Modification of polymer based activated carbon with chemical vapor deposition and graphitization methods: İnvestigation of its applications

In this study, polymer-based spherical activated carbons with different surface areas and pore structures were synthesized using the suspension polymerization method. Carbon molecular sieves (CMS) were produced from polymer-based spherical activated carbon with a surface area of 1984.0557 m2/g, a total pore volume of 1.7206 cm3/g and an average pore diameter of 34.688 Å using the chemical vapor deposition method. The factors affecting CMS production (deposition temperature, methane flow rate and deposition time) and their levels were optimized with the Face Centered Composite Design (FCCD) experimental design method, using N2 isotherms. While CMS1 had the highest N2 adsorption capacity among the CMSs produced, CMS8 had the most pyrolytic carbon accumulated in its pores. When both the N2 isotherm and SEM images of CMS8 were examined, it was determined that the material was heterogeneous, possesing both micro and meso pores. In the other part of the study, graphitic carbon (GK) was produced by graphitization of polymer-based spherical activated carbon with a surface area of 952.7325 m²/g, a total pore volume of 0.3893 cm³/g, and an average pore diameter of 16.345 Å. Initially, studies were conducted under atmospheric pressure and vacuum to determine the effect of pressure on graphitization, and after examining the N2 isotherms of the obtained GKs, it was decided to continue working under vacuum. Subsequently, in a vacuum environment at a constant temperature (1750 °C), graphitization durations of 10 and 20 hours were tested, while the 5-hour duration was found to be sufficient for minimal impact on graphitization as determined from the N2 isotherms. Therefore, to reduce production costs, the 5-hour graphitization period was selected. Finally, GK production was carried out at 1000, 1250, 1500, and 1750 °C to determine the effect of temperature on graphitization. BET, SEM, and RAMAN analyses of the produced GKs indicated that graphitization was higher at 1750 °C. Thus, the adsorption and desorption studies of BTEX (Benzene, Toluene, Ethylbenzene, Xylene) were performed using TD-GC-MS (Thermal Desorption-Gas Chromatography-Mass Spectrometry) on the GK-V-5-1750 sample obtained at 1750 °C for 5 hours in a vacuum, and the results revealed that the GK-V-5-1750 product had similar properties to the commercial material Tenax®.