Energy & Fuels, Vol.11, No.2, 348-353, 1997
Environmental-Pollution Control Devices Based on Novel Forms of Carbon - Heavy-Metals
The use of electrochemistry is an effective means to remove heavy metal contaminants from aqueous effluent streams. In this project, the development and testing of novel carbon materials for the electrochemical removal of heavy metal ions from aqueous wastes have been carried out. Both electroplating and electrosorption were employed by using a packed bed of the carbon material in a flow-through electrochemical remediation cell. The main focus of this work was to develop and test a cathodic material with a large ratio of surface area to volume. To this end, a packed bed of conductive carbon, either as carbon fibers or as carbon foams, was utilized. The increased surface area helps minimize the length of electrode through which the solution must pass. This decreased distance leads to reduced resistance to solution flow. The removal of cadmium, lead, copper, and nickel from aqueous samples using a small-scale electrolytic cell has been demonstrated. Removal efficiencies above 90% have been observed. Continuous removal of lead over a 72 h period was demonstrated at these levels. An effluent concentration below 10 ppm was observed for an inlet solution feed of 100 ppm. The use of electrolytic remediation an waste streams proved successful for the selective removal and recovery of metals. The removal of nickel ions from solution directly onto the bare carbon material was inefficient. By plating a small amount of copper onto the carbon surface prior to use, enhanced removal was obtained. At pH 7.0, a removal efficiency for nickel of 89% was achieved.
Keywords:RETICULATED VITREOUS CARBON;ELECTRODE