In-situ dual applications of ionic liquid coated Co2+ and Fe3+ co-doped TiO2: Superior photocatalytic degradation of ofloxacin at pilot scale level and enhanced peroxidase like activity for calorimetric biosensing

Abstract

In the present study the synthesis of an inexpensive solar light responsive Co2+ and Fe3+ co-doped TiO2 (CoFeTiO2) for efficient photocatalytic degradation of ofloxacin (OFL) in addition to its excellent activity as peroxidase mimics has been reported. The as-synthesized material was fully investigated morphologically and structurally by X-ray diffraction (XRD) analysis, field emission-scanning electron microscopy (FE-SEM), Fourier transform infrared (FTIR) and UV diffuse reflectance spectroscopy (UV-DRS). The morphology of the as-synthesized CoFeTiO2 appeared to be more dispersed, porous and uniform. The UV-DRS analysis showed that the band gap of the as-synthesized TiO2, FeTiO2, CoTiO2, CoFeTiO2 was measured as 3.31, 3.22, 3.15 and 3.04 eV, respectively. The pilot scale experiments were conducted in a simple non-concentrating solar photoreactor by using the as-synthesized CoFeTiO2 having total volume of 5 L. To synergize the photocatalytic process the photocatalytic reactor was added with peroxymonosulfate (HSO5−). The effect of various process parameters like [HSO5−]0, flow rate and [CoFeTiO2]0 were optimized. The assessment of degradation products (DPs) of OFL and then their toxicity analysis suggested the as-synthesized CoFeTiO2 provides a safe route for the solar light induced photocatalytic degradation of OFL. The as-synthesized Co-FeTiO2 was also applied as novel peroxidase mimetic that can catalyze 3,3′,5,5′-tetramethylbenzidine (TMB) when H2O2 serves as oxidant. The results showed that the color response and the peroxidase like response of CoFeTiO2 highly rely on the concentration of H2O2 and thus the as-synthesized material can successfully be applied for the calorimetric sensing of H2O2.