Comprehensive optimization and kinetic-thermodynamic evaluation of methyl green adsorption from aqueous solutions using an innovative α-FeOOH@Luffa fiber composite

This study introduces α-FeOOH@Luffa, a novel composite for the adsorptive removal of methyl green (MG) from aqueous solutions. Utilizing fractional factorial design (FrFD) and response surface methodology (RSM), we optimized six parameters to enhance the adsorption process. The findings reveal a maximum adsorption capacity of 256.32 mg g⁻¹ at an optimal pH of 9 within 60 min. The adsorption behavior aligns with the Langmuir isotherm and follows pseudo-second-order kinetics, indicating strong adsorption dynamics. The process is characterized as exothermic and spontaneous, supported by a high correlation between observed and predicted removal efficiencies (R² = 98.03%). Furthermore, the composite exhibits excellent regeneration capabilities, maintaining adsorption efficiency across six consecutive cycles. These results underscore the potential of α-FeOOH@Luffa as a cost-effective and eco-friendly solution for wastewater treatment, paving the way for further investigations into its application for other persistent pollutants.