Influence of furnace atmospheres and potassium hydroxide activation on the properties of bamboo activated carbon and its adsorption towards 4-nitrophenol

Abstract

Bamboo activated carbon (BAC) was synthesized as adsorbent for 4-NP adsorption due to its incredible adsorptive capability that has led it to its popularity. The effect of furnace atmospheres (argon, limited-air, vacuum), carbonizing temperatures (400–600 ℃), and activating temperatures (500–700 ℃) were investigated to achieve the largest surface area (SBET) of BAC. Its properties were analysed by using BET, FTIR, LVSEM, XRD, TGA, and Elemental analysis. The 4-NP adsorption was conducted by varying the pH (3−11), BAC dosages (0.05–0.4 g L-1), and 4-NP initial concentrations (10–100 mg L-1). Consequently, the argon-treated BAC (A67) had the highest SBET (1795.38 m2 g-1), stating that 600 ℃ of carbonizing temperature with 700 ℃ of argon flow activating temperature is the best condition to synthesize the BAC. The best adsorption efficiency (95.12%) was achieved by using A67 (pH 5, 0.2 g L-1, 50 mg L-1) with its maximum adsorption capacity (411.95 mg g-1). The Redlich-Peterson was the best-fitted isotherm model whereas the Pseudo-Second-Order (PSO) and Elovich were the best-fitted kinetic models for the 4-NP adsorption on BAC. The adsorption mechanism was analysed by applying the IPD model to the experimental data and was depicted in an insightful illustration. Overall, this research provides valuable insights into the adsorbent synthesis processes and highlights the importance of furnace atmospheres and KOH activation in tailoring the properties and adsorption activity of bamboo activated carbon adsorbents. The findings contribute to the development of sustainable and efficient adsorbent materials derived from renewable resources, with significant implications for environmental remediation and waste treatment applications.