Photo-oxidative degradation of synthetic organic pollutant p-nitrophenol

Abstract

In the present study, photo-oxidation of a hazardous and refractory aromatic compound p-nitrophenol in its aqueous solution by strong oxidizing agent hydrogen peroxide in the presence of UV radiations emitted from UV source is investigated. The UV+H 2O2 combination generates hydroxyl radicals having very high oxidation potential which helps in complete mineralisation of the organic pollutants. The photo-oxidative degradation of p-nitrophenol (PNP) is carried out using two different UV sources, namely an 8 W low pressure mercury vapour lamp and a 125 W medium pressure mercury vapour lamp to evaluate its effect on oxidative degradation. Complete degradation of the substrate and decolourisation are achieved in 5 and 2 h with 8 W and 125 W mercury vapour lamp, respectively. The initial substrate concentrate is kept at 1 x 10 -4 mol/L. The photo-oxidation process is found to be strongly pH dependent.