Silica removal by a novel electrochemical system

O. Gorni-Pinkesfeld, D. Hasson, H. Shemer, R. Semiat

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

The presence of silica in brackish water greatly complicates desalination processes. Mitigation of silica scale by dosage of anti-scalants has proved to be an elusive task. The common method of silica removal is by its precipitation at high pH with polyvalent metal hydroxides. A convenient way for achieving a high pH is by applying an electric current in an electrochemical cell. Silica removal was investigated using a novel electrochemical technique, based on a cation exchange membrane (ECM). The ECM system overcomes a major drawback of current electrochemical technology, enabling reduction of the cathode area by a factor of 10 to 20. The effects of current density and pH on the silica precipitation were studied. Results support the hypothesis that silica removal is an adsorption process rather than a chemical precipitation reaction. The highest silica removal was achieved at the optimal Mg to Si02 molar ratio of 4:1. Silica depletion increased with current density reaching an asymptotic limit of 92% at a solution pH of 10.8, and a current density of 200 A/m2. Results of this study indicate that silica removal by the ECM system can be aviable | process.

Original languageEnglish
Title of host publicationNACE International - Corrosion Conference and Expo 2016
PublisherNational Assoc. of Corrosion Engineers International
Pages171-185
Number of pages15
ISBN (Electronic)9781510821354
StatePublished - 2016
Externally publishedYes
EventCorrosion 2016 - Vancouver, Canada
Duration: 6 Mar 201610 Mar 2016

Publication series

NameNACE - International Corrosion Conference Series
Volume1
ISSN (Print)0361-4409

Conference

ConferenceCorrosion 2016
CountryCanada
CityVancouver
Period6/03/1610/03/16

Keywords

  • Adsorption mechanism
  • Brackish water
  • Desalination
  • Silica removal
  • Silica scaling

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