Synthesis And Characterization Of MCM-41&ZSM-5/MCM-41and Research Of Molecular Sieve Supporting TiO₂-photocatalysts

MCM-41mesoporous molecular sieve and ZSM-5/MCM-41composite molecularsieve，are important adsorbents and catalysts,which have the advantages of large surfacearea, high thermal stability, high channel order degree, adjustable pore size; while TiO2, asa kind of important photocatalyst, has high catalytic activity, stable chemical properties,non-toxicity, cheap and easy to gain. The preparation condition and physical properties ofMCM-41mesoporous molecular sieve and ZSM-5/MCM-41composite molecular sievewere investigated in this paper, including the characterization and photocatalyticperformance test preparation of TiO2/MCM-41molecular sieve andTiO2/ZSM-5/MCM-41molecular sieve. The physical properties were characterized bymulti-method including XRD, FT-IR, TEM, SEM, N2adsorption analysis and TG-DTA,and the text of decolorization of Rhodamine B solution, as a probe reaction, to evaluatethe photocatalytic properties, the results are as follows:MCM-41molecular sieves could be prepared by hydrothermal reaction, near-roomtemperature method in acidic conditions and that in alkaline conditions. By comparingthese three reaction condition, MCM-41molecular sieve by hydrothermal methodpossesses regular crystalline phase, large pore volume long-range order and wide surfacearea. The best synthesis condition for preparation by hydrothermal measure in molar ratioof CTAB: SiO2: Na2O: H2O is0.12:1.0:0.12:65.0. And the best crystallization conditionis48h at110°C.The prepared ZSM-5/MCM-41composite molecular sieve particles, with multilayered or lamellar shapes, has two pore structures and crystalline phases. The bestconditions of alkali treatment process are that0.5g ZSM-5zeolite was used as precursorafter alkali treatment in0.2mol/L NaOH aqueous solution for15min. And the bestcrystallization condition is also48h at110°CTiO2/MCM-41molecular sieve was prepared from MCM-41molecular sieve underhydrothermal condition used as support with TiO2loading on it. The preparation ofTiO2/ZSM-5/MCM-41molecular sieve was similar with that applied in synthesis of TiO2/MCM-41molecular sieve. These two samples both contain TiO2particles which arewell dispersed including anatase-TiO2crystal phase and part of rutile-TiO2phase. Thephotocatalytic degradation of Rhodamine B solution was used for probe experiment todeterminate their photocatalytic performance, and the results show that, the0.04gTiO2/MCM-41sample of load rate of0.40with heat-treatment under500°C for4hpossessed better photocatalytic property to decolour the solution of Rhodamine B, whichis similar with the results of TiO2/ZSM-5/MCM-41sample.And the maximumdecolorization rate of both samples could reach over99%.