Development of a more efficient emulsion liquid membrane system with a dilute polymer solution for extraction of penicillin G

So as to find a more efficient emulsion liquid membrane (ELM) system for extraction of penicillin G from simulated media, further study was done on batch and continuous ELM systems with a dilute polymer solution in addition to our previous ELM work examined in more detail in this work. The study was carried out in the batch ELM system varying membrane composition and Na₂CO₃ concentration in the internal phase. Compared to the previous work, the polymer-dissolved ELM system with higher concentrations of Na₂CO₃ in the internal phase and lower concentrations of surfactant in the membrane phase produced much higher extraction efficiency. Also, an optimized emulsion composition from the batch system was applied to continuous extraction of penicillin G in the extraction column of Oldshue–Rushton type, and in view of the fact that high enrichment ratio of penicillin G was still obtained, development of a practical ELM system for penicillin G extraction seemed feasible.     

Liquid-liquid extraction for efficient synthesis and separation by utilizing micro spaces

Enhancement of mass transfer between two phases and improvement of extraction efficiency are expected if features of micro spaces are adopted for a liquid-liquid two-phase process. In this work, three extraction operations, contact flow in a Y-shaped microchannel, segmented flow and emulsification, have been investigated. Extraction using segmented flow is dependent on mass transfer by molecular diffusion and its rate is enhanced by the internal circulation flow generated inside slugs. The extraction rate can be controlled precisely by adjusting operational parameters such as the flow rate and the flow rate ratio. Liquid-liquid two-phase separation can be achieved instantly. Thus, continuous operation of a process involving liquid-liquid extraction and then two-phase separation is expected to be possible. For extraction based on emulsification, rapid extraction is made possible owing to significant increase in the interfacial area. Though extraction itself is rapid, liquid-liquid separation may take a long time because coalescence of stable emulsions requires time. It is suitable for systems strongly requiring only rapid extraction. Advanced reaction-separation systems can be developed by combining the extraction operations, making full use of the characteristics of segmented flow or emulsification and the reaction.     

Synergistic extraction and separation of mixture of lanthanum and neodymium by hollow fiber supported liquid membrane

Separation of lanthanum and neodymium by supported liquid membrane has been studied. Synergistic extraction and recovery of lanthanum and neodymium with thenoyltrifluoroacetone (HTTA) in benzene have been found by the addition of Trioctylamine (TOA). Results indicate that percentage of extraction is highly dependent on pH of feed solution, which the maximum value is 2.5. When TOA was added to HTTA, the percentage of extraction and recovery considerably increased due to synergism. Lanthanum can be extracted and recovered more than neodymium because of the adduct formation constant,β ₁ . Theβ ₁ values decreased with an increase in atomic number of lanthanide and showed a difference between lanthanum and neodymium. Percentage of extraction and recovery is enhanced when the HTTA concentration is increased, but its difference is larger when TOA concentration is increased. Finally, multi-column module of supported hollow fiber membrane was used and the percentage and difference of extraction and recovery was found to be more increased due to resident time.     

Performance of hollow fiber supported liquid membrane on the extraction of mercury(II) ions

The extraction and recovery or stripping of mercury ions from chloride media using microporous hydrophobic hollow fiber supported liquid membranes (HFSLM) has been studied. Tri-n-octylamine (TOA) dissolved in kerosene was used as an extractant. Sodium hydroxide was used as a stripping solution. The transport system was studied as a function of several variables: the concentration of hydrochloric acid in the feed solution, the concentration of TOA in the liquid membrane, the concentration of sodium hydroxide in the stripping solution, the concentration of mercury ions in the feed solution and the flow rates of both feed and stripping solutions. The results indicated that the maximum percentages of the extraction and recovery of mercury ions of 100% and 97% were achieved at the concentration of hydrochloric acid in the feed solution of 0.1 mol/l, the concentration of TOA at 3% v/v, the concentration of sodium hydroxide at 0.5 mol/l and the flow rates of the feed and stripping solutions of 100 ml/min. However, the concentration of mercury ions from 1–100 ppm in the feed solution had no effect on the percentages of extraction and recovery of mercury ions. Thus, these results have identified that the hollow fiber supported liquid membrane process has high efficiency on both the extraction and recovery of mercury (II) ions. Moreover, the mass transfer coefficients of the aqueous phase (k _i ) and membrane or organic phase (k _m ) were calculated. The mass transfer coefficients of the aqueous phase and organic phase are 0.42 and 1.67 cm/s, respectively. The mass transfer coefficient of the organic phase is higher than that of the aqueous phase. Therefore, the mass transfer controlling step is the diffusion of the mercury ions through the film layer between the feed solution and the liquid membrane.     

Mass transfer modeling of membrane carrier system for extraction of Ce(IV) from sulfate media using hollow fiber supported liquid membrane

A theoretical and experimental study on the extraction and stripping of Ce(IV) ions from sulfate media using microporous hydrophobic hollow fiber supported liquid membrane has been performed. The experiments were made in the recycling mode. Tri-n-octylamine (TOA) was used as extractant diluted in kerosene and sodium hydroxide was use as strip solution. The mathematical model focused on the extraction side of a liquid membrane system. The aqueous feed mass transfer coefficient (k_i) and the organic mass transfer coefficient (k_m) which were calculated from the model were 9.47 X 10^-2 and 6.303 cm/s, respectively. Therefore, the rate controlling step is the diffusion of the cerium complex across a liquid membrane. In addition, the mass transfer modeling was performed and the validity of the developed model was evaluated with experimental data and found to tie in well with the theoretical value when the concentration of TOA was higher than 5% (v/v).     

Selective recovery of palladium from used aqua regia by hollow fiber supported with liquid membrane

This research study was aimed at recovering palladium from used aqua regia by means of a hollow fiber thoroughly supported with liquid membrane. The liquid membrane, consisting of two extractants—thioridazine HCl and oleic acid-solubilized in chloroform—was used to coat the rmcroporous hollow fiber throughout. Sodium nitrite, a stripping agent, which was fed through the shell side, flowed counter-currently with the feed solution fed via the tube side. The following factors were investigated: the concentrations of the two extractants and of sodium nitrite, the pH of used aqua regia, the flow rates of both the feed and stripping solution, and the number of runs in the hollow fiber module. It was found that after a 30-mmute operation, 29.10% of palladium ion was optimally recovered at 0.0005-M thioridazine and 0.05-M oleic acid. With reference to the precious metals recovered, the following order was recorded: Pd(II)>Pt(IV)>Cu(II)>Au(III). It was observed that synergistic extraction could be gained at the concentration level of the extradants, regulated in the experiment. The liquid membrane system had long-term stability and even after the third run, it could still recover palladium up to 65%.     

乌桕脂脂肪酸提取和分离的研究

由油脂精细化工的理论和实践,提出乌桕脂脂肪酸提取和分离的清洁工艺,并与现有工艺比较,说明该工艺的优越性     

An efficient and cost-effective solvent extraction for recovery of phenol and its hydroxy derivatives from aqueous medium

A cost-effective solvent extraction process for recovery of phenol and its hydroxy derivatives from aqueous medium was developed. Four different solvents—Tributyl phosphate (TBP), Triphenyl phosphate (TPP), Methyl isobutyl ketone (MIBK) and Oleic acid (OA)—selected based on their miscibility with water. The extraction efficiency (EE) of the selected solvents was studied. A reversed-phase HPLC system connected to an RP, C18 column was used to analyze the aqueous medium to evaluate the performance of the selected solvents. TBP exhibited the best extraction performance, while TPP and MIBK proved to be good when large amount of solvent was used. However, OA was found to be inefficient to extract the solutes under investigation. Interestingly, a different salvation property was observed and elucidated using the solvation theory.     

Predispersed solvent extraction of negatively complexed copper from water using colloidal liquid aphron containing a quaternary ammonium salt

Negatively complexed copper ion by complexing agent like EDTA (Ethylenediaminetetraacteic acid) was removed by predispered solvent extraction (PDSE) using colloidal liquid aphrons (CLAs) made out of Trioctylmetylammonium chloride (Aliquat 336) diluted with nonpolar kerosene. PDSE was found to have higher mass transfer rate than conventional solvent extraction under experimental conditions without mechanical mixing. The effect of type of water-soluble surfactants, phase volume ratio (PVR), concentration of anionic Sodium Dodecyl Benzene Sulfonate (SDBS) on PDSE was investigated. In addition, the effect of anionic SDBS on back extraction in PDSE was also studied. Under experimental conditions with enough mechanical mixing, the amount of copper transferred to Aliquat 336 core from the pregnant phase was compared in both PDSE by using anionic SDBS and conventional solvent extraction. It is concluded that PDSE using Aliquat 336 CLA can be used for treatment of negatively complexed copper without the influence of surfactant. To optimize CLAs-based process, stability of CLAs containing a quaternary ammonium salt Aliquat 336 diluted with kerosene in the continuous phase was investigated by measuring the volume released to surface. To destabilize CLAs, H⁺, OIL were added. Stability of CLAs was estimated by comparing the half-life obtained. Break-up of destabilization follows pseudo-first-order reaction kinetics at low ionic strength. But, pseudo-first-order model cannot be applied to a region of high ionic strength.     

Separation of As(III) and As(V) by hollow fiber supported liquid membrane based on the mass transfer theory

Separation of As(III) and As(V) ions from sulphate media by hollow fiber supported liquid membrane has been examined. Cyanex 923 was diluted in toluene and used as an extractant. Water was used as a stripping solution. The extractability of As(V) was higher than As(III). When the concentration of sulphuric acid in feed solution and Cyanex 923 in liquid membrane increased, more arsenic ions were extracted into liquid membrane and recovered into the stripping solution. The mathematical model was focused on the extraction side of the liquid membrane system. The mass transfer coefficients of the aqueous phase (k _i ) and organic phase (k _m ) are 7.15×10⁻³ and 3.45×10⁻² cm/s for As(III), and 1.07×10⁻² and 1.79×10⁻² cm/s for As(V). Therefore, the rate-controlling step for As(III) and As(V) in liquid membrane process is the mass transfer in the aqueous film between the feed solution and liquid membrane. The calculated mass transfer coefficients agree with the experimental results.     

One-through selective separation of copper,chromium and zinc ions by hollow fiber supported liquid membrane

The separation of a mixture of Cu(II), Cr(VI) and Zn(II) simultaneously from a sulfate media using two consecutive hollow fiber microporous liquid membrane extraction systems has been studied. The experiments were made in the one-through mode. LIX84-I and Aliquat336 were used as carrier extractants for copper and chromium in the first and second hollow fiber modules, respectively. Pure copper and pure chromium ions are extracted and stripped from first and second hollow fiber modules, respectively, but zinc ions cannot be extracted by both extractants due to pH conditions used in this study and remain in the raffinate. Results indicate that the percentage of extraction is highly dependent on pH of the feed solution and the pH value is 2.5 for the maximum extraction. The percentage of extraction of copper and chromium ions is enhanced when the concentration of LIX84-I and Aliquat336 is increased of which both maximum value is 0.5 M, and these results also occur in stripping phase. The influence of sulfuric acid and sodium hydroxide concentration in strip solution of each column was examined, and it was found that the percentage of extraction and stripping is further increased due to the difference of driving force. The maximum percentage of extraction for copper is 33% and 92% for chromium. The experimental results indicated the feasibility of separation and recovery of these metals from the dilute solution by using membrane technology     

Semi-batch extraction of anthocyanins from red grape pomace in packed beds: experimental results and process modelling

A semi-batch extraction process of anthocyanins was studied in a packed bed. Methanol was used as solvent and the raw material studied consisted of skins of the tempranillo grape, which was obtained from the pomace from red wine vinification. The results show large diffusional effects due to strong control from the mass transfer. The best results were obtained using a high temperature and a high flow rate. A penetration model is proposed in terms of a bed of spherical particles. The model provides a value for the diffusion coefficient of the solute within the solid matrix. It can be seen that the adjustment of the model is satisfactory and that it is able to predict, to a reasonable extent, the yield of the extraction process.     

Viability of the separation of Cd from highly concentrated Ni−Cd mixtures by non-dispersive solvent extraction

The separation of nickel and cadmium from highly concentrated solutions by means of non-dispersive solvent extraction (NDSX) has been studied in this work. Extraction and back-extraction processes were carried out simultaneously in a batch mode using two parallel modules and the organic phase flowing in a closed circuit. Starting with concentrations of 0.37 M of Cd and 0.37-0.68 M of Ni in the feed aqueous phase, 1 M of H₂SO₄ in the back-extraction phase, and using D2EHPA as extractant, the viability of the separation-concentration of Cd from that mixture has been confirmed. Under the experimental conditions, the separation process was run at a constant rate of mass transport, thus leading to a selectivity factor in the concentration step ρ = 67 mol Cd/mol Ni.     

An alternative sequential extraction process for maximal utilization of bioactive components from Korean red ginseng

Two types of sequential extraction process (SEP) for the recovery of bioactive components from Korean red ginseng were examined. As a SEP (normal SEP, nSEP), Korean red ginseng was sequentially treated using hot water and n-hexane for the successive extraction of water-soluble and lipid-soluble components. Also by changing the sequential order of solvents, an alternative SEP (reverse SEP, rSEP) in which n-hexane extraction was followed by hot water extraction, was proposed. Regardless of the sequential order of solvents, the recovery yield of acidic polysaccharide (AP) and crude saponin (CS) showed no significant change. On the other hand, in the rSEP, the lipid-soluble fraction was obtained from red ginseng with an enhanced recovery yield, four times higher than that in nSEP. Additionally, from dose-response assays to assess the effects of lipid-soluble components on the proliferation of human hepatoma (HepG2) and breast (MCF-7) cancer cell lines, it was found that hexane extract of red ginseng (HER) in rSEP has higher efficacy than the hexane extract of red ginseng marc (HERM) obtained in nSEP. This strongly suggested that rSEP would be a more attractive industrial process in terms of the efficacy of lipid-soluble extract as well as the recovery yield.     

Process intensification in extraction by liquid emulsion membrane (LEM) process: A case study; enrichment of ruthenium from lean aqueous solution

Process intensification in extraction as a unit operation can be realized through liquid emulsion membrane (LEM) process by combining extraction and stripping in one stage eliminating the need of stripper. LEM technique is very useful to enrich very lean aqueous phase containing precious metal to aid the recovery process. The technique is illustrated by applying the same to enrich platinum group noble metal, ruthenium (Ru) from its aqueous solution. The liquid membrane phase consisted of extractant (trioctylamine) dissolved in liquid paraffin modified with 1-octanol and the surfactant used was Monemul 80. The strip phase found to be very effective was perchloric acid. To facilitate extraction tin(II) chloride was added to the aqueous feed phase containing Ru at 20 ppm level. Various process parameters affecting the performance of LEM process such as extractant, surfactant, strip phase concentrations, the batch extraction time, the treat ratio and the speed of agitation were studied at bench scale to aid process development.     

Filtration performance of ceramic membrane for the recovery of volatile fatty acids from liquid organic sludge

This research focused on the filtration performance of a membrane-coupled fermenter system for dissolved organics recovery from liquid organic sludge. Over the range 0.1-5 μm, the magnitude of total membrane resistance (R₁) is ranged as follows in the order: 0.1 μm>0.2 μm>0.5 μm>1 μm>2 μm>5 μm. The cake layer resistance (R_c) occupied about 68-88% of total resistance. The decline of permeation flux was mainly attributed to R_c, which was formed by a strong deposition from physicochemical interactions of solids on the membrane surface. Higher suspended solids concentration of suspension caused lower permeation flux. However, there was not a proportional relation beyond a certain SS concentration. The cross-flow velocity on the membrane surface was faster, which resulted in higher permeation flux and also more efficiency with low transmembrane pressure. The appropriate pH of suspension was in the range of 5.0 to 6.0 for dissolved organics recovery as well as permeation flux. It is possible for bacteria to be separated perfectly with 0.1 μm and 0.2 μm membrane pore sizes. Based on experimental results, optimal membrane pore size for the recovery is believed to be around 1 μm.     

Sulphoxide ligands inbicyclooctanium based ionic liquid: Novel solvent systems for the extraction of f-elements

The extraction of Pu⁴⁺, PuO₂²⁺, Am³⁺, and Eu³⁺ by structurally modified sulphoxides in 1-hexyl-1,4-diaza [2.2.2] bicyclooctanium Bis(trifluoromethylsulfonyl)imide was investigated at 25 ± 2 °C in an aqueous acidic medium. The extraction process followed ‘cation exchange’ mechanism. The phenyl substituted ligands showed higher extraction efficiency due to steric and electronic factors and followed the trend: Allyl phenyl sulphoxide (APSO) > Benzyl phenyl sulphoxide (BPSO) > Benzyl methyl sulphoxide (BMSO). The extraction process was thermodynamically spontaneous and only one ligand was found to coordinate in the extracted species for all the metal ions. Oxalic acid was found suitable for Pu⁴⁺ stripping. PuO₂²⁺, Am³⁺, and Eu³⁺ were efficiently back extracted by the Na₂CO₃ solution. APSO-IL system showed excellent radiolytic stability and all the three solvent systems were found highly selective.     

Supercritical CO2 extraction of dittany oil: Experiments and modelling

The extraction of oil from dittany (Origanum dictamnus) using supercritical carbon dioxide was investigated. The experiments were performed in a bench scale apparatus at the pressures of 100 and 150 bar and at the temperatures of 40 and 60 °C. The effect of the solvent flow rate and the mean particle diameter of dittany on the extraction yield was also investigated at 100 bar and 40 °C. It is shown that the extraction yield increases with pressure, while the increase of temperature and mean particle diameter leads to the opposite effect. Different flow rates of SCCO₂ lead to similar extraction yields. Finally, the overall extraction curves are well correlated by a mass balance model of plug flow, in which the intraparticle diffusion resistance has the controlling role.