Advanced Oxidation Processes (AOPs) alternative methods for degradation of toxic pollutants from wastewater

Abstract

The degradation of some toxic pollutants like chlorobenzenes, nitrobenzene and 4-chloroaniline in various advanced oxidation system such as: UV/ H2O2, UV-VIS/Fe-TiO2 and UV-VIS/TiO2/ H2O2 were studied. The influence of working conditions (pH0, H2O2 dose, photocatalyst dose, pollutant initial concentration and irradiation time) on pollutant degradation rate constant and efficiency were investigated. For any studied advanced oxidation systems, pollutant degradation followed a pseudo first order kinetics. The degradation pathway of chlorinated and nitro aromatic pollutants includes initial •OH radicals attack to aromatic ring with hydroxylated intermediates formation, followed by their step by step oxidation up to carboxylic acids. Inorganic ions like Cl-, NO3-, NH4+ are also formed as mineralization products.

Keywords

• chlorobenzene
• nitrobenzene
• 4-chloroaniline
• photocatalyst
• h2o2
• kinetics and pathway degradation