Employing UV/H2O2 Process for Degradation of 2,4-Diaminotoluene in Synthetic Wastewater

Background & Aims of the Study: Toluene-2, 4-diamine (TDA) is a famous carcinogenicaromatic amine that is mostly employed as an intermediate in the production of dyes and toluenediisocyanate. In this study, degradation and mineralization of TDA were investigated byUV/H2O2 process.Materials & Methods: This study is an experimental investigation on a laboratory scale. Thestudy was performed on synthetic wastewater that holds TDA. The influence of differentoperating variables such as the initial dosage of H2O2 and TDA, additive salts and pH wasinvestigated. The optimization of variables was done by one factor at a time method.Results: The results specify that the degradation efficiency relies on the H2O2 and TDAconcentrations, so that, reduces as the initial concentrations of TDA are improved, but, itenhances with increasing the extent of H2O2 until an optimum value and then decreases to someextent. The reaction rate significantly reduced with an increase in initial pH value in alkalinesolution, which means hydroxide ions could inhibit the degradation of TDA. The removal timewas increased with an increase in the initial concentration of TDA. The optimal conditions wereobtained at pH of 7, initial concentration of pollutant and hydrogen peroxide at 0.5x10(-3) Mand 3.5x10(-2) M, respectively. At optimum condition, the removal of TDA and ChemicalOxygen Demand (COD) was 97.6 and 43.5%, respectively.Conclusions: The results of this work show that separate UV radiation and H2O2 oxidationprocess can hardly degrade TDA from contaminated water and the UV/H2O2 process can beemployed for complete degradation of TDA. The removal of TDA in UV/H2O2 process followsthe pseudo-first order kinetics and the first order rate constants (k=35.7x10(-3)min(-1) andhalf-life of reaction (t(1/2)=19.4min) were determined.