ZSM-5 zeolite is widely used in catalytic cracking of hydrocarbon, but the conventional ZSM-5 zeolite deactivates quickly due to its simple microporous and long diffusion pathway. Many studies have been done to overcome these disadvantages recently. In this review, four main approaches for enhancing the catalytic performance, namely synthesis of ZSM-5 zeolite with special morphology, hierarchic...

An evaluation of natural zeolite as a microorganism carrier in nitrifying reactors operated in batch mode was carried out. Specifically, the influence of zeolite particle sizes of 0.5, 1.0 and 2.0 mm in diameter on microorganism adherence to zeolite, ammonium adsorption capacity and the identification of microbial populations were assessed. The greatest amount of total biomass adhered was obser...

This study reports on the EPR of C r 5 + and C u 2 + ions, introduced by solidand liquid-state reactions with the synthetic zeolites 3A, 4A and 5A, and the natural zeolite clinoptilolite. C r 3 + was oxidized to Cr 5 + in the samples, the coordination around Cr 5 + being square pyramidal. Superhyperfine (shf) interaction of Cr with A1 nucleus was observed in both solidand liquid-stateintroduced...

considering the point that the existence of heavy metals in the wastewater are so dangerous forthe environment and it would have many bad consequences for all the creatures including human beings, wemust try out the ways that make us capable of adsorbing these heavy metals. in order to accomplish this goal we should use a method called adsorbing. in this study the adsorption of copper ions in h...

A natural zeolite (Z-N), rich in clinoptilolite, was modified (Z-Al) by incorporation of hydrated aluminum oxide (HAlO) for the simultaneous phosphate and ammonium removal. The incorporation of surface hydroxyl groups (≅Al-OH) into the zeolite structure, as active groups for phosphate removal, was characterized by acid-base titrations (pHPZC=4.5±0.2). The phosphate sorption increases from 0.6 m...

immobilization of catalysts on the surface of some inert supports makes therecovering step easier. because of the specific physicochemical properties, zeolites are good candidate as catalyst supports. in this study, zeolite x was synthesized by natural kaolin and tio2 was incorporated into zeolite phase by impregnation method. degradation of safranin orange, methylene blue and 2,4–dinitroanilin...