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Using the hydrothermal crystallization method, a highly crystalline series of H-ZSM-5 zeolites were prepared in different Si/Al molar ratios (ranging from 25 up to 250). The performance of prepared catalysts was a subject of assessment in the process of methanol dehydration to dimethyl ether (DME), where a stainless steel fixed-bed flow reactor at 573 K and 16 barg with WHSV of 26.5 h -1 was used. The catalysts were characterized by BET, XRD, NH 3 -TPD, ICP, TGA/DTA, TPH, and SEM techniques. According to the experimental results, the catalytic activity and surface acidity were increased with an increase in the Si/Al molar ratio up to 125 and then decreased. The sample with a Si/Al molar ratio of 125 [H-ZSM-5( 125)] exhibited the best conversion and highest activity in methanol dehydration to DME. Before a comprehensive study was made on the synthesized zeolite catalysts, the dehydration reaction with crude methanol was studied over a commercial H-ZSM-5 catalyst under identical conditions. Results show that prepared catalysts have a better performance than commercial ones.

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In this work, we have developed a convenient method for the rapid and selective separation of Mo(vi) from aqueous solution by using a novel magnetic Mo(vi) ion imprinted polymer (Mo(vi)-MIIP) as the sorbent.