Selective separation of trace nickel(II) and gold(I) ions via hollow fiber supported liquid membrane enhanced by synergistic extractants D2EHPA/TBP

This work presents the selective and simultaneous separation of nickel (Ni2+) and gold ([Au(CN)(2)](-)) ions, in trace amounts, from alkaline solution via hollow fiber supported liquid membrane (HFSLM) technique. HFSLM is challengingly carried out in real rinse wastewater generated by the ENIG plating process. The influence of various chemical parameters, including the type of extractant and their concentrations, molar ratios of mixed extractant as well as type of strippant, are also studied. The organophosphorus extractant mixtures of D2EHPA and TBP provide a synergistic effect for target Ni2+ ions but has an antagonistic effect as regards the extraction of nontarget [Au(CN)(2)](-) ions. Compared to other inorganic acids, HCl is seen to be the most suitable strippant for the selective stripping. Results demonstrate that percentages of extraction and stripping of Ni2+ ions achieved 85.7 and 83.2%, respectively. In contrast, percentages of extraction and stripping of non-target [Au(CN)(2)](-) ions attained 15.6 and 1.94%. (C) 2021 The Author(s). Published by Elsevier B.V. on behalf of King Saud University.

Automated summary

This study presents the selective separation of nickel and gold ions from real rinse wastewater using the HFSLM technique, with organophosphorus extractant mixtures showing a synergistic effect on target Ni2+ ions but an antagonistic effect on non-target [Au(CN)(2)](-) ions. HCl was found to be the most suitable stripping agent, with high extraction and stripping percentages achieved for Ni2+ ions compared to non-target [Au(CN)(2)](-) ions.