Optimization and evaluation of the efficiency of sono-Fenton and photo-Fenton processes in the removal of 2, 4, 6 trinitrotoluene (TNT) from aqueous solutions

Abstract

The adverse health effects of trinitrotoluene (TNT) include allergies, liver and blood damage, and carcinogenesis. The present study aimed to optimize the sono-Fenton and photo-Fenton processes for the removal of TNT from aqueous solutions. TNT removal was evaluated at various pH (acidic, neutral, and alkaline), pollutant concentrations (10, 30, 50, 100, and 120 mg/l), H₂O₂ concentration (10-80 mM), and ferrous ions (0.5-4 Mm). After the optimization of the parameters, the appropriate UV irradiation time and optimal time of ultrasonic waves were determined for the removal of this compound. TNT concentration was measured using high-performance liquid chromatography. Increased hydrogen peroxide from 10 to 40 mMole/l led to higher TNT degradation (45.3% to 88.4% and 40 to 80 mMole/l), while the removal rate decreased from 88.4% to 79%. At the optimal H₂O₂ concentration, increased pH (3±0.2 to 11±0.2) decreased TNT decomposition from 88.4% to 23.5%. In addition, increased time (5 to 60 minutes) led to the higher photo-Fenton process efficiency (68.6% to 89%). The maximum photo-Fenton efficiency was achieved in optimal conditions at the TNT concentration of 10 mg/L (97%) and 60 minutes, while the efficiency of the sono-Fenton process in optimal conditions was 100% at 20 minutes. Therefore, it was concluded that the sono-Fenton process was effective in the removal of TNT.