Preparation of grape branch-derived porous carbon by one-step blending and its multifunctional applications

Abstract

In this study, an innovative methodology is presented for the rapid one-step synthesis of carbon materials with high specific surface area through doping and activation processes, utilizing ball milling techniques to reduce the particle size of the materials effectively and to achieve activation and doping. Nitrogen-doped grape branch carbon (NGBC) was characterized by abundant micro- and mesoporous structures with specific surface areas up to 1364 m2/g and high nitrogen content (atomic fraction of 4.89 %). At pH 8 and room temperature, NGBC showed excellent adsorption performance for malachite green (MG, a cationic dye) and reactive blue 19 (an anionic dye) with adsorption capacities of 409.91 mg/g and 213.36 mg/g, respectively, and the material can be reused several times. The analysis of adsorption kinetics revealed that multiple factors controlled the adsorption process of NGBC on MG, and the analysis of adsorption isotherms showed that the adsorption process was mainly monomolecular layer adsorption. Compared with the common carbon-based adsorbents for biomass currently available on the market, NGBC showed better adsorption efficacy, indicating its great potential for practical application. Further, when NGBC was applied to electrochemical performance tests as supercapacitor electrodes, the introduction of nitrogen significantly improved the specific capacitance and ion transport properties of the porous carbon material, effectively reducing the electrical resistance. At a current density of 0.5 A/g, the nitrogen-doped porous carbon showed a specific capacitance of 258.4 F/g, much higher than that of the undoped 136.8 F/g, as well as a high specific capacitance retention of 90.43 % after 5000 cycles. The sensitivity analysis points out that nitrogen source and labor expenditure are the key factors in the cost components. This research not only provides a simple method for industrialized recovery and reuse of grape branches, but also lays an experimental and theoretical foundation for promoting further applications of biomass waste in the fields of water purification and supercapacitor electrode materials.