A pilot experiment with newly developed electrodes was tested for removal of contaminating salts from brick masonry where plaster peeling was a problem. A high concentration of sulfate was found at the height where the paint peeling was most pronounced. The concentrations of chloride and nitrate were smaller, though in dangerous concentrations at some points. In the applied electric field, chloride and nitrate were efficiently removed. Sulfate, on the other hand, was less mobile, due to lower solubility of sulphate salts and thus lower percentage in ionic form and mobile for electromigration. The mean concentration of sulfate was decreased from 0.68 wt% to 0.46 wt% during the approx. 4 months of treatment. The removal rate for sulphate did not decrease significantly during the treatment period and it is expected that reduction in sulphate concentration could continue over longer duration. The electrode units worked perfect and efficiently prevented the acid produced at the anode from reaching the masonry. The contaminating ions from the masonry concentrated inside the electrodes and were removed from the site with the electrodes.
|Title of host publication||Salt Weathering on Buildings and Stone Sculptures : Proceedings from the international conference|
|Number of pages||392|
|Publisher||DTU Byg, Danmarks Tekniske Universitet|
|Publication status||Published - 2008|
|Event||1st International Conference on Salt Weathering on Buildings and Stone Sculptures - The National Museum, Copenhagen, Denmark|
Duration: 22 Oct 2008 → 24 Oct 2008
Conference number: 1
|Conference||1st International Conference on Salt Weathering on Buildings and Stone Sculptures|
|Location||The National Museum|
|Period||22/10/2008 → 24/10/2008|
Ottosen, L. M., Rörig-Dalgaard, I., & Villumsen, A. (2008). Electrochemical removal of salts from masonry - Experiences from pilot scale. In Salt Weathering on Buildings and Stone Sculptures: Proceedings from the international conference (pp. 341-250). DTU Byg, Danmarks Tekniske Universitet.