Synthesis of hierarchical porous carbon sphere via crosslinking of tannic acid with Zn2+ for efficient adsorption of methylene blue

Abstract

Hierarchical porous carbon spheres (HPCS) were synthetized utilizing tannic acid as biomass source and Zn2+ as cross-linking agent. Metal Zn2+ prove to be pivotal in the preparation of materials, which can promote the formation of spherical structure and make materials have both micropores and mesopores. The adsorbent has regular spherical shape, specific surface areas of>1000 m2/g, the maximum adsorption capacity (qmax) of methylene blue is 697 mg/g. It has stable adsorption performance in a broad pH environment (3–11), and the methylene blue removal remains at 91.9% after five cycles. The hierarchical porous structure is beneficial to the immobilization process of methylene blue, and hydrogen bonding, π-π interaction and electrostatic attraction are the main forces for the immobilization of methylene blue. This research offers a promising way for the exploration of biomass-based materials for efficacious dye removal.