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, G. J. Witkamp

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

45 Citations (Scopus)

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
Pages (from-to)137-143
Number of pages7
JournalDesalination
Volume344
DOIs
Publication statusPublished - 1 Jul 2014
Externally publishedYes

Funding

This work was performed in the TTIW-cooperation framework of Wetsus, Centre of Excellence for Sustainable Water Technology ( www.wetsus.nl ). Wetsus is funded by the Dutch Ministry of Economic Affairs , the European Union Regional Development Fund , the Province of Fryslân , the City of Leeuwarden and the EZ/Kompas program of the “ Samenwerkingsverband Noord-Nederland ” and by the Joint Research Programme of the Dutch Water Companies . The authors would like to thank the participants of the research theme “Clean Water Technology” for the discussions and their financial support. We would like to thank Michel van den Brink for the ICP analysis, Arie Zwijnenburg for the SEM–EDX analysis and Ruud Hendrikx for the XRD analysis. Finally, we also would like to thank the reviewers for their comments, which helped to improve the quality of this paper.

FundersFunder number
City of Leeuwarden
Dutch Ministry of Economic Affairs
European Regional Development Fund
Samenwerkingsverband Noord-Nederland

    Keywords

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

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