• Korean Journal of Metals and Materials
• /
• v.56 no.12
• /
• pp.870-877
• /
• 2018

Cyanex 272 shows the highest separation factor for the rare earth elements from hydrochloric acid solution among the organophosporus acidic extractants, D2EHPA and PC 88A. Solvent extraction of Tb(III) from weak hydrochloric acid solution with an initial pH 3 to 6 was compared with Cyanex 272, its mixture with Alamine 336, and ionic liquid with Aliquat 336. The solvent extraction reaction of Tb(III) using Cyanex 272 was the same as that of light rare earth elements. Synergism was observed for the extraction of Tb(III) by the mixture with Alamine 336 when the initial concentration ratio of Cyanex 272 to Alamine 336 was higher than 5. Use of the ionic liquid led to a great increase in the extraction percentage of Tb(III) from the same initial extraction conditions. While the equilibrium pH of the mixture was always lower than the initial pH, under some conditions extraction with the ionic liquid resulted in a higher equilibrium pH than the initial pH. The loading capacity of the mixture and the ionic liquid was the same and 2.6 times larger than that using Cyanex 272 alone. Ionic liquid was recommended as a suitable extractant for the extraction of Tb(III) from hydrochloric acid solution based on the ease of handling and higher extraction percentage.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.1
• /
• pp.113-116
• /
• 2011

Slope analysis method was applied to determine the stoichiometry of the solvent extraction reaction of Ni(II) by Alamine336 from strong HCl solution range from 1 to 10 M. Solvent extraction data was obtained from the literature. The effective equilibrium constant for the solvent extraction reaction was estimated by considering the ionic equilibria of $NiCl_2$ in the HCl solution. The measured distribution coefficients of Ni(II) agreed well with those calculated in this study. Our results suggest that further study on the measurement of the activities of nickel complexes at high HCl solution need to be done.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.2
• /
• pp.248-253
• /
• 2006

For the determination of vitamin I using high performance liquid chromatography (HPLC), the most critical and time consuming step is the Quantitative extraction of all vitamin E homologs from sample matrix. Three different extraction methods were compared to determine vitamin E in grains. Saponification used alkaline hydrolysis followed by solvent extraction. Direct solvent extraction included dispersing the samples in hot water, addition of isopropanol and $MgSO_4$, and extraction of the analytes with extracting solvent with Polytron homogenization. Using Soxhlet extraction, the samples were extracted in a Soxhlet apparatus with hexane containing butylated hydroxytoluene (BHT). Vitamin E content in 14 grains were analyzed and compared by three different extraction methods. Generally, the highest values were observed from direct solvent extraction and Soxhlet extraction followed by saponification. a-Tocopherol equivalent (a-TE) levels in grains ranged from 0.32 a-TE/100 g in prosomillet to 5.12 a-TE/100 g in black rice.

• Korean Journal of Metals and Materials
• /
• v.46 no.12
• /
• pp.823-829
• /
• 2008

The solvent extraction process for the recovery of vanadium from leaching solution of SCR(selective catalytic reduction) spent catalyst was investigated by using Alamine336 as an extractant. The effects of experimental conditions, such as initial pH and concentration of sulfate ion, and ammonia concentration of stripping solution were studied. The extraction percentage of vanadium were increased with the increase of initial pH of leaching solution and decreased with the increase of sulfate ion. More than 99% of vanadium in leaching solution were extracted and stripped at the A/O ratio of 1.0 in 2 stages. On the basis of these results, an optimum solvent extraction process which vanadium was effectively recovered from SCR spent catalyst was proposed.

• Journal of Environmental Science International
• /
• v.10 no.5
• /
• pp.381-386
• /
• 2001

The characteristics of precipitation separation and solvent extraction separation of magnesium from the waste bittern were studied experimentally In the result of precipitation separation, the size of magnesium hydroxide precipitated was not affected on pH, but decreased with increasing the precipitation temperature. The purity of magnesium oxide precipitated was increased with pH beyond pH 11. From the solvent extraction separation, the equilibrium extraction ratio of magnesium was increased with pH and temperature of extraction phase, the concentration of stripping phase, and with decreasing pH of stripping phase. The extractant of Aliquat 336 and Acid 810 mixture was more effective than that of DCH18C6 and $D_2EHPA$ mixture in the extraction separation of magnesium.

• Applied Chemistry for Engineering
• /
• v.7 no.1
• /
• pp.203-213
• /
• 1996

In physical and reactive extraction system using equilibrium extraction equipment, the effects of extractants, concentration of extractant, and solvent on the degree of extraction were investigated. The organic acids used were acrylic acid and metacrylic acid. Extractants were n-octylamine(OA), di-n-octylamine(DOA), tri-n-octylamine(TOA) and tri-octylmetyl ammonium chloride(TOMAC ; Aliquat 336). We found that the degree of extraction for reactive extraction was 2~9 times than that for physical extraction and that effect of extractants on the degree of extraction of organic acid was the order of OA

• Korean Chemical Engineering Research
• /
• v.58 no.2
• /
• pp.273-279
• /
• 2020

In this study, conventional solvent extraction (CSE), microwave-assisted extraction (MAE), and ultrasound-assisted extraction (UAE) were compared for the recovery of paclitaxel from biomass. As a result of investigating the effect of the extraction solvent type (acetone, chloroform, ethanol, methanol, methylene chloride), methanol was the most suitable for all extraction methods. In the case of MAE and UAE using methanol, most of the paclitaxel (> 95%) was recovered by only one extraction. The recovery rate of paclitaxel increased with the increase of extraction temperature (25-45 ℃), microwave power (50-150 W), and ultrasonic power (180-380 W) for MAE and UAE. In addition, SEM analysis showed that the biomass surface structure was slightly corrugated in CSE, while in the MAE and UAE, it was very rough and destroyed by strong impact.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.9
• /
• pp.2488-2492
• /
• 2010

A method is described for the determination of the Po nuclides in a water sample. After the Po nuclides were purified from interfering elements in a water sample using a manganese dioxide precipitation followed by a solvent extraction method, the Po nuclides were deposited onto the silver plate. A large volume of the water sample was effectively pretreated with manganese dioxide precipitation method. To determine the optimum conditions for plating Po, the effects of the pH, volume, temperature and time on the Po deposition were investigated in hydrochloric acid solution. The investigated determination method of Po nuclides with solvent extraction was applied to a tap water sample.

• Food Science and Preservation
• /
• v.7 no.2
• /
• pp.177-183
• /
• 2000

A supercritical fluid extraction was performed for the extraction of phenolics from grape seeds which up to now have been discarded. The optimum condition for extraction process was predicted through response surface methodology using central composit experimental design. The extraction amount of grape seed phenolics was increased by increasing extraction temperature, pressure, and concentration of co-solvent (ethanol). The optimum extraction conditions were 84.83$^{\circ}$C, 51.50MPa and 1.27% ethanol. The yield of phenolics using SFE was higher with 3 folds than ethanol and 4 folds than hexane but less than 80% methanol. In the respects of food poisoning, the approved solvents were restricted to ethanol and hexane. So, SFE for extraction of phenolics could be powerful alternative method for solvent extraction.

• KSBB Journal
• /
• v.19 no.6 s.89
• /
• pp.421-426
• /
• 2004

The extraction and separation of isoflavones from Korean soybean were peformed by various mechanical and chemical extraction methods. They included solvent extraction, stirring, supersonification and sub/supercritical water extraction. From the experimental results of the variation of solvent extraction by change in composition, the increase in extraction of a specific compound by stirring or supersonic energy, and the application of supercritical fluid with superior solvating power over solvents, the sonification was the most desirable extraction method in extracting aglycone isoflavones, daidzein and genistein from Korean soybean.