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Uphill transport and mathematical model of Pb(II) from dilute synthetic lead-containing solutions across hollow fiber supported liquid membrane
(2012-05-15)
Suren, Sira
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Wongsawa, Thidarat
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Pancharoen, Ura
;
Prapasawat, Tatchanok
;
Lothongkum, Anchaleeporn Waritswat
This work presents an experimental investigation and mathematical model of Pb(II) separation and stripping from relatively low-level lead-containing synthetic solutions through a hollow fiber supported liquid membrane (HFSLM) by using di-2-ethylhexyl phosphoric acid (D2EHPA) in toluene as an extractant or carrier. The separation was studied on several variables: concentration of D2EHPA, types of stripping solutions (distilled water, HNO <inf>3</inf>, H <inf>2</inf>SO <inf>4</inf> and HCl), concentration of the selected stripping solution, flow patterns of feed and stripping solutions, types of lead-containing solutions (Pb(NO <inf>3</inf>) <inf>2</inf> and PbCl <inf>2</inf>), and flow rates of feed and stripping solutions. The results remarkably showed that HFSLM could successfully reduce a very low concentration of Pb(II) in feed solution to less than the regulatory discharge limit of 0.2mg/L issued by the Ministry of Industry and the Ministry of Natural Resource Environment, Thailand. The highest extraction and stripping results were achieved by using 0.03M D2EHPA, 0.9M HCl at equal flow rates of feed and stripping solutions of 100mL/min using a single-pass of feed solution and circulating of stripping solution. High percentages of extraction and stripping were observed from both Pb(NO <inf>3</inf>) <inf>2</inf> and PbCl <inf>2</inf> solutions. The kinetics of Pb(NO <inf>3</inf>) <inf>2</inf> and PbCl <inf>2</inf> separation were corresponded to second-order reaction with the rate constants of 1.49 and 1.51L/mgmin, respectively. The prediction of Pb(II) concentrations in the outlet Pb(NO <inf>3</inf>) <inf>2</inf> and PbCl <inf>2</inf> feed solutions obtaining from mathematical model were in good agreement with the experimental results at the average percent deviations of 4% for Pb(NO <inf>3</inf>) <inf>2</inf> solution and 8% for PbCl <inf>2</inf> solution. © 2012 Elsevier B.V.
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Enhancement of uranium ion flux by consecutive extraction via hollow fiber supported liquid membrane
(2009-09-01)
Lothongkum, A. W.
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Ramakul, P.
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Sasomsub, W.
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Laoharochanapan, S.
;
Pancharoen, U.
The enhancement of uranium separation from trisodium phosphate, a by-product, from monazite processing through a supported liquid membrane system by a consecutive extraction using the synergistic extractants is first time demonstrated in this work. Feed solution was trisodium phosphate solution containing uranium ions of 45 ppm, and the stripping solution was nitric acid solution. The effects of types and concentrations of the extractants, concentration of HNO<inf>3</inf>, flow rates of feed and stripping solutions and the numbers of cycles on extraction efficiency were investigated. D2EHPA, Cyanex 923, TBP, TOA and Aliquat 336 dissolved in kerosene were used as the extractants. The results showed that by using the synergistic extractant of Aliquat 336 mixed with TBP, the percentages of extraction and stripping or recovery considerably increased higher than those obtained by a single extractant. For the seventh-cycle separation by one-module operation using 0.1 M Aliquat 336 and 0.06 M TBP mixture, 0.5 M HNO<inf>3</inf>, and equal flow rates of feed and stripping solutions at 100 mL/min, the percentages of extraction and stripping reached 99 and 53 in 350 min. The amount of uranium ions remaining in trisodium phosphate solution was 0.22 ppm, which stayed within the standard value of technical grade trisodium phosphate of 3 ppm. © 2009 Taiwan Institute of Chemical Engineers.
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Selective recovery of nickel ions from wastewater of stainless steel industry via HFSLM
(2009-05-12)
Lothongkum, Anchaleeporn Waritswat
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Khemglad, Yuttapong
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Usomboon, Nantawat
;
Pancharoen, Ura
High concentration of heavy metal ions in all kinds of effluents, especially in wastewater is of great concern for hazardous pollution due to their high toxicities and wide environmental spreading. The selective stripping or recovery of nickel ions from wastewater of the stainless steel-cold rolled plate process by hollow fiber supported liquid membrane was studied. The optimum conditions were examined in a batch process. The pH of feed, types and concentrations of the extractants, concentration of the stripping solution (sulfuric acid), flow rates of feed and stripping solutions, and volumetric ratio of feed to stripping solutions were investigated. The extractants, i.e., D2EHPA, Cyanex 301, Cyanex 272 and LIX 860-I were dissolved in kerosene as a membrane solution, which was supported by a microporous hydrophobic hollow fiber membrane extractor. Consequently, two consecutive modules of hollow fiber were applied to recover more nickel ions. The results showed that LIX 860-I was the most effective to selectively retrieve nickel ions from wastewater at a feed pH of 4. The percentage of the recovery and selectivity of nickel ions increased in accordance with an increase in the concentration of LIX 860-I and decreased after the concentration of LIX 860-I was higher than 0.8 M. It was found that the percentage of recovery of nickel ions increased with sulfuric acid concentration and lower flow rates of feed and stripping solutions. Higher nickel ions were obtained at the flow rates of feed and stripping solutions of 100 ml/min and reduced when the flow rates increased. In addition, in this study it is recommended to use equal volume of feed and stripping solutions of 3500:3500 (ml:ml) to attain more nickel ions recovery. For a single-module operation, the percentage of recovery of nickel ions was 58%, and 87% by double-module operation. © 2008 Elsevier B.V. All rights reserved.
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Synergistic separation of yttrium ions in lanthanide series from rare earths mixture via hollow fiber supported liquid membrane
(2009-03-01)
Ramakul, Prakorn
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Supajaroon, Tossaporn
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Prapasawat, Tatchanok
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Pancharoen, Ura
;
Lothongkum, Anchaleeporn W.
Separation of yttrium ions from the mixture of rare earths in lanthanide series has been examined by a microporous hydrophobic hollow fiber supported liquid membrane. Cyanex 272 and TBP in kerosene are used separately as an extractant. Nitric acid solution is used as a stripping solution. Increasing the concentration of Cyanex 272 increases the percentages of extraction and stripping of yttrium from rare earths but slightly percentages are obtained by TBP. Interestingly, when TBP is added with Cyanex 272, the percentages of extraction and stripping increases. This is due to the synergistic effect of the extractants. Moreover, yttrium can be selectively extracted and stripped more than other lanthanide ions because the equilibrium constant decreases with an increase in atomic number or decreases with the ionic radius of the lanthanides. In other words, yttrium is separated selectively due to the smallest ionic radius while other lanthanides are separated with a decrease in ionic radius or an increase in atomic number. © 2009 The Korean Society of Industrial and Engineering Chemistry.
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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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Purely separation of mixture of mercury and arsenic via hollow fiber supported liquid membrane
(2007-09-01)
Sangtumrong, Seewalee
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Ramakul, Prakom
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Satayaprasert, Chairit
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Pancharoen, Ura
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Lothongkum, Anchaleeporn W.
The separation of mercury(II) and arsenic(III) ions from chloride media has been examined through a hollow fiber supported liquid membrane using tri-n-octylamine (TOA) as an extractant dissolved in toluene. The transport system was studied as a function of several variables: the concentration of the hydrochloric acid feed solutions, the concentration of TOA in the liquid membrane, the concentration of sodium hydroxide in the recovery solutions. According to the system, mercury(II) ions were extracted using TOA by rejecting arsenic (III) ions into raffinate because of the different forms of the mercury(II) and arsenic(III) ions in hydrochloric acid solutions. The maximum percentage of recovery for mercury(II) was 95 %; 100 % selectivity was obtained.

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