Effect of Preparation Process on the Physicochemical Properties of Activated Carbon Prepared from Corn Stalks

Abstract

The preparation of activated carbon (AC) from agricultural and forestry wastes is one of the effective methods for resource utilization. In this study, AC was prepared from corn stalk (CS) by pyrolysis, one-step activation, and two-step activation to determine the optimum preparation method. Based on this, a single-factor design was used to investigate the influence of activating agents (KOH, NaOH, KOH/NaOH), activation temperatures (600, 700, 800 °C), and activation times (60, 90, 120 min) on the physicochemical properties of AC. The physicochemical properties of AC were characterized by Thermal gravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Cyclic voltammetry (CV). The results showed that the AC obtained by the one-step activation method (KOH, 800 °C, 120 min) exhibited a rich pore structure and excellent electrochemical properties (Ipa = 159.8 μA, Ipc = −169.5 μA). However, for the two-step activation method, the AC exhibited a poor pore structure and electrochemical properties (Ipa = 130.8 μA, Ipc = −129.9 μA). In addition, one-step activation provides high-quality AC in a shorter activation time than two-step activation.