Silica removal to prevent silica scaling in reverse osmosis membranes

S. Salvador Cob*, B. Hofs, C. Maffezzoni, J. Adamus, W. G. Siegers, E. R. Cornelissen, F. E. Genceli Güner, Geert-Jan Witkamp

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Reverse osmosis membranes are increasingly used in drinking water treatment. However, the production of a concentrate stream is the main disadvantage of its application. Increasing the recovery of the membranes in order to have the smallest amount of concentrate possible is an attractive approach. In the absence of bivalent cations in the feed water, silica and silica-derived precipitants are limiting factors in high-recovery reverse osmosis operations. The removal of silica in a separate pretreatment process might be the solution. Several methods were tested to remove silica. Precipitation of silica with Fe(OH)3, Al(OH)3 and silica gel was investigated, and also the removal of silica using a strongly basic anion (SBA) exchange resin.Al(OH)3 was the most effective precipitant for silica, removing nearly all of the molecularly dissolved silica. However, a residual amount of aluminum remained in solution, and aluminosilicate colloids were not removed. The use of the SBA exchange resin also showed a good performance, removing up to 94% of the silica. However, further investigations, such as checking whether the residual small amounts of silica and aluminum can still cause scaling in the membrane, need to be conducted.

Original languageEnglish (US)
Pages (from-to)137-143
Number of pages7
JournalDesalination
Volume344
DOIs
StatePublished - Jul 1 2014

Keywords

  • Aluminum ions
  • High recovery
  • Ion exchange
  • Precipitation
  • Scale control

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Science(all)
  • Water Science and Technology
  • Mechanical Engineering

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