<p>The galvanizing process involves applying protective zinc coating on the metal surface to prevent corrosion. Galvanizing industry effluents contain heavy metal pollutants such as zinc, iron, lead, chromium, etc. Most of these pollutants are hazardous. It is extremely essential to treat these effluents before discharge to protect the environment from their harmful effects. There are conventional separation processes such as chemical precipitation, adsorption, electrochemical treatment, etc., for the separation of heavy metals. In recent years, membrane separation processes have become increasingly prominent due to their compact design, functionality at ambient temperature, and the benefit of not generating secondary pollutants. Ultrafiltration, a pressure-driven membrane separation process, has become an emerging technology for treating galvanizing effluents. This paper focuses on the removal and recovery of heavy metal contaminants from galvanizing industry effluent by size-enhanced ultrafiltration using a water-soluble form of biopolymer chitosan, carboxymethyl chitosan as a complexing medium. The parameters such as the initial pH of the feed, loading ratio, and initial concentration of metal ions (Cu²⁺, Ni²⁺, Zn²⁺, Cr⁶⁺, and Fe³⁺) were taken into consideration, and their effect on the percentage rejection and percentage recovery of metal ions were examined. The metal ion concentration was analyzed using inductively coupled plasma mass spectrometry. The recovery studies were conducted followed by the separation studies, through lime neutralization to recover the metal ions for reuse in industrial applications. The maximum retention of metal ions was observed to be more than 95%, and the maximum recovery of Zn²⁺ and Fe³⁺ was found to be 92% and 84%, respectively.</p> Graphical abstract <p></p>