Novel Biosorption Method for Eliminating Methylene Blue Dye from Wastewater Using Sweet Potato Peels

This study explores the use of sweet potato peels, Ipomoea batatas (SPP) as biosorbent for elimination of Methylene Blue, Methylthioninium chloride (MB) dye from aqueous solutions. Batch adsorption experiments were performed to evaluate the effects of key variables, including adsorbent dosage, contact time, and initial dye concentration, on the removal efficiency of MB. The results demonstrated that the removal efficiency of MB increased with the adsorbent dosage, reaching an optimal value of 72% at a dosage of 1.0 g/100 mL, corresponding to a maximum adsorption capacity of 7.2 mg/g. Additionally, the adsorption process achieved equilibrium at 50 minutes of contact time. However, higher concentrations of MB in the solution led to a decrease in removal efficiency, likely due to the saturation of the adsorbent surface. Further analysis using FTIR spectroscopy revealed the presence of functional groups such as hydroxyl, carboxyl, and phenolic groups on the sweet potato peel surface, which play a crucial role in the adsorption process. Kinetic modeling using the pseudo-second-order model revealed that the pseudo-second-order model provided the best fit with R² > 0.99, confirming chemisorption behavior. The study concluded that sweet potato peels are an effective, eco-friendly adsorbent for MB dye removal, demonstrating a low-cost and sustainable approach to wastewater treatment. The findings highlight the potential of this agricultural byproduct in addressing water pollution concerns, providing a viable solution aligned with environmental conservation efforts.