E-Publication DOI

Electrodesalination of sandstones with irregular shapes and uneven distribution of salts

Ottosen, L. M.; Skibsted, G.; Præstholm, T.

Jahr: 2014

Datei zum Herunterladen: pdf (16 pages, 385.0 KB)

Beschreibung:
Electrochemical desalination of stone is based on application of an electric
potential gradient. In case the electrodes are placed in a poultice, which
buffer the acid from oxidation of water at the anode, the methods has
shown very effective. Most investigations have been carried out in
laboratory scale on stones with an even salt distribution. This investigation
was designed to answer different questions arising if the method is to be
applied to sculptures and monuments with an uneven salt distribution and
irregular shapes. Laboratory experiments were made with stones samples
from a historic warehouse. The sampling was in connection to renovation.
Before the renovation an on-site experiment was made as a part of the
investigation.
The initial concentration in the stone segments for the different laboratory
experiments varied reflecting the inhomogeneous distribution in the wall.
Whether the electrodes were placed on the same side of the stone or on
two opposite sides did not influence the removal rate of Cl- and NO3. A
stone part, which was not placed directly between the electrodes, was
desalinated, but with a slower rate than the other parts. Two stone parts
were isolated from each other during the desalination, and the current
mainly passed through the part with high salt concentration. The on-site
experiment was successful. Chloride was removed to a very low level in
all depth of the investigation (10 cm) and from cathode end to anode end,
though the desalination had not finished as the concentration was still little
too high in the anode end. All together 131 g Cl- was removed during 5½
month. All results showed that the method had potential for desalination of
monuments with irregular surfaces and salt distribution.
Keywords: electrodesalination, sandstone, electrode placement

Zitation:
Ottosen, L. M.; Skibsted, G.; Præstholm, T.:
Electrodesalination of sandstones with irregular shapes and uneven distribution of salts. Royal Institute for Cultural Heritage, Koninkljik Instituut voor het Kunstpatrimonium (KIK), Institut royal du Patrimoine artistique (IRPA) 2014
doi:10.5165/hawk-hhg/263