Removal of Lead from Contaminated Water and Clay Soil Using a Biosurfactant

Lead removal from water and contaminated soils was investigated using biosurfactant, anionic, and nonionic surfactants in continuously stirred batch reactors. Lead-contaminated water up to 100 mg/L and clay soil up to 3,000 mg/kg were used in this investigation. The surfactant concentration up to 10 critical micelle concentration was used. The speciation of lead into the micelles was quantified and the lead removal efficiency depended on the level of contamination, surfactant type, and concentration. Of the surfactants used, biosurfactant (produced from used vegetable oil) had the best removal efficiency (75%) at a lead contamination of 100 mg/L in water at pH of over 12. The Fourier-transformed infrared spectroscopy study showed that the carboxyl group in the biosurfactant was effective in removing the lead from the solution. Langmuir and Freundlich relationships were used to represent the micelle partitioning of lead in the surfactant solutions. Desorption of lead from contaminated kaolinite clay was represented using linear isotherms. The biosurfactant solution had a higher micelle partitioning for the lead from contaminated water and desorbing the lead from the contaminated soil compared to the other chemical surfactants.