In these studies, cordierite was mechanically synthesized after a sol-gel process. The effect of milling time of cordierite was investigated. Aluminium nitrate nonahydrate, magnesium nitrate hexahydrate and tetraethylorthosilicate (TEOS) were used as starting materials. Gels obtained were mechanically activated in planetary ball mill by at 300rpm grinding speed and grinding time (15min, 30min, 45min and 60min). Powders produced were characterized by X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) and Energy Dispersive X-Ray (EDX). XRD analysis proved that α-cordierite was formed at lower temperature (1200°C) as compliment to without grinding, whereby it is formed at1300°C. FESEM analysis shows the size of the cordierite were in submicron scale. EDX analysis proved that magnesium, aluminium, silicon and oxygen are elements existed in cordierite.
WO3 particles were synthesized using sol-gel method. The WO3 particles was prepared using 0.4 M of sodium tungstate dehydrate for 21 h at 90 °C. The photocatalytic activity of WO3 particles in removal of RhB dye followed first order kinetics in both visible light and UV light irradiation. The investigation showed that WO3 particles degraded RhB dye more effectively under UV irradiation (43.2 %) than visible irradiation (2.6 %) in 75 min. The poor photodegradation efficiency was attributed to the narrow excitation band of visible light source. Besides, the scavenger tests indicated that the holes and hydroxyl radicals were the dominant reactive species in photocatalytic degradation of RhB dye. Based on these findings, the photodegradation mechanism of RhB dye by WO3 particles is proposed.