Removal of cadmium from industrial effluents by electrocoagulation process using iron electrodes
Heavy metal species are some of the most common pollutants that are found in industrial wastewaters. Because of their toxicity, these species can have a serious impact if released into the environment as a result of bioaccumulation, and they may be extremely toxic even in trace quantities. One such a heavy metal, cadmium, along with its compounds, is widely used in pigments, as heat stabilizers for plastics, for corrosion resistance of steel and cast iron, metal plating, phosphate fertilizer, mining, pigments, alloy industries, in soldering and brazing, and in the battery industry (Ni-Cd batteries). Cadmium is highly toxic and there is some evidence that it is carcinogenic (Hiatt and Huff, 1975). The harmful effects of Cadmium include a number of acute and chronic disorders, such as “itai-itai” disease, renal damage, emphysema, hypertension, and testicular atrophy (WHO, 1984; Leyva-Ramos, 1997). When ingested by human beings, cadmium that is not excreted immediately has a long half-life of several hundred days, so that a low dose exposure over a long period of time can lead to a high body burden. In view of its persistence as a cumulative poison and the low tolerance of the human body towards cadmium, it is of interest to develop schemes for the removal of heavy metals from wastewaters prior to their disposal. Such disposal is, of course, subject to strict environmental regulation.