration, was developed which could achieve both high solute recovery and high product concentration. 169 refs., 57 figs., 15 tabs.
Extraction equilibria of acetic acid and propionic acid with hexane solutions of trioctyl amine, trioctyl phosphine oxide, and tributyl phosphate were studied. The species formed in the systems were estimated, and the distribution coefficients and the equilibrium constants for these species were evaluated.
The trioctylamine (TOA)/methylene chloride (MC)/n-hexane system was used as the extraction agent for the extraction of lactic acid. Curves of equilibrium and hydration were obtained at various temperatures and concentrations of TOA. A modified mass action model was proposed to interpret the equilibrium and the hydration curves. The reaction mechanism and the corresponding parameters which best represent the equilibrium data were estimated, and the concentration of water in the organic phase was predicted by inserting the parameters into the simple mathematical equation of the modified model. The concentration of MC and the change of temperature were important factors for the extraction and the stripping process. The stripping was performed by a simple distillation which was a combination of temperature-swing regeneration and diluent-swing regeneration. The type of inactive diluent has no influence on the stripping. The stripping efficiencies were about 70%.
Phase equilibria governing the reactive extraction of citric acid from aqueous solution into solutions of tri-n-octylamine in the single solvents toluene, chloroform and methyl isobutyl ketone are investigated. In addition to batch extraction experiments, infrared spectroscopic measurements were performed. These spectroscopic investigations yield information about the stoichiometry of complex formation. All measurements were carried out at 298.15 K. A model for the liquid-liquid equilibrium which takes into account chemical reactions as well as physical interactions in both phases is used to correlate the experimental data. In comparison with earlier work, the model was extended to include the partitioning of the amine as well as its influence on the aqueous phase pH. The model reliably describes the partitioning of acid, water and organic compounds into the coexisting phases. New model parameters are also presented in order to complement recent publications on the partitioning of other single carboxylic acids (acetic and oxalic acids) into the same water/organic solvent systems.
Phosphoryl and tertiary amine solvents and solvent mixtures have been investigated for extraction of acetic and formic acids from water. Among phosphoryl compounds, equilibrium distribution coefficients (KD) increase in the order phosphate < phosphonate < phosphine oxide. Tributyl- and trioctylphosphine oxides give higher values of KD than the corresponding triphenyl compound. Trioctylamines give higher values of KD than tributylamine, apparently because of higher solubility of the reaction product in the solvent phase. KD for acetic acid exhibits a maximum value at intermediate solvent compositions of trioctylamines or phosphine oxides and a diluent.
Coextraction of water during extraction of succinic acid by Alamine 336 in different diluents has been measured. The amounts of coextracted water lie in the same order as the solubilities of water in the diluents without amine present. Water coextraction with different acids follows the order fumaric > malonic > maleic = succinic > lactic > acetic. The effects of temperature on extraction of succinic and lactic acids by Alamine 336 with chloroform and methyl isobutyl ketone (MIBK) diluents have been measured. Enthalpies and entropies of complex formation have been derived from the results and are interpreted in terms of the differences in interactions among the species involved. Two approaches for regeneration through back-extraction into an aqueous phase are considered.
Studies have been made of the extraction of acetic, lactic, succinic, malonic, fumaric, and maleic acids by Alamine 336, an aliphatic, tertiary amine extractant, dissolved in various diluents. The results were interpreted by a 'chemical modeling' approach, in which the stoichiometries of acid-amine complexes and corresponding equilibrium constants which best represent the experimental results were determined. The acids studied differed in pKa and in the presence or absence of functional groups other than the primary carboxyl group. Diluents were chosen from different chemical classes - electron donating, electron accepting, polar, and nonpolar - so as to examine the effects of diluent-complex interactions.
Extractions of carboxylic acids by tertiary and quaternary amines were studied under various equilibrium pHs ranging from 2.0 to 8.5. The quaternary amine Aliquat 336 extracted both dissociated and undissociated forms of acids, whereas the tertiary amine Alamine 336 extracted only the undissociated acid. Pure Aliquat 336 also had higher distribution coefficients, K(D), than Alamine 336 at all pHs. In the intermediate pH range, K(D) decreased with increasing the equilibrium pH of the aqueous phase. However, in the extremely high and low pH ranges, K(D) remained unchanged with pH. This pH dependency of K(D) can be modeled by using a three-parameter equation derived from general chemistry principles. Extractions were also conducted with two diluents, kerosene and 2-octanol. In general, the polar diluent, 2-octanol, increased the extracting power of Alamine 336 by providing more solvating capacity for the nonpolar amine. In contrast, neither the polar nor the nonpolar diluent was active when used with Aliquat 336.
Tertiar amines are effective extractants for the recovery of carboxylic acids from aqueous solution. An approach for regeneration and product recovery from such extracts is to back-extract the carboxylic acid with a water-soluble, volatile tertiary amine, such as trimethylamine. The resulting trimethylammonium carboxylate solution can be concentrated and thermally decomposed, yielding the product acid and the volatile amine for recycle. In this paper, equilibrium data are presented that show near-stoichiometric recovery of carboxylic acids for amine extracts. For rumaric and succinic acids, partial evaporation of the aqueous back-extract decomposes the carboxylate and yields the acid product in crystalline form. The decomposition of aqueous solutions of trimethylammonium lactates stops short of forming the acid product, because of its greater water solubility and tendency for self-association. Methods of further purifying the crystals are evaluated along the processing implications of the results.
Different extractants (trioctylphosphine oxide and secondary, tertiary, and quaternary amines) and solid sorbents (tertiary and quaternary amines) were investigated as agents for recovery of acetic acid as part of a process for production of calcium magnesium acetate (CMA) from fermentation acetic acid. The pH and temperature dependencies for uptake of acetic acid by these extractants and sorbents were measured, along with the degrees of regeneration by aqueous suspensions of slaked dolomitic lime. These results enable identification of agents having optimal basicity. Among the extractants, the secondary amine Amberlite LA-2 gave the best combined performance for extraction and regeneration. Among the sorbents, a tertiary amine, Amberlite IRA-35, gave the best performance. Trioctylphosphine oxide does not maintain capacity in the pH range (about 6) most attractive for acetic acid fermentation. Slurried crushed dolomite is not sufficiently basic to accomplish regeneration.
A process for the Production of the deicing salt, calcium magnesium acetate, is described. A crucial step for technical and economic feasibility is the organic extraction of acetic acid from dilute aqueous streams. This work focuses on selection of two organic systems chosen for pilot studies: a phosphine oxide (50%) and a tertiary amine (20%) in an aliphatic hydrocarbon (30%); a tertiary amine (40%) in cyclohexanone. Almost 50 candidate systems were screened, the equilibrium behavior of each system . determined experimentally or from the literature, and the extraction capabilities of several classes of candidate systems were characterized. An equilibrium model was used to compare the relative efficiency of the systems. Their relative efficiency, economy, physical interphase behavior, tendency toward side reactions, and toxicity were employed to select the above two candidates.
The effect of a water-insoluble organic acid, di(2-ethylhexyl)phosphoric acid (D2EHPA), on the extraction equilibrium of acetic acid from aqueous media with xylene solutions of tri-n-octylamine (TOA) was systematically investigated. In the absence of D2EHPA, the formulation of the extracted species in the organic phase and equilibrium constants for the formation of these species were numerically determined. Synergistic and antagonistic effects on the extraction of acetic acid were observed in the presence of D2EHPA, mainly depending on the concentration of TOA and the concentration ratio of D2EHPA to TOA. Finally, the influence of temperature on the extraction of acetic acid with TOA and/or D2EHPA was investigated.
The parameters of lactic acid separation from fermentation broths by Emulsion-Liquid Membranes (ELMs) have been optimized. Using these parameters, lactic acid can be separated up to 90%, concentrated up to 3 times and cleared of most of its by-products. Only about 1% of glucose and amino acids is permeated together with the lactic acid. With these parameters, not only lactic acid but also other monocarboxylic acids can be separated, the better and faster the lower the pKa-value of the acid the fewer polar side groups it carries. When separating dicarboxylic acids, the mass transfer is hindered by the second carboxylic group. The smaller the distance between the two carboxylic groups, the slower is the separation of the acid. When several organic acids are separated from the same fermentation broth, their mutual influence is not very strong, at least when the concentrations of the acids are about 100 mmol/l. However, sulphuric acid which is added to the fermentation broth throughout permeation to maintain the broth at a constant pH, does exert a strong influence. In order to reduce the competition between the organic and sulphuric acids during permeation to a minimum, as little as possible sulphuric acid is used. However, a certain quantity of sulphuric acid is necessary to maintain the pH of the fermentation broth during permeation at 4.5, otherwise organic acid separation would become too slow.
Reactive extraction of lactic acid was performed continuously in a packed column. The 0.6 M trioctylamine (TOA)/l-chlorobutane
system was used as an extradant. The initial concentration of lactic acid was 10 wt% based on fermentation results. Raschig
rings (5 and 7 mm diameter) were used to measure hydrodynamic data. Disperse phase holdup was nearly constant at Vd<0.8Vd,f.It can be seen that the flooding data obtained from this study were consistent with the literature. NTU and HTU were calculated.
NTU varied from 1 to 2 and HTU from 96 cm to 44 cm with variation of Vd. The overall mass transfer coefficients of the continuous phase were nearly constant to 8.98x 10-5 mol/cm2s with variation of Vd.
Within the framework of a program aiming to improve the existing extractive recovery technology of fermentation products, the state of the art is critically reviewed. The acids under consideration are propionic, lactic, pyruvic, succinic, fumaric, maleic, malic, itaconic, tartaric, citric, and isocitric, all obtained by the aerobic fermentation of glucose via the glycolytic pathway and glyoxylate bypass. With no exception, it is the undissociated monomeric acid that is extracted into carbon-bonded and phosphorus-bonded oxygen donor extractants. In the organic phase, the acids are usually dimerized. The extractive transfer process obeys the Nernst law, and the measured partition coefficients range from about 0.003 for aliphatic hydrocarbons to about 2 to 3 for aliphatic alcohols and ketones to about 10 or more for organophosphates. Equally high distribution ratios are measured when long-chain tertiary amines are employed as extractants, forming bulky salts preferentially soluble in the organic phase.
Separation processes based on reversible chemical complexation
- King
C.J. King, Separation processes based on reversible chemical complexation, in: R.W. Rousseau (Ed.), Handbook of
Separation Process Technology, Wiley, New York, 1987,
Chapter 15.
Hollow fiber membrane con-with trioctylamine
- A Gabelman
- S T Hwang
A. Gabelman, S.T. Hwang, Hollow fiber membrane con-with trioctylamine/ethylene chloride/n-hexane, Sep. Sci. Technol. 31 (1996) 1123. tactors, J. Membr. Sci. 159 (1999) 61.
Extraction equilibria of organic acids with tri-permeation of organic acids
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Juang, R.-T. Wu / Separation and Purification Technology 17 (1999) 225–233 K. Kawano, Extraction equilibria of organic acids with tri-permeation of organic acids, Chem. Eng. Technol. 15 (1992) 363. n-octylphosphine oxide, J. Chem. Eng. Jpn. 23 (1990) 734.
Com-For amine systems the amount of extraction R
- A A Chaikhorskii
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A.A. Chaikhorskii, B.P. Nikolskii, B.A. Mikhailov, Com-For amine systems the amount of extraction R.-S.
Process for recovery of organic acids from tion
- Y Su
- Y Jiang
Y. Su, Y. Jiang, Process for recovery of organic acids from tion, in: W.S.W. Ho, K.K. Sirkar ( Eds.), Membrane Hand-book, Van Nostrand Reinhold, New York, 1992, aqueous solutions, US Patent 4,705,894, 1987.
Extraction of citric acid with primary amine N 1923 , Gaodeng Xuexiao extractant systems for acetic acid removal for calcium magnesium acetate production
- Z H Wang
- Z L Gao
- S X Sun
- J L Shen
Z.H. Wang, Z.L. Gao, S.X. Sun, J.L. Shen, Extraction of
citric acid with primary amine N 1923
, Gaodeng Xuexiao
extractant systems for acetic acid removal for calcium magnesium acetate production, Ind. Eng. Chem. Res. 31
- R.-S Juang
- R.-T Wu
R.-S. Juang, R.-T. Wu / Separation and Purification Technology 17 (1999) 225–233
Aliquat 336 is recom- (1996) 160. mended due to its higher extractability Extracother hand, TBP is the second attractive candidate tion equilibria of lower carboxylic acids with long chain because TBP is less expensive than TOPO. There alkylamine
- Y Kawano
- K Kusano
- K Kondo
- F Nakshio
the organic phase at Z>5. Aliquat 336 is recom-
(1996) 160.
mended due to its higher extractability. On the
[12] Y. Kawano, K. Kusano, K. Kondo, F. Nakshio, Extracother hand, TBP is the second attractive candidate
tion equilibria of lower carboxylic acids with long chain
because TBP is less expensive than TOPO. There
alkylamine, Kagaku Kogaku Ronbunshu 8 (1982) 404.
is no hardly any temperature dependence by
[13] Y. Kawano, K. Kazushito, F. Nakshio, Extraction and
interfacial adsorption equilibria of aqueous acetic acid and
Distribution of citric, and H 2 SO 4 may react with the extractants, making acetic and oxalic acids between water and organic solutions continuous operation less beneficial. of tri-n-octylamine, Fluid Phase Equilib
- T Kirsch
- H Ziegenfub
- G Maurer
Na
2
CO 3
is used as stripping agent because HCl
[14] T. Kirsch, H. Ziegenfub, G. Maurer, Distribution of citric,
and H 2
SO 4
may react with the extractants, making
acetic and oxalic acids between water and organic solutions
continuous operation less beneficial.
of tri-n-octylamine, Fluid Phase Equilib. 129 (1997) 235.
Handbook of Solvent Extraction
- C J King
C.J. King, Acetic acid extraction, in: T.C. Lo, M.H. Baird,
C. Hanson ( Eds.), Handbook of Solvent Extraction,
Wiley, New York, 1983, pp. 567-573.
Solvent equilibria for extraction Fig. 7. Effect of temperature on distribution ratio of acetate of carboxylic acids from water
- J M Wardell
- C J King
J.M. Wardell, C.J. King, Solvent equilibria for extraction
Fig. 7. Effect of temperature on distribution ratio of acetate
of carboxylic acids from water, J. Chem. Eng. Data 23
ions with Aliquat 336.
(1978) 144.
Extraction equilibria of organic acids with tripermeation of organic acids
- K Kawano
K. Kawano, Extraction equilibria of organic acids with tripermeation of organic acids, Chem. Eng. Technol. 15
(1992) 363.
Hollow fiber membrane conwith trioctylamine/ethylene chloride/n-hexane
- A Gabelman
- S T Hwang
A. Gabelman, S.T. Hwang, Hollow fiber membrane conwith trioctylamine/ethylene chloride/n-hexane, Sep. Sci.
Technol. 31 (1996) 1123.
tactors, J. Membr. Sci. 159 (1999) 61.
Acetic acid extraction
- King
Complex formation in non-aqueous solutions. X. Interaction of tridecylamine with acetic acid
- Chaikhorskii
Distribution of acetic acid between water and organic solutions of tri-n-octylamine
- Ziegenfub
Extraction of citric acid with primary amine N1923
- Wang