Alkaline Modified Archidendron jiringa Peel as an Efficient Biosorbent for Methylene Blue Dye Removal

Abstract

Archidendron jiringa peel was investigated as a biosorbent for the removal of methylene blue (MB) dye from aqueous solutions. The raw Archidendron jiringa peel (RAJ) was modified using a sodium hydroxide solution to enhance its adsorption capacity. The modification process resulted in a cleaner and uniform surface on the peel, as revealed by SEM micrograph characterization. Batch experiments demonstrated that the chemically modified Archidendron jiringa peel (MAJ) exhibited higher adsorption capacity compared to the RAJ, attributable to the improved surface properties. Kinetic studies indicated that the adsorption process followed pseudo-first-order kinetics. Isotherm modeling revealed that the adsorption of MB conformed well to the Langmuir isotherm model, indicating monolayer adsorption. The maximum adsorption capacity increased from 22.09 mg g^-1 for the RAJ to 42.18 mg g^-1 for the MAJ. The adsorption capacity was influenced by pH,with higher adsorption observed at pH values above the point of zero charge (pH_zpc), while it decreased with increasing biosorbent dosage due to adsorption site saturation. Overall, these results demonstrate the potential of NaOH modified A. jiringa peel as an effective biosorbent for the removal of MB dye from wastewater.