Removal of traces of highly explosive trinitrotoluene from TNT red water by using graphene nanocomposites prepared from solid wastes: an example of circular economy.

The defence munition is primarily composed of high-intensity explosive chemicals such as trinitrotoluene (TNT) and the manufacturing of TNT generates highly intense red-colored effluents consisting of TNT and its derivatives, sulfonates, and nitrobenzene. As of date, there is no comprehensive treatment for TNT red water. In this study, we propose to treat TNT from red water using different graphene nanocomposites, i.e., GN-G and GN-S, synthesized from graphite and sludge, respectively. The sludge used in the preparation of GN-S was obtained from the chemical coagulation of TNT red water using a mixture of organic acid coagulants. Both these graphene nanocomposites (GNCs) were intercalated with iron salts to produce layered GNCs, and by using atomic force microscopy distance between layers was determined. The GN-S showed high surface area and pore volume of 748 m2 g-1 and 0.55 cm3 g-1 respectively. Owing to these textural properties, GN-S have shown adsorption capacity of 242.3 mg g-1 for TNT from TNT red water. The sludge generated during the treatment of TNT red water was utilized for GN-S preparation, which has proven to be an efficient and reusable adsorbent. Furthermore, the process of preparing GN-S and treating TNT red water aligns with the concept of circular economy.