Stripping Phase Research Articles

Green formulation for synthetic dye extraction using synergistic mixture of acid-base extractant

Synthetic dyes especially reactive dye that are usually discharged into the wastewater are considered as toxic and harmful to the aquatic organisms and human. Various methods have been introduced to remove the reactive dyes. In this study, a green synergistic extractant has been formulated in the vegetable oil to enhance the extraction efficiency of liquid-liquid extraction (LLE) process for the Orange 3R removal. Several types of extractants were investigated as the extractant and synergist extractant to increase the extraction performance such as acidic, basic and neutral extractants. Interestingly, the results showed that Aliquat 336 and D2EHPA have shown their potentialities as an extractant and a synergist extractant, respectively. Both extractants were formulated in the cooking palm oil as a diluent at the concentrations of 0.1 M Aliquat 336 and 0.08 M D2EHPA. Using the aforementioned optimum conditions, about 90% of the Orange 3R has been successfully extracted with the highest synergistic coefficient (SC) of 67.2. In the meantime, the back extraction study have indicated that NaOH was capable of working as a potential stripping agent where almost 100% of dyes were successfully stripped out from the loaded organic-dye phase into the stripping phase. In conclusion, the green synergist formulation has offered a great prospective for the Orange 3R extraction via LLE process.

Ionic liquids as bulk liquid membranes on levulinic acid removal: A design study

Ionic liquids are considered as green solvents because of their remarkable properties. In view of this, imidazolium-based ionic liquids were used as a bulk liquid membrane (BILM) for levulinic acid removal. Four different hydrophobic ionic liquids, 1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIM][Tf2N], 1-Butyl-3-methylimidazolium hexafluoro phosphate [BMIM][PF6], 1-Hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [HMIM][Tf2N], 1-Hexyl-3-methylimidazolium hexafluorophosphate [HMIM][PF6], were used in the membrane phase. Tributyl phosphate was used as a carrier (0–2 mol/L) in the membrane, and NaOH solutions (0–4 N) were used as stripping phase respectively. Various parameters such as initial levulinic acid concentration in the feed, carrier concentration and ionic liquid type in the membrane, and NaOH concentration in the stripping phase were examined by using D-optimal design. D-optimal design based on the Response Surface Methodology (RSM) is a design method that provides the relationship between independent and dependent factors with a minimum number of experiments. Levulinic acid was successfully transported through BILM using imidazolium-based ionic liquids. Extraction and stripping removal efficiencies were selected as dependent variables and calculated from the experimental results. The experimental results were analyzed by analysis of variance (ANOVA). According to ANOVA, the second order model equations were obtained for dependent variables and have been the good fit with the experimental results. The optimal conditions for BILM process were performed to obtain the higher removal efficiencies. The highest extraction and stripping efficiencies have obtained in case of higher concentration values of TBP and NaOH. Additionally, the molar fluxes at extraction and stripping interfaces were calculated from experimental data. As a result, this design study showed that ionic liquids as bulk liquid membranes can be used on levulinic acid removal.

Factors influencing separation selectivity of rare earth elements in flat sheet supported liquid membranes

Separation selectivity of the mixture yttrium-neodymium-dysprosium using bis (2-ethylhexyl) hydrogen phosphate (D2EHPA) as extractant in a flat sheet supported liquid membrane was studied by simulations. A new definition of selectivity and a diffusional-kinetic transient model were used in the calculations. Resistance distribution between the phases, stripping phase pH, extractant concentration and initial feed concentration have great influence on selectivity and process time and their appropriate management would improve separation. The analysis of selectivity using the present model would be a useful tool to design a multistage process aimed at the separation of a multicomponent mixture of rare earth elements into its constituents.

Evaluation of activated composite membranes for the facilitated transport of phenol

Abstract In this work the results on the first use of an activated composite membrane (ACM) containing Cyanex 923 for the extraction and transport of phenol are presented. A new dense layer-ACM configuration constituted by piperazine showed better stability than that prepared with 1,3-phenylenediamine. The effects of several parameters on the transport of phenol such as feed phase pH, carrier concentration and stripping phase composition were evaluated. The performance of the membrane was also evaluated during continuous additions of phenol and for a long period of time, observing the same rate of extraction and reextraction. Moreover, phenol transport was evaluated starting from synthetic wastewater of resin production plants type. The results exhibit the potential use of ACMs in the elimination and transport of organic species, even when analyte is initially found in complex solutions.

Evaluation of the emulsion liquid membrane performance on the removal of gadolinium from acidic solutions

This work evaluates the performance of emulsion liquid membrane (ELM) for the extraction of gadolinium(III) from acidic solution. The ELM was made up of di-(2-ethylhexyl) phosphoric acid (D2EHPA) as carrier, Span 80 (sorbitol monooleate) as emulsifying agent, commercial kerosene as organic diluent and Nitric acid as stripping phase. Important physical and chemical variables affecting the ELM performance for the extraction of gadolinium(III) such as carrier concentration, mixing time, surfactant concentration, agitation speed, initial pH of the feed phase, internal phase concentration, treatment ratio, and feed phase concentration were systematically investigated. Results indicated that the highest gadolinium(III) extraction can be attained after 10 min of mixing by using 0.05 M D2EHPA, 1.5% (v/v) Span 80, 1.0 M nitric acid as stripping phase at feed phase pH of 2, agitation speed of 180 rpm, and treatment ratio of 1:10. At the optimum condition, simultaneous quantitative extraction (>99%) and stripping (>79%) of gadolinium were achieved. Furthermore, the overall mass transfer coefficient was calculated and the results revealed that the extraction was interfacially controlled.

Electrodriven transport of chromium (VI) using 1-octanol/PVC in polymer inclusion membrane under low voltage

The transport behaviour of Cr(VI) from the aqueous phase through a polymer inclusion membrane (PO-PIM) containing 1-octanol (OCT) as carrier and polyvinyl chloride (PVC) as support at a low voltage drive (0–30 V) is investigated. The correlation between the OCT content and the surface or cross-sectional micromorphology of PO-PIM is also analysed. Under optimised mass transfer conditions, the transmission rules and mechanism of Cr(VI) under an electrodriven membrane extraction system are investigated. Results show that the surface and interior of PO-PIM exhibit micro/nanopores with an OCT content exceeding 50% (w/w). The mass transfer behaviour of OCT to Cr(VI) conforms to the proton coupling mechanism. The voltage drive effectively solves the residue problem of Cr(VI) in the membrane phase, and the permeability coefficient (P) of PO-PIM to Cr(VI) increases with the voltage. The P of PO-PIM to Cr(VI) reaches 43.38 μm·s−1 at 30 V when the OCT content is 82.8% and the feed and stripping phases are pH 2.0 HCl solution and 0.1 mol·L−1 NaOH solution environments, respectively. After the introduction of hydrophobic kerosene into the membrane phase, the stability of the membrane is significantly enhanced. When the composition ratio of kerosene/OCT/PVC is 0.8:2.2:0.5 and the voltage is 30 V, the initial current density rise is only 0.1 A and the pH increases slightly with the repeated use of PO-PIM to four cycles.

Optimization of extraction conditions using central composite design for the removal of Co(II) from chloride solution by supported liquid membrane

The extraction conditions for the removal of cobalt(II) from chloride aqueous solution were studied by using supported liquid membrane. The effects of four factors such as the acidity of feed solution (pH), Cyanex301 concentration, cobalt ion concentration in the feed phase as well as sulfuric acid concentration in the stripping phase were investigated by using central composite design which is a subcategory of response surface methodology. The optimum conditions obtained for pH, Cyanex301 concentration, initial cobalt concentration in feed solution, and sulfuric acid concentration were 6, 1mol/L, 98.86mg/L and 1.26mol/L, respectively. The percentage of cobalt extraction equal to 48.21% obtained from the predicted model was in agreement with the experimental data (45.84%), after 3.5h in the experimental conditions. In addition, the other factors such as the types of solvent as a diluent, stripping solution, and the types of extractants and mixtures were studied at the optimum point. The results showed that the percentage of cobalt extraction achieved was 46.85% within 3.5h, in the extraction conditions (Cyanex301 as an extractant, kerosene or chloroform as a diluent and the mixture of sulfuric acid and nitric acid as the stripping phase).

Solvent extraction of nickel ions from electroless nickel plating wastewater using synergistic green binary mixture of D2EHPA-octanol system

A study on the synergistic green solvent extraction of nickel ions from real electroless nickel plating wastewater using an organic phase containing a binary mixtures of Di (2-ethylhexyl) phosphoric acid (D2EHPA) and octanol in palm oil was conducted. The effects of diluent composition, synergist, carrier and stripping agent types and its concentrations were experimentally investigated and the optimum conditions were determined. Results revealed that both D2EHPA and octanol acted as a carrier and synergist, respectively. A significant synergistic effect occurred when the octanol helped destroy the dimer structure of D2EHPA for cation exchange mechanism with nickel ions, hence improving the nickel ions extraction up to 90% with the maximum distribution ratio of 8.8 under optimum condition of 0.7M D2EHPA and 15% (v/v) octanol in palm oil. Afterwards, the stripping experiment showed that nickel ions could be recovered from the loaded mixture of carrier using 1.0M nitric acid solutions. Besides, the slope analysis method showed that the nickel ions were extracted from weak acidic electroplating feed solution as nickel-D2EHPA-octanol complex and recovered as nickel nitrate complex in the stripping phase. Thus, it can be concluded that the green synergistic formulation containing binary mixtures of D2EHPA-octanol system is one of the promising approaches as well as a green and efficient separation method for nickel ions extraction from the real electroless nickel plating wastewater.

Characterization of polymer inclusion membranes (PIM) containing phosphonium ionic liquids and their application for separation of Zn(II) from Fe(III)

AbstractBACKGROUNDHydrometallurgical separation of Zn(II) from Fe(III) from HCl solutions is an important issue to regenerate spent effluents. Polymer inclusion membranes (PIMs) are an attractive technique for selective separation and concentration of low concentrated target metal ions, as an alternative to liquid–liquid extraction.RESULTSPIMs containing phosphonium ionic liquids trihexyl(tetradecyl)phosphonium chloride (Cyphos IL101) or bis(2,4,4‐trimethylpentyl)phosphinate (Cyphos IL104), as metal ion carriers, o‐nitrophenyloctyl ether (NPOE) as a plasticizer and triacetate cellulose (CTA) as a polymer matrix were prepared and characterized by contact angle measurements, scanning electron microscopy, atomic force microscopy and nanoindentation measurements. An important aspect was to determine the influence of PIMs ageing on their morphology and efficiency of Zn(II) transport. Finally, PIMs were applied for separation of Zn(II) from Fe(III).CONCLUSIONThe surface of the IL‐containing PIMs was characterized as hydrophilic, rough, without apparent pores. However, phase contrast images indicated that the plasticized membranes were not fully homogeneous. Stability of the PIMs, particularly of those without the plasticizer or without the carrier, is affected by ageing. Finally, a membrane‐based successful separation of Zn(II) from Fe(III) was developed with 1 mol L‐1 HCl as a stripping phase for Fe(III), while the majority of Zn(II) were retained in the feed phase (SFe(III)/Zn(II) = 8.85). © 2017 Society of Chemical Industry

Nitrogen removal and intentional nitrous oxide production from reject water in a coupled nitritation/nitrous denitritation system under real feed-stream conditions

A Coupled Aerobic-anoxic Nitrous Decomposition Operation (CANDO) was performed over five months to investigate the performance and dynamics of nitrogen elimination and nitrous oxide production from digester reject water under real feed-stream conditions. A 93% conversion of ammonium to nitrite could be maintained for adapted seed sludge in the first stage (nitritation). The second stage (nitrous denitritation), inoculated with conventional activated sludge, achieved a conversion of 70% of nitrite to nitrous oxide after only 12 cycles of operation. The development of an alternative feeding strategy and the addition of a coagulant (FeCl3) facilitated stable operation and process intensification. Under steady-state conditions, nitrite was reliably eliminated and different nitrous oxide harvesting strategies were assessed. Applying continuous removal increased N2O yields by 16% compared to the application of a dedicated stripping phase. These results demonstrate the feasible application of the CANDO process for nitrogen removal and energy recovery from ammonia rich wastewater.

Simultaneous extraction and enrichment of reactive dye using green emulsion liquid membrane system

ABSTRACTCurrently, an extractive green palm oil-based emulsion liquid membrane (ELM) has been used for simultaneous extraction and enrichment of Reactive Red 3BS from simulated synthetic dye wastewater. The ELM consists of two main phases, which are organic liquid membrane (LM) and stripping solution. During the extraction process, the ELM was dispersed into the simulated synthetic dye wastewater containing the Reactive Red 3BS complexes. The organic LM contains tridodecylamine (TDA), Sorbitan Monooleate (Span 80) and palm oil as a carrier, surfactant and diluent, respectively. The sodium bicarbonate (NaHCO3) was used as stripping solution for the enrichment process. Several important parameters that affected the simultaneous extraction and enrichment of Reactive Red 3BS, such as carrier and stripping agent concentrations, extraction time and treat ratio, were investigated. The results showed that almost 90% of Reactive Red 3BS ions were successfully extracted with 10 times enrichment in the stripping phase at the optimum conditions of 0.2 M TDA, 0.1 M NaHCO3, 5 min of extraction time and 1:5 of treat ratio. Hence, it can be concluded that palm oil possesses a high potential as green diluent in future technology, especially in ELM process for the removal and recovery of Reactive Red 3BS from synthetic dye wastewater.

Reverse micelle Extraction of Antibiotics using an Eco-friendly Sophorolipids Biosurfactant

Reverse micelles extraction of erythromycin and amoxicillin were carried out using the novel Sophorolipids biosurfactant. By replacing commonly used chemical surfactants with biosurfactant, reverse micelle extraction can be further improved in terms of environmental friendliness and sustainability. A central composite experimental design was used to investigate the effects of solution pH, KCl concentration, and sophorolipids concentration on the reverse micelle extraction of antibiotics. The most significant factor identified during the reverse micelle extraction of both antibiotics is the pH of aqueous solutions. Best forward extraction performance for erythromycin was found at feed phase pH of approximately 8.0 with low KCl and sophorolipids concentrations. Optimum recovery of erythromycin was obtained at stripping phase pH around 10.0 and with low KCl concentration. On the other hand, best forward extraction performance for amoxicillin was found at feed phase pH around 3.5 with low KCl concentration and high sophorolipids concentration. Optimum recovery of erythromycin was obtained at stripping phase pH around 6.0 with low KCl concentration. Both erythromycin and amoxicillin were found to be very sensitive toaqueous phase pH and can be easily degraded outside of their stable pH ranges.

Application of Bulk Liquid Membrane Technique for Cadmium Extraction from Aqueous Solution

The extraction of cadmium from aqueous solution using kerosene as a bulk liquid membrane (BLM) with Tri-n-butyl phosphate (TBP) as a carrier was experimentally investigated under various operating conditions. The effects of feed and strip pH, feed initial concentration, TBP concentration, and strip to feed volume ratio on the cadmium ions transport efficiency were investigated. A stripping agent EDTA was used to enhance the transport efficiency of the cadmium ions. Flax and sesame oils were also considered as green liquid membrane alternatives to kerosene. They were evaluated in terms of extraction and separation efficiency. Cadmium extraction and stripping efficiencies of 89 and 94% were, respectively, obtained under specific conditions (100 ppm initial concentration of cadmium ions, 10% (v/v) TBP concentration, (1:2) strip to feed volume ratio, feed phase pH of 3, and strip phase pH of 11). The kinetics of $$\hbox {Cd}^{2+}$$ transport across BLM was investigated using kinetic model derived from the kinetic law of two consecutive irreversible first-order model. Both flax and sesame oils were found less efficient than kerosene in cadmium extraction and stripping rates.

Intensification of emulsion liquid membrane extraction of uranium(VI) by replacing nitric acid with sodium nitrate solution

Use of emulsion liquid membrane (ELM) extraction of uranium(VI) from lean streams containing nitric acid using tri-n-butyl phosphate (TBP) suffers from major drawback that TBP transports nitric acid to the strip phase, thereby reducing the driving force for extraction. This problem is completely eliminated by using near neutral sodium nitrate solution as the feed. The membrane phase is light liquid paraffin, containing TBP and the strip phase is aqueous sodium carbonate. Emulsion is stabilized using polymeric surfactant system, which exhibits low rate of leakage of the strip phase and no noticeable swelling of the emulsion. The key step is pH control of the continuous phase between 4.0 and 4.5 in order to neutralize sodium carbonate leaking from the emulsion phase. Effect of concentration of NaNO3 in the feed phase, Na2CO3 in the strip phase and volume ratio of the feed to the strip phase, on the rate of extraction of uranium(VI) and its enrichment, is studied. Using this process, it is possible to achieve nearly quantitative extraction of uranium(VI) with enrichment factor greater than 60. The superiority of the present process is established by comparing its performance with ELM extraction of uranium(VI) from nitric acid.

Desalination of Sea Water Using Polymer Inclusion Membran (PIM) With Aliquat 336-TBP (Tributhyl Phosphate) as Carrier Compound

Desalination of Sea Water using Polymer Inclusion Membrane has been done. PIM is known has high stability membrane to overcome the instability of liquid membrane. PIM was placed among two phase : source phases was sea water and feed phases was aquadest. Efficiency of desalination is known by determining salinity concentration and ion Na+ in feed phases and stripping phases using refractometer and AAS. while membrane characterization is done using FTIR. SEM and UV-Vis spectroscopy. The PIM membrane that is produced has thin. transparent. clear and flexible properties. The result showed that PIM transport for 24 hours give the highest of salinity transport. there are 92.68% is transported from feed phases and 84.87% in stripping phases. Membrane characterization result by FTIR and UV spectroscopy showed that PIM membrane is stable enough.

Analysis of the Critical Safety Thickness for Pretreatment of Mined‐Out Areas Underlying the Final Slopes of Open‐Pit Mines and the Effects of Treatment

Where a mined‐out area underlies a slope, it is a direct threat to slope safety and stability. This is of particular concern where a mined‐out area underlies the slope of an open‐pit mine, and it has a serious impact on the design and safety measures used for the mine. If a mined‐out area underlying the final slope of an open‐pit mine is not treated adequately and at the appropriate time, it may cause the slip failure of the final slope during the service life of the mine, posing a serious threat to the safety of personnel and equipment during the stripping phase. In light of the potential for such problems, this paper analyzes the instability mode and failure characteristics of an open‐pit slope near a mined‐out area in China using geological field survey and the polar stereographic projection method. The scale span method, in combination with engineering analogy and consideration of open‐pit mining technology, is then used to determine the critical safety thickness at which pretreatment of mined‐out areas should be carried out. A pretreatment process to infill the mined‐out area during construction of open‐pit mine steps is put forward, and its effects on slope stability and reliability are comprehensively evaluated. The results show that circular sliding is the most appropriate instability mode for a slope near a mined‐out area. The failure initiates through breakage in the roof of the mined‐out area, which induces subduction sliding of the free face of the slope at the left boundary of the mined‐out area and subsequent failure of the entire regional slope. Comprehensive analysis methods are used to determine that the critical safety thickness at which a mined‐out area under the final open‐pit slope should be pretreated is 24 m. The recommended treatment countermeasure is to transfer filling slurry into the mined‐out area through drilling holes in benches. This can satisfy the stability and reliability requirements for the slope under different working conditions.

Selective separation and enrichment of neodymium and gadolinium by emulsion liquid membrane using a novel extractant CYANEX® 572

In present study, the novel commercial extractant, CYANEX® 572, was applied for selective separation and enrichment of neodymium and gadolinium through an emulsion liquid membrane. Response surface methodology (RSM) based on central composite design (CCD) is carried out to explore the relationships between process variables namely, carrier concentration, initial pH of feed phase, surfactant concentration and mixing speed, and their interactions. The contours and 3D response surfaces of selective extraction of Gd(III) were achieved and significance of four important variables and their interactions on extraction efficiency of Gd(III) and Nd(III) and separation factor were found out. Also, three regression models for them were developed. A multiple optimization was performed to evaluate the best possible goals for the responses, simultaneously. Results indicated that the maximum separation factor of Gd(III) over Nd(III) was achieved using 0.75 M CYANEX® 572 as minimum concentration of carrier, initial feed pH of 1.56, surfactant concentration of 4% (v/v) and mixing speed of 135 rpm. Under the optimum condition, the extraction percentage of Gd(III) was maximum (67.45%), while the extraction percentages of Nd(III) was minimum (28.98) and the separation factor was found to be 3.78. Under the optimized condition, further experiments were conducted to investigate the effect of hydrochloric acid as internal stripping phase on the stripping efficiencies and enrichment factors were examined. At the internal concentration of 0.5 M, the stripping efficiency and enrichment factor reached the maximum of 89.04% and 12.01 for Gd(III), and 19.45% and 1.13 for Nd(III).

Extraction of Ethylparaben by emulsion liquid membrane: Statistical analysis of operating parameters

Ethylparaben, alkyl esters of p-hydroxybenzoic acid, is an endocrine disruptor that interfere glandular activity and hormone production and even with considerable elimination of them using conventional treatment methods, it is still recognized in river water samples at high concentrations. In this study, Emulsion Liquid Membrane (ELM) consisted of trioctylamine (TOA) as carrier, n-heptane as diluent, Span 80 as surfactant and Na2CO3 as the stripping solution was used for the removal of ethylparaben (EP) from aqueous solution. Studies were conducted to analyse the effect of various operating parameters. Effect of factors like carrier concentration (C), stripping phase concentration (N), speed of homogenizer (H), surfactant concentration (S) on the extraction of EP were evaluated with Taguchi's method. Statistical analysis of variance (ANOVA) was applied to analyze the effect of each parameter and stripping phase concentration (0.5 N Na2CO3) followed by speed of homogenizer (13500 rpm) were found to be the most influencing parameters. Photomicrographs of emulsions and droplet size analyzer were used to study the impact of speed of homogenizer on emulsion droplet size and size distribution. Dispersion destabilization of the emulsion was detected by Turbiscan. Atomic force microscopy and Fourier transform infrared spectroscopy were used to analyse dimensions, shape of emulsion droplet and also to confirm bonding and the presence of different functional groups. Experimental design for multivariable optimization by Taguchi had also been implemented. Using a stable emulsion at optimum condition ∼90% extraction of EP was achieved.

Purification of recombinant human interferon gamma from fermentation broth using reverse micellar extraction: A process optimization study

ABSTRACTIn the present investigation, we have shown a single step purification of IFN-γ from the fermentation broth of recombinant Kluyveromyces lactis (K. lactis) strain, using cationic surfactant based reverse micellar extraction (RME) system. The forward and back extraction processes were optimized in order to improve the overall extraction process. 78%, 93% and 98% forward extraction efficiencies (FEE) were obtained after the process by using aqueous phase pH 12, 150 mM CTAB and 0.2 M NaCl respectively. Afterwards, back extraction efficiency (BEE) was maximized by the optimization of stripping phase pH, isopropyl alcohol (IPA) and potassium chloride (KCl) concentration by employing Taguchi’s method of orthogonal array. Stripping phase pH 7, 15% IPA & 0.8 M KCl were found to be the best possible parameters producing 83% BEE. The usage of IPA has proven to reduce the effect of micellar-micellar based interaction, which was reflected as an improvement in BEE. This study demonstrates that the reverse micellar system is a highly promising and efficient tool for the direct extraction of recombinant proteins from fermentation broth. Moreover, this system holds a high potential to be an integral part of the downstream process used in biopharmaceutical industry.

Separation and Recovery of Cadmium(II) from Wastewater of Zinc Mining by Using Hollow Fiber Supported Liquid Membrane

The extraction and recovery of cadmium(II) via a hollow fiber supported liquid membrane (HFSLM) containing D2EHPA as a carrier dissolved in kerosene. The various effects on extraction and recovery cadmium were studied pH of feed phase, concentration of extractant and pH of stripping phase. The extraction and recovery of cadmium by using the hollow fiber supported liquid membrane method were 97% and 57%, respectively. The transport of cadmium ions was achieved by driving force of the concentration gradient. The behavior of extraction and/or recovery in HFSLM could be demonstrated in mass-transfer coefficient among feed phase, membrane phase and stripping phase. Determining the limiting step controlling the mass transfer of cadmium ion used the permeability coefficient.