3. Results and discussion
3.1. Catalyst characterization
3.1.1. Fourier transform infrared (FTIR) spectra
As shows in Fig. 1, the absorption band around 1050 cm–1 arose from
the SiOSi bonds, suggesting the generation of SiO2 in the RHA800.
The adsorption peak at around 991 cm−1 showed the presence of
Si–O–Ca bond in the 30% RHA800-800 catalyst which was an evidence
for loading of CaO on RHA800 surface, and this band was due to the
formation of calcium silicate.An absorption band observed at around 3650 cm−1 and 1620 cm−1 could be assigned to the bending
OH mode of water molecules physisorbed on the surface of the solid.
The band at 1470 cm−1 was assigned to the symmetric stretching vibrations
of OCO bonds of unidentate carbonate at the surface of
the CaO [25]