CO2-responsive functional cotton fibers decorated with Ag nanoparticles for “smart” selective and enhanced dye adsorption

Novel Ag nanoparticles (NPs) decorated CO2-responsive cotton fiber (PCCF@Ag) as eco-friendly adsorbent was prepared via in-situ growth of Ag NPs on the poly(2-(dimethylamino) ethyl methacrylate-co-4-acryloyloxybenzophenone) coated cotton fiber. The as-prepared PCCF@Ag displayed excellent adsorption performance toward both anionic and cationic dyes with or without CO2 stimulation, even under a wide range of pH from 3 to 11. The maximum adsorption capacities of the as-prepared PCCF@Ag toward anionic dye (1538.5 mg g-1 for MO) and cationic dyes (944.0 mg g-1 for MEB and 415.6 mg g-1 for NR) were satisfactory. The adsorption processes were described better by the Langmuir isotherm and pseudo-second-order kinetic models, respectively. Notably, upon CO2 stimulation, the PCCF@Ag exhibited significantly enhanced adsorption capacity toward anionic dyes, following ultrafast adsorption rate, which made the PCCF@Ag could selectively adsorb anionic dyes from mixture because of greatly different adsorption rates between anionic dyes (adsorption equilibrium within 2 min) and cationic dyes (adsorption equilibrium over 12 h). Additionally, the PCCF@Ag could maintain over 91.0% of adsorption capacity even after ten cycles, indicating its outstanding reusability. Meanwhile, the as-obtained PCCF@Ag exhibited excellent antibacterial activity. Overall, the as-obtained PCCF@Ag could be considered as a promising dye scavenger for wastewater remediation.