Precious metals enrichment from wastewater solution using emulsion liquid membrane process (original) (raw)
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Jurnal Teknologi, 2014
Liquid semiconductor waste has become a serious problem to the environment due to the toxicity of heavy metals in the wastewater. However the monetary value of precious metals such as gold, silver and palladium has become a great concern nowadays. Therefore this study is investigating the recovery of palladium by emulsion liquid membrane (ELM) process using di-(2-ethylhexyl) phosphoric acid (D2EHPA) as a carrier. The important parameters affecting the extraction of palladium such as concentrations of carrier and stripping agents, extraction time and treat ratio were investigate. This experiment was conducted using a mixer-settler in a batch system. The results showed that more than 90% of palladium was extracted using 0.05M D2EHPA, 0.1 M H2SO4 as a stripping agent, 5 minutes extraction time, and 1:3 treat ratio. However, the study on emulsion stability showed unstable results due to the leakage and swelling occurrence during the extraction process. As a conclusion, the research shows that ELM has the potential to extract palladium from simulated waste solution using D2EHPA as a mobile carrier.
REMOVAL OF HEAVY METAL FROM AQUEOUS WASTEWATER BY EMULSION LIQUID MEMBRANE
Extraction and recovery of heavy metal from waste water using Liquid Membrane technology is more efficient than methods such as precipitation that form sludge that needs to be disposed in landfills. A green emulsion liquid membrane (ELM) has been formulated in this work using an environmental-friendly refined palm oil as the main diluent of ELM to recover zinc ions from aqueous waste solution using di-(2-ethylhexyl) phosphoric acid (D2EHPA) as a highly selective carrier with double Water-Oil-Water emulsion. This system promotes many advantages including simple operation, high selectivity, low energy requirement, and single stage extraction and stripping process. In this study ELM process was used to transport zinc metal ion from aqueous feed phase to stripping phase which was prepared by using H2SO4, HCl, and HNO3. This extraction was done in a Batch-type stirred tank at room temperature with different types of vegetable oils green solvent. For green ELM process the various vegetable oils have been studied as diluents, such as palm oil, sesame oil, coconut oil, soyabean oil and for further studies we found that palm oil is more effective vegetable oil which gives more recovery of zinc ion from wastewater. The effect of various parameters such as, pH of the feed solution, concentration of the stripping phase, surfactant concentration, carrier concentration, F/M phase ratio, O/I phase ratio, contact time of the double emulsion etc. were studied. After determining the optimum conditions it was possible to extract zinc metal ion up to 62% from aqueous feed phase in a single stage extraction.
2017
Emulsion Liquid Membrane (ELM) process is one of the alternative techniques to extract solutes from wastewater. It has been given considerable attention due to its advantages such as simultaneous extraction and recovery in a single step operation, non-equilibrium mass transfer, high fluxes, low energy consumption, reusability and high selectivity. The main concern in order to achieve high stability in the process is the size of internal droplets of primary emulsion. This study aims to investigate the affecting parameters such as concentration of surfactant, emulsification speed and emulsification time. ELM process containing bis(2,4,4- trimethylpentyl) monothiophosphinic acid (Cyanex 302) as a mobile carrier in kerosene and acidic thiourea as stripping agent was used. The stability results showed that 2.8 µm of droplet diameter was formed at favorable condition of 2 % w/v surfactant concentration, 12,000 rpm of emulsification within 3 min of emulsification time. At this condition, 8...
A New Emulsion Liquid Membrane Based on a Palm Oil for the Extraction of Heavy Metals
Membranes, 2015
The extraction efficiency of hexavalent chromium, Cr(VI), from water has been investigated using a vegetable oil based emulsion liquid membrane (ELM) technique. The main purpose of this study was to create a novel ELM formulation by choosing a more environmentally friendly and non-toxic diluent such as palm oil. The membrane phase so formulated includes the mobile carrier tri-n-octylmethylammonium chloride (TOMAC), to facilitate the metal transport, and the hydrophilic surfactant Tween 80 to facilitate the dispersion of the ELM phase in the aqueous solution. Span 80 is used as surfactant and butanol as co-surfactant. Our results demonstrate that this novel ELM formulation, using the vegetable palm oil as diluent, is useful for the removal of hexavalent chromium with an efficiency of over 99% and is thus competitive with the already existing, yet less environmentally friendly, ELM formulations. This result was achieved with an optimal concentration of 0.1 M NaOH as stripping agent and an external phase pH of 0.5. Different water qualities have also been investigated showing that the type of water (deionized, distilled, or tap water) does not significantly influence the extraction rate.
The extraction of nickel by emulsion liquid membranes using Cyanex 301 as extractant
Canadian Journal of Chemical Engineering, 2018
The removal of nickel ions from waste streams discharged from mining and metal plating industries has become a popular research topic over the past few decades. In this work, the emulsion liquid membrane (ELM) technique was used to remove nickel ions from synthetic aqueous solutions using bis(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex 301) as the extractant. Sulphuric acid was selected as the internal stripping agent. Central composite design methodology was used to obtain the optimum conditions, with the factors selected in the design being extractant concentration, stripping agent concentration, NiSO 4 solution pH, and NiSO 4 solution/emulsion volume ratio. It was found that the extractant concentration, stripping agent concentration, and NiSO 4 solution/emulsion volume ratio had a significant effect on nickel removal. Optimum operating conditions achieved a maximum nickel removal of more than 99 %. Validation tests confirmed the good agreement between the predicted and experimental data. The emulsion was successfully broken afterwards and the oil phase was re-tested. The effects of kinetics, loading capacity, and pH variation tests between the emulsion phase and organic phase were investigated. Zeta potential measurements suggest a final pH of around 2.0 is desirable for the post-reaction treatment of the emulsion droplets.
Extraction of Silver Ions from Aqueous Solutions by Emulsion Liquid Membrane
2016
A comprehensive study pertaining to the emulsion liquid membrane (ELM) extraction process to enrich dilute aqueous solutions of silver salt is presented. The study has highlighted the importance and influence of membrane composition for maximizing the extraction of Ag+ ions. The liquid membrane was made up of Cyanex-302 as an extractant and the industrial solvent mainly consists of paraffinic and naphthenic hydrocarbons (C10-C14) as a diluent, Montane®-80 (sorbitan monooleate) as the surfactant and nitric acid solution as the stripping solution. The selection of the extractant (Cyanex-302) and the stripper (HNO3) was based on conventional liquid–liquid extraction studies. The role of pH as an important parameter in the LEM process for extraction of Ag+ was studied. Extraction of Ag+ increased with an increase in strip phase and carrier concentration. The fundamental parameters (emulsion stability, pH of the feed aqueous solution, agitation speed, surfactant concentration, strip phas...
— In the present work the process of extraction of cadmium, copper, zinc, and iron metal ions was studied using Emulsion Liquid Membrane (ELM) technique. Emulsion liquid membrane system depends on the preparation primary water-in-oil emulsion then emulsified the primary emulsion in water to produce double water-in-oil-in-water emulsion. Therefore three liquid phases will occurs: internal (receiving) phase, liquid membrane phase, and external phase. The internal and external phases are miscible with each other but separated by the membrane phase which is immiscible with both. The membrane was prepared by dissolving the extractant D2EHPA (di-2-ethylhexylphosphoric acid) used as a mobile carrier, and sodium dodecyl sulphonate, a surfactant, in kerosene. The internal (receiving) phase was prepared by dissolving sulfuric acid in water. The effect of variables: initial concentration of metal ions in the feed phase, surfactant concentration, carrier concentration, sulfuric acid concentration in the receiving (internal) phase, agitation time, volume ratio of the external feed phase to the primary water-in-oil emulsion, and pH of feed were studied on the percentage removed of metal ions in experiments carried out in a batch-type stirred vessel at 30 o C. The results showed that the percent removed of metal ions was in general increase with increasing of surfactant concentration, carrier concentration, sulfuric acid concentration in the internal phase, agitation time, and pH of feed and decrease with the volume ratio of the external feed phase to the primary water-in-oil emulsion. The results show that it is possible to recover 98 % of metal ions mixture.
Emulsion Liquid Membrane for Cadmium Removal: Determination of Liquid Membrane Components
Journal of Physical Science, 2018
Removal of cadmium is very important as it is one of several harmful heavy metals commonly found in textile wastewater. This study focused on determination of emulsion liquid membrane (ELM) components for cadmium removal. Carrier, diluent and stripping selection was done by contacting feed phase (150 ppm cadmium) with organic solution at ratio of 1:1. Both solutions were mixed at 500 rpm for 24 h using magnetic stirrer, then the samples were allowed to settle and separate. The results of the study showed that in comparison with acid solution, basic solution containing trioctylamine (TOA), kerosene and NH 3 as the carrier, diluent and stripping agent, respectively provided the best performance for cadmium removal using ELM. In addition, the ordering of the extraction in terms of magnitude for the diluents was highly correlated with the polarity, solubility and viscosity. Low polarity and viscosity, and high solubility of the diluent are preferred.
Procedia Engineering, 2016
Industrial effluent containing metal ions especially from semiconductor industry is considered as a serious environmental pollutant. A green emulsion liquid membrane (ELM) has been formulated in this research using an environmental-friendly refined palm oil as the main diluent of ELM to recover the chromium from wastewater. The feasibility of using palm oil-based ELM for chromium extraction and its stability were investigated. Several parameters, including carrier concentration, agitation speed, internal phase concentration, treat ratio, and agitation time, which could affect the extraction and recovery performance of chromium in ELM process, were attempted. The results showed that 0.2 M of TOMAC, 600 rpm for agitation speed and 1.0 M of NaOH, 2:1 for treat ratio provided enhancement of emulsion stability and almost 100% of chromium was extracted and recovered.
Journal of the Brazilian Chemical Society, 2006
Foi estudada a extração de íons cádmio(II) a partir de soluções aquosas ácidas, usando, em uma cela de transferência sob agitação, uma membrana líquida em emulsão, (MLE) preparada pela mistura de querosene com D2EHPA (um ácido alquilfosfórico) como carregador móvel e Span-80 como surfactante. A membrana MLE permitiu transporte eficiente do metal, da solução de alimentação para o extrato de coleta em experimentos realizados a 25 ºC. As variáveis significativas no transporte de cádmio através da membrana foram a concentração do extrator e a quantidade de metal na solução alimentadora. A concentração de HCl como agente de coleta afetou somente a taxa inicial de extração do metal, mas não a extensão da extração. A quantidade de surfactante usada neste estudo estabilizou a membrana adequadamente, mas o uso de uma quantidade maior produziu uma menor taxa de extração inicial devido à resistência inferfacial mais alta. Os resultados experimentais sugerem a possibilidade de recuperação ou remoção de metais tóxicos de soluções aquosas diluídas em um extrator baseado em membranas líquidas emulsificadas. It is studied the extraction of cadmium(II) ions from acidic aqueous solutions using a stirred transfer cell-type emulsion liquid membrane (ELM) prepared by dissolving in kerosene, with D2EHPA (an alkylphosphoric acid) as mobile carrier and Span-80 as surfactant. The ELM allowed efficient metal transport from the feed solution to the stripping liquor in experiments carried out at 25 ºC. The significant variables on cadmium transport through the membrane were extractant concentration and metal content in the feed metal-donor solution. Concentration of HCl as stripping agent affected only the initial metal extraction rate but not the extraction extent. The surfactant content used in this study stabilized the membrane adequately, but the use of a higher content produced a smaller initial extraction rate due to higher interfacial resistance. The experimental results suggest the possibility of recovering or removing valuable or toxic metals from dilute aqueous solution in an extractor based on emulsified liquid membranes.