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A new emulsion liquid membrane based on a palm oil for the extraction of heavy metals.

Björkegren S, Karimi RF, Martinelli A, Jayakumar NS, Hashim MA - Membranes (Basel) (2015)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Applied Surface Chemistry, Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden. sanna.bjorkegren@chalmers.se.

ABSTRACT
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.

No MeSH data available.


The phases in a water-in-oil-in-water emulsion (w/o/w). O = Oil (Yellow) and W = Water (Gray for external phase and blue for interal phase).
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membranes-05-00168-f001: The phases in a water-in-oil-in-water emulsion (w/o/w). O = Oil (Yellow) and W = Water (Gray for external phase and blue for interal phase).

Mentions: The removal and recovery of heavy metals from wastewater and industrial effluents is environmentally and economically driven as much as it is a health issue. In large parts of the world, such as Southeast Asia, the contamination of groundwater and water resources is a major concern wherefore efficient, economic, and sustainable methods for purification of water are required. An example of a metal that can be found is chromium, which exists in both its trivalent, Cr(III), and hexavalent, Cr(VI), form. Hexavalent chromium is highly poisonous, an oral dose of 2–5 g Cr(VI) can be fatal to an adult human [1]. The World Health Organization (WHO) has a provisional guideline value of 0.05 ppm for the total chromium concentration in drinking water [2]. It is therefore important to purify wastewater before it reaches the environment. The extraction capability of liquid membranes has been used successfully in many areas, such as metal ion extraction, separation of inorganic species, and biochemical and biomedical applications [3]. Although the first patent on liquid membranes was published in 1968 [4], the field of liquid membranes as a separation technique is still expanding in research and in its application as an industrial separation process. Liquid membranes consist of three distinct phases: the feed phase, the membrane phase, and the stripping phase, as schematically shown in Figure 1. Among the different kinds of liquid membranes, e.g., bulk liquid membrane (BLM), supported liquid membrane (SLM), and emulsion liquid membrane (ELM), the double emulsion in ELM results in the highest mass transfer area in addition to a high selectivity and a high metal transfer flux, due to the possibilities of incorporating chemical components that enhance the metal transport [5,6]. Also, ELM combines the stripping and extraction processes in a single step [7,8] and is an elaborated form of solvent extraction. Another benefit of using ELM from an environmental viewpoint is the low energy demand compared to pressure-driven membrane processes [9]. In addition, the ELM can be prepared using relatively simple materials and equipment.


A new emulsion liquid membrane based on a palm oil for the extraction of heavy metals.

Björkegren S, Karimi RF, Martinelli A, Jayakumar NS, Hashim MA - Membranes (Basel) (2015)

The phases in a water-in-oil-in-water emulsion (w/o/w). O = Oil (Yellow) and W = Water (Gray for external phase and blue for interal phase).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4496638&req=5

membranes-05-00168-f001: The phases in a water-in-oil-in-water emulsion (w/o/w). O = Oil (Yellow) and W = Water (Gray for external phase and blue for interal phase).
Mentions: The removal and recovery of heavy metals from wastewater and industrial effluents is environmentally and economically driven as much as it is a health issue. In large parts of the world, such as Southeast Asia, the contamination of groundwater and water resources is a major concern wherefore efficient, economic, and sustainable methods for purification of water are required. An example of a metal that can be found is chromium, which exists in both its trivalent, Cr(III), and hexavalent, Cr(VI), form. Hexavalent chromium is highly poisonous, an oral dose of 2–5 g Cr(VI) can be fatal to an adult human [1]. The World Health Organization (WHO) has a provisional guideline value of 0.05 ppm for the total chromium concentration in drinking water [2]. It is therefore important to purify wastewater before it reaches the environment. The extraction capability of liquid membranes has been used successfully in many areas, such as metal ion extraction, separation of inorganic species, and biochemical and biomedical applications [3]. Although the first patent on liquid membranes was published in 1968 [4], the field of liquid membranes as a separation technique is still expanding in research and in its application as an industrial separation process. Liquid membranes consist of three distinct phases: the feed phase, the membrane phase, and the stripping phase, as schematically shown in Figure 1. Among the different kinds of liquid membranes, e.g., bulk liquid membrane (BLM), supported liquid membrane (SLM), and emulsion liquid membrane (ELM), the double emulsion in ELM results in the highest mass transfer area in addition to a high selectivity and a high metal transfer flux, due to the possibilities of incorporating chemical components that enhance the metal transport [5,6]. Also, ELM combines the stripping and extraction processes in a single step [7,8] and is an elaborated form of solvent extraction. Another benefit of using ELM from an environmental viewpoint is the low energy demand compared to pressure-driven membrane processes [9]. In addition, the ELM can be prepared using relatively simple materials and equipment.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Applied Surface Chemistry, Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden. sanna.bjorkegren@chalmers.se.

ABSTRACT
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.

No MeSH data available.