Application of Sunlight for Treatment of Crystal Violet Dye by Fenton-Like and Photo-Fenton-Like Effect of Operating Parameters

Abstract

The dyes are considered as one of the biggest sources of water pollution. Degradation of these compounds have to be carried out via, AOT's (Advanced Oxidation Technologies) due to their weak biodegradation or their high persistent in different compartments of the environment. The aim of this study is to test direct photodegradation and some advanced oxidation technics (AOTs) in absence of light (Fenton-like) and in its presence (photo-Fenton-like /UV and photo-Fenton-like/Solar ) to obtain a total decolorization and mineralization of an cationic dye in aqueous solution: the Crystal Violet  (CV).The degradation rate is strongly dependent of hydrogen peroxide dose, pH,potassium monopersulfate concentration and light source. Best operatory conditions were found to be pH of 3, hydrogen peroxide concentration was 0.5mM,oxone concentration was 10^-1M and artificial light (254 nm).The reaction efficiencies have been compared for the same system .The obtained results showed that color removal followed the increasing order: photolysis/UV (5.3%) < photolysis/Solar (15.7%) < (Fe(III)/H₂O₂ (19.4 %) <Fe(III)/ H₂O₂/sunlight (62.5%) < Fe(III)/ H₂O₂/UV_254nm (72.3%) < Fe(III)/ H₂O₂/Oxone/UV_254nm (99%) with a reaction time of 30 minutes. The efficiency of substrate mineralization in each process has been discussed by total chemical oxygen demand content of CV solutions.