A novel plasma electrolysis cleaning technique applied on Islamic glass lamps: An experimental study

Abstract

A novel plasma technique has been used for the first time in cleaning Islamic glass lamps samples covered with soot. Pulsed high voltage high frequency power supply was designed to sustain a gas discharge between a cathodic metallic pin and anodic water electrode. The glass samples were immersed completely inside the water and discharge take place over the surface of the water in open air. Different kinds of active species were formed over and inside the water surface including hydroxyl group (OH), atomic oxygen (O), atomic hydrogen (H) molecular hydrogen (H₂), Hydrogen peroxide (H₂O₂) and UV radiation. The cleaning mechanisms will be discussed in this research at different discharge current, 0.268, 0.36 and 0.4A at exposure time range from 5 min. to 20 min., applied at fixed frequency (10 kHz) and sustaining voltage (500v). All currents successfully cleaned 95.5% from soot from the bare glass surfaces (parts without enamel). Cleaning results of enameled surfaces varied from current to another, at 0.268A plasma could clean 76% from the soot and at 0.36A, plasma could clean 65% from the soot. The third current (0.4A) causes destruction for the enamel by removing parts from them. It could be concluded that, small current is considered the safest and successful one to be used in cleaning the Islamic glass samples despite the relatively long time of exposure to plasma. The previous results will enable us to consider the possibility of using this novel technique in cleaning historical Islamic glass lamps pieces in various museums and archaeological stores.