Super porous TiO sub(2) photocatalyst: Tailoring the agglomerate porosity into robust structural mesoporosity with enhanced surface area for efficient remediation of azo dye polluted waste water

Abstract

The low surface area of TiO sub(2) (50 m sup(2)g sup(-1) - Degussa P25) due to randomly oriented, agglomerated nanostructures and charge carrier recombination tendency, has till date been its major limitation for photocatalytic remediation of polluted wastewater. This study presents an innovative process to design super porous TiO sub(2) nanostructures with high effective surface area (238 m sup(2)g sup(-1)), robust, structurally ordered mesoporosity via a simple sol-gel assisted reflux method. Detailed material characterization studies suggest that the higher degree of intermolecular ligation in novel templates such as butanetetracarboxylic or tricarballylic acid modified titanium hydroxide gels resulted in retainment of the porous structure during the urea assisted combustion synthesis. The induction of robust structural porosity is accompanied by a reduction in pore size distribution, an increase in pore volume leading to significantly higher total surface area of the synthesized TiO sub(2). Detailed investigation of dye adsorption kinetics and photocatalytic degradation kinetics, complemented by kinetic modeling analysis confirmed that the super porous TiO sub(2) with robust mesoporous structure outperforms the rest of synthesized TiO sub(2) catalyst (having only agglomerate porosity) in terms of its superior adsorption capacity, faster diffusion kinetics and photocatalytic activity for degradation of Amaranth dye. Thus, the super porous TiO sub(2) shows promising potential for application in sustainable photocatalytic technology for remediation of wastewater contaminated with azo dyes.