Hierarchical porous activated carbon fibers with a BET surface area of 2231 m² g⁻¹ and a pore volume of 1.16 cm³ g⁻¹ were made from polyacrylonitrile through pre-oxidation and chemical activation. This type of material contains a large amount of nitrogen-containing groups (N content > 8.1 wt%) and consequently basic sites, resulting in a faster adsorption rate and a higher adsorption capacity for CO₂ than pure carbon materials with analogous structures under the same conditions. Moreover, its adsorption capacity for CO₂ was more than 3.3-times higher than that for N₂. In particular, it showed a much higher CO₂ adsorption capacity than zeolite 13X, which is conventionally used to capture CO₂, in the presence of H₂O.

Bimodal mesoporous carbon nitride is synthesized using Triton X-100 as a template and melamine and glutaraldehyde as precursors through polymerization and carbonization. The structures and surface chemical properties of carbon nitrides are characterized and compared by nitrogen adsorption isotherms, TG, FT-IR spectra and SEM images. The results show that the mesopore sizes in the carbon nitride are centered at 3.8 nm and 10–40 nm. The pyrolysis and decomposition of the polymer to form the condensation cross-linking ring structures takes place at 350–700 °C. The nitrogen atom in the carbon nitride exists in C–N and N–H states. As a Candida rugosalipase immobilization support, the mesoporous carbon nitride displays a higher amount of immobilization and improves the thermal stability of Candida rugosalipase, which still displays higher catalytic activity after 4 runs.

Polyacrylonitrile/lignin sulfonate (PAN/LS) blend fibers were spun via a wet spinning process. The fiber structure, mechanical properties and thermal stability of the precursor fibers were studied by FT-IR, SEM, tensile tester, and TG-DSC. Results indicated that there was no chemical crosslinking between PAN and LS during the process of wet spinning. PAN and LS had good compatibility in the blend fibers. LS could weaken the skin of the blend fibers and reduce the fiber structure defects. The increase of dope concentration could improve the fiber structure and mechanical properties. LS blending with PAN could reduce fiber weight loss in the thermal stabilization process, and most importantly the precursor fibers could be stabilized rapidly without fiber fusion. Through polymer blending and wet spinning, this study provided a promising way to prepare a precursor fiber for carbon fiber.