The increasing demand for sustainable water treatment solutions has prompted the development of bio-based adsorbent materials with enhanced adsorption performance for target contaminants. This study presents the fabrication of an eco-friendly nanofibrous membrane derived from fish gelatin, aimed at addressing the limitations of conventional synthetic adsorbents in dye removal applications. The membrane was engineered through electrospinning and chemically modified via the Maillard reaction using glucose-6-phosphate as a natural cross-linker. This cross-linking process improved the membrane’s mechanical stability, moisture resistance, and surface charge distribution, resulting in a highly effective adsorbent for cationic pollutants. The introduction of phosphate-functionalized surfaces significantly enhanced electrostatic interactions, leading to a high methylene blue adsorption capacity of 59.56 mg g-1 with rapid adsorption equilibrium achieved within 15 min. The nanofibrous structure maintained its integrity and surface charge stability over 6-adsorption-desorption cycles, retaining over 84.5 % efficiency even under fluctuating pH conditions. Furthermore, biodegradation studies confirmed the rapid decomposition of the used membrane in compost environments, reinforcing its sustainability as a green water purification material. The findings highlight the potential of surface-engineered gelatin-based nanofibrous membranes as an innovative, scalable, and environmentally friendly alternative to conventional adsorption technologies.