Mesoporous activated carbon derived from fruit by-product by pyrolysis induced chemical activation: optimization and mechanism for fuchsin basic dye removal

Abstract

In this study, pineapple crown (PC) feedstock residues were utilized as a potential precursor toward producing activated carbon (PCAC) via pyrolysis induced with ZnCl₂ activation. The PCAC has a surface area (457.8 m²/g) and a mesoporous structure with an average pore diameter of 3.35 nm, according to the Brunauer–Emmett–Teller estimate. The removal of cationic dye (Fuchsin basic; FB) was used for investigating the adsorption parameters of PCAC. The optimization of significant adsorption variables (A: PCAC dose (0.02–0.1 g/100 mL); B: pH (4–10); C: time (10–90); and D: initial FB concentration (10–50 mg/L) was conducted using the Box-Behnken design (BBD). The pseudo-second-order (PSO) model characterized the dye adsorption kinetic profile, whereas the Freundlich model reflected the equilibrium adsorption profile. The maximum adsorption capacity (q_max) of PCAC for FB dye was determined to be 171.5 mg/g. Numerous factors contribute to the FB dye adsorption mechanism onto the surface of PCAC, which include electrostatic attraction, H-bonding, pore diffusion, and π–π stacking. This study illustrates the utilization of PC biomass feedstock for the fabrication of PCAC and its successful application in wastewater remediation.

Keywords:

• Activated carbon
• adsorption
• box-Behnken design
• pineapple crown
• pyrolysis

Acknowledgments

The authors are thankful to Faculty of Applied Sciences, Universiti Teknologi MARA (UiTM) for the research facilities. The author (Ahmad Hapiz) is thankful to the Government of West Nusa Tenggara (NTB) Province, Indonesia, as well as the Education Development Institute (LPP) NTB and the Regional Research and Innovation Agency (BRIDA) NTB for providing a fully funded scholarship. The author (Zeid A. ALOthman) is thankful to the Researchers Supporting Project No. (RSP2023R1), King Saud University, Riyadh, Saudi Arabia.