Inclusion separation of alkali metals in emulsion liquid membranes by nanobaskets of calix[4]crown-3

Abstract

Nano-assisted inclusion separation of alkali metals from basic solutions was reported by an inclusion-facilitated emulsion liquid membrane process. The novelty of this study is application of nanobaskets of calixcrown in the selective and efficient separation of alkali metals as both the carrier and the surfactant. For this purpose, two diacids, p-tert-butylcalix[4]arene-1,2-crown-3 in the cone and the 1,2alternate conformation, as well as another diacid, p-tert-butylcalix[4]arene-1,2-thiacrown-3 in the cone conformation, were synthesized. Their inclusion-extraction parameters were optimized, including the calixcrown scaffold (04, 4 wt%) as the carrier/demulsifier, commercial kerosene as the diluent in the membrane, sulphonic acid (0.2 M) and ammonium carbonate (0.4 M) as the strip and the feed phases; the phase and the treat ratios were 0.8 and 0.3, mixing speed (300 rpm), and initial solute concentration (100 mg/L). The selectivity of the membrane was examined for more than ten interfering cations was examined and the results reveled that, under the optimized operating condition, the degree of inclusion-extraction of alkali metals was as high as 98-99%.