1,721,094 research outputs found
I tufi vulcanici nel costruito storico: vulnerabilità e possibili trattamenti per la conservazione e il restauro
No full textCon questa ricerca si intende approfondire le conoscenze su alcuni litotipi che afferiscono a due importanti formazioni vulcanoclastiche: l???Ignimbrite Campana sia in facies gialla che grigia e il Tufo Giallo Napoletano.
Questi materiali, largamente utilizzati nell???architettura storica della regione Campania, rappresentano un patrimonio storico-culturale, la cui tutela e conservazione deriva direttamente da un???approfondita conoscenza non solo del litotipo stesso ma anche del contesto in cui questo è utilizzato come materiale da costruzione.
A tal fine sono stati censiti gli impieghi principali delle vulcanoclastiti sia come materiale da costruzione che come lapideo ornamentale e la loro distribuzione nelle aree di maggiore interesse storico. Sono state poi valutate le principali caratteristiche di questi geomateriali al fine di migliorare la conoscenza dei litotipi dal punto di vista mineralogico, chimico e soprattutto dei parametri petrofisici, poco conosciuti a tutt???oggi. Sono state osservate le modificazioni che i tufi subiscono nel tempo in conseguenza della interazione con gli agenti del degrado, sostanzialmente l???umidità (o acqua di infiltrazione) che costituisce il veicolo più importante per il degrado della pietra e le variazioni di temperatura. Al contempo sono stati approfonditi anche i processi chimici e fisici connessi ai fenomeni di alterazione, valutando le modificazioni indotte nella pietra in seguito ai trattamenti di invecchiamento artificiale. È stato infine verificato l???impiego sperimentale di consolidanti e protettivi, con l???obiettivo di migliorare le caratteristiche di compattezza e resistenza della roccia, modificandone la struttura interna e limitando per quanto possibile le infiltrazioni d'acqua meterorica
Ba and Co removal from water by elution through fixed beds of phillipsite- and/or chabazite-rich tuffs
No full textEvaluation of Italian phillipsite and chabazite as cation exchangers for Ba2+ and Co2+.
No full textThe cation exchange properties of Na-exchanged phillipsite and chabazite for Ba2+ and Co2+, two cations present in many nuclear power plants wastewaters, were investigated at 25°C and 0.1 total normality, from either a kinetic or a thermodynamic points of view. Kinetic curves showed a rather fast exchange reaction for both cations, as equilibrium was mostly reached in about one day. Results of 2Na+ ⇄ Ba2+ and 2Na+ ⇄ Co2+ equilibria, interpreted in terms of distribution coefficient (Kd) and separation factor (αBA) and discussed on the basis of the known structural features of the two zeolites, evidenced a moderate to good selectivity of chabazite and phillipsite for Ba, which preludes to possible utilizations of Italian tuffs in the removal of this cation from wastewaters of nuclear origin. On the contrary, selectivity for Co was demonstrated to be very poor
Evaluation of Italian phillipsite and chabazite as cation exchangers for Ba2+ and Co2+.
No full textThe cation exchange properties of Na-exchanged phillipsite and chabazite for Ba2+ and Co2+, two cations present in many nuclear power plants wastewaters, were investigated at 25°C and 0.1 total normality, from either a kinetic or a thermodynamic points of view. Kinetic curves showed a rather fast exchange reaction for both cations, as equilibrium was mostly reached in about one day. Results of 2Na+ ⇄ Ba2+ and 2Na+ ⇄ Co2+ equilibria, interpreted in terms of distribution coefficient (Kd) and separation factor (αBA) and discussed on the basis of the known structural features of the two zeolites, evidenced a moderate to good selectivity of chabazite and phillipsite for Ba, which preludes to possible utilizations of Italian tuffs in the removal of this cation from wastewaters of nuclear origin. On the contrary, selectivity for Co was demonstrated to be very poor
Mineralogical and technical features of zeolite deposits from northern Latium volcanic district.
No full textModeling pedogenization of zeolitized tuffs. II: effect of water and phenolic substances on weathering rates of Campanian Ignimbrite (yellow facies)
No full textSperimentazione sulla pedogenesi di suoli da tufi zeolitizzati (ignimbrite campana
Evaluation of Italian phillipsite and chabazite as cation exchangers for Ba2+ and Co2+
No full textThe cation exchange properties of Na-exchanged phillipsite and chabazite for Ba2+ and Co2+, two cations present in many nuclear power plants wastewaters, were investigated at 25°C and 0.1 total normality, from either a kinetic or a thermodynamic points of view. Kinetic curves showed a rather fast exchange reaction for both cations, as equilibrium was mostly reached in about one day. Results of 2Na+ ⇄ Ba2+ and 2Na+ ⇄ Co2+ equilibria, interpreted in terms of distribution coefficient (Kd) and separation factor (αBA) and discussed on the basis of the known structural features of the two zeolites, evidenced a moderate to good selectivity of chabazite and phillipsite for Ba, which preludes to possible utilizations of Italian tuffs in the removal of this cation from wastewaters of nuclear origin. On the contrary, selectivity for Co was demonstrated to be very poor
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