Removal of Lead Ions from Aqueous Solution by Sorptive-Flotation Using Limestone and Oleic Acid

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A simple, rapid and economic procedure was presented to remove lead(II) from aqueous solution under the optimized conditions. It is based on the sorption of Pb2+ ions from aqueous solutions onto limestone fines (LS), which is an inexpensive and widespread over the globe, followed by flotation with oleic acid (HOL) surfactant. The different parameters (namely: solution pH, sorbent, surfactant and lead concentrations, shaking times, ionic strength, temperature and the presence of foreign ions) influencing the sorptive-flotation process were examined. Nearly, 99% of Pb2+ ions were removed from aqueous solutions at pH 7 after shaking for 5 min and at room temperature (~25 oC). The procedure was successfully applied to recover lead(II) spiked to some natural water samples. A mechanism for sorption and flotation is suggested.