Use of electrolysis

Shipwrecks and Salvage‎ > ‎7. Conservation‎ > ‎

Identify the use of electrolysis as a means of removing salt

  • Impregnated salts can be removed from artefacts by leaching, which involves immersion in pure water, or another suitable solution, for a certain period until the object involved is only saturated with the water or solution.
  • Chlorides are difficult to remove from some artefacts, such as iron objects, by leaching, as they can be present as insoluble salts trapped in other deposits.
  • Electrolysis is a more efficient method for the removal of chloride from some artefacts and involves the following in the case of iron:
    • The iron artefact becomes the cathode.
    • A stainless steel mesh anode is used.
    • An electrolyte of dilute sodium hydroxide is used.
    • Chloride ions are freed from the solids on the artefact’s surface and migrate towards the anode, removing them from the iron.
    • At the anode, water oxidises to oxygen.