Optimization study of methylene blue dye adsorption on Chamaerops humilis fibers biosorption using a central composite design

Abstract

This research explores the effectiveness of Chamaerops humilis (CH) fibers as a biosorbent for the adsorption of Methylene Blue (MB) dye from aqueous solutions. The fibers were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR). To optimize the dye removal process, a Design of Experiments methodology, specifically Central Composite Design (CCD), was applied. Factors such as solution pH, adsorbent dosage, contact time, and temperature were varied. The CCD analysis identified the optimal conditions for maximum removal efficiency (99.87%) of a 10 mg/L MB solution, which were: 1.06 g/L of CH fiber dosage, pH 9.6, and a contact time of 60 minutes. The adsorption process aligned well with a pseudo-second-order kinetic model, and the maximum adsorption capacity of CH fibers was determined to be 9.422 mg/g. Thermodynamic parameters, including Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) changes, were calculated, confirming that the adsorption is spontaneous and endothermic. The study highlights the potential of Chamaerops humilis fibers as an efficient and eco-friendly adsorbent for MB dye removal, offering a sustainable and cost-effective solution for wastewater treatment, particularly in industrial effluent management.