Optimization of banana trunk-activated carbon production for methylene blue-contaminated water treatment

Abstract

This experiment was run to characterize the banana trunk-activated carbon through methylene blue dye adsorption property. The H₃PO₄ chemical activating agent was used to produce activated carbons from the banana trunk. A small rotatable central composite design of response surface methodology was adopted to prepare chemically (H₃PO₄) activated carbon from banana trunk. Three operating variables such as activation time (50–120 min), activation temperature (450–850 °C), and activating agent concentration (1.5–7.0 mol/L) play a significant role in the adsorption capacities (q) of activated carbons against methylene blue dye. The results implied that the maximum adsorption capacity of fixed dosage (4.0 g/L) banana trunk-activated carbon was achieved at the activation time of 51 min, the activation temperature of 774 °C, and H₃PO₄ concentration of 5.09 mol/L. At optimum conditions of preparation, the obtained banana trunk-activated carbon has adsorption capacity 64.66 mg/g against methylene blue. Among the prepared activated carbons run number 3 (prepared with central values of the operating variables) was characterized through Fourier transform infrared spectroscopy, field emission scanning microscopy, and powder X-ray diffraction.