Composite Formation of Active Biochar from Pomegranate Peel with Magnetite and Alginat Beads for Methylene Blue Adsorption Using Box-Behnken Design

The aim of this study was to develop an innovative material by combining the properties of magnetic biochar derived from orange peels and hydrogel beads (BCA-Mag/AB) and to apply this material for the adsorption of methylene blue dye in water. The BCA-Mag/AB were synthesized using physical crosslinking methods and was characterized using various techniques. The surface functional groups were analyzed using FTIR, the crystal structure was examined through XRD, the surface area was determined by BET, the pore distribution was assessed via BJH, thermal stability was evaluated with TGA, surface morphology was investigated using SEM, and the surface element percentages were analyzed with EDX. The specific surface area obtained through nitrogen adsorption was found to be 455.4 m2/g, and the total pore volume was 0.268 cm3/g. The removal of methylene blue dye on BCA-Mag/AB was investigated concerning three variables using Box-Behnken Design (BBD) as follows: A: BCA-Mag/AB dosage (0.02-0.1 g); B: contact time (20-150 min); and C: initial pH (2-10). Adsorption kinetic and isotherm analyses indicated that the adsorption of methylene blue onto BCA-Mag/AB was governed by pseudo-first-order and Freundlich models. The adsorption mechanisms of methylene blue on the BCA-Mag/AB surface were associated with electrostatic interaction, hydrophobic interaction, and pi-pi stacking. The results suggest that BCA-Mag/AB could be an effective and locally available candidate adsorbent for the removal of dye pollutants from contaminated industrial wastewater.