Elucidating the porous and chemical structures of ZnCl2-activated polyacrylonitrile on a fiberglass substrate

Abstract

ZnCl₂-activated polyacrylonitrile (PAN) coated onto a fiberglass substrate was prepared in N₂ at 450 °C. The porous and chemical structures were characterized by using N₂ adsorption at 77 K, XPS, FTIR, competitive adsorption of CO₂/CH₄ and the adsorption of Cs⁺, Sr²⁺ and Ag⁺. The activated PAN displays a high BET surface area up to 1012 m² g⁻¹, a broad mesopore size distribution as well as a major micropore size distribution. Up to 19.3 wt% of nitrogen, which is probably in the form of pyridinic and pyrrolic structures, is incorporated in the chemically activated PAN. HCl uptake results show that such a material has a higher amount of weakly basic functional groups compared to a commercially available ACF15. The activated PAN also exhibits a higher selectivity coefficient for CO₂/CH₄ at STP and higher adsorption amounts for Cs⁺, Sr²⁺ and Ag⁺ than ACF15. It is proposed that nitrogen-containing, weakly basic functional groups positioned on the suitable-sized pore walls improve the adsorption ability of the activated PAN toward CO₂, Cs⁺, Sr²⁺ and Ag⁺.