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1.
Ramakul Prakorn Songkun Eakkapit Pattaweekongka Weerawat Hronec Milan Pancharoen Ura 《Korean Journal of Chemical Engineering》2006,23(1):117-123
The transport of Co(II) through hollow-fiber-supported liquid membrane containing di-(2-ethylhexyl) phosphoric acid (D2EHPA)
diluted in kerosene was examined. The mass transfer rate, expressed as permeability, P, focused on diffusion through the aqueous
layer in the feed solution, the organic layer and the aqueous layer in the stripping solution. Experiments were performed
as a function of aqueous feed solution velocity (100-500 ml/min), carrier concentration (0.1-20% v/v), aqueous stripping solution
velocity (100-1,000 ml/min) and feed concentration (100-1,000 ppm) with 0.1 M HCl in the product phase. pH of the feed solution
was 5.0. The measured permeabilities were compared to generally accepted mass transfer correlations. The validity of the prediction
was evaluated with the experimental data, and the data were found to tie in well with the theoretical values. The model is
the reported describing that the rate limiting step in the transport of the ion was the diffusion through both aqueous films,
feed and stripping, whereas the organic resistance of the membrane was negligible. From this study, the model has good potential
for the prediction of permeability of Co(II). 相似文献
2.
Prakorn Ramakul Milan Hronec Ura Pancharoen 《Korean Journal of Chemical Engineering》2007,24(2):282-287
−Purification of 2-mercaptobenzothiazole (91.9% purity) by solvent extraction was studied. The extraction of impurities present
in crude 2-MBT (e.g. benzothiazole, sulfides and sulfur containing compounds) was carried out at temperatures between 70-180°C
using various solvents and their mixtures of different polarity. The highest purity of 2-MBT, above 99% was obtained using
nitrobenzene, toluene and ethanol, even at a concentration of 2-MBT above 50 wt%. Increasing temperature and decreasing concentration
of the raw material have a positive influence on the purification process. A comparable efficiency of purification was observed
also with mixed solvents, (toluene with ethanol, acetone and aniline) possessing the same polarities. A correlation between
the polarity indexes (PI) of mixed solvents and experimentally obtained purity of 2-MBT was found. The highest purity of 2-MBT
provides extraction of the raw material with mixed solvents having PI 3.8-4.4. 相似文献
3.
Natchanun Leepipatpaiboon Ura Pancharoen Niti Sunsandee Prakorn Ramakul 《Korean Journal of Chemical Engineering》2014,31(5):868-874
The extraction and stripping of uranium(VI) from other impurity elements in yellowcake was performed simultaneously in one stage by a hollow fiber supported liquid membrane. Uranium ions were selectively extracted from yellowcake using TBP as the extractant, while thorium and some rare earth elements were rejected in the raffinate. The optimization method was carried out using 32 factorial design. The concentration of nitric acid in the feed solution and the concentration of TBP in the liquid membrane were regarded as factors in the optimization. A mass transport model focusing on the boundary layer of the extraction side was also applied. The model can predict the concentration of uranium in the feed tank at different times. The validity of the developed model was statistically evaluated through a comparison with experimental data, and good agreement was obtained. 相似文献
4.
Dolapop Sribudda Thanaporn Wannachod Prakorn Ramakul Ura Pancharoen Suphot Phatanasri 《Korean Journal of Chemical Engineering》2016,33(1):197-206
The separation of Hg(II) and As(V) from produced water by hollow fiber contactors was investigated. Two identical hollow fiber modules were employed. The first module was used for extraction, while the second module was used for stripping. The optimum conditions achieved were 14% (v/v) of Aliquat336, 0.07 M thiourea, volumetric flow rate of 100 mL/min for aqueous solution and 0.02 M HCl of stripping solution. At such conditions, the maximum extraction of Hg(II) and As(V) attained 100% and 78.78%, respectively. Concurrently, the maximum stripping of Hg(II) and As(V) reached 47.88% and 6.66%, respectively. The overall mass transfer coefficients of Hg(II) and As(V) extraction were 2.31×10?6 and 1.15×10?6m/s, while the Hg(II) and As(V) stripping exhibited the overall mass transfer coefficients of 8.37×10?7 m/s and 9.05×10?7 m/s, respectively. Mass transfer coefficients of the organic layer diffusion (k0) had the most effect on the overall mass transfer coefficients. 相似文献
5.
Prakorn Ramakul Tossaporn Supajaroon Tatchanok Prapasawat Ura Pancharoen Anchaleeporn W. Lothongkum 《Journal of Industrial and Engineering Chemistry》2009,15(2):224-228
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. 相似文献
6.
Parnuwat Usapein Anchaleeporn W. Lothongkum Prakorn Ramakul Ura Pancharoen 《Korean Journal of Chemical Engineering》2009,26(3):791-798
The selective extraction of Cr(VI) from waste pickling solution of the stainless steel-cold rolled plate process by hydrophobic
hollow fiber supported liquid membrane (HFSLM) was investigated. The effects of various parameters— types of organic extractants,
i.e., metyl trioctylammonium chloride (Aliquat 336), tri-n-octylamine (TOA), tri-n-butyl phosphate (TBP) and the mixture of
Aliquat 336 and TBP, concentration of the selected extractant, types of stripping solutions (NaCl and NaOH), pH and concentration
of the selected stripping solution, and the operating temperature—were studied. The feed and stripping solutions flowed countercurrently.
The results showed that the coexisting contamination in spent pickling solution of Fe(II) and Ni(II) ions had no significant
effect on Cr(VI) extraction. Among the extractants used in this study, Aliquat 336 was a specific carrier to attain the highest
percentage of Cr(VI) extraction. About 70% extraction was achieved by using 0.11 M Aliquat 336 and 0.5 M NaCl at pH 7. The
percentage of stripping slightly increased when the concentration of NaCl increased. In addition, it was found that the operating
temperature of 20, 30, 40, and 50 °C had almost no influence on the percentages of extraction and stripping of Cr(VI). The
calculated diffusion energy of Cr(VI) extraction was 15.14 kJ/mol. 相似文献
7.
Natchanun Leepipatpiboon Ura Pancharoen Prakorn Ramakul 《Korean Journal of Chemical Engineering》2013,30(1):194-200
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, Alamine300 concentration 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. 相似文献
8.
Ramakul?Prakorn Nakararueng?Kwanta Pancharoen?UraEmail author 《Korean Journal of Chemical Engineering》2004,21(6):1212-1217
The separation of a mixture of Cu(II), Cr(VI) and Zn(II) simultaneously from a sulfate media using two consecutive hollow
fiber microporous liquid membrane extraction systems has been studied. The experiments were made in the one-through mode.
LIX84-I and Aliquat336 were used as carrier extractants for copper and chromium in the first and second hollow fiber modules,
respectively. Pure copper and pure chromium ions are extracted and stripped from first and second hollow fiber modules, respectively,
but zinc ions cannot be extracted by both extractants due to pH conditions used in this study and remain in the raffinate.
Results indicate that the percentage of extraction is highly dependent on pH of the feed solution and the pH value is 2.5
for the maximum extraction. The percentage of extraction of copper and chromium ions is enhanced when the concentration of
LIX84-I and Aliquat336 is increased of which both maximum value is 0.5 M, and these results also occur in stripping phase.
The influence of sulfuric acid and sodium hydroxide concentration in strip solution of each column was examined, and it was
found that the percentage of extraction and stripping is further increased due to the difference of driving force. The maximum
percentage of extraction for copper is 33% and 92% for chromium. The experimental results indicated the feasibility of separation
and recovery of these metals from the dilute solution by using membrane technology 相似文献
9.
Ekapong Uedee Prakorn Ramakul Ura Pancharoen Anchaleeporn W. Lothongkum 《Korean Journal of Chemical Engineering》2008,25(6):1486-1494
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
i
) and membrane or organic phase (k
m
) 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. 相似文献
10.
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. 相似文献