Effect of Sodium Carbonate on the Cloud Point in Alkyl Ether/Brine Systems: Apparent Relation with Dynamic Interfacial Tension Minimum

Moundher Hadji, Mohamed Aoudia, Adil Al-Rubkhi, Rashid S. Al-Maamari, Amel Hadj-Ziane-Zafour

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The effect of Na2CO3 on the cloud point in Na2CO3/surfactant/brine was investigated using two series of nonionic surfactants, C13EOx and C17EOx. The cloud point, Tcp, was found to decrease linearly with increasing Na2CO3 concentration. This was attributed to Na+ and particularly to CO3 2−salting-out effect. The slope a = dTcp/d[Na2CO3] became more and more negative as the degree of ethoxylation is increased, suggesting that the higher the number of ethylene oxide (EO) groups the stronger is the cloud point depression for a given increment in Na+and CO3 2−ions in solution. This was also illustrated by the linear variation of ΔTcp = Tcp,0 − Tcp,[Na2CO3] with the surfactant degree of ethoxylation.

Original languageEnglish
Pages (from-to)1223-1229
Number of pages7
JournalJournal of Surfactants and Detergents
Issue number6
Publication statusPublished - Nov 1 2016



  • Cloud point
  • Enhanced oil recovery
  • Nonionic surfactant
  • Salting-out effect
  • Soap

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Surfaces, Coatings and Films
  • Physical and Theoretical Chemistry

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