<p>The applicability of chemically treated potato peel (MPP) as a sustainable biosorbent for the removal of Pb²⁺ ions and methylene blue (MB), investigated independently in single-solute systems, from aqueous media is explored in this study. Optimal Pb²⁺ adsorption was observed at an initial concentration of 800&#xa0;mg/ L using 0.15&#xa0;g of MPP after 120&#xa0;min of contact at pH ≈ 6.0, whereas methylene blue exhibited its highest removal efficiency at a lower initial concentration of 400&#xa0;mg/ L under comparable batch conditions. The sorption performance was assessed in 25 mL solution volumes for each contaminant separately, yielding maximum adsorption capacities of 370.37, 416.67, and 476.19&#xa0;mg/g for Pb²⁺ at 298, 308, and 318&#xa0;K, respectively, and 181.81, 227.27, and 285.71&#xa0;mg/g for MB. Kinetic analyses showed that both systems were well described by the pseudo-second-order model, indicating the involvement of surface-controlled adsorption processes. Furthermore, thermodynamic evaluations demonstrated that the processes were endothermic and occurred spontaneously. These findings substantiate the potential of MPP as a low-cost, renewable, and efficient adsorbent for wastewater purification targeting toxic metals and synthetic dyes when evaluated individually under comparable experimental conditions.</p>