Solar-light driven photocatalytic water detoxification is currently getting an immense prominence due to its enhanced economic viability and sustainability than UV-light driven photocatalysis. The key factor that coerces the process to be UV-light driven is the wide band gap of semiconductors used as photocatalysts. Key challenges for enhancing efficiency involve use of entire solar spectrum for photo-stimulation and suppressing recombination of e-/h+ pair apart from addressing usual challenges of reactor design, mass transfer and mixing. In recent years, researchers are using chemically modified doped nanoparticles as new photocatalytic materials for visible light activation of the catalyst. Although doping allows catalyst activation in the visible range, it doesn’t solve the enigma of low efficiency of the process that occurs due to recombination of generated e-/h+ pair. Dye sensitization, which has been widely studied in the development of solar cell technology, is a simpler method for activation photocatalyst but has not been studied extensively for photocatalytic water treatment. Mostly, heavy metal dyes have been used for sensitizing TiO2 till date. However, the novelty of this study lies in the fact that dyes used here have been extracted from naturally abundant resources. Natural dye sensitization of TiO2 for water decontamination is still in the nascent stage, which has been broadly reconnoitered here. Dried Mangosteen peels are used here as the source of dye. Different organic pollutants have been chosen for this study as model compounds which includes organic dyes like methylene blue and industrial wastes like phenol. The degradation of diverse organic contaminants delineates the adaptability of the process. It encompasses a detailed kinetic and parametric study of these pollutant degradations. The experiments in this study have been designed according to the principle of Design of Experiments (DOE) to have a precise conception of the effect of parameters on reaction yields. It also comprises of the comprehensive characterization of newly produced photocatalyst through XRD and BET analyses. Further, a radical scavenging study would determine the principle radical responsible for the detoxification which further establishes the plausible mechanism. This study not only discerns a new facet of natural dye-sensitization for water sanitization but also unlocks innovative expanses where this process can be further expended.

Solar-light driven photocatalytic degradation of organic pollutants using natural dye-sensitized TiO2

255th National Meeting (2018)

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