This study intended to examine and assess the performance of raw and treated Eriobotrya Japonica seed waste for the adsorption-based removal of methylene blue dye from an aqueous solution. The effects of several factors, including pH, adsorbent dose, and initial concentration, on the elimination of this dye were examined. To optimize the removal process, a Box-Behnken design (BBD) based on response surface methodology (RSM) was employed to evaluate the influence of key variables, adsorbent dose, initial dye concentration, and pH, along with their interactions. The findings demonstrated that the statistical analysis reveals a high significance of the dye for raw and treated Eriobotrya Japonica seed waste, with extremely weak probability values (p < 0.0001). The optimal conditions achieved were the adsorbent dose = 21.21 mg, initial dye concentration = 7.54 mg/L, and pH = 10.92 for the raw waste and adsorbent dosage = 21.75 mg, initial dye concentration = 7.5 mg/L, and pH = 11.7 for the extracted waste. These conditions result in a dye removal efficiency of 99.48% and 99.88% for raw and treated Eriobotrya Japonica seed waste, respectively. The methylene blue adsorption kinetics on the adsorbent can be precisely represented by an effective pseudo-second-order equation. The Freundlich model showed a significantly better fit to the experimental results compared to the Langmuir model.