Adsorptive Performance of High Surface Area Date Palm Bunch Activated Carbon Towards Methyl Violet and Fuchsin Basic Dyes Removal: Thermochemical Activation And Statistical Optimization

Abstract

Herein, date palm (Phoenix dactylifera) bunch (DPB) waste was transformed into activated carbon (DPAC) adsorbent by using microwave-induced ZnCl₂ activation for 15 min at a power of 600 W. Several analytical methods were used to explain the physicochemical parameters of DPBAC including XRD, pH_pzc, BET, SEM–EDX, and FTIR. Afterwards, the adsorptive performance of DPBAC was thoroughly investigated for the removal of two structurally different organic dyes namely methyl violet (MV) and fuchsin basic (FB). The key adsorption parameters, including the dose of DPBAC (A: 0.02–0.06 g), the solution pH (B: 4–10), and the contact time (C: 2–20 min) were statistically optimized using the Box-Behnken design with response surface methodology (RSM-BBD). The Freundlich isotherm model exhibits the best fit for explaining the isotherm data for both the MV and FB dyes, whereas the pseudo-second-order model shows an accurate description of the kinetic data. Thus, DPBAC shows maximum adsorption capacities (q_max) for319.9 mg/g (MV) and 246.9 mg/g (FB) respectively. The possible DPBAC surfacec interaction with MV and FB dye molecules can be assigned to various pathways including pore filling, electrostatic attraction, π-π stacking, and H-bonding. The finding of this study indicates that date palm bunch can be effectively converted into large surface area activated carbon with the potential application for removal of cationic dyes from wastewater.