Activated Carbon Nanofiber Production for the Removal of Pollutants

In the present work, activated carbon nanofibers were produced in three steps consist of electrospinning of Polyacrylonitrile solution in dimethyl formamide as a precursor, stabilization of the electrospun web and simultaneous carbonization and physical activation of the stabilized nanofibers in N₂ atmosphere. In each step, the optimum conditions were selected by changing the effective parameters. In electrospinning process, parameters including concentration, applied voltage and feeding rate on precursor diameter and final webs uniformity were studied by SEM. The effects of stabilization parameters such as temperature, dwelling time and heating rate on the extent of stabilization reaction were evaluated using FTIR and DSC techniques. Porosity and surface structure of the produced activated carbon nanofibers were analyzed using nitrogen adsorption measurements. Results revealed that specific surface area, porosity and total pore volume of obtained activated carbon nanofibers enhanced during the physical activation. Increasing the activation temperature from 800 to 1200􀔨 caused porosity and pore volume development up to 60% and 0.532 cm³/g, respectively. Results also showed that activation temperature of 1200􀔨 for one hour leading to the desirable specific surface area of 840m²/g. Pore width of all samples was calculated about 0.7 nm confirming micro-porous structure of produced PAN based activated carbon nanofibers. Comparing dye adsorption for different adsorbents included chitin, powder activated carbon and the produced activated carbon nanofiber showed the highest efficiency for the later.