Adsorption of toluene on Si(100)/SiO2 substrate and mesoporous SBA-15

Adsorption of toluene on Si(100)/SiO2 substrate and mesoporous SBA-15 has been studied by using energy dispersive X-ray analysis (EDAX), Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) techniques. Contact angle technique is used to study the adsorption kinetics of toluene on Si(100)/SiO2 and thermal stability of adsorbed toluene layer. Scanning electron microscopy (SEM) technique is used to observe SBA-15 particles before and after toluene adsorption. Thermogravimetric (TGA) technique is employed to understand the thermal behavior of toluene layer on SBA-15. Adsorption kinetics fit fairly well with Langmuir isotherms giving adsorption rate constant, k(a) = 0.000054 M-1 S-1. SEM pictures clearly reveal assembly of SBA-15 particles mediated by toluene adsorption. EDAX and XPS results confirm toluene adsorption. FTIR results show presence of aromatic bends, ring stretch, combination bands, C-H stretch, methyl C-H symmetric and asymmetric stretches indicating toluene adsorption. Thermal stability study also indicates toluene adsorption. (c) 2005 Elsevier B.V. All rights reserved.