Kinetic study of CTMA+ removal from the pores of the Ti-MCM-41 molecular sieve

• Published in: Journal of thermal analysis and calorimetry 2015, Vol.119 (1), p.197-204
• Main Authors: Fontes, Maria S. B., Melo, Dulce M. A., Barros, Joana M. F., Braga, Renata M., Melo, Marcus A. F., Fontes, Vilsineia A.
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Chemistry; Chemistry and Materials Science; Inorganic Chemistry; Measurement Science and Instrumentation; Physical Chemistry; Polymer Sciences
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-014-4099-2

Thermogravimetry analysis was used to study the thermal decomposition of Ti-MCM-41 to determine the best calcination conditions. Ti-MCM-41 molecular sieve was synthesized using a hydrothermal route in which Ti ions were incorporated into the pore channels of MCM-41 starting from a hydrogel method according to the following molar composition: 1.00 CTMABr:4.00 SiO 2 : X TiO 2 :1.00 Na 2 O:200.00 H 2 O. Physicochemical properties of samples were investigated using XRD, FTIR, and N 2 adsorption–desorption to confirm the incorporation of TiO 2 nanoparticles inside of MCM-41 mesoporous without destroying its structure. The high temperatures facilitate the rapid removal of the surfactant; however, it caused destruction of the MCM-41 structure by breaking the bonds of the silica tetrahedral structure. The procedures to obtain the apparent activation energies of CTMABr decomposition were based on the kinetic model proposed by Flynn-Wall using thermal analysis of data performed with heating rates 5, 10, and 20 °C min −1 .