Trinitrotoluene (TNT) is one of the most widely used compounds in civilian industries like mining, dyes, and photographic chemicals, etc. During the TNT production, some undesired nitrotoluenes are present. The use of vacuum technology has been effective in separating and purifying nitrotoluene impurities. One of the effective methods in purifying TNT compounds is the use of an ejector, which, by creating a vacuum as well as ultrasonic conditions, makes it possible to separate the impurities. Thus, the objective of the present research is to use a special design obtained from coding and optimization of the device geometry to remove and purify nitrotoluene compounds. The effect of different parameters (primary pressure on mass flow rate of primary and secondary flows, isentropic efficiency coefficients on mass flow rate of fluids, constant area section to throat cross section, exit diameter of primary nozzle to throat diameter, and primary fluid temperature) on ejector  performance was investigated. The CFD tool and COMSOL Multiphysics software 5.6 were used to simulate the ejector and to validate the data. In the second part of the simulation, DWSIM software was used to ensure that the use of these operating conditions is applied to purify nitrotoluene compounds. The results showed that the ejector at very low pressures and high temperatures could concentrate TNT in crude TNT (84 wt%) to 98.45 wt% in the final product.

Background: Trinitrotoluene (TNT) is one of the most well-known and oldest explosive agents. In the recent decade, bioenvironmental, biochemical, and biological effects of TNT exposure have been more in the spotlight. In this study, we aimed to evaluate spirometric parameters in workers of a TNT factory exposed to TNT and other related fumes and dusts compared with the unexposed controls.Methods: In this case-control study, spirometry was done for TNT factory workers (cases) and matched healthy controls, and their results were compared with each other. Matched controls were selected from workers who worked in the same geographic area without any history of TNT or other chemical materials exposure. Spiro metric studies were done during the early hours of day.Results: Overall, 90 subjects (47 TNT exposed cases and 43 controls) were included. The two groups showed no significant difference in demographic characteristics and smoking habits. In spirometry, it was found that the cases had significantly lower forced vital capacity (91.4 ± 13.7% vs. 100.2 ± 13.0%, P = 0.002), forced expiratory volume in 1 second (98.0 ± 14.9% vs. 104.7 ± 12.5%, P = 0.024) and peak expiratory flow (98.4 ± 17.3% vs. 107.9 ± 21.7%, P = 0.025) compared with controls. According to spirometric findings, 10 cases (21.3%) and no controls had restrictive pattern, which means TNT factory workers had 1.27 (CI: 1.09-1.47, P = 0.001) fold risk for development of restrictive patterns.Conclusion: Chronic exposure to TNT or prolonged working in TNT factories may predispose the workers to respiratory disorders. In addition to regular screening programs, preventive measures and devices should be considered for TNT factory workers to reduce the harms.

Soil contamination with TNT is a serious environmental hazard due to the toxic and mutagenic effects of TNT. Bioremediation is an environmentally safe method in the treatment of explosive-contaminated sites. In the present research, after selection of superior bacteria in the aqueous phase, bioremediation of TNT contaminated clay soil at 1000 mg/kg was performed in slurry phase, which resulted in a maximum TNT removal of 89% after 15 days. Afterwards, the effects of operational and environmental factors were examined via the two-level fractional factorial design method (27-3IV) for seven factors, i.e., glucose (2, 8 g/l), yeast extract (0, 0.2 g/l), (NH4)2 SO4 (0.1, 0.5 g/l), Tween 80 (1, 5 g/l) and slurry concentrations (20, 40% w/v) as well as inoculum size (5, 10% v/v) and temperature (20, 35oC). Among these factors, significant factors were found to be slurry, surfactant and glucose concentrations as well as inoculum size. In addition, considerable interactions were observed between glucose and the other significant factors.