کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1696764 1519143 2006 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Characterization of surface acidity of an acid montmorillonite activated with hydrothermal, ultrasonic and microwave techniques
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات ژئوشیمی و پترولوژی
پیش نمایش صفحه اول مقاله
Characterization of surface acidity of an acid montmorillonite activated with hydrothermal, ultrasonic and microwave techniques
چکیده انگلیسی

The surface acidity of montmorillonite treated by conventional hydrothermal reaction with acids as well as ultrasonic- and microwave-assisted acid digestion was studied using diffuse reflectance FT-IR (DRIFT) spectroscopy of adsorbed pyridine molecules. An attempt for semi-quantitative measurement of Brønsted acidity generated during the acid digestion was also carried out. The conventional hydrothermal, ultrasonic- and microwave-assisted acid digestion yielded strong Brønsted acid sites of similar nature and strength, which retained pyridine up to 400–450 °C. Strong Lewis acid sites were also developed at higher temperature (> 300 °C), which were able to retain pyridine at 450 °C. The results show that surface acidity of similar strength can be generated with conventional hydrothermal treatment at 80 °C for 4 h or ultrasonic-treatment at room temperature for 1 h or microwave-assisted acid digestion for 10 min using 3 N concentration of H2SO4. Therefore, microwave- and ultrasonic-assisted acid digestions are potential and rapid alternative methods to conventional hydrothermal acid digestion for preparing acid-activated clays.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Clay Science - Volume 31, Issues 1–2, January 2006, Pages 16–28
نویسندگان
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