Simultaneous Removal of Heavy Metals from water: Effect of pH and Removal Time

Recently many scientists are focused on removal of pollutants from wastewater. Toxic Heavy metals have harmful and hazardous effects on human health and ecology. Up to now severalmethods such as chemical precipitation, ion-exchange, membrane filtration, adsorption, electrochemical treatment have been used to remove toxic heavy metal ions from wastewaters and minimize their health risks. Although all of these techniques can be employed for wastewater treatment, they also have some inherent advantages and limitations [1-3]. Antimony is one of the toxic metals and has much concern in terms of toxicological and environmental. Antimony has been extensively used in power transmission equipment, alloys, batteries, cable sheathing, andbearing metal. Among the most important uses of antimony in nonmetal products are ceramic enamels, paints, textiles, rubber compounds, glass and pottery abrasives phosphorus, and certain types of matches. Antimony and its compounds were listed as priority pollutants by theunited states environ- mental protection agency and the european union due to its toxicity and implication in cancer development [4-6]. Antimony exists in environment as a result of natural processes and human activities [7-10]. The toxicological effects of antimony depend onits chemical form and oxidation state. In the environmental samples, antimony exists mainly in the pentavalent and trivalent oxidation states. The Sb(III) compounds have ten times higher acute toxicity than the Sb(V) species [4-6]. Lead is another toxic heavy metal and itstoxicity is well established. All over the world guidelines set the maximum acceptable concentration of lead in drinking water at very low levels [11]. In this study, the simultaneousremoval of both antimony and lead from water has been studied by iron sacrificial plates. The effect of removal time and pH of the water sample on removal of heavy metal ions has been investigated. Scanning electron microscope images of the precipitate obtained after water treatment show the formation of small nanoparticles with this method. Inductively coupled plasma–mass spectrometry results showed that the concentration of antimony and lead in water depends on both time and pH of the water. Based on these results we found that the pH of waterand the removal time play important role on removal efficiency. We suggest this easy,inexpensive, high efficiency, and promising method for removal of heavy metals from water

کلیدواژه ها:

Antimony ، Lead ، Water treatment ، Nanoparticles