Photocatalytic Degradation of Phenolics by N-Doped Mesoporous Titania under Solar Radiation

Priti A Mangrulkar,Sadhana S Rayalu,Jyotsna S Meshram,Sanjay P Kamble,Nitin K Labhsetwar,Meenal M Joshi

doi:10.1155/2012/780562

Abstract

In this study, nitrogen-doped mesoporous titania was synthesized by templating method using chitosan. This biopolymer chitosan plays the dual role of acting as a template (which imparts mesoporosity) and precursor for nitrogen. BET-SA, XRD, UV-DRS, SEM, and FTIR were used to characterize the photocatalyst. The doping of nitrogen into TiO2lattice and its state was substantiated and measured by XPS. The photocatalytic activity of the prepared N-doped mesoporous titania for phenol ando-chlorophenol degradation was investigated under solar and artificial radiation. The rate of photocatalytic degradation was observed to be higher foro-chlorophenol than that of phenol. The photodegradation ofo-chlorophenol was 98.62% and 72.2%, while in case of phenol, degradation to the tune of 69.25% and 30.58% was achieved in solar and artificial radiation. The effect of various operating parameters, namely, catalyst loading, pH, initial concentration and the effect of coexisting ions on the rate of photocatalytic degradation were studied in detail.

Highlights

Photocatalysis is a rapidly evolving and efficient technology for purification of water
One step-template-free solvothermal method to synthesize N-doped mesoporous titania microspheres was reported by Chi et al [14], whereby mesoporous spheres were formed by crystallite aggregation from controlled alcoholysis of titania precursor and reacting urea with titania to dope nitrogen in mesostructure
In continuation with our previous work wherein we had reported the photo reduction of methyl orange dye by Ndoped mesoporous titania, we investigated the photo oxidation properties of the synthesized photocatalyst

Summary

Introduction

Photocatalysis is a rapidly evolving and efficient technology for purification of water It plays a vital role in degrading several toxic organic pollutants into less toxic or nontoxic and safe compounds by their partial and/or by their complete mineralization. The preparation of mesoporous titania is reported by using a templating method. Mesoporous titania with visible light absorption ability are promising as efficient photocatalysts. Synthesizing mesoporous titania with nonmetal doping like nitrogen to enhance visible light activity seems to be promising area of research. One step-template-free solvothermal method to synthesize N-doped mesoporous titania microspheres was reported by Chi et al [14], whereby mesoporous spheres were formed by crystallite aggregation from controlled alcoholysis of titania precursor and reacting urea with titania to dope nitrogen in mesostructure. The photocatalyst has shown promising activity in phenol and ochlorophenol photodegradation under visible light

Experimental

Results and Discussion

Effect of Various Parameters on Photocatalytic Degradation

Comparative Evaluation of Photodegradation of Phenolics

Mechanistic Aspects of the Photocatalytic Degradation of Phenolics

Conclusions