Inclusion desalination of alkali metal cations by emulsion liquid membranes and nano-baskets of p-tert-calix[4]arene bearing di-[N-(X)sulfonyl carboxamide] and di-(1-propoxy) in para-cone conformation

Nano-assisted inclusion separation of alkali metal cations from basic aqueous solutions was reported by inclusion-facilitated emulsion liquid membrane process. The novelty of this study is application of nano-baskets of calixarene in the selective and efficient separation of alkali metal cations as both the carrier and the surfactant. For this aim, four derivatives of p-tert-calix[4]arene bearing different sulfonamide moieties were synthesized and their inclusion–extraction parameters were optimized including the calixarene scaffold 3 (4 wt.%) as the carrier/demulsifier, the commercial kerosene as diluent in 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 of 0.8 and 0.3, mixing speed (300 rpm), and initial solute concentration (100 mg/L). The selectivity of membrane over more than ten interfering cations was examined and the results revealed that under the optimized operating condition, the degree of inclusion–extraction of alkali metal cations was as high as 98–99%.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Nano-assisted inclusion separation of alkali metals by ELM was reported. ► Application of nano-baskets in ELM separation of alkali metals was studied. ► Four derivatives of calix[4]arene bearing different sulfonamides were synthesized. ► The inclusion–extraction parameters of ELM were optimized. ► Under the optimized condition, the degree of inclusion–extractions was 98–99%.