Photocatalytic degradation of toxic organic compounds in water, soil and air by semiconductor catalysts such as TiO2 and ZnO has received much attention over the last two decades. However, the low quantum yield, easy agglomeration and difficult post-separation of these inorganic catalysts limit their application for large-scale applications.Metal-organic frameworks (MOFs) are the latest class of ordered porous solids that being intensively studied as a novel class of hybrid inorganic-organic material with ultrahigh porosity, enormous internal surface areas, together with the extraordinary tailorability of structure, dimension, size and shape. Recently exploring performance of MOF as a new nanophotocatalyst is attracting interest of researchers working in the fields of chemistry, chemical engineering, material scienceand others. Although the photocatytic application of MOF materials is still at the early stage compared with the other applications of them such as gas storage, separation, biomedical application and heterogeneous catalysis, the currently available results have revealed that the design and construction of MOFs for photocatalyst functionality are very active. The present review aims tointroduce MOF materials, the synthesized methods and highlights the progress attempts for using the mas a nanophotocatalyst for degradation of pollutants.

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 natural deposit of these zeolites and purify methods are not cost-effective. Therefore, introducing an effective method to prepare these zeolites is necessary. In this study, hydroxy sodalite and phillipsite have been synthesized respectively from clinoptilolite and volcanic ash at hydrothermal conditions in the presence of alkaline solutions. Mineralogical studies show that K, Na and Cl ions are necessary in SOD and PHI structure. The effect of K+ concentrations and temperature in the presence of constant value of Na+ and Cl- are being considered as the variable parameters in the present experiment. NaCl used as source of Na+ and Cl- ions. Alkaline solutions were prepared by using 2 to 12 grams KOH powder and synthesize mixture were heated at temperatures of 100 and 150oC. Results of this study show that phillipsite is synthesized at 100 and 150oC in all runs. Hydroxy sodalite is appeared just in 150oC by using clinoptilolite as initial material. Analcime formed as by-product of volcanic ash phase transition at 150oC.

Manganese-based octahedral molecular sieves of the type K-OMS-2 (cryptomelane structure) were prepared via reflux method by synproportionation of KMnO4 and Mn2+ in acidic aqueous suspension. For this method, different manganese anions (sulphate, chloride and acetate) were used, which exert a strong influence on the prepared materials. Several techniques such as X-ray diffraction, Fourier transformer infrared, Raman spectroscopy, transmission electron microscopy, differential and gravimetric thermal analysis and H2-temperature programmed reduction were used to characterize the prepared samples. The results revealed that the prepared samples were mainly pure mono-phase cryptomelane materials. The obtained K-OMS-2 material on using the sulphate anion has more available lattice oxygen as compared to that prepared by the other anions. The catalytic activity of the prepared samples was tested towards the oxidative dehydrogenation of cyclohexane. Over the K-OMS-2RS sample, cyclohexane conversion was significantly higher than the other prepared samples.