Porous carbon based on polyvinylidene fluoride: Enhancement of CO2 adsorption by physical activation

Global warming has become a crucial issue and various efforts have been made to mitigate the emission of CO2, the most dominant greenhouse gas. Adsorption is considered a promising technology for CO2 capture, and carbon materials are good candidates for CO2 adsorption. In this study, highly porous carbons were prepared from polyvinylidene fluoride by single-step physical activation under CO2 flow at temperatures of 700-950 °C. The effect of activation temperature on the characteristics and CO2 adsorption properties of the prepared porous carbons was studied. Additionally, the dependence of CO2 adsorption capacity on various textural properties was investigated to identify the most important factor that determines CO2 adsorption. Both surface area and pore volume increased proportionally with activation temperature because of the newly produced pores and enlarged pore size within the carbon. Additionally, CO2 adsorption is highly dependent on the volume of pores that are below 0.70 nm in size. Among the samples tested, the porous carbon prepared at 800 °C exhibited maximum CO2 adsorption capacities of 6.05 and 3.84 mol kg−1 at 0 and 25 °C, respectively, besides showing good CO2/N2 selectivity, excellent recyclability, easy regeneration, and rapid adsorption-desorption kinetics.