Nearly all atoms contributing to the local structure of Bransted acid sites in zeolites exhibit isotopes accessible for multinuclear solid-state nuclear magnetic resonance (NMR) investigations. Therefore, in the last 15 years, NMR spectroscopy has found numerous applications for the determination of the types of hydroxyl proton in zeolites, of their concentration, accessibility, and mobility, a...

Hierarchical zeolites containing tin were obtained, characterized and used in a reaction of catalytic isomerization of dihydroxyacetone (DHA) to lactic acid and alkyl lactates. These catalysts are characterized by preserved crystallinity and primary microporosity with the simultaneous existence of secondary porosity regarding mesopores, which facilitates access of large molecules of reagents to...

zeolites due to their structures can be used as molecular sieves for purification of materials and solutions. zeolites with phi and sod structure are so common and applicable for this purpose. hydroxy sodalite and phillipsite are the more abundant members of zeolites which display good selectivity for very small molecules and some ions such as sr, pb, zn, cu and rb. there is not any pure natura...

Catalysts are important to the chemical industry and environmental remediation due to their effective conversion of one chemical into another. Among them, composite catalysts have attracted continuous attention during the past decades. Nowadays, composite catalysts are being used more and more to meet the practical catalytic performance requirements in the chemical industry of high activity, hi...

nay zeolites with different framework si/al ratios were synthesized via hydrothermal technique. structural characteristics of the synthesized zeolites were determined by using xrd, xrf, sem, bet analyses. the effects of operating conditions of hydrothermal dealumination, i.e. time, temperature and partial pressure of water vapor on dealumination of the y zeolites framework and their structure w...

Porous solids with organized multiple porosity are of scientific and technological importance for broadening the application range from traditional areas of catalysis and adsorption/separation to drug release and biomedical imaging. Synthesis of crystalline porous materials offering a network of uniform micro- and mesopores remains a major scientific challenge. One strategy is based on variatio...

current article describes application of zeolites in fluid catalytic cracking (fcc). the use of several zeolitic additives for the production light olefins and reduction of pollutants is described. application of zeolites as fluid catalytic cracking (fcc) catalysts and additives due to the presence of active acid sites in the zeolite framework  increase the formation of desired cracking product...

The cages and channels of aluminosilicate zeolites provide a novel environment for molecular and nanoparticle assembly for photochemical reactions. In their dehydrated forms, zeolites can be active participants in reactions with photoexcited entrapped molecules as electron donors and acceptors. The charge-separated species thus formed are stabilized for hours. With hydrated zeolites, the encaps...