LAMELLAR INORGANIC ION-EXCHANGERS.BEHAVIOUR OF γ-TITANIUM PHOSPHATE IN THE H⁺/Na⁺ION-EXCHANGE

%Calorimetric Determinations of Ba2+ and La3+ in the Ion-Exchange Process Involving Pure and Modified α-Titanium Phosphates

“…Preparation of α-Titanium Phosphate in the Sodium Form (TPNa). This modified matrix was prepared through a batch method, following an established procedure. , Briefly, this method consisted in dispersing 0.50 g of TPH in 64.0 cm 3 of 0.10 mol dm -3 sodium chloride (Nuclear). The suspension was slowly titrated with 36.0 cm 3 of 0.10 mol dm -3 sodium hydroxide (Nuclear) and stirred for 120 h at 298 K to complete the ionic exchange.…”

“…Preparation of α-Titanium Phosphate in the Butylammonium Form (TPBA). This intercalated compound was prepared as previously. , Thus, 1.0 g of TPH was added to 76.0 cm 3 of 0.10 mol dm -3 of an aqueous solution of n -butylamine (Aldrich) and stirred for 24 h at 298 K. The solid was centrifuged, washed with bidistilled water, and dried for 24 h at 313 K. The isolated compound 10,13 Ti(HPO 4 ) 2 ·1.05H 2 N(CH 2 ) 3 CH 3 ·1.5H 2 O exhibed an interlayer distance of 1839 pm.…”

“…The thermal effect caused by the reaction was recorded after each addition. The same procedure was used to follow the thermal effect of the exchanger suspended in water and also the titrant solution added in water. , …”

“…A significant amount of investigations are devoted to ion-exchange reactions, with the great majority focused on structural features of these exchangers, probable in exploring the excellent chemical and thermal stabilities and also the facility in developing favorable ion-exchange properties. , Thus, the ion-exchange behavior of those materials has been applied with the complete series of alkaline metals and calcium, barium, and strontium with the matrixes of titanium and zirconium hydrogen phosphate in α or γ crystalline structures. − However, some thermodynamic data for the ion-exhange reactions are reported for α- or γ-titanium and α- or γ-zirconium phosphates in investigations involving alkaline metals 6-8,11,12 and transition metals Co(II) and Ni(II) with γ-titanium hydrogen phosphate, for which the corresponding ionic isotherms at distinct temperatures were obtained. The same exchange process was followed through calorimetric determinations with crystalline α-titanium phosphate and crystalline or amorphous zirconium phosphate. ,− While the exchange behavior of α-titanium hydrogen phosphate has been investigated, only few studies are found with other kinds of this modified matrix.…”

“…The same exchange process was followed through calorimetric determinations with crystalline α-titanium phosphate and crystalline or amorphous zirconium phosphate. ,− While the exchange behavior of α-titanium hydrogen phosphate has been investigated, only few studies are found with other kinds of this modified matrix. However, those exchangers containing sodium and n -butylammonium intercalated forms were recently explored. , …”