This study presents the utilization of peanut shell agricultural wastes to create environmentally acceptable and cost-efficient biosorbents for the adsorption of cationic methylene blue (MB) dye from water-based solutions. The present study focuses on the production of two biosorbents obtained from peanut shell bio-wastes. The indicated materials comprise unprocessed (SP), as well as sodium hydroxide treated (SPS). The biosorbents undergo analysis using a range of Energy dispersive X-ray spectroscopy (EDX), techniques, such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Brunauer, Emmett and Teller (BET) analysis, N2 adsorption isotherm, X-ray diffraction (XRD), Thermogravimetric analysis (TGA), and determination of the point of zero charge. The batch adsorption approach is employed to determine the ideal operational parameters for removing MB from aqueous solutions. The maximum adsorption capacities were 314.24, and 336.24mg/g for PS, and SPS respectively. The collected kinetics data suggests that the adsorption process of the dye is more accurately characterized by the pseudo-second order model rather than the pseudo-first order model. The equilibrium data exhibited a robust correlation between the dye adsorption and the Langmuir equilibrium isotherm model. An analysis has been conducted on the thermodynamic parameters ΔG°, ΔH°, and ΔS°. The negative standard free energy change (ΔG°) values for both biosorbents demonstrate the inherent spontaneity of the adsorption process. The negative values of ΔH° can explain the exothermic behavior displayed by both biosorbents. The biosorbents derived from peanut shell were efficiently employed for the removal of modest levels of color from different water samples. The adsorption of MB onto SPS is enhanced by many interactions, including pore-filling, electrostatic attraction, π–π, and H-bonding interactions. Methylene blue molecules can diffuse through all the pores of PS, and SPS via pore diffusion.