Preparation of divinylbenzene homopolymeric microcapsules with highly porous membranes by in situ polymerization with solvent evaporation.

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As a fundamental investigation of the separation and recovery of rare earth metals from an aqueous solution, the extraction characteristics of lanthanum and cerium have been studied by using microcapsules containing a metal extractant. As the extractant, 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (EHPNA), was used. The extractant was successfully encapsulated in microcapsules during the in situ microencapsulation process. The extractabilities of the metals into the microcapsules were determined from the extraction isotherms of the metal ions.From the Langmuir model, the saturation amount of metal extracted and the extraction equilibrium constants were determined. The metal extraction rates were also measured using the microcapsules containing EHPNA. As a result, it was shown that the overall extraction process of the metals was controlled by a chelating complex formation reaction between the metal and EHPNA.

Section: Solvent Extraction Research and Development Japan Vol 18mentioning

confidence: 99%

A Fundamental Study on the Extraction of Rare Earth Metals using Microcapsules Containing an Extractant

Kondo

Matsuo

Matsumoto

2011

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“…After gelation, alginate gel particles, each entrapping an organic droplet, were collected by filtration, added to distilled water in a round bottomed separation flask, in a previous paper [11], and then heated at 333K…”

Section: Preparation Of Large Size Microcapsulesmentioning

confidence: 99%

“…To solve Solvent Extraction Research and Development, Japan, Vol. 17, 215 -224 (2010) these problems, the immobilization of the extractant [1][2][3][4] and microencapsulation of the extractant have been investigated [5][6][7][8][9][10][11][12][13]. Microcapsules encapsulating extractants which have been applied in solvent extraction systems are expected to be effective separation media for various substances such as metals [5][6][7][8][9][10][11][12][13], organic acids [14][15][16], antibiotics [17,18], and environmental hazardous substances [19,20], because of the high separation properties of the encapsulated extractant, which has been demonstrated in the solvent extraction system, and because of the high capacity for the extracted chemicals in their internal core.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Large Size Microcapsules Containing Tri-<i>n</i>-octylamine by <i>In situ</i> Polymerization Combined with a Gel Inclusion Method and Their Extraction Behavior

Shiomori

Saeki

Sana

et al. 2010

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Large size microcapsules containing tri-n-octylamine (TOA) with a diameter of larger than 2 mm were prepared by in situ polymerization with a gel inclusion of an organic droplet. A copolymer of styrene and divinylbenzene was used as the capsule wall material. When the concentration of TOA was high, the structure of the microcapsules was mono-cored with a thin wall and large cavity. However, at low TOA concentration, the structure changed to a matrix type filled with the copolymer. The TOA content in the microcapsules increased linearly with the initial TOA concentration in the organic phase until 60wt%. The extraction of acetic acid into the microcapsules was successfully carried out. It was possible to reuse the microcapsules 4 times and the extracted amount of acetic acid into the microcapsules was constant during their reuse.

Section: Introductionmentioning

confidence: 99%

Separation and Recovery of Precious and Base Metals using a Column Packed with Microcapsules Containing an Extractant

Kondo

Ishihara

Matsumoto

2010

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A fundamental investigation of the separation and recovery of PdCl 4 2-, PtCl 6 2-, HCr 2 O 7 -, Cu 2+ , Ni 2+ and Zn 2+ from an aqueous solution by using microcapsules containing a metal extractant has been undertaken. As extractants, 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (EHPNA) and tri-n-octylamine loaded with hydrochloric acid (TOA-HCl) were used. The extractants were successfully encapsulated in microcapsules during the in situ microencapsulation process. The extractabilities of the metals into the microcapsules were estimated from the extraction isotherm of the metal ions. According to the Langmuir model, the saturation amount of metal extracted and the extraction equilibrium constant were determined. The microcapsules containing EHPNA and TOA-HCl were suitable for the extraction of base metal ions and precious metal ions, respectively. Using a reactor in which two columns packed with each microcapsule containing EHPNA and TOA-HCl are connected in series, the separation and recovery of precious metals from base metals was examined. In this way, the mutual separation of precious metals can be successfully achieved by feeding a suitable eluent stepwise into the column.