سال انتشار: ۱۳۹۰

محل انتشار: پنجمین همایش تخصصی مهندسی محیط زیست

تعداد صفحات: ۶

نویسنده(ها):

Ali Hassanvand – Separation Processes Research Group SPRG, Department of Engineering, University of Kashan,
Morteza Asghari – Separation Processes Research Group (SPRG), Department of Engineering, University of Kashan,

چکیده:

One of the environmental pollutions is the existence of heavy metals in chemical processes. Some ways can be used for eliminating heavy metals from chemical processes that one of them is using zeolites. Molecular sieves and zeolites are materials whose crystalline frameworks form nanometer or subnanometer pores. A variety of different crystal structures are known having a range of pore sizes. Because the pore sizes are usually smaller than 2 nm, they are classified as microporous materials. Although microporous materials have ordered structure over the nanometer scale, they do not typically have ordered structure at larger dimensions. Synthesis of microporous materials is usually conducted by high temperature treatment (80-200 °C) of aqueous synthesis gels. The process of heating aqueous mixtures to elevated temperatures for crystallization is typically described as hydrothermal synthesis. The raw materials for synthesis of microporous materials include silicon and aluminum containing precursors, an organic structure directing agent (SDA), and a fluoride-containing mineralizing agent. AlPO4-5 nano-zeolite has been synthesized via hydrothermal technique. The crystals have been structurally characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray analysis (EDAX). With decreasing crystallization temperature and increasing during, the sizes of AlPO4-5 crystals have been decreased and crystallinty was increased.Effect of crystallization temperature and duration on morphology of the powder has been studied