Hydrogen ion exchange on amorphous silica in seawater

C. H. Culberson, R. M. Pytkowicz, E. L. Atlas

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


The amount of hydrogen ion exchange on the surface of amorphous silica in seawater was measured as a function of pH at 2 and 25°C. Hydrogen ion exchange with the cations present in seawater is pH dependent and at 25°C the fraction of the surface in the cation form increases from 9% at pH 7 to 22% at pH 8. The exchange is temperature dependent and at 2°C and pH 8, 14% of the exchange sites are occupied by cations, as opposed to 22% of the exchange sites at 25°C. These results were used to calculate the buffer capacity of a model sediment consisting of pore water and amorphous silica. For a sediment of 70% porosity, pH 7.7, and 25°C, the buffer capacity of sediment plus pore water is 67 times the buffer capacity of pure seawater.

Original languageEnglish (US)
Pages (from-to)43-54
Number of pages12
JournalMarine Chemistry
Issue number1
StatePublished - Apr 1975
Externally publishedYes

ASJC Scopus subject areas

  • Oceanography
  • Chemistry(all)
  • Environmental Chemistry
  • Water Science and Technology


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