Design of microwave-supported activated carbon derived from lentil processing residual for efficient heavy metals adsorption and supercapacitor applications

In this study, the re-evaluation of lentil processing residual (LPR) in the form of microwave-supported activated carbon (LPRAC) and its use as a potential sorbent for the removal of Co2+ and Mn2+ heavy metals and also as a supercapacitor electrode material is presented. The differential thermogravimetric analysis (TG-DTA), BrunauerEmmett-Teller (BET) analysis, scanning electron microscope (SEM), energy dispersive X-ray (EDX) spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and cyclic voltammetry methods were employed to analyze thermal feature, specific surface area, surface morphology, surface functional groups, and electrochemical behavior, respectively. During adsorption, the maximum uptake capacities were 145.5 and 300.56 mg/g for Co2+ and Mn2+, respectively. In a supercapacitor, the LPRAC electrode has a capacitance of 187.65 F/g and a capacitance retention of 92 % at 0.04 A/g after 1000 cycles. The superior adsorption and electrochemical performance of LPRAC indicates that this material can be a strong candidate for both wastewater treatment and energy storage applications.