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Calcined Mg–al layered double hydroxides for uptake of trace levels of bromate from aqueous solution / Ramesh Chitrakar in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9280-9285 Titre : Calcined Mg–al layered double hydroxides for uptake of trace levels of bromate from aqueous solution Type de document : texte imprimé Auteurs : Ramesh Chitrakar, Auteur ; Akinari Sonoda, Auteur ; Yoji Makita, Auteur Année de publication : 2011 Article en page(s) : pp. 9280-9285 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Aqueous  solution  Uptake  Calcination Résumé : Layered double hydroxides of Mg and Al (Mg-Al LDH) were synthesized with OH-, Cl-, or CO32- as charge compensating anions. The materials were calcined at 500 °C in air. The bromate uptakes of calcined and uncalcined LDH materials were investigated from 0.78 μmol/dm3 bromate solution. Results show that uncalcined LDH exhibited no bromate uptake, although calcined LDH exhibited bromate uptake: the initial bromate concentration of 0.78 μmol/dm3 decreased to less than 0.078 μmol/dm3, the maximum contaminant level established for bromate in drinking water. The rate of bromate uptake of calcined LDH was slow to attain equilibrium in 48 h. The bromate uptake data of calcined LDH agreed well with the Freundlich model. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395872 [article] Calcined Mg–al layered double hydroxides for uptake of trace levels of bromate from aqueous solution [texte imprimé] / Ramesh Chitrakar, Auteur ; Akinari Sonoda, Auteur ; Yoji Makita, Auteur . - 2011 . - pp. 9280-9285. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9280-9285 Mots-clés : Aqueous  solution  Uptake  Calcination Résumé : Layered double hydroxides of Mg and Al (Mg-Al LDH) were synthesized with OH-, Cl-, or CO32- as charge compensating anions. The materials were calcined at 500 °C in air. The bromate uptakes of calcined and uncalcined LDH materials were investigated from 0.78 μmol/dm3 bromate solution. Results show that uncalcined LDH exhibited no bromate uptake, although calcined LDH exhibited bromate uptake: the initial bromate concentration of 0.78 μmol/dm3 decreased to less than 0.078 μmol/dm3, the maximum contaminant level established for bromate in drinking water. The rate of bromate uptake of calcined LDH was slow to attain equilibrium in 48 h. The bromate uptake data of calcined LDH agreed well with the Freundlich model. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395872

Selective uptake by akaganeite (B - FeOOH) of phosphite from hypophosphite and phosphite solutions / Ramesh Chitrakar in Industrial & engineering chemistry research, Vol. 51 N° 2 (Janvier 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 2 (Janvier 2012) . - pp. 972-977 Titre : Selective uptake by akaganeite (B - FeOOH) of phosphite from hypophosphite and phosphite solutions Type de document : texte imprimé Auteurs : Ramesh Chitrakar, Auteur ; Yoji Makita, Auteur ; Takahiro Hirotsu, Auteur Année de publication : 2012 Article en page(s) : pp. 972-977 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Uptake Résumé : The anion-exchange properties of akaganeite (β-FeOOH) with phosphite (H2PO3― and HPO32― ) are reported herein. Uptake of phosphite by akaganeite followed the Freundlich isotherm model with exchange capacity of 1.0 mmol/g, and high distribution coefficients in multianion solution of 2.0 mmol/dm3 concentration (7.0 x 103 cm3/g at pH 3.9). Akaganeite displayed nearly constant uptake of phosphite (0.9 mmol/g) at pH 2.5―6.0. The kinetics on uptake of phosphite rapidly reached an equilibrium in 4 h. Akaganeite was also found to be feasible for high uptake of phosphite (1.2 mmol/g) and low uptake of hypophosphite (<0.10 mmol/g) at pH 6.3 from a highly concentrated binary solution containing 0.70 mol/dm3 phosphite, and 0.20 mol/dm3 hypophosphite. Akaganeite can be regenerated and reused for uptake of phosphite with an exchange capacity equivalent to that of the original akaganeite. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25476430 [article] Selective uptake by akaganeite (B - FeOOH) of phosphite from hypophosphite and phosphite solutions [texte imprimé] / Ramesh Chitrakar, Auteur ; Yoji Makita, Auteur ; Takahiro Hirotsu, Auteur . - 2012 . - pp. 972-977. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 2 (Janvier 2012) . - pp. 972-977 Mots-clés : Uptake Résumé : The anion-exchange properties of akaganeite (β-FeOOH) with phosphite (H2PO3― and HPO32― ) are reported herein. Uptake of phosphite by akaganeite followed the Freundlich isotherm model with exchange capacity of 1.0 mmol/g, and high distribution coefficients in multianion solution of 2.0 mmol/dm3 concentration (7.0 x 103 cm3/g at pH 3.9). Akaganeite displayed nearly constant uptake of phosphite (0.9 mmol/g) at pH 2.5―6.0. The kinetics on uptake of phosphite rapidly reached an equilibrium in 4 h. Akaganeite was also found to be feasible for high uptake of phosphite (1.2 mmol/g) and low uptake of hypophosphite (<0.10 mmol/g) at pH 6.3 from a highly concentrated binary solution containing 0.70 mol/dm3 phosphite, and 0.20 mol/dm3 hypophosphite. Akaganeite can be regenerated and reused for uptake of phosphite with an exchange capacity equivalent to that of the original akaganeite. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25476430