Influence of pH on the degradation kinetics of nitrophenol isomers in a heterogeneous photocatalytic system

Comparison of several advanced oxidation processes for the decolorization of Reactive Red 120 azo dye in aqueous solution

“…Maximum decomposition with 90% was observed at pH 3. Degradation of organic compounds exhibited different behaviors depending on pH studied [29][30][31]. The zero point charge pH (pH zpc ) for anatase TiO 2 used in this study was around pH ≈ 4 [31,32].…”

Photodegradation of toluic acid isomers by UV/TiO2

“…At pH values of under 4.88, the quantity of HO 2 · increased with decreasing pH, accelerating the reactions and the production of OH radicals. Several investigations have also found that the reaction rate of UV/TiO 2 increased as the pH decreased [3,8,13]. Various reaction mechanisms, including the attack by OH radicals, direct oxidation by positive holes and direct reduction by electrons are responsible for the photodegradation of organic compounds.…”

Separation and Purification Technology

“…It is speculated that the intermediates may compete with salicylic acid for activation sites on the surface of the photocatalysts, thus hindering the photocatalytic degradation. Augugliaro et al [10] investigated the use of photocatalytic procedure to deal with nitrophenol isomers aqueous solution and indicated that higher initial concentrations of nitrophenol isomers lead to lower decomposition rates. Qamar et al [11] indicated that as the initial concentrations of the dye increases, the color of the irradiating mixture becomes more and more intense which prevents the penetration of light to the surface of the catalyst.…”