Comparison of simple ozonation and direct hydrogen peroxide processes in TNT removal from aqueous solution

Abstract

Oxidation of 2,4,6-trinitrotoluene (TNT) using simple ozonation and direct hydrogen peroxide was studied. An analytical method based on the HPLC (high performance liquid chromatography) system was used for TNT detection. The influence of parameters such as pH of the solution (3-10), initial TNT concentration (10-100 mg/L), dosage of ozone (0.2-1 g/hr), H2O2/TNT molar ratio (250-1,000), and reaction time (15-60 min) on TNT degradation ratio were investigated. Maximum TNT degradation efficiency occurred at pH = 10, initial TNT concentration = 20 mg/L, dosage of ozone = 1 g/hr in simple ozonation (90), while this amount was obtained in H2O2 oxidation process with pH = 3, initial TNT concentration of 10 mg/L and H2O2/TNT molar ratio = 1,000/L. The results of kinetic experiments were shown to follow pseudo-second reaction. It can be recommended that simple ozonation seems to be the best at TNT degradation from aqueous solution. However, low TNT concentration could be reduced by performance of the hydrogen peroxide process, in which case, a longer reaction time is also required.