<span style="font-size:11.0pt;font-family:"Calibri","sans-serif"; mso-ascii-theme-font:minor-latin;mso-fareast-font-family:"Times New Roman"; mso-hansi-theme-font:minor-latin;mso-bidi-font-family:Arial;color:black; mso-ansi-language:EN-US;mso-fareast-language:EN-US;mso-bidi-language:AR-SA">Selective pertraction of Pd (II) across a solid supported liquid membrane using thiamacrocycle S₆-pentano-36 as an ionophore</span>

Abstract

<span style="font-size:11.0pt;font-family:" calibri","sans-serif";="" mso-ascii-theme-font:minor-latin;mso-fareast-font-family:"times="" new="" roman";="" mso-hansi-theme-font:minor-latin;mso-bidi-font-family:arial;color:black;="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">Thiamacrocycle-facilitated co-transport of Pd (II) from dilute nitrate· acidic solutions has been examined across solid supported liquid membrane (SSLM) deploying S₆-P-36 as the novel ionosphere. Under the optimum conditions, micro amounts of palladium could be effectively transported from a feed (1 <i>M</i> HNO₃) solution across an organic thiacrown membrane into the product side containing strip-pants like 2 <i>M</i> NH₄SCN. Its concentration in the source phase decreased as [Pd]_f,t= [Pd]_f,o exp(-<i>K</i>_obs<i>t</i>). The apparent rate constant (<i>K</i>_obs) increased with increasing carrier concentration and became nearly constant above 0.02 <i>M</i> S₆-Pentano-36. With increase in nitric acid concentration from 0.1 to 5 <i>M</i>HNO₃, Kobs decreased. A polytetrafluroethylene thin film support coded as TE-35 and toluene as membrane solvent were invariably used. Among the several reagents tested, ammonium thiocyanate served most efficiently as the strippant. More than 95% of palladium could be readily transported from diverse matrices through 0.05 S₆-Pentano-36 into dilute aqueous ammonium thiocyanate strippant in about 6-7 h.</span>