Investigation on the Role of Agitation in the Desalination Process of Ceramics

Abstract

The porous structure of excavated ancient potteries (especially potteries with a firing temperature below 1000 ̊C) are in general saturated with salts. Desalination is therefore one of the primary steps in the conservation and restoration process of historical porous materials. Since salinity can cause significant damage to ceramic artifacts, they must be subjected to a careful process of desalination. As water-sensitive clay-based ceramics may deteriorate or collapse during long periods of contact with water, alternative desalination methods should be identified to minimize potential damage to the pottery material. New methods such as raising the temperature of the washing water and/or using surfactants have also been suggested as alternative techniques in the desalination process to avoid long periods of contact time. In this study, acceleration of the desalination process based on a unified theoretical formulation is discussed and the role of agitation to enhance the rate of desalination is demonstrated. It was found that the main cause of deficiency in current desalination processes is due to a stagnant liquid layer near the interface of the ancient object and the water, known as concentration polarization. Agitation enhances the efficiency of desalination by minimizing the thickness of the concentration polarization layer.