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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: Span 80 is used as surfactant and butanol as co-surfactant.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 effect of stripping agent concentration after 7 min. Both membranes contain 2.5 wt% Span 80, 1 wt% Tween 80, 0.35 wt% TOMAC, while membrane A also contains 1 wt% butanol.
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membranes-05-00168-f008: The effect of stripping agent concentration after 7 min. Both membranes contain 2.5 wt% Span 80, 1 wt% Tween 80, 0.35 wt% TOMAC, while membrane A also contains 1 wt% butanol.

Mentions: Role of the stripping agent. A suitable concentration of the stripping agent in the internal phase is one of the important factors in an ELM formulation. In Figure 8 the extraction of Cr(VI) after 7 min is shown as a function of NaOH concentration, demonstrating that the removal significantly depends on the presence of the stripping agent, which in turn should be present at an optimal concentration. This result is consistent with the results of Goyal et al. for a kerosene based ELM [5]. The highest Cr(VI) removal is achieved at a NaOH concentration of 0.1 M, while a further increase in the NaOH concentration results in worse performance. At higher concentrations a stronger pH gradient is created, increasing the difference in osmotic pressure and consequently risk of swelling of the internal droplets. The consequent rupture will cause a reduction of NaOH in the internal phase, which reduces the amount of NaOH available for the stripping reaction with the metal complex.


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 effect of stripping agent concentration after 7 min. Both membranes contain 2.5 wt% Span 80, 1 wt% Tween 80, 0.35 wt% TOMAC, while membrane A also contains 1 wt% butanol.
© Copyright Policy
Related In: Results  -  Collection

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

membranes-05-00168-f008: The effect of stripping agent concentration after 7 min. Both membranes contain 2.5 wt% Span 80, 1 wt% Tween 80, 0.35 wt% TOMAC, while membrane A also contains 1 wt% butanol.
Mentions: Role of the stripping agent. A suitable concentration of the stripping agent in the internal phase is one of the important factors in an ELM formulation. In Figure 8 the extraction of Cr(VI) after 7 min is shown as a function of NaOH concentration, demonstrating that the removal significantly depends on the presence of the stripping agent, which in turn should be present at an optimal concentration. This result is consistent with the results of Goyal et al. for a kerosene based ELM [5]. The highest Cr(VI) removal is achieved at a NaOH concentration of 0.1 M, while a further increase in the NaOH concentration results in worse performance. At higher concentrations a stronger pH gradient is created, increasing the difference in osmotic pressure and consequently risk of swelling of the internal droplets. The consequent rupture will cause a reduction of NaOH in the internal phase, which reduces the amount of NaOH available for the stripping reaction with the metal complex.

Bottom Line: Span 80 is used as surfactant and butanol as co-surfactant.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.