Industrial Wastes as Potentional Sorbents of Heavy Metals

Abstract

Industrial wastes can be used as sorbents of heavy metals. Nowadays, the wastes materials are studied as sorbents and the sorption capacities and other properties are comparable or better than in the case of natural or specially prepared sorbents. Blast furnace slag, steel making slag, laboratory and industrial pyrolysis product from tires and coke dust were selected as potential sorbents of heavy metals. The characterization of materials was performed by infrared spectroscopy and kinetic models of sorption were determined. Laboratory and industrial pyrolyzed tires and coke dust contain mainly pure carbon without other functional groups on the contrary to brown coal containing hydroxyl and carboxyl functional groups, which affected sorption properties. Slags contain mainly silicates. The sorption capacities of waste materials were compared with brown coal as example of natural sorbents. The sorption experiments were carried out by batch technique in aqueous medium at ambient condition. The metal ions Cu(II) and Pb(II) were selected as adsorbates. Sorption of metal ions was studied in the concentration range 2 – 40 mmol · l -1 . The sorption capacities show that blast furnace slag, laboratory and industrial pyrolysis product from tires and coke dust exhibit the comparable values of removal amounts. The brown coal exhibits better results than other carbonaceous materials. Steel making slag’s sorption capacities are 0.65 mmol · g -1 for Cu(II) and 0.32 mmol · g -1 for Pb(II). The steel making slag is the best sorbent from the studied wastes for both cations. The sorption properties and mechanism can be predicted from the obtained sorption data.