Synergistic green extraction of nickel ions from electroplating waste via mixtures of chelating and organophosphorus carrier

The discharge of electroplating waste containing nickel ions has led to environmental issues owing to the toxicity problem mainly to the aquatic organisms and humans. Liquid-liquid extraction offers a great potential treatment for nickel removal with several advantages of simple, high efficiency and high separation factor. In this study, a green synergistic liquid-liquid extraction of nickel ions from electroplating waste solution using chelating oxime (LIX63) and organophosphorus (D2EHPA) carriers individually as well as their synergistic mixture has been studied. The result demonstrated that about 83% of nickel ions have been successfully extracted via the mixture system of 0.08M LIX63 +0.02M D2EHPA with the maximum synergistic enhancement factor, Rmax of 29.56. Meanwhile, the back extraction study also revealed that HNO3 was the most suitable stripping agent while the diluent screening also showed that palm oil has high potential to be incorporated as a diluent in the green synergistic liquid-liquid extraction of nickel.