Abstract. The removal of heavy metals from acidic waste streams, such as phosphoric acid, is a critical challenge in the chemical process fertilizers industry. Heavy metals in these streams can cause significant environmental and health risks, including ecosystem contamination and bioaccumulation in food chains. Furthermore, their presence poses severe health hazards to humans, emphasizing the importance of effective treatment solutions to ensure safer fertilizer production. In this study, emulsion liquid membranes (ELMs) were investigated for the recovery of Nickel ions from highly acidic synthesized phosphoric acid. Two carrier agents, Alamine-336 and D2EHPA, were examined in combination with Soltrol 220 and kerosene as diluents. Emulsion preparation influencing key parameters, such as carrier concentration, solvent type, and emulsion-to-feed phase ratios were optimized. Alamine-336 demonstrated superior extraction efficiency and membrane robustness compared to D2EHPA. Emulsion stability and performance over multiple extraction cycles were analyzed by utilizing a membrane leakage method based on pH monitoring. Results reveal achieving high Nickel removal across repeated tests, with minimal loss in emulsion integrity, confirming the potential of the system for recyclable operation. These findings highlight the potential of Alamine-336-based ELMs as a sustainable solution for heavy metal recovery, offering both high efficiency and recyclability for treating industrial acidic waste streams.
