Thiol-functionalized silica-mixed matrix membranes for silver capture from aqueous solutions: Experimental results and modeling

A. R. Ladhe, P. Frailie, D. Hua, M. Darsillo, D. Bhattacharyya

Research output: Contribution to journalArticlepeer-review

62 Scopus citations

Abstract

The study deals with an aqueous phase application of mixed matrix membranes (MMMs) for silver ion (Ag+) capture. Silica particles were functionalized with 3-mercaptopropyltrimethoxy silane (MPTMS) to introduce free thiol (-SH) groups on the surface. The particles were used as the dispersed phase in the polysulfone or cellulose acetate polymer matrix. The membranes were prepared by the phase inversion method to create more open and interconnected porous structures suitable for liquid phase applications. The effects of the silica properties such as particle size, specific surface area, and porous/nonporous morphology on the silver ion capture capacity were studied. It was demonstrated that the membranes are capable of selectively capturing silver from a solution containing significant concentrations of other metal ions like Ca2+. The membranes were studied to quantify the dynamic capacity for silver ion capture and its dependence on residence time through the adjustment of transmembrane pressure. The thiol-Ag+ interaction was quantified with quartz crystal microbalance in a continuous flow mode experiment and the observations were compared with the membrane results. One-dimensional unsteady state model with overall volumetric mass transfer coefficient was developed and solved to predict the silver concentration in the liquid phase and the solid silica phase along the membrane thickness at varying time. The breakthrough data predicted using the model is comparable with the experimental observations. The study demonstrates successful application of the functionalized silica-mixed matrix membranes for selective aqueous phase Ag+ capture with high capacity at low transmembrane pressures. The technique can be easily extended to other applications by altering the functionalized groups on the silica particles.

Original languageEnglish
Pages (from-to)460-471
Number of pages12
JournalJournal of Membrane Science
Volume326
Issue number2
DOIs
StatePublished - Jan 20 2009

Bibliographical note

Funding Information:
The authors acknowledge the support of Huber Corporation for this research. P. Frailie was a NSF/REU student. Partial support was also provided by the NIEHS-SBRP program.

Keywords

  • Breakthrough curves
  • Mixed matrix membrane
  • Quartz crystal microbalance
  • Silica
  • Thiol-silver interaction
  • Unsteady state model

ASJC Scopus subject areas

  • Biochemistry
  • General Materials Science
  • Physical and Theoretical Chemistry
  • Filtration and Separation

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