A Comparative Study on the Cloud Point Extraction Behavior of Copper(II) from Sulphate Medium by N,N′-Bis(Salicylidene)Ethylenediamine using Triton X-100 and Tergitol 15-S-7 as Non-ionic Surfactants

Cloud point extraction (CPE) experiments were carried out for separation of copper(II) from aqueous saline sulphate medium with the Schiff's base chelating extractant, N,N'-bis(salicylidene) ethylenediamine (H(2)SALEN), using the polyethoxylated alcohol Tergitol 15-S-7 as a biodegradable non-ionic surfactant. The obtained results were compared with those previously obtained in presence of Triton X-100. The effects of the main experimental parameters such as pH, extractant concentration, and non-ionic surfactant concentration on the cloud point extraction behavior of copper(II) with H(2)SALEN were studied and discussed. The use of both systems namely, Triton X-100/ H(2)SALEN/Na2SO4 and Tergitol 15-S-7/H(2)SALEN/Na2SO4, led to very good extraction efficiency and concentrating ability for Cu(II) pollutant. Indeed, nearly 100% extraction efficiency with a minimal volume fraction of the surfactant-rich phase, phi(s), was achieved at pH 7.25 and 8 in the systems Tergitol 15-S-7/ H(2)SALEN/Na2SO4 and Triton X-100/H(2)SALEN/Na2SO4, respectively. The Tergitol 15-S-7/H(2)SALEN/Na2SO4 extraction system was found to be more efficient for Cu(II) removal compared to Triton X-100/H(2)SALEN/Na2SO4 system, providing higher concentration factor, C-f, and a lesser separation temperature, T-s. The analysis of the extraction data revealed that the cloud point process of copper proceeds via a cation exchange mechanism. The stoichiometry of the extracted complexes was ascertained by the Yoe-Jones mole ratio method having a composition of 1:1 [Cu: H(2)SALEN].