Correlation between H-ZSM-5 crystal size and catalytic performance in the methanol-to-aromatics reaction

The porosity of H‐ZSM‐5zeolite is known to facilitate the diffusion of molecules in the methanol‐to‐aromatics(MTA)reaction.The activity and selectivity of the H‐ZSM‐5catalyst in the MTAreaction has been studied as a function of crystal size.ZSM‐5zeolites with different crystal sizeswere successfully synthesized by conventional hydrothermal methods.Tailoring ZSM‐5particle sizewas easily controlled by changes to the sol‐gel composition,and in particular,the deionized waterto tetrapropylammonium hydroxide ratio,and crystallization time.The structure of the H‐ZSM‐5zeolites were characterized by X‐ray diffraction and the morphology of the zeolite particles wasdetermined by scanning electron microscopy.N2adsorption‐desorption measurements establishedchanges to the textural properties,and compositional properties were characterized by X‐ray fluorescencespectroscopy.Acidity measurements of the catalysts were measured by pyridine‐adsorbedFourier transform infrared spectroscopy and the temperature‐programmed desorption of ammonia.After subjecting the catalysts to the MTA reaction,the total amount of coke formed on the spentdeactivated catalysts was determined by thermal gravimetric analysis.The results show that theSiO2/Al2O3molar ratios and acidic properties of the H‐ZSM‐5samples are similar,however,thenano‐sized hierarchical ZSM‐5zeolite with an additional level of auxiliary pores possesses a higher

东营地区某污水厂强化反硝化脱氮技术研究

本文采用DN-RTC碳源投加优化控制系统,研究碳源投加方式对硝化反硝化脱氮效能的影响,并且对DN-RTC系统的运行状况、灵敏度、出水TN(总氮)达标以及碳源单耗情况进行分析。结果表明:DN-RTC碳源投加优化控制系统相较于手动控制表现出更好的稳定性;碳源自动投加比手动投加平均出水TN降低10.44%,出水TN稳定达标;经过优化的自动投加相较于手动投加年度碳源单耗降低19.98%,碳源成本大大降低,证明碳源自动投加对反硝化脱氮有更优越的性能。

β-FeOOH/SiO2非均相芬顿催化剂的制备及染料废水处理研究

采用制备工艺简单、操作条件温和的方法合成了SiO2负载β-FeOOH非均相Fenton催化剂。采用单因素法优化催化剂的制备条件以及SiO2负载β-FeOOH非均相Fenton催化剂处理染料废水的最佳工艺条件。结果表明,在最佳工艺条件下,该催化剂对甲基橙、亚甲基蓝和罗丹明B的去除率可达97.93%、90.44%、99.25%。SiO2负载β-FeOOH非均相Fenton催化剂制备过程简单、操作条件温和,将其应用于降解染料废水时无需调节pH值,对染料废水降解效果较好,有望实现工业化生产。