Equilibrium Studies on the Synergic Liquid‐Liquid Extraction Process of Copper(II) from Sulphate Media with Mixtures of some Bidentate Mono‐Schiff Bases and Acyclic Polyether Non‐ionic Surfactant in Chloroform

The liquid‐liquid extraction of copper(II) with bidentate mono‐Schiff base extractants(HL), namely, N‐salicylideneaniline (SA), N‐(2‐hydroxy‐1‐naphthalidene)aniline (HNA), N‐salicylidene‐1‐naphthylamine (SN), and N‐(2‐hydroxy‐1‐naphthalidene)‐1‐naphthylamine (HNN), from a weakly acidic sulphate media into chloroform was studied in both the absence and the presence of acyclic polyether non‐ionic surfactant (S). In the absence of the non‐ionic surfactant, the extractability of copper(II) was 92.6% with SA, 89% with HNA, 81% with SN, and 80% with HNN. The estimated extraction constants, (log K_ex) of the four extractants revealed that the extraction efficiency increased in the order HNN< SN< HNA<SA. Besides, it was found that copper(II) was extracted as CuL₂ (HL) with SA and HNA, and as CuL₂ with SN and HNN. The extraction of copper(II) was significantly enhanced with HL into chloroform upon the addition of a non‐ionic surfactant. An extractability of 100% was reached. The stoichiometry of the extracted complexes was CuL₂S. The synergic extraction ability of extractants changed in the order SA>HNA>SN～HNN, whereas, the synergic effect fell in the order HNN>SN>HNA～SA.