naa a22 4500 510774806 CHVBK 20180411083226.0 cr unu---uuuuu 180411e20131201xx s 000 0 eng 10.1007/s12210-013-0257-x doi (NATIONALLICENCE)springer-10.1007/s12210-013-0257-x NH4 exchange in chabazite, heulandite-clinoptilolite, and phillipsite [Elektronische Daten] [Elio Passaglia, Angela Laurora] In order to evaluate the NH4 exchange capacity of the chabazite, heulandite-clinoptilolite, and phillipsite zeolite species, crystals of "amygdaloidal” occurrence with different chemical compositions were treated in batch (static method) and in column (dynamic method) with 1N NH4Cl solution in varying experimental conditions (temperature, grain size). The degree of exchange was expressed as the percentage of each exchanged cation (Ca, Na, and K) with respect to the theoretical value calculated from the original chemical composition. The total percentage of the exchanged cations was also reported. The 70°C static treatments evidenced that the exchange was especially high in chabazite. At the same temperature the exchange increased in heulandite-clinoptilolite at decreasing grain size. With respect to the 70°C treatments, the room temperature static treatments showed a lowered exchange in phillipsite and heulandite-clinoptilolite, and subordinately in chabazite. In the dynamic treatments, the exchange was significantly higher in chabazite than in phillipsite and heulandite-clinoptilolite, and increased at decreasing grain size. On the whole, chabazite revealed the highest degree of exchange. The exchange capacity was slightly influenced by the Si/(Si+Al) ratio, and strongly influenced by the type of exchangeable cation present in the examined zeolite species, since the degree of Na and K exchange is generally higher than that of Ca. The ratio between divalent and monovalent cation exchange resulted to be roughly correlated to the total degree of exchange, thus suggesting that kinetic factors are involved in the monovalent vs. divalent cation exchange processes, also according to their ionic potential values. Accademia Nazionale dei Lincei, 2013 Antimicrobial peptides nationallicence Extrinsically labeled peptide nationallicence Model membranes nationallicence Static fluorescence nationallicence Time-resolved fluorescence nationallicence Passaglia Elio Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia, Largo S. Eufemia, 19, 41121, Modena, Italy aut Laurora Angela Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia, Largo S. Eufemia, 19, 41121, Modena, Italy aut Rendiconti Lincei Springer Milan 24/4(2013-12-01), 369-376 2037-4631 24:4<369 2013 24 12210 https://doi.org/10.1007/s12210-013-0257-x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s12210-013-0257-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Passaglia Elio Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia, Largo S. Eufemia, 19, 41121, Modena, Italy aut NATIONALLICENCE 700 1- Laurora Angela Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia, Largo S. Eufemia, 19, 41121, Modena, Italy aut NATIONALLICENCE 773 0- Rendiconti Lincei Springer Milan 24/4(2013-12-01), 369-376 2037-4631 24:4<369 2013 24 12210 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer