Investigation the effects of Al-grafting and calcination temperature on acidity and physicochemical properties of silica SBA-15

• Main Authors: Orouj Reza, Rashidzadeh Mehdi, Irandoukht Akbar, Sadighi Sepehr
• Format: Article
• Language: English
• Published: Serbian Chemical Society 2020-01-01
• Series: Journal of the Serbian Chemical Society
• Subjects: silica sba-15; post-synthesis al-grafting; acidity; physicochemical properties
• Online Access: http://www.doiserbia.nb.rs/img/doi/0352-5139/2020/0352-51392000021O.pdf

In this study, the effect of calcination temperature and Si/Al mole ratio on acidity and physicochemical properties of silica SBA-15 were investigated. Silica SBA-15 samples were calcined at 350, 450 and 550°C, and then post-synthesis, the Al-grafting method was applied to incorporate aluminum species into their framework with Si/Al mole ratio of 10 and 30. Characterizations using small angle XRD and N2 adsorption–desorption techniques indicated that the hexagonal mesoporous structure was retained after performing Al-grafting even at the high aluminum loading. Moreover, FTIR results implied that the aluminum species were incorporated into the SBA-15 framework. NH3-TPD results showed that by decreasing Si/Al mole ratio at all calcination temperatures, the number of weak acid sites increased in comparison to those of the pure SBA-15 samples. Additionally, the maximum total acidity of synthesized samples was observed at the calcination temperature of 450°C with Si/Al mole ratio of 30.