Enhanced photocatalytic activity of titania in the presence of KNO3 on the photodegradation of dyes

Pristine TiO2 nanoparticles were synthesized using the sol-gel method. Morphological and size distribution patterns of the photocatalyst were determined using transmission electron microscopy, scanning electron microscopy and Brunuer-Emmett-Teller (BET) technique. Raman spectroscopy and powder X-ray diffraction were carried out to yield structural composition of TiO2. The photocatalyst was further used to photodegrade bromophenol blue (BPB) and methyl orange (MO), two anionic dyes, in the presence of KNO3. The addition of KNO3 improved the photodegradation of the dyes. The highest dye removal was observed after the addition of 5 mgL−1 of KNO3. The effect of pH upon the removal of the dyes was studied. Over 80% of BPB was removed, while 40% of MO was removed at pH 1. The results gave good correlation between radical-scavenging and improved photoactivity. Increased radical-scavenging effect was measured by the decrease of DPPH at 517 nm.