کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
73826 49072 2013 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Direct activation of microcrystalline zeolites
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
پیش نمایش صفحه اول مقاله
Direct activation of microcrystalline zeolites
چکیده انگلیسی

In this work a direct activation route of zeolites is assessed. It consists of NH4-exchanging the as-synthesized solids before removing the organic template. Calcination afterwards serves to combust the organic template and creates the Brønsted sites directly; thus applying merely a single thermal step. This method simplifies their activation and the material suffers less thermal stress. The approach was particularly effective for microcrystalline beta and ferrierite zeolites. Thorough investigation of the template content and materials’ texture points out to three relevant effects that can explain the effective exchange process: partial removal of the template during exchange creates substantial microporosity (ferrierite), the remaining template is reorganized within the pores (ferrierite) and finally, void space can exist due to the non-perfect matching between the network and template (beta). This shorter method appears suited for microcrystalline zeolites; it was ineffective for crystalline MFI types.

Figure optionsDownload as PowerPoint slideHighlights
► Zeolites beta and ferrierite were NH4-exchanged before removing the organic template.
► Calcination then serves to burn the organic template; creating Brønsted sites directly.
► The method does not work for MFI-types.
► Various phenomena are relevant to rationalize this route.
► The material’s properties are comparable to the conventional route.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Microporous and Mesoporous Materials - Volume 171, 1 May 2013, Pages 208–214
نویسندگان
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