Fabrication and Evaluation of Mesoporous Polyvinyl Alcohol Based Activated Carbon Fiber

Polyvinyl alcohol (PVA) based activated carbon fibers (ACFs) with a high mesoporosity were fabricated. The surface area and pore volume distribution could be tailored by carefully controlling the activation temperature and time. A mesopore volume fraction of 0.66 was obtained by activation at 1173 K for 120 min or 1273 K for 90min. Raman spectra indicated that more defective in graphitic structure was found for more mesoporous samples. Adsorption experiments demonstrate that the ACF had good adsorption capacity to both small molecular size iodine and the larger size methylene blue with adsorption capacities up to 1934 and 709 mg/g, respectively. The adsorption kinetics of methylene blue onto the PVA-ACFs was simulated with both pseudo-second-order kinetic model and intraparticle diffusion equation. With an increase of mesopores, the rate limitation from the intraparticle diffusion was dramatically reduced. Consequently, the pseudo-second-order adsorption rate constant reached up to 7 times higher.