Amphiphilic mercapto-1,2,4-triazole Schiff bases as novel efficient extracting ligands for recovery of nickel(II) from highly saline chloride media in chloroform-water mixture.

This work dealt with the extractive performance and behaviors of new three Schiff base amphiphiles ligands derived from 3-mercapto-1,2,4-triazole and different alkyl chains for recovery of nickel(II) from concentrated saline chloride medium (1 M ± 0.01) at 30 ± 1 °C. The chloroform has been used as solvent for research purposes only. The effects of the main experimental parameters such as extraction time, pH, extractant concentration and ionic strength of the aqueous medium on the extraction process of nickel(II) with amphiphilic Schiff bases (ASBn) were studied and compared. The analysis of extraction data revealed that the synthesized Schiff bases exhibit a better and faster extractability than many extractants reported in the literature. The extraction constants, log Kex, of these chelating extractants increased with an increase in the alkyl chain. A good recovery (E = 75–100%± 0.05) of nickel was obtained with amphiphilic Schiff bases. The hydrophobic Schiff base amphiphile (ASB18) was the most effective extractant for nickel ions from chloride solutions in the acidic pH range (2.41 − 2.90 ± 0.02). Ni(II) was readily extracted by ASB18 in 5 min. Extracted complexes NiL2 into chloroform phase were ascertained by slope analysis method for all extractants. The extraction mechanism of nickel(II) have been finally suggested. The results obtained are promising and can find practical applications such as for recovering of Ni(II) from Ni-MH battery wastes and electroplating industries effluents. However, in view of the acute toxicity of the solvent chloroform, implementation of this process in large-scale nickel processing strategies needs to be thoroughly evaluated from an environmental perspective. [ABSTRACT FROM AUTHOR]