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Prakorn, Ramakul,Ura, Pancharoen 한국화학공학회 2003 Korean Journal of Chemical Engineering Vol.20 No.4
Separation of lanthanum and neodymium by supported liquid membrane has been studied. Synergistic extraction and recovery of lanthanum and neodymium with thenoyltrifluoroacetone (HTTA) in benzene have been found by the addition of Trioctylamine (TOA). Results indicate that percentage of extraction is highly dependent on pH of feed solution, which the maximum value is 2.5. When TOA was added to HTTA, the percentage of extraction and recovery considerably increased due to synergism. Lanthanum can be extracted and recovered more than neodymium because of the adduct formation constant, β₁. The β₁ values decreased with an increase in atomic number of lanthanide and showed a difference between lanthanum and neodymium. Percentage of extraction and recovery is enhanced when the HTTA concentration is increased, but its difference is larger when TOA concentration is increased. Finally, multi-column module of supported hollow fiber membrane was used and the percentage and difference of extraction and recovery was found to be more increased due to resident time.
Prakorn Ramakul,Niti Sunsandee,Natchanun Leepipatpiboon 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.6
−The enantioselective separation of levocetirizine via a hollow fiber supported liquid membrane was examined. O,O'-dibenzoyl-(2R,3R)-tartaric acid ((-)-DBTA) diluted in 1-decanol was used as a chiral selector extractant. The influence of concentrations of feed and stripping phases, and extractant concentration in the membrane phase, was also investigated. A mathematical model focusing on the extraction side of the liquid membrane system was presented to predict the concentration of levocetirizine at different times. The extraction and recovery of levocetirizine from feed phase were 75.00% and 72.00%, respectively. The mass transfer coefficients at aqueous feed boundary layer (kf) and the organic liquid membrane phase (km) were calculated as 2.41×102 and 1.89×102 cm/s, respectively. The validity of the developed model was evaluated through a comparison with experimental data, and good agreement was obtained.
Prakorn Ramakul,Thanyarutt Teerachaiyapat 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.1
Hollow fiber supported liquid membrane was applied as a reactor to synthesize ethyl lactate from lactic acid. Lactic acid in the feed solution was extracted by tri-n-octylamine (TOA) and stripped by ethanol with p-toluene sulfonic acid acting as the catalyst to form ethyl lactate. Central composite design (CCD) was used to determine the significant factors and their interactions. The response surface was applied for optimization. An optimized yield of 30% was predicted and its validity was evaluated by comparison with experimental results at different concentrations of lactic acid in the feed solution, with good agreement achieved.
Prakorn Ramakul,Natchanun Leepipatpiboon,Chamaiporn Yamoum,Uthen Thubsuang,Sirapop Bunnak,Ura Pancharoen 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.3
An experimental investigation was carried out to reduce the concentration polarization at feeding interphase between feed solution and liquid membrane imposing flow instabilities. The periodic operation of the hollow fiber supported liquid membrane for separation of lanthanide metal by using D2EHPA as extractant dissolved in kerosene. The operating flow rate of the feed solution was varied according to a symmetric square wave function around time-average values of 200, 300 and 400 ml/min. Time periods ranging from 18 to 3 minutes and amplitudes of 50 and 100 ml/min were investigated. The results of these periodic tests were compared with results obtained from the conventional steadystate mode of operation. It has been found that the periodic operation leads to higher stripping concentration or higher ion flux than that obtained from the corresponding steady state operating conditions. This is because periodic operation disturbs concentration polarization in the boundary layer between the feed solution and liquid membrane. It has also been found that the ion flux increases with increasing amplitudes and decreasing time periods of the forcing function. However, when the period is less than 3 minutes the flux decreases because the liquid membrane is peeled out from the pores of hollow fiber.
Prakorn Ramakul,Natchanun Leepipatpiboon,Ura Pancharoen 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.1
The separation of cobalt(II) and nickel(II) ions by HFSLM has been presented. The feed solution is 0.5M thiocyanate containing 300 ppm each of cobalt(II) and nickel(II) ions, whereas extractant is Alamine300 and the stripping solution is ammonia. Cobalt(II) is more preferable with Alamine300 than nickel(II). The effects of pH, Alamine300concentration and ammonia concentration were investigated. Seven diluents were used: hexane, decanol, chlorobenzene,benzene, dichloromethane, ethylene dichloride and chloroform with different polarity indexes, from 0.1-4.1. Nickel(II)ion which is unpreferable with Alamine300 was used as a tracer to determine the membrane stability. The polarity of the diluents was found to be the main factor influencing the extraction performance and stability of a liquid membrane. The decreasing of polarity of the diluent can prolong the membrane stability, but the percentages of extraction and stripping decreased. The longest lifetime, 200 minutes, was obtained by using hexane as a diluent with the polarity index of 0.1.
Prakorn Ramakul,Tossaporn Supajaroon,Tatchanok Prapasawat,Anchaleeporn W. Lothongkum,Ura Pancharoen 한국공업화학회 2009 Journal of Industrial and Engineering Chemistry Vol.15 No.2
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. Published by Elsevier B.V. All rights reserved.
Prakorn Ramakul,Unchalee Mooncluen,Yachanapa Yanachawakul,Natchanun Leepipatpiboon 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.5
The mutual separation of lanthanum(III) and cerium(IV) was performed by using a hollow fiber supported liquid membrane. D2EHPA was used as an extractant. The effects of the sulfuric acid concentration in the feed solution, D2EHPA and strippant on the percentage of extraction and stripping were examined. The separation of lanthanum(III) by 4% (v/v) D2EHPA was achieved while cerium(IV) was rejected in the feed solution. A mathematical model focusing on the interface layer was presented to predict the thickness of the layer. The relationship between flux and layer thickness was in good agreement with experimental results and mass transfer theory.
( Ramakul Prakorn ),( Pancharoen Ura ) 한국화학공학회 2003 Korean Journal of Chemical Engineering Vol.20 No.4
Separation of lanthanum and neodymium by supported liquid membrane has been studied. Synergistic extraction and recovery of lanthanum and neodymium with thenoyltrifluoroacetone (HTTA) in benzene have been found by the addition of Trioctylamine (TOA). Results indicate that percentage of extraction is highly dependent on pH of feed solution, which the maximum value is 2.5. When TOA was added to HTTA, the percentage of extraction and recovery considerably increased due to synergism. Lanthanum can be extracted and recovered more than neodymium because of the adduct formation constant, β₁. The β₁ values decreased with an increase in atomic number of lanthanide and showed a difference between lanthanum and neodymium. Percentage of extraction and recovery is enhanced when the HTTA concentration is increased, but its difference is larger when TOA concentration is increased. Finally, multi-column module of supported hollow fiber membrane was used and the percentage and difference of extraction and recovery was found to be more increased due to resident time.