Effect of pH, Ions and Ionic Strength on TiO2-mediated Photodegradation of Brilliant Orange

Abstract

The photodegradation of Brilliant Orange (BO), an anionic mono azo dye used in textile and leather industries, was investigated in aqueous
TiO2 suspension under UV irradiation. The effect of pH on degradation rate was investigated. The experimental results indicated that
photocatalytic reaction was favoured in acidic medium. The degradation was minimum at pH 6 which is zero point charge of TiO2. The
effect of different ions and ionic strength on photodegradation was also investigated. Na+, Zn2+, Al3+ and Pb2+ ions were used to see the
cationic effect and NO3
-, CO3
2-, Cl- ions were used to see the effect of anions. Pb2+ ion enhanced the percent degradation 25 times more than
the degradation without it. The effect of ionic strength was studied using different concentrations of Pb(NO3)2 solution. Photodegradation
was found to increase with the increase of ionic strength.