Extraction and separation of zinc and ch

The treatment of electroplating effluents containing heavy metals like zinc (Zn) and chromium (Cr) is essential to reduce environmental pollution and conserve natural resources. This study aims to selectively extract and separate Zn and Cr from electroplating effluent using a solvent extraction technique. Initial experiments were conducted utilizing a synthetic solution composed of Zn (1.78 g/L) and Cr (3.6 g/L), employing a 10% DE2PHA solution diluted with kerosene. Various process parameters such as pH, time, O/A ratio, and loading capacity were systematically optimized. The results revealed that 98.17% of Zn could be effectively extracted within 5 minutes at an equilibrium pH of 2.5, maintaining an O/A ratio of 1. For stripping the loaded organic phase, 10% H2SO4 was utilized. Validation of the optimum extraction conditions was performed using the actual electroplating effluent obtained from M/s Sinha Electrochemical Plant, Jamshedpur, India. The complete extraction of Zn from the original effluent occurred within the same timeframe and conditions, leaving 99% of Cr in the raffinate. The purified solution can subsequently be processed to yield metal or salts through methods like evaporation, precipitation, electrowinning, or crystallization.