High surface area mesoporous carbon from black cumin (Nigella sativa) processing industry solid residues via single-stage K2CO3 assisted carbonization method: Production optimization, characterization and its some water pollutants removal and supercapacitor performance

In this study, solid residues (BR) from the black cumin (Nigella sativa) processing industry, an abundant and sustainable raw material, were converted into high surface area mesoporous activated carbon (AC) under optimum production conditions using a single-stage K2CO3 assisted carbonization method. The optimal AC (BRAC) which had the highest BET surface area (2211 m2/g), total pore volume (1.262 cm3/g), and mean pore diameter (2.8 nm) was achieved in the conditions of a K2CO3 impregnation ratio of 1:1, a carbonization temperature of 900 °C, and a carbonization period of 1 h. To test its adsorption performance from the aqueous phase, methylene blue dye, oxytetracycline antibiotic, and lead metal ions were selected as model water pollutants and found to be 714.3, 833.3, and 500.0 mg/g, respectively, at 25 °C Also, the electrode made of BRAC showed electrochemical capacitor performance with a high gravimetric capacitance (210 F/g) and cyclic stability (95 %). [Display omitted] •Carbonization at 900 °C for 1 h and a 1:1 impregnation ratio were found as optimal conditions.•The effective process variable was found to be the impregnation ratio.•An AC with a BET surface area of 2211 m2/g and a mesopore fraction of 60.2 % was produced.•The maximum sorption capacity for MB, OTC, and Pb(II) was found to be 714.3, 833.3, and 500.0 mg/g, respectively.•A supercapacitor with high gravimetric capacitance (210 F/g) and cyclic stability (95 %) was produced.