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Sheet-like ZSM-5 zeolites with varied b-axis thicknesses (92, 160, 264 and 407 nm, respectively) and equivalent Si/Al molar ratios (ca. 150) were prepared using urea as additive in the aluminosilicate gels, and studied with respect to their performance in benzene alkylation with methanol. The ZSM-5 samples have similar textural properties and acidic properties. Catalytic tests show that these catalysts exhibit comparable benzene conversions of ca. 64% at 400 °C and WHSV of 2 h−1. The correlation between the selectivity of toluene and xylene and the ZSM-5 crystal size in the b-axis can be established. As the b axis length is decreased from 407 to 92 nm, the selectivity to toluene and xylene increases obviously from 80.3 to 87.4%, which is attributed to enhanced diffusion property of ZSM-5 zeolite. This finding provides an alternative strategy to improve the selectivity of toluene and xylene in the alkylation of benzene with methanol over ZSM-5-based catalysts. [ABSTRACT FROM AUTHOR]

Sonolysis could be more practical for water treatment than traditional catalytic methods in some specific situations. However, the practical application is limited by the low degradation rate. In this work, the Cr doped SrTiO3 was prepared by hydrothermal method, and the Cr-doping results in the decreased crystal symmetry, which leads to the rough surface and a large number of pores of the sample. The appearance of a large number of holes increases the specific surface area and enhances the gas adsorption performance of the sample, which can promote the cavitation. The optimized Cr-doped SrTiO3 can degrade 95.4% rhodamine B (5 mg/L) in 10 min under ultrasound irradiation (53 kHz, 350 W). Furthermore, the improvement of sonolysis degradation with the Cr doped SrTiO3 is universal for dyes, such as methyl blue (MB), methyl orange (MO) and rhodamine B (RhB). The role of active species in ultrasonic catalysis and the synergistic mechanism of ultrasound and catalyst were systematically studied by adding sacrificial agents and changing the reaction atmosphere. This work indicates that the incorporation of finely modified inorganic particles is effective for efficient water treatment. [ABSTRACT FROM AUTHOR]