Graphene oxide fibers, production, characterization and utilization on the adsorption of sulfur dioxide

Fossil fuel combustion and other industrial activities cause the emission of sulfur dioxide (SO2) gas. SO2 is an air pollutant gas and a very toxic for human health and nature. Hence, cleaning of this harmful gas is an important issue. Graphene which is two-dimensional material has excellent mechanical, chemical, thermal properties, and many application areas such as energy storage devices, gas adsorption, sensing devices, and optical electronics. Further, graphene oxide (GO) is examined as a good adsorbent because of its important features such as functional groups (epoxy, carboxyl and hydroxyl) on the surface and layered structure. As a fiber form, the SO2 adsorption properties of the fibers are usually investigated on carbon fibers. This thesis seeks to investigate the adsorption capabilities of graphene oxide fibers. For this purpose, graphene oxide was produced primarily by Hummers method and graphene oxide fiber were synthesized by the wet spinning method.To see the different effects, reduction process by hydrazine hydrate, activated carbon addition, poly(vinyl) alcohol (PVA) coating and single coagulation bath application were tried on GO fibers. Monitoring of the morphology of GO fibers was carried out by SEM and AFM, also other qualitative and quantitative analyses like XRD, FTIR, Raman, conductivity and tex number were performed. TGA was used characterize the thermal properties of fibers and most importantly the surface areas of fibers were calculated by BET analysis.It has been seen that process parameters such as dispersion preparation method, pH value of dispersion, the content of coagulation bath, reduction process, and additional materials affect the final properties of graphene oxide fiber. Nonwoven based structure produced by GO fibers has an SO2 adsorption capacity itself, approximately 310-320 mg SO2/1 g of sample. However nonwoven structure produced by activated carbon doped GO fiber has 3 times higher SO2 adsorption capacity than reference GO fiber.In accordance with adsorption capacity results, activated carbon doped sample has higher BET surface area.