Neem leaf powder an economical adsorbent for methylene blue removal

In this study, powdered neem leaves (NLP) were evaluated as low-cost, effective, and eco-friendly adsorbents for the removal of methylene blue (MB) dye from industrial wastewater. NLP demonstrated high adsorption efficiency owing to its heterogeneous surface and porous structure, as confirmed by Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Batch adsorption experiments were conducted to determine the optimal operating conditions, including the dye concentration, pH, contact time, and adsorbent dosage. The best results were obtained at pH 6, with an adsorbent dosage of 1.5 g and contact time of 24 h, achieving a removal efficiency of 82%. The adsorption data fit well with both the Langmuir and Freundlich isotherm models, with a maximum adsorption capacity of 41.5223 mg/g and a Freundlich constant (K) of 14.967 (L/mg). These results indicated that NLP is a promising and cost-effective material for treating dye-contaminated wastewater • An economical and low-cost adsorbent was prepared using neem leaf powder. • The adsorbent effectively removes methylene blue dye from an aqueous solution. • Nonlinear Langmuir model accurately describes adsorbent behavior (R 2 = 0.993) • Separation factor (RL < 1) shows that adsorption is favorable. • Relative error and RMSE analyses confirm the model's high predictive accuracy