Hydrothermal synthesis of zeolites from pumice in alkaline and saline environment

The Synthesis and Characterization of Low-Cost Mesoporous Silica SiO2 from Local Pumice Rock

“…The natural variability of pumice's composition allows for a wide range of physical and chemical properties, which provides the opportunity for upgrading this mineral resource. It can be utilized to obtain various synthetic zeolites with open framework structures, using hydrothermal and sol-gel processes [4-6]. Recently, the production of silica from cheap raw materials has attracted much attention because it is more economical than conventional methods, which are based on the synthesis of pure silica from tetraethyl-orthosilicate (TEOS) using the sol-gel process [7, 8] or from quartz sand by alkaline-melting at high temperature [9].…”

“…The natural variability of pumice's composition allows for a wide range of physical and chemical properties, which provides the opportunity for upgrading this mineral resource. It can be utilized to obtain various synthetic zeolites with open framework structures, using hydrothermal and sol-gel processes [4][5][6].…”

A novel synthetic route to hydroxyapatite–zeolite composite material from steel slag: investigation of synthesis mechanism and evaluation of physicochemical properties

“…Recently, zeolite synthesis from siliceous waste materials and minerals has been extensively investigated to reduce the amount of industrial waste or to produce commercially valuable products at a lower cost. [1][2][3][4][5][6][7][8][9][10] Zeolites are aluminosilicate microporous materials with large surface areas containing exchangeable cations within their structure. 11 The zeolite chemical formula is expressed as M m [Al m Si n O 2(m+n) ]$xH 2 O, where M is alkali cations electrostatically incorporated into the extra-framework.…”

Πειραματική Μελέτη Του Υδροθερμικού Μετασχηματισμού Φυσικών Και Διογκωμένων Περλιτών Της Νήσου Μήλου Σε Χαμηλές Συνθήκες Πίεσης Και Θερμοκρασίας

“…Οι ερευνητές στα πειράματα που διενέργησαν παρατήρησαν το σχηματισμό ζεόλιθου ZK-19, φιλλιψίτη, υδροξυσοδάλιθου και φαϋασίτη. Ο φαϋασίτης σχηματίστηκε σε συγκέντρωση NaOH μεγαλύτερη από 120 g/l, δίχως την παρουσία NaCl, ενώ όταν χρησιμοποιήθηκε NaCl οι ζεολιθικές φάσεις σχηματίστηκαν σε χαμηλότερες συγκεντρώσεις NaOH, οδηγώντας στο συμπέρασμα ότι η συγκέντρωση του αντιδρώντος διαλύματος διαδραματίζει σημαντικό ρόλο στο είδος του σχηματιζόμενου ζεόλιθου (Ottanà et al, 1982).…”