The Preparation Of PAN Composite Activated Carbon Fibers And Its Adsorbing Performance Of Low Concentration SO₂

With high specific strength, high specific surface area and other features, Polyacrylonitrile (PAN) activated carbon fiber is paid more and more attention. Compared to other fibers, the polyacrylonitrile (PAN) based carbon fibers showed excellent performance, especially in the air in low concentration of sulfur dioxide adsorption. The PAN composite carbon fiber was prepared by electrostatic spinning method. Through scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), thermogravimetry and derivative thermogravimetry (TG-DTA), BET, we analysis the surface and structure of the PAN fiber, pre-oxidation fiber, and the carbonized fiber after activation. We test the adsorption properties of the prepared compound activated carbon fiber by used simulation sulfur dioxide gas. The adsorption rate was studied under different experimental conditions.The results show that the best spinning conditions for the PAN/TBT compound activated carbon fiber are:The spinning solution concentration is16%, the spinning voltage is18kV, and the receiving distance is30cm. Through TG-DTA analysis, we obtained the pre-oxidation and carbonization temperature and time are list as follow:The pre-oxidation temperature of PAN/TBT fiber is280℃, the pre-oxidation time is2h, the carbonization temperature is600℃, and the carbonization time is5h. The optimal spinning conditions of PAN/PVP composite fiber are:The spinning solution concentration is14%, the spinning voltage is16kV, the receiving distance is25cm, the pre-oxidation temperature is280℃, pre-oxidation time is2h, carbonization temperature is560℃, the carbonization time is4h. After impregnate in H3PO4(1mol/L) for12h, these two carbon fiber was activated in CO2atmosphere at700℃. X-ray diffraction (XRD), Fourier transforms infrared (FTIR) analysis showed that the anatase TiO2of PAN/TBT composite fibers after carbonization at600℃and the rutile type appeared at650℃.After carbonization and activated, the structure of PAN/PVP composite fibers gradually transform into a stable structure of turbostratic. The obtained activated carbon fibers were characterized by BET analysis. The results were that the specific surface area of PAN/TBT-ACF and PAN/PVP-ACF were1042m2/g and1149m2/g. The microspore volume proportion was more than90%in both of the ACF.This article is based on the application of fuel cell, so according to the PEMFCs conditions, we select the adsorption temperature as60℃, the SO2as35mL/min. We investigate the adsorption property of the two activated carbon fibers. The results show that the adsorption rate of PAN/TBT-ACF and PAN/PVP-ACF both increase as the SO2concentration increase, and the adsorption rate get to saturation at0.8μg/mL. The adsorption rate increase gradually and reached saturation at25mm as the adsorption column height increase. With the temperature increasing, the adsorption rate of ACF gradually decrease, but the decline is not obviously at60℃.