Electrochemical desalination of the ionic mixture measured in the vault of Rørby Church - Laboratory scale

Salt induced deterioration of the vault in Rørby Church has resulted in extensive deterioration of the vault itself and of the murals on the lower surface of the vault. The upper surface of the vault has previously been covered with cement mortar. After removing this cement mortar some of the bricks erode and form brick powder. The brick powder was collected in 2002, 2005 and 2011 and measured for the most common salts in Danish vault structures. On the basis of the actual measured ions two different salt mixtures were made and used for contamination of brick specimens. By use of an applied electric DC field the nitrate and chloride contents were reduced to very low contents and the sulphate content was significantly reduced in the main part of the specimens. According to the results of the experiments it seems likely that the present ions in the upper part of the vault of Rørby church can be extracted electrochemically if the salts in the construction can be dissolved.