Construction of lysine-functionalized flexible porous carbon nanofiber membrane for high-efficiency formaldehyde adsorption

Porous carbon materials are widely used in adsorption and catalysis due to their highly adaptable pore structures and high specific surface areas. Nevertheless, porous carbon materials still face the bottleneck problem of mechanical strength and flexibility. Herein, we construct a porous carbon nanofiber membrane composed of beaded fibers and traditional straight fibers, demonstrating exceptional flexibility and efficient formaldehyde adsorption performance. Specifically, we regulate polyacrylonitrile solutions with different concentrations via a dual-nozzle electrospinning technique, followed by using controllable pre-oxidation and carbonization progress, obtaining flexible carbon nanofiber material with a hierarchical micro/mesoporous and beaded network structure. The softness of porous carbon nanofiber membrane is comparable to nonwoven fabrics and significantly lower than tissue paper, and it goes through 1000 buckling cycles at 50% deformation without damage. Furthermore, dynamic impregnation with lysine endows materials with synergistic physical and chemical adsorption, making its formaldehyde adsorption capacity reached 3.44 mg/g under ambient conditions, which shows great performance improvement compared with unimpregnated materials (0.8 mg/g). In this sense, this material overcomes the traditional trade-off between rigidity and adsorption performance in carbon materials, offering a possible solution for indoor formaldehyde purification.