REMOVAL OF CADMIUM FROM INDUSTRIAL WASTE WATER BY USING BIOMATERIALS

Abstract

BACKGROUND: The heavy metal pollution and toxic organic compounds are of greater concern for human and environmental health because of discharges to water, air, and the terrestrial environment. Cadmium is one of the heavy metal, which is non- essential for microorganisms and other life forms and exerts foxic action on them after cellular uptake. There are reports concerning morphological, biochemical, toxicological and physiological changes caused by cadmium in microorganisms. Cadmium may influence heart diseases in human beings. Therefore, proper treatment of industrial wastewater is essential before releasing into the recipient environment. The aim of the present research work is to find a newer eco-friendly wastewater treatment technology mainly concerning the removal toxic elements in the contaminated water system.

METHODS: A synthetic wastewater sample was prepared and real samples were collected. Activated carbon of Tridax procumbens (Asteraceae; Compositae), was used as biomaterial. Batch adsorption experiments were performed for determination of contact time, effect of adsorbent dose, control of pH and temperature. Cadmium ion- specific electrode system was used for the analysis of free cadmium ion concentrations in test samples.

RESULTS: In the present investigation, the rate of removal of Cd (11) ions in synthetic wastewater is mainly controlled by pH of the solution. The adsorption starts at pH 3.5 and steeply rises to 6.5. Ar this pH 98 percent, removal of Cd (IT) was achieved. The optimum contact time was estimated to be 180 minutes and the amount of bioadsorbent used was 4.0g. The removal of Cd (IT) was completed within 90 minutes in dilute solutions of 25 PPM. However, at higher concentrations (50 and 100 PPM), the removal was completed only after 120 and 180 minutes, respectively. In real sample analysis, complete removal of Cd (II) was achieved by using 4.0g of activated carbon of the bloadsorbent within 180 minutes of contact time.

CONCLUSION: The biomaterial employed in this experimental study is harmless to human beings. The percent removal of Cd (IT) under the conditions employed here, is 98 with an effective dose of 4.0 g of bioadsorbent. Complete removal of Cd (IT) in electroplating unit wastewater is achieved. This process can be effectively used in CO (IT) and other heavy metals removal in industrial wastewater.