Adsorption Study Of Benzene And Toluene Using PAN Activated Carbon Fibre

In this study,characterization and adsorption kinetics of PAN ACF for gas streams containing benzene and toluene was carried out.Bought pre-oxidized PAN was physically activated using carbon dioxide gas.Activation methods were altered to try and find the optimal conditions for obtaining the highest yield,and the biggest surface area for the adsorption/desorption studies.Carbon fibres carbonized at a heating rate of 15?/min to 1000? then activated at 1000? for 100 minutes emerged victorious as they had a higher average of percentage yield and surface area.Surface Characterization of the activated PAN was carried out using different spectroscopic techniques.This included SEM,FTIR,XPS and BET techniques.The surface area study was done using the BET method.The SBET values were found to be in the range of 1750-600 m2/g.From N2 adsorptions isotherm it was clear that a uniform pore size and distribution was achieved during the activation process.A closer look at the surface morphology was achieved with the use of SEM;it was used to show magnified surfaces of the activated carbon revealing the increased surface porosity which was achieved after activation.PAN ACF are expected to have amine and nitrile functional groups on the surface;this was confirmed by use of the FTIR and XPS spectroscopic methods.From the FTIR spectra of both pre-oxidized PAN and PAN ACF,the peaks at the wavelength of 2500-2000 cm-1,1400 cm-1 which are all associated with either amine or nitrile groups were present.The presence and concentration of Nitrogen,carbon,oxygen elements was done using XPS for both Pre-oxidized and PAN ACF.The atomic percentage concentration of carbon and nitrogen was found to increase after physical activation of PAN while the oxygen concentration decreased.The activated carbon fibre was then used for adsorption/desorption studies of gas streams containing benzene and toluene.From the breakthrough experiments PAN ACF was found to have better adsorption capacity for benzene and toluene compared to a bought viscose ACF material.PAN/ACF with higher surface area,pore volume and a bigger pore diameter were found to be more effective for VOCs adsorption.For desorption studies the adsorbent was heated on a heating plate for an hour at 300?.The filters were recycled 3 times and from the experimental result,the regeneration technique was very effective because the breakthrough time and adsorption capacities did not deviate much from the first run.