Solar Photocatalytic Degradation of Typical Indoor Air Pollutants Using TiO2Thin Film Codoped with Iron(III) and Nitrogen

Shuaijie Wang,Xingxing Cheng

doi:10.1155/2015/259829

Abstract

A type of iron and nitrogen codoped titania thin film was prepared by sol-gel method to degrade three typical indoor air pollutants: formaldehyde (HCHO), ammonia (NH3), and benzene (C6H6) under solar light. X-ray diffraction (XRD), UV-Vis spectroscopy, and energy dispersive spectra (EDS) were employed to characterize the photocatalysts. The results showed that the Fe/N codoped TiO2had a stronger absorption in the visible region than pure, Fe-doped, and N-doped TiO2and exhibited excellent photocatalytic ability for the degradation of indoor HCHO, NH3, and C6H6. When the three pollutants existed in indoor air at the same time, the removal percentages of HCHO, NH3, or C6H6after 6 h photocatalytic reaction under solar light reached 48.8%, 50.6%, and 32.0%. The degradation reaction of the three pollutants followed the pseudo-first-order kinetics with the reaction rate constants in the order of 0.110 h−1for ammonia, 0.109 h−1for formaldehyde, and 0.060 h−1for benzene. The reaction rate constant decreased with the increase of initial reactant concentration, which reflected that there was oxidation competition between the substrate and its intermediate during the photocatalytic process.

Highlights

Indoor air quality within buildings has been paid great attention, since many metropolitans generally spend more than 80% of time in indoor environment [1]
A new solar photocatalyst, TiO2 thin film codoped with iron(III) and nitrogen, was developed with flat glass as carrier to degrade three typical indoor air pollutants, formaldehyde, ammonia, and benzene, under solar light
Formaldehyde, ammonia, and benzene exist in the indoor air at the same time usually, so the kinetics of photocatalytic reaction was studied with the experimental data of mixed pollutants over the Fe/N codoped TiO2 thin film

Summary

Introduction

Indoor air quality within buildings has been paid great attention, since many metropolitans generally spend more than 80% of time in indoor environment [1]. In the enhancement of the photoresponse of TiO2 from ultraviolet to the visible range without decreasing photocatalytic activity, the modification to titania by doping with metal or nonmetal has been considered as one of the most promising methods [10,11,12,13,14,15]. Zhao et al prepared the B-Ni codoped photocatalyst using the modified sol-gel method They pointed out that incorporation of B into TiO2 could extend the spectral response to the visible region and that Ni doping could increase greatly the photocatalytic activity [21]. A new solar photocatalyst, TiO2 thin film codoped with iron(III) and nitrogen, was developed with flat glass as carrier to degrade three typical indoor air pollutants, formaldehyde, ammonia, and benzene, under solar light. The research finding provides a feasible way for enhancement of indoor air quality

Experimental Procedure

Results of Characterization

Photocatalytic Experiment

Conclusions