Nature's waste turned savior: Optimizing pineapple peel–based activated carbon for effective Remazol Brilliant Violet dye adsorption using response surface methodology

Abstract

The novelty of this work demonstrated a sustainable and low–cost approach to producing pineapple peel activated carbon (PiPAC) and utilizing the pyrolysis process for wastewater treatment. Due to its high porosity, PiPAC exhibited strong adsorption properties for remazol brilliant violet 5R (RBV) dye. PiPAC's performance was evaluated using characterization techniques such as Brunauer–Emmett–Teller (BET), Scanning Electron Microscopy (SEM), X–Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, and Energy–dispersive X–ray spectroscopy (EDX). Response surface methodology (RSM) was applied to optimize the preparation of PiPAC, with the activation temperature (AcTe) of CO2, activation time (AcTi) of CO2, and impregnation ratio (IR) of KOH serving as manipulated variables. The best PiPAC preparation conditions were 732 ℃, 1.96 h, and 3.0 for AcTe and AcTi of CO2 and IR of KOH, respectively. At 60 °C, the PiPAC– RBV dye exhibited a maximum adsorption capacity (qmax) of 74.86 mg/g. Kinetic investigations adhered to a pseudo–first–order (PFO) model, while equilibrium isotherm research defined the Vieth Sladek model for PiPAC–RBV dye. The regeneration effectiveness for the PiPAC–RBV dye adsorption was 54.1 % for the third cycle without any surface morphological alterations to PiPAC. The potential mechanisms—hydrogen bonding, n–π interactions, and π–π interactions—were shown to be involved in the adsorption of PiPAC–RBV dye. For future work, sustained research and improvement would advance sustainable adsorbents for wastewater treatment procedures.