A cross-linked polymer inclusion membrane for enhanced gold recovery from electronic waste

Bosirul Hoque, Spas D. Kolev, Robert W. Cattrall, Thiruvancheril G. Gopakumar, M. Inês G.S. Almeida*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

A cross-linked polymer inclusion membrane (CL-PIM) incorporating the extractant trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate (Cyphos® IL 104) was developed for the first time for the enhanced Au(III) recovery from aqua regia digests of electronic waste (discarded mobile phones). Cellulose triacetate (CTA), poly(vinyl chloride) (PVC) and poly(vinylidene fluoride-co-hexafluropropylene) (PVDF-HFP) were examined as base polymers. The suitability of poly(ethylene glycol) dimethylacrylate (PEGDMA), poly(ethylene glycol) divinyl ether (PEGDVE) and N-ethylmaleimide (NEM) as cross-linking agents, and the possibility of using triarylsulfonium hexafluorophosphate (TASHFP) and 2,2-dimethoxy-2-phenylacetophenone (DMPA) as initiators were investigated. It was demonstrated that the CL-PIMs composed of Cyphos® IL 104 (30 wt%), PVDF-HFP, PEGDMA (base polymer to cross-linking agent ratio 6:4) and DMPA (1 wt%) or TASHFP (2 wt%) transported Au(III) from 2.5 mol L−1 hydrochloric acid solutions twice as fast as their non-CL-PIM counterpart, showing excellent stability over five successive transport experiments. However, in aqua regia feed solutions (6 mol L−1 acidity) only the CL-PIM containing TASHFP was able to achieve complete Au(III) recovery. AFM studies revealed that the PVDF-HFP-based CL-PIMs had a much higher surface contact area when compared to their non-CL counterpart, and this is proposed to be the reason for their superior transport performance. The CL-PIM that showed good transport efficiency in aqua regia was also applied to aqua regia digests of electronic waste from two mobile phones, and Au(III) was selectively recovered in less than 24 h, while other metals present in significantly higher concentrations were not transported.

Original languageEnglish
Pages (from-to)54-62
Number of pages9
JournalWaste Management
Volume124
DOIs
StatePublished - 1 Apr 2021
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2021 Elsevier Ltd

Keywords

  • Cross-linking
  • Cyphos® IL 104
  • Gold recovery
  • Polymer inclusion membrane (PIM)
  • Waste electrical and electronic equipment (WEEE)

ASJC Scopus subject areas

  • Waste Management and Disposal

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