Synthesis of activated carbon from banana peels for dye removal of an aqueous solution in textile industries: optimization, kinetics, and isotherm aspects

Treatment of harmful chemicals using materials at our disposal is the way forward to be. This study presents the activation of waste banana peels and the investigation of the bio-adsorption potential for dye removal from an aqueous solution. The banana peel was activated both thermally and chemically by a preliminary study of a 0.5–2.5 M of sulfuric acid concentration, and 50–90 °C of temperature for 1–5 h of activation time. Activation at 1.5 M of acid concentration, at 70 °C for 3 h showed a promising efficacy of about 90% of dye removal. The activated banana peel was characterized by proximate analysis, BET, TGA, SEM, XRD, and FTIR. BET results showed activated banana peels to be porous materials with a surface area of 302 m2/g. The capacity of the adsorbent with different variable ranges (adsorption time 20–140 min, pH 1.0–7.0, adsorbent dose 1–4 g/L and initial dye concentration 20–80 mg/L) was conducted based on a preliminary study. The adsorption process was optimized numerically and the results were the following: adsorption time of 60 min, pH 3, adsorbent dose of 2 g/L and an initial dye concentration of 40 mg/L. In the adsorption study, the pseudo-second-order kinetics model and Langmuir isotherm model were the best fit to describe the adsorption process.