Development of melamine-impregnated alginate capsule for selective recovery of Pd(II) from a binary metal solution
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Date
2021
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Cleaner Production
Abstract
An “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).
Description
Research Article
Keywords
Melamine, Calcium alginate barrier, Pd(II) selectivity