Tailor and Control of Acidic Strength in Ordered Mesoporous Aluminosilicates by Using Preformed Zeolite Precursors

The acidic strength of ordered mesoporous aluminosilicates of MAS-2, MAS-3, MAS-7 and MAS-9 and mi-croporous crystals of Y, L, beta, and ZSM-5 zeolites was systemically investigated by temperature-programmed desorption of ammonia (NH3-TPD). Due to the use of preformed zeolite precursors of Y, L, beta and ZSM-5, the ordered mesoporous aluminosilicates with distinguished acidic strength were obtained, being dependent on the type of preformed zeolite precursors. Therefore, the acidic strength of these mesoporous aluminosilicates could be tai-lored and controlled.

Synthesis of Mesoporous Chromium Silicates Molecular Sieves in Strong Acidic Media by Assembly of Preformed CrS1 Precursors with Triblock Copolymer

Chromium-incorporated mesoporous silica materials （MCrS） have been successfully prepared in strong acidic media by assembly of preformed CrSI precursors with triblock copolymer of the Pluronic type （P123） by a two steps procedure. Various techniques including XRD, N2 adsorption, FT-IR spectroscopy, diffuse reflectance UV-vis （DRUV-vis） and EPR were employed for the materials characterization. MCrS materials have a hexagonal structure with uniform mesopores and contain Cr（V） and Cr（VI） under low and high Cr content and that the mesoporous walls contain the MFI structure building units.

Simultaneous removal of ammonia and N-nitrosamine precursors from high ammonia water by zeolite and powdered activated carbon

When adding sufficient chlorine to achieve breakpoint chlorination to source water containing high concentration of ammonia during drinking water treatment, high concentrations of disinfection by-products（DBPs） may form. If N-nitrosamine precursors are present, highly toxic N-nitrosamines, primarily N-nitrosodimethylamine（NDMA）, may also form. Removing their precursors before disinfection should be a more effective way to minimize these DBPs formation. In this study, zeolites and activated carbon were examined for ammonia and N-nitrosamine precursor removal when incorporated into drinking water treatment processes.The test results indicate that Mordenite zeolite can remove ammonia and five of seven N-nitrosamine precursors efficiently by single step adsorption test. The practical applicability was evaluated by simulation of typical drinking water treatment processes using six-gang stirring system. The Mordenite zeolite was applied at the steps of lime softening, alum coagulation, and alum coagulation with powdered activated carbon（PAC） sorption. While the lime softening process resulted in poor zeolite performance, alum coagulation did not impact ammonia and N-nitrosamine precursor removal. During alum coagulation, more than67% ammonia and 70%–100% N-nitrosamine precursors were removed by Mordenite zeolite（except 3-（dimethylaminomethyl）indole（DMAI） and 4-dimethylaminoantipyrine（DMAP））. PAC effectively removed DMAI and DMAP when added during alum coagulation. A combination of the zeolite and PAC selected efficiently removed ammonia and all tested seven N-nitrosamine precursors（dimethylamine（DMA）, ethylmethylamine（EMA）, diethylamine（DEA）, dipropylamine（DPA）, trimethylamine（TMA）, DMAP, and DMAI） during the alum coagulation process.

Preparation of Mesoporous Molecular Sieves Al-MSU-S Using Ionic Liquids as Template

Mesoporous molecular sieves Al-MSU-S has been prepared from the precursor of zeolite Y using ionic liquids 1-hexadecane-3-methylimidazolium bromide （CMIMB） as a template in basic medium, which exhibited larger pore diameter, pore volume and surface area than that synthesized using cetyl trimethyl ammonium bromide （CTAB） template.