Crystalline calcium phenylphosphonate—thermodynamic data on n-alkylmonoamine intercalations

The influence of chitosans with defined degrees of acetylation on the thermodynamic data for copper coordination

“…The calorimetric data from the thermal effects of adsorption were acquired by a calorimetric titration technique performed in a precision calorimetric system, a Thermometric 2277 thermal activity monitor [17][18][19][20]. In each calorimetric titration a glass calorimetric vessel with maximum capacity 20.0 cm 3 was loaded with 50.0 mg of the biopolymer suspended in 19.0 cm 3 of doubly distilled water and maintained under mechanical turbine stirring (90 rpm) at 298.15 ± 0.02 K. For each titration at least 10 increments of 10 µl of the titrant solution, 0.10 mol dm −3 Cu(NO 3 ) 2 , were added to the suspension and the thermal effects recorded after each addition.…”

“…The individual calorimetric titration experiments were carried out in duplicate and the thermal effect of the reaction Q r , the hydration, Q h , and the dilution, Q d for each experimental point of the calorimetric titration [17][18][19][20] must be considered to give the net Q int value,…”

“…To evaluate the results obtained from the isotherms of adsorption and to determine the mole fraction of the ion in solution, the data were adjusted to the Langmuir model [17][18][19][20]23], assuming that a monolayer of cation formed on the biopolymer, expressed by the equation…”

“…These data form a heterogeneous system, in which the desired biopolymer, suspended in aqueous medium, was calorimetrically titrated with the cation. The purpose of this study was to explore biopolymer-cation interactions at the solid/liquid interface, taking into account earlier successes with a series of inorganic heterogeneous systems [18][19][20].…”

Influência do agente precipitante na preparação do óxido de nióbio (V) hidratado pelo método da precipitação em solução homogênea

“…Isso indica que a capacidade de troca iônica está relacionada com a cristalinidade do óxido de nióbio (V) hidratado que, conseqüente-mente, depende do tipo de agente precipitante utilizado. A presença de lamelas nos materiais preparados com carbonato de amônio na PSH e na precipitação convencional indica a possível utilização desses materiais em processos de intercalação e pilarização 6,7,[18][19][20] . Com os valores obtidos pelas curvas da Figura 3, calcularam-se as distâncias interplanares dos picos existentes e compararam-se com as distâncias das fichas JCPDS.…”