O−n−S self-doped hierarchical porous carbon synthesized from lotus leaves with high performance for dye adsorption

Abstract

Three-dimensional porous carbon was fabricated using lotus leaves as a renewable precursor. The as-synthesized carbon had a high surface area (3601 m2/g), suitable O−N−S self-doping, and three-dimensional (3D) architecture with interconnected micro/meso/macropores, together with proper pore size distribution. Consequently, these admirable features endowed porous carbon as a superadsorbent for dye removal with ultrahigh adsorption capacity for rhodamine B (9444.39 mg/g) and reliable cyclability (>97% capacitance retention after 10 cycles). The adsorption of dye onto the as-prepared carbon was a spontaneous endothermic process and followed the pseudo-second-order kinetic model and the Langmuir isotherm model. The π−π stacking, hydrogen bond, and acid−base interactions were proposed to mainly account for the combination of the adsorbate and the adsorbent. Overall, these values indicated the high-performance biomass-derived carbon as a dye adsorbent and may boost the large-scale production and application of 3D hierarchical porous carbon with heteroatom doping in the field of wastewater treatment.