removal of lead ions from aqueous solution by sorptive-flotation using limestone and oleic acid

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.