Removal of Trinitrotoluene with Nano Zerovalent Iron Impregnated Graphene Oxide

Nano zerovalent iron (nZVI) impregnated reduced graphene oxide (nZVI-rGO) hybrid was prepared via gaseous hydrogen reduction of anhydrous iron(III) chloride (FeCl3) on the surface of thermally exfoliated reduced graphene oxide (rGO) nanosheets without using any toxic reducing agent, surfactant, or stabilizing agent. Characterization of prepared samples was carried out using various techniques. Morphological study showed that prepared rGO possesses a fewlayered wrinkled paper-like structures and nZVI particles of similar to 30 nm size were homogeneously dispersed on the surface of rGO nanosheets. Fourier transform infrared (FTIR), X-ray diffraction (XRD), and energy dispersive X-ray spectrometry (EDS) analyses indicated that oxygen-containing functional groups decreased in the order of graphite oxide (GO) > rGO > nZVI-rGO. Removal studies of trinitrotoluene (TNT) were carried out using graphite (G), GO, rGO, and nZVI-rGO with the aid of high-performance liquid chromatography (HPLC). Kinetic models were applied to establish the rate and mechanism of adsorption of TNT on different adsorbents, and intraparticle diffusion model based on initial adsorption characteristics was employed to ascertain mechanism of film and intraparticle diffusion in the adsorption process. The removal rate and adsorption capacity was found to be highest for nZVI-rGO, which renders this adsorbent to be a potential futuristic adsorbent for removal of explosives.