Photocatalytic activity of Cobalt-doped Fe2TiO5 nanoparticles from natural Ilmenite using acid leaching steps under visible light

Abstract

This research project was primarily carried out to observe the photocatalytic decolourisations of Cobalt-doped Fe2TiO5 nanoparticles in wastewater contaminated with dyes. The possibility of using commonly accessible Ilmenite as a raw material in a low-cost, non-toxic, stable, and highly reactive process of synthesising the aforementioned Fe2TiO5 is also explored in this research. Acid-leaching techniques were used, to remove impurities. Then Ammonia solution was used for precipitation, followed by filtration, drying, and calcination at 7000 C to produce Fe2TiO5 nanoparticles. Cobalt salt was added to the acid leachate, and the same precipitating and calcination procedure was followed to produce CoO/Co2O3/Co3O4/Fe2TiO5, which were then characterised utilising PXRD, Raman spectroscopy, XRF, XPS and SEM. PXRD patterns collected to identify the crystal structure of the synthesised nanoparticles show the presence of pseudobrookite, Fe2TiO5 and α-Fe2O3. Moreover, finding peaks in PXRD analysis for CoO/Co2O3/Co3O4 is challenging due to the low concentration of Co utilised. Raman analysis part depicts the existence of α-Fe2O3 and the anatase phase of TiO2 in the Cobalt-doped sample. XRF analysis was performed on a Cobalt-doped sample to identify the elemental distribution of Ti, Fe, Co and other elements. XPS analysis reveals the presence of Ti, Fe, O, C, and Co in the Cobaltdoped sample, confirming the CoO/Co2O3/Co3O4/Fe2TiO5 composition. The aforementioned analysis techniques confirm the Fe2TiO5/TiO2 in the initially synthesised undoped sample. SEM image of synthesised Fe2TiO5 shows the distribution of an irregular nanostructure of small and large nanoparticles. However, the Cobalt-doped sample shows how the irregularity is disturbed. The catalytic activity of Fe2TiO5/TiO2 and Cobalt-doped catalysts was observed in the presence and absence of persulfate under sunlight using UV visible spectroscopy. The CoO/Co2O3/Co3O4/Fe2TiO5 nanoparticles showed 37.31% dye removal for Methylene Blue after 2 hours, which was an insignificant result under sunlight. However, the addition of persulfate also did not show any significant improvement in the dye removal percentage, with only 32.54% decolouration of Methylene Blue observed after 2 hours. These results show a negligible photocatalytic effect in Cobalt-doped Fe2TiO5 nanoparticles using low concentrations of Cobalt.