<p>In this study, <i>Panaeolus antillarum</i> mushroom was used as a novel, unmodified, and cost-effective biosorbent for the removal of vanadium ions from aqueous solutions. The mushroom, derived from agricultural waste-based cultivation, was characterized by using FT-IR, SEM, and EDX to elucidate the functional groups and surface features involved in biosorption. FT-IR analysis revealed the presence of hydroxyl, carboxyl, amine, carbonyl, and phosphoryl groups, which collectively contributed to multidentate vanadium binding via ion exchange and electrostatic interactions. SEM micrographs confirmed a highly porous and fibrillar morphology, while EDX analysis of vanadium-loaded biomass showed a substantial vanadium signal absent in the raw sample, validating successful sorption. Batch adsorption experiments showed that biosorption was strongly pH-dependent, and maximum uptake was obtained at pH 2.5. At optimal conditions, the mushroom exhibited a competitive adsorption capacity of 163.93&#xa0;mg·g⁻¹ and removal efficiency higher than 95%. Isotherm modeling favored the Langmuir and Temkin models, suggesting monolayer adsorption and significant adsorbent–adsorbate interaction. Thermodynamic parameters confirmed that the&#xa0;standard state free energy change is negative (Δ<i>G</i>^o &lt; 0) and the process is&#xa0;exothermic (Δ<i>H</i>^o &lt; 0). The proposed method is applied for the removal of V(V) ions from the oiled ash waste liquors using mushroom biomass. Under the optimized conditions, mushrooms successfully recovered vanadium species from waste leach liquors with high adsorption efficiency.</p> Graphical Abstract <p></p>