Silica scaling in forward osmosis: From solution to membrane interface

Ming Xie, Stephen R. Gray

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)

Abstract

Membrane silica scaling hinders sustainable water production. Understanding silica scaling mechanisms provides options for better membrane process management. In this study, we elucidated silica scaling mechanisms on an asymmetric cellulose triacetate (CTA) membrane and polyamide thin-film composite (TFC) membrane. Scaling filtration showed that TFC membrane was subjected to more severe water flux decline in comparison with the CTA membrane, together with different scaling layer morphology. To elucidate the silica scaling mechanisms, silica species in the aqueous solution were characterised by mass spectrometry as well as light scattering. Key thermodynamic parameters of silica surface nucleation on the CTA and TFC membranes were estimated to compare the surface nucleation energy barrier. In addition, high resolution X-ray photoelectron spectroscopy resolved the chemical origin of the silica-membrane interaction via identifying the specific silicon bonds. These results strongly support that silica scaling in the CTA membrane was driven by the aggregation of mono-silicic acid into large silica aggregates, followed by the deposition from bulk solution onto the membrane surface; by contrast, silica polymerised on the TFC membrane surface where mono-silicic acid interacted with TFC membrane surface, which was followed by silica surface polymerisation.

Original languageEnglish
Pages (from-to)232-239
Number of pages8
JournalWater Research
Volume108
Early online date2 Nov 2016
DOIs
Publication statusPublished - 1 Jan 2017

Keywords

  • Cellulose triacetate
  • Forward osmosis
  • Polyamide
  • Silica aggregation
  • Silica polymerisation
  • Silica scaling

ASJC Scopus subject areas

  • Ecological Modelling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

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