Wei, W.Qiu, Y.Zhao, Y.Zhang, K.Ji, Y.Gao, H.Bediako, J.K.Yun, Yeoung-Sang.2021-04-282021-04-282021http://ugspace.ug.edu.gh/handle/123456789/36270Research ArticleAn “ionic barrier” concept is proposed to introduce selectivity function to adsorbents towards precious metals (PMs) in the present study. As a model system, melamine-impregnated alginate capsule (MIAC) was prepared and used as a Pd(II) selective adsorbent from a binary metal solution containing Pt (IV) and Pd(II). The MIAC exhibited excellent Pd(II) selectivity for a pH around 4.3, where the selectivity coefficient reached a high value of 2190.66. In comparison to the very low Pt (IV) uptake, a high maximum uptake of Pd(II) was estimated of 316.92 ± 9.50 mg/g by the Langmuir isotherm model. Sorptiondesorption studies showed that the MIAC had a good reutilization property. The selective process for Pd(II) recovery was proposed as follows: the electroneutral Pd(OH)2 but not anionic PtCl5 first penetrate the outer ionic barrier; then, the penetrated Pd(OH)2 was bound by the inner melamine through chelation. The ionic barrier-based sorbent thus can be considered as an alternative one for separation and recovery of Pd(II).enMelamineCalcium alginate barrierPd(II) selectivityArticle