Photocatalytic Degradation of Aniline Using TiO2Nanoparticles in a Vertical Circulating Photocatalytic Reactor

F. Shahrezaei,A. A. L. Zinatizadeh,A. Akhbari,Y. Mansouri

doi:10.1155/2012/430638

Abstract

Photocatalytic degradation of aniline in the presence of titanium dioxide (TiO2) and ultraviolet (UV) illumination was performed in a vertical circulating photocatalytic reactor. The effects of catalyst concentration (0–80 mg/L), initial pH (2–12), temperature (293–323 K), and irradiation time (0–120 min) on aniline photodegradation were investigated in order to obtain the optimum operational conditions. The results reveal that the aniline degradation efficiency can be effectively improved by increasing pH from 2 to 12 and temperature from 313 to 323 K. Besides, the effect of temperature on aniline photo degradation was found to be unremarkable in the range of 293–313 K. The optimum catalyst concentration was about 60 mg/L. The Langmuir Hinshelwood kinetic model could successfully elucidate the effects of the catalyst concentration, pH, and temperature on the rate of heterogeneous photooxidation of aniline. The data obtained by applying the Langmuir Hinshelwood treatment are consistent with the available kinetic parameters. The activated energy for the photocatalytic degradation of aniline is 20.337 kj/mol. The possibility of the reactor use in the treatment of a real petroleum refinery wastewater was also investigated. The results of the experiments indicated that it can therefore be potentially applied for the treatment of wastewater contaminated by different organic pollutants.

Highlights

Aniline is one of the most toxic pollutants; it is released into the environment after its use in the manufacturing of dyes, rubber, polymers, herbicides, pesticides, fungicides, and pharmaceuticals [1]
Several solutions are proposed in this regard, including adsorption [3], chemical oxidation [4, 5], biological [6], and catalytic wet air oxidation (CWAO) [7]
Most of the studies on aniline decomposition by advanced oxidation processes (AOPs) up to date have not provided in depth on the degradation kinetics which are important scientific information; this study investigated into more details on kinetics of aniline degradation by UV/TiO2 in order to develop the rate equations which can provide fundamental knowledge for future use

Summary

Introduction

Aniline is one of the most toxic pollutants; it is released into the environment after its use in the manufacturing of dyes, rubber, polymers, herbicides, pesticides, fungicides, and pharmaceuticals [1]. Because of its toxic and recalcitrant nature and the wide application of aniline containing chemicals, aniline is considered to be an increasing threat to both the environment and human health. Aniline has aroused great attention and is classified as a persistent organic pollutant by the European Economic Community and US Environmental Protection Agency [2]. There is an urgent need to develop efficient and economical methods to remove this pollutant from wastewater. The main drawback of these techniques relates to the disposal of the spent contaminated activated sludges, the control of the appropriate reaction conditions, low efficiencies and reaction rates, and operation only within a narrow pH range [8, 9]

Methods

Results

Conclusion