Development of Photo-Fenton oxidation as green strategy for phenol degradation enhancement via DMF-controlled TiO2 nanotubes under various oxidizing agents

Abstract

Photo-Fenton oxidation has been successfully developed as an emerging strategy for the treatment of hazardous organics from synthetic wastewater. For this purpose, single-layered TNTs have been successfully synthesized through TiO2-P25 as a precursor, DMF and alkaline solution via a simple hydrothermal method at 180 °C for 3 h. The as-developed TNTs were characterized through XRD, TEM, BET surface area, FTIR, XPS and DRS techniques. TNTs produced in DMF provided a higher specific surface area of 214.021 m2/g with a narrow bandgap energy of 2.58 eV. The photoreactivity of DMF-controlled TNTs was investigated to catalyze the decomposition of oxidants namely FeCl3 and H2O2 to harvest free hydroxyl radicals and finally its significance for the remediation of phenol upto 98.77% in visible-light irradiation. To our knowledge, this research first investigated that solvent-controlled TNTs photocatalyst could successfully activate oxidizing agents for wastewater treatment. Langmuir–Hinshelwood kinetic model was successfully followed phenol degradation results providing the highest R2 upto 0.993. Several thermodynamic parameters as enthalpy = 34.15 kJ/mol, entropy = 71.22 kJ/mol K, Gibbs free energy = −10.10 to −11.13 kJ/mol and activation energy = 30.92 kJ/mol were recommended that phenol degradation method is favorable and spontaneous in nature. The increasing temperature was more suitable for phenol removal onto DMF-controlled TNTs.