Extraction of Hexavalent Chromium from Aqueous Stream by Emulsion Liquid Membrane (ELM)

Choudhury, A.; Sengupta, Samik; Bhattacharjee, Chiranjib; Datta, Siddhartha

doi:10.1080/01496390903409617

Cited by 18 publications

(9 citation statements)

References 12 publications

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“…A full emulsion dispersion to form the W/O/W interface occurs with increasing contact time. 30 Hence, it is believed that this duration of extraction time is decent enough for a stable emulsion. Besides, the emulsion size also decreases with extraction time, which is attributed to a more uniform size of globule dispersion, thus promoting exceptional emulsion stability.…”

Section: Resultsmentioning

confidence: 99%

Stability Study of Emulsion Liquid Membrane via Emulsion Size and Membrane Breakage on Acetaminophen Removal from Aqueous Solution Using TOA

et al. 2020

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The purpose of this study is to explore the emulsion liquid membrane stability for acetaminophen (ACTP) removal from aqueous solution. In this work, the membrane phase was prepared by dissolving trioctylamine (TOA) with kerosene and Span80. The stability of the emulsion in terms of emulsion size, membrane breakage, and its efficiency in removing ACTP was considered for the optimization of parameters. Investigation on the stability of emulsion was carried out by manipulating the concentration of stripping agent, agitation speed, extraction time, and treat ratio. The best condition to produce a very stable emulsion was achieved at 0.1 M of stripping agent concentration, with 300 rpm of agitation speed for 3 min of extraction time with a treat ratio of 3:1. Eighty-five percent of ACTP successfully stripped into the emulsion with minimum membrane breakage of 0.17% through this experiment.

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Section: Resultsmentioning

confidence: 99%

Stability Study of Emulsion Liquid Membrane via Emulsion Size and Membrane Breakage on Acetaminophen Removal from Aqueous Solution Using TOA

et al. 2020

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“…5 demonstrates that the separation percentage of H 2 S increases with the increase of carrier concentration from 0 to 5.0 wt-%, but further rise would lead to the reduction of separation percentage. These results may be explained by the fact that, with the increase of carrier concentration, the concentration of the H 2 S·DEA complex also raises at the interface between the external phase and membrane phase, which would increase the concentration gradient in the membrane phase and the separation percentage of H 2 S. Increasing the DEA concentration excessively would lead to higher membrane viscosity, which in turn also intensifies the resistance of H 2 S transfer [23]. Therefore, the separation efficiency of H 2 S decreases slightly.…”

Section: Effect Of Carrier Concentrationmentioning

confidence: 81%

“…Furthermore, the same rule at every speed is valid, i.e., the separation percentage is enhanced with the longer stir- ring time at the initial stage; after a peak, it decreases slowly. This is because that at the initial time, the increase of stirring time reduces the diameter of the emulsion globules, which would increase distinctly the number of droplets and the mass transfer area, therefore, the separation percentage is improved [23]. However, with longer stirring time the breakage of the globules is also increased, which causes the separated H 2 S to return to the external phase.…”

Section: Effect Of Stirring Speedmentioning

confidence: 94%

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Separation of Hydrogen Sulfide from Wastewater by Emulsion Liquid Membranes

Zhang

2011

Chem Eng & Technol

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Hydrogen sulfide was separated from highly saline wastewater by emulsion liquid membranes (ELMs). Such membranes consist of polyalkenyl succinimide as emulsifying agent, diethanolamine as carrier, kerosene as membrane, and sodium hydroxide as stripping solution. The effect of four surfactants on the stability of ELMs was investigated and every operational parameter was tested. The highest achievable separation efficiency was 99.73 % for a 100 mg L -1 solution. Obviously, the salinity of the external phase has a negligible effect on the separation of H 2 S using ELMs. IntroductionHydrogen sulfide (H 2 S) is a detrimental material in some industry processes. Because of its volatility, it harms the operator's health when inhaled and also causes environmental pollution even at very low concentrations [1,2]. It can be deadly depending on concentration and duration of exposure. Eye irritation starts to occur at 10-20 ppm, and a concentration over 1000 ppm might lead to death [3]. The corrosion of H 2 S in wastewater also causes serious failures of casting tubes and other metal equipment. Therefore, the control of H 2 S became a major concern in industrial wastewaters [4]. Several methods have been used to treat H 2 S, such as biofilters and biotrickling filters [5,6], adsorbents [7,8], and catalytic oxidations [9,10]. These methods all provide satisfactory removal efficiency, however, the process flows are complicated and the treatment cost is higher. For wastewaters with high salinity in the oil field, the above-mentioned methods have some shortcomings.The emulsion liquid membrane (ELM) technique was invented first by Li in 1968 [11, 12]. Typically, a stable emulsion with two immiscible phases is formed which subsequently is dispersed into wastewater as the external phase [13]. Normally, the internal phase is a stripped agent aqueous solution, the external phase contains the target substance, and the membrane phase is the oil phase containing a surfactant to remove the external and internal phases. The internal and external phases are usually miscible. The target substance is removed from the feed phase through the membrane phase and recovered from the internal aqueous phase by finally breaking the emulsion.The ELM technique has four advantages: (i) large mass transfer area, (ii) high diffusion rate, (iii) separation and stripping in one system, and (iv) wide adaptability and high separation efficiency [14][15][16]. Therefore, ELM processes have been frequently used in purification or separations, such as for hydrocarbons [17], organic acids and amines [18,19], wastewater treatment [20,21], metal ions [22][23][24][25], and so on. The experimental results demonstrated that the ELM was a successful technique and the extraction efficiency was above 90 %. However, there was no available information in the literature on the separation of H 2 S in wastewater using ELMs. Therefore, a new attempt was carried out.Here, separation of H 2 S from wastewater with high salinity using the ELM technique was performed. The wastewater...

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“…These advantages include less energy requirement, high separation selectivity, high mass transfer rate and less residence time [7]. To date, ELM technique has been used for the separation of many materials such as phenol [8], amino acids [9] and metals such as silver [10], gold [11], molybdenum [12], arsenic [13], platinum [14], rhodium [15], cadmium [16], cobalt [17], copper [18,19], uranium [20], palladium [21], chromium [22], zinc [23], zirconium [24] neodymium and gadolinium [25].…”

Section: Introductionmentioning

confidence: 99%

Investigation of experimental results and D-optimal design of hafnium ion extraction from aqueous system using emulsion liquid membrane technique

2020

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Hafnium metal is used in a wide range of industries such as microprocessor manufacturing, nuclear reactors and special alloys due to its physical, chemical and radiation properties. Emulsion liquid membrane (ELM) is an effective and efficient alternative for heavy metal separation compared to conventional methods due to high selectivity, energy-saving, high mass transfer and low operating capital. In this study, Cyanex 572 as a carrier, Span 85 as a surfactant, hydrochloric acid as an internal phase and kerosene as a diluent were used. In the first part of the study, the stability of the emulsions was investigated. The most stable emulsions were obtained by adding PIB polymer (3% w/v), Span 85 surfactant (3% w/v) and stirring for 15 min. In the second part, the separation of hafnium metal ions from aqueous solutions was investigated using ELM technique. The highest separation was obtained at 4% (v/v) as carrier concentration, 4% (w/v) as surfactant concentration, the membrane-to-feed volume ratio of 20/100 and W/O/W emulsion stirring rate and time equal to 400 rpm and 5 min, respectively. Moreover, to optimize the factors influencing the tests, the design of experiment (DOE) was performed using D-optimal method via Design Expert 10 software. Based on DOE results, the maximum extraction (> 99%) was achieved when the carrier concentration, the surfactant concentration, W/O/W emulsion stirring time, W/O/W emulsion stirring rate and emulsion volume/feed phase ratio were 4.49% v/v, 3.90% w/v, 11.49 min, 310.54 rpm and 2:1, respectively.

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Extraction of Hexavalent Chromium from Aqueous Stream by Emulsion Liquid Membrane (ELM)

Cited by 18 publications

References 12 publications

Stability Study of Emulsion Liquid Membrane via Emulsion Size and Membrane Breakage on Acetaminophen Removal from Aqueous Solution Using TOA

Stability Study of Emulsion Liquid Membrane via Emulsion Size and Membrane Breakage on Acetaminophen Removal from Aqueous Solution Using TOA

Separation of Hydrogen Sulfide from Wastewater by Emulsion Liquid Membranes

Investigation of experimental results and D-optimal design of hafnium ion extraction from aqueous system using emulsion liquid membrane technique

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