Super porous TiO2 photocatalyst: Tailoring the agglomerate porosity into robust structural mesoporosity with enhanced surface area for efficient remediation of azo dye polluted waste water

• Published in: Journal of environmental management 2020-03, Vol.258, p.110029-110029, Article 110029
• Main Authors: Naik, Amarja P., Mittal, Hemant, Wadi, Vijay S., Sane, Laxmi, Raj, Abhijeet, Alhassan, Saeed M., Al Alili, Ali, Bhosale, Sheshanath V., Morajkar, Pranay P.
• Format: Article
• Language: English
• Subjects: Adsorptive separation; Amaranth dye; Butanetetracarboxylic acid; Kinetic modeling; Photocatalytic dye degradation; Super porous TiO2
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2019.110029

The low surface area of TiO2 (50 m2g-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 TiO2 nanostructures with high effective surface area (238 m2g-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 TiO2. Detailed investigation of dye adsorption kinetics and photocatalytic degradation kinetics, complemented by kinetic modeling analysis confirmed that the super porous TiO2 with robust mesoporous structure outperforms the rest of synthesized TiO2 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 TiO2 shows promising potential for application in sustainable photocatalytic technology for remediation of wastewater contaminated with azo dyes. [Display omitted] •Super porous TiO2 with robust structural mesoporosity, enhanced surface area has been synthesized.•Ti(OH)4 gels have been innovatively modified with butanetetracarboxylic acid and urea to transform agglomerate porosity in to robust, structural mesoporosity.•Significant improvements in the Amaranth dye adsorptive separation capacity and photocatalytic degradation efficiency have been measured.•Detailed kinetic modeling analysis, signify the potential of super porous TiO2 for application in self-sustainable photocatalytic water purification technology.