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Adsorption-elution properties of newly synthesized adsorbents
React. Polym. 17 (1992)115-139
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and pH). The retention of cations on methacrylate ion-exchangers were compared with those on derivatives of styrene-divinylbenzene and silica gel. The detection limits obtained using the usual apparatus and method were 2.5 x 10 -s g. References: J.
Chromatogr.,509 (1990) 369-367;
J.
Chromatogr.,475 (1989) 209-217.
Adsorption-elution properties of newly synthesized adsorbents T. Itagaki, T. M o r i t a , J. W a t a n a b e a n d H. T e s h i m a
Research Center Mitsubishi Kasei Corporation, 1000, Kamoshida-cho, Midori-ku, Yokohama 227, Japan Synthetic adsorbents with large surface areas were developed. The adsorbents were made of styrene and divinylbenzene monomers. They were synthesized by a two-step reaction, polymerization and alkylation reaction. Adsorption capacities of several substances were examined and were characterized for groups of adsorbents: (1) adsorbents as having almost the same surface area with different peak pore radius; (2) adsorbents having different surface areas with almost the same peak pore radius. The substances were chosen from an antibiotic intermediate and proteins with various molecular weights (those molecular weights were in the range from several hundreds to tens of thousands). According to the adsorption capacity measurements, there exists a good correlation between adsorption capacities for cephalosporin-C and the surface areas of adsorbents. However, in the case of large molecules like proteins, adsorbed amounts are affected by the pore sizes of the adsorbents. Molecular sieve effects due to pore size distribution of adsorbents are effective for the separation of small from large molecules like proteins. Reference: M. Streat, Ion Exchange for Industry, Ellis-Horwood, 1988, p. 232.
Thermodynamic study of ion exchange of alkaline earth metal ions on a weak cation-exchanger, Bio-Rex 70 B.L. J a n g i d a 1, P.V. A c h u t h a n 2 a n d M. S u n d a r e s a n 1
1Analytical Chemistry Division, Bhabha Atomic Research Centre, Bombay 400085, India 2 Fuel Reprocessing Division, BARC, Bombay 400085, India Standard free energy, enthalpy and entropy changes for the cation exchange of magnesium, calcium, strontium and barium with sodium ions on a carboxylic type weak cation-exchanger, Bio-Rex 70 resin, has been estimated in dilute 0.1 N aqueous chloride solutions from ionic distribution and calorimetric measurements at 298 K. The strong binding for the alkaline earth metal ions by the resin was reflected by the large negative values of the standard free energy changes. The exchange reactions were endothermic and the endothermicity was maximum for calcium-sodium exchange due to the stronger complex formation between the calcium and carboxylate ionogenic group. The reactions were thus entropy driven. The magnitude of the selectivities of the alkaline earth metal ions were significantly higher than those on polystyrene sulfonate type of exchangers. The order of selectivity was calcium > barium = magnesium > strontium. The higher selectivity and the random order of the selectivity have been attributed to the greater dehydration and complexing of the cations by the RCOO- group.
Investigation on kinetics of polyvalent ions in selective ion-exchangers A.I. Kalinitchev, T . D . S e m e n o v s k a y a , V.Ja. F i l i m o n o v a n d T . D . S h e p e t y u k
Institute of Physical Chemistry, USSR Academy of Science, Lenin Avenue 31, Moscow 117915, USSR Our previous theoretical model of ion-exchange kinetics in selected systems is extended for polyvalent ion-exchangers. Kinetic investigations were carried out on the selective ion-exchangers ANKB-35 and AN-18-10P for H-RNi, Ni-RH, O-RAg, C1-RCu and Ni-RNa exchangers using a home-made flow cell filled with a thin layer of
123
and pH). The retention of cations on methacrylate ion-exchangers were compared with those on derivatives of styrene-divinylbenzene and silica gel. The detection limits obtained using the usual apparatus and method were 2.5 x 10 -s g. References: J.
Chromatogr.,509 (1990) 369-367;
J.
Chromatogr.,475 (1989) 209-217.
Adsorption-elution properties of newly synthesized adsorbents T. Itagaki, T. M o r i t a , J. W a t a n a b e a n d H. T e s h i m a
Research Center Mitsubishi Kasei Corporation, 1000, Kamoshida-cho, Midori-ku, Yokohama 227, Japan Synthetic adsorbents with large surface areas were developed. The adsorbents were made of styrene and divinylbenzene monomers. They were synthesized by a two-step reaction, polymerization and alkylation reaction. Adsorption capacities of several substances were examined and were characterized for groups of adsorbents: (1) adsorbents as having almost the same surface area with different peak pore radius; (2) adsorbents having different surface areas with almost the same peak pore radius. The substances were chosen from an antibiotic intermediate and proteins with various molecular weights (those molecular weights were in the range from several hundreds to tens of thousands). According to the adsorption capacity measurements, there exists a good correlation between adsorption capacities for cephalosporin-C and the surface areas of adsorbents. However, in the case of large molecules like proteins, adsorbed amounts are affected by the pore sizes of the adsorbents. Molecular sieve effects due to pore size distribution of adsorbents are effective for the separation of small from large molecules like proteins. Reference: M. Streat, Ion Exchange for Industry, Ellis-Horwood, 1988, p. 232.
Thermodynamic study of ion exchange of alkaline earth metal ions on a weak cation-exchanger, Bio-Rex 70 B.L. J a n g i d a 1, P.V. A c h u t h a n 2 a n d M. S u n d a r e s a n 1
1Analytical Chemistry Division, Bhabha Atomic Research Centre, Bombay 400085, India 2 Fuel Reprocessing Division, BARC, Bombay 400085, India Standard free energy, enthalpy and entropy changes for the cation exchange of magnesium, calcium, strontium and barium with sodium ions on a carboxylic type weak cation-exchanger, Bio-Rex 70 resin, has been estimated in dilute 0.1 N aqueous chloride solutions from ionic distribution and calorimetric measurements at 298 K. The strong binding for the alkaline earth metal ions by the resin was reflected by the large negative values of the standard free energy changes. The exchange reactions were endothermic and the endothermicity was maximum for calcium-sodium exchange due to the stronger complex formation between the calcium and carboxylate ionogenic group. The reactions were thus entropy driven. The magnitude of the selectivities of the alkaline earth metal ions were significantly higher than those on polystyrene sulfonate type of exchangers. The order of selectivity was calcium > barium = magnesium > strontium. The higher selectivity and the random order of the selectivity have been attributed to the greater dehydration and complexing of the cations by the RCOO- group.
Investigation on kinetics of polyvalent ions in selective ion-exchangers A.I. Kalinitchev, T . D . S e m e n o v s k a y a , V.Ja. F i l i m o n o v a n d T . D . S h e p e t y u k
Institute of Physical Chemistry, USSR Academy of Science, Lenin Avenue 31, Moscow 117915, USSR Our previous theoretical model of ion-exchange kinetics in selected systems is extended for polyvalent ion-exchangers. Kinetic investigations were carried out on the selective ion-exchangers ANKB-35 and AN-18-10P for H-RNi, Ni-RH, O-RAg, C1-RCu and Ni-RNa exchangers using a home-made flow cell filled with a thin layer of