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Mass transfer resistance and response surface methodology for separation of platinum (IV) across hollow fiber supported liquid membrane
(2016-10-25)
Wongkaew, Krirkratthawit
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Wannachod, Thanaporn
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Mohdee, Vanee
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Pancharoen, Ura
;
Arpornwichanop, Amornchai
The separation of platinum (IV) from wastewater across hollow fiber supported liquid membrane was successful in reaching 96% extraction and 88% stripping using 10% (v/v) trioctylmethyl-ammonium chloride (Aliquat 336) as the extractant. The mass transfer resistances were (1/k<inf>a</inf>) 3.297 × 104 s/cm, (1/k<inf>m</inf>) 0.164 × 104 s/cm, (1/k<inf>o</inf>) 3.404 × 104 s/cm and (1/K) 6.865 × 104 s/cm. The system was governed by the mass transfer resistance from the liquid-membrane. Response surface methodology was used to qualify and estimate the influence of operating conditions. Predicted model with experimental data were in good agreement at a standard deviation of 1%.
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A reaction flux model for extraction of Cu(ii) with LIX84i in HFSLM
(2011-09-01)
Pancharoen, Ura
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Wongsawa, Thidarut
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Lothongkum, Anchaleeporn W.
Hollow fiber supported liquid membrane (HFSLM) is a favorable method to extract both valuable compounds and heavy metal pollutants such as chromium, copper, and nickel at a very low concentration. In this work, the extraction of Cu(II) by LIX84I dissolved in kerosene was theoretically and experimentally investigated. A model to estimate the percentage of extraction of copper ions from synthetic water considering the effect of reaction flux in membrane phase of the HFSLM system was studied. H<inf>2</inf>SO<inf>4</inf> solution was used as the stripping solution. The facilitated transport mechanism of the chemical reaction at the feed-membrane interface was taken into account in the model equations. The percentage of copper ion extraction was plotted against its initial concentration in feed and also feed flow rate. Subsequently, the separation time and separation cycle were determined in accordance with the simulated values of copper ion concentration and the feed flow rate from the model. The modeled results were in good agreement with the experimental data at the average percentage of deviation about 2%. © Taylor & Francis Group, LLC.
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The effective recovery of praseodymium from mixed rare earths via a hollow fiber supported liquid membrane and its mass transfer related
(2011-01-12)
Wannachod, Pharannalak
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Chaturabul, Srestha
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Pancharoen, Ura
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Lothongkum, Anchaleeporn W.
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Patthaveekongka, Weerawat
The recovery of praseodymium from mixed rare earths via a hollow fiber supported liquid membrane (HFSLM) was examined. Bis(2,4,4-trimethylpentyl) phosphinic acid - known as Cyanex 272 - was used as an extractant carrier. The stripping solution was hydrochloric acid solution. The experiments examined in functions of the concentrations of the carrier in liquid membrane, the (initial) pH's of initial feed solution within the acidic-pH range, the concentrations of hydrochloric acid, the flow rates of feed and stripping solution, and the operation mode of runs through the hollow fiber module. In addition, the influence of circulation of the stripping solution at various numbers of runs through the HFSLM on the outlet concentration of praseodymium ions in the stripping solution was observed. Mass transfer mechanism in the system was investigated. Extraction equilibrium constant (K<inf>ex</inf>), distribution ratio (D), permeability (P) and mass transfer coefficients were determined. The aqueous-phase mass-transfer coefficient (k<inf>i</inf>) and organic-phase mass-transfer coefficient (k<inf>m</inf>) were reported to 0.0103 and 0.788 cm s-1, respectively, in which k<inf>m</inf> is much higher than the k<inf>i</inf>. Thus it suggests the rate-controlling step is the diffusion of praseodymium ions through the film layer between the feed solution and the liquid membrane. Model prediction of the dimensionless concentrations and separation factors were also put on trial in this paper. The results showed promising agreement with the experimental data. © 2010 Elsevier B.V. All rights reserved.
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Performance of hollow fiber supported liquid membrane on the extraction of mercury(II) ions
(2008-11-01)
Uedee, Ekapong
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Ramakul, Prakorn
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Pancharoen, Ura
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Lothongkum, Anchaleeporn W.
The extraction and recovery or stripping of mercury ions from chloride media using microporous hydrophobic hollow fiber supported liquid membranes (HFSLM) has been studied. Tri-n-octylamine (TOA) dissolved in kerosene was used as an extractant. Sodium hydroxide was used as a stripping solution. The transport system was studied as a function of several variables: the concentration of hydrochloric acid in the feed solution, the concentration of TOA in the liquid membrane, the concentration of sodium hydroxide in the stripping solution, the concentration of mercury ions in the feed solution and the flow rates of both feed and stripping solutions. The results indicated that the maximum percentages of the extraction and recovery of mercury ions of 100% and 97% were achieved at the concentration of hydrochloric acid in the feed solution of 0.1 mol/l, the concentration of TOA at 3% v/v, the concentration of sodium hydroxide at 0.5 mol/l and the flow rates of the feed and stripping solutions of 100 ml/min. However, the concentration of mercury ions from 1-100 ppm in the feed solution had no effect on the percentages of extraction and recovery of mercury ions. Thus, these results have identified that the hollow fiber supported liquid membrane process has high efficiency on both the extraction and recovery of mercury (II) ions. Moreover, the mass transfer coefficients of the aqueous phase (k <inf>i</inf> ) and membrane or organic phase (k <inf>m</inf> ) were calculated. The mass transfer coefficients of the aqueous phase and organic phase are 0.42 and 1.67 cm/s, respectively. The mass transfer coefficient of the organic phase is higher than that of the aqueous phase. Therefore, the mass transfer controlling step is the diffusion of the mercury ions through the film layer between the feed solution and the liquid membrane. © 2008 Springer.
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Separation of As(III) and As(V) by hollow fiber supported liquid membrane based on the mass transfer theory
(2008-01-01)
Prapasawat, Tatchanok
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Ramakul, Prakorn
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Satayaprasert, Chairit
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Pancharoen, Ura
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Lothongkum, Anchaleeporn W.
Separation of As(III) and As(V) ions from sulphate media by hollow fiber supported liquid membrane has been examined. Cyanex 923 was diluted in toluene and used as an extractant. Water was used as a stripping solution. The extractability of As(V) was higher than As(III). When the concentration of sulphuric acid in feed solution and Cyanex 923 in liquid membrane increased, more arsenic ions were extracted into liquid membrane and recovered into the stripping solution. The mathematical model was focused on the extraction side of the liquid membrane system. The mass transfer coefficients of the aqueous phase (k <inf>i</inf> ) and organic phase (k <inf>m</inf> ) are 7.15×10 -3 and 3.45×10-2 cm/s for As(III), and 1.07×10-2 and 1.79×10-2 cm/s for As(V). Therefore, the rate-controlling step for As(III) and As(V) in liquid membrane process is the mass transfer in the aqueous film between the feed solution and liquid membrane. The calculated mass transfer coefficients agree with the experimental results. © 2008 Springer.

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