Remediation of heavy metal contaminated soil using saponin

This study reports the feasibility of remediation of a heavy metal(HM) contaminated soil using saponin,an environmentally-friendly extractant.Batch experiments were performed to test the influence of saponin pH,concentration,and contact time on remediation of HM contaminated soil.An empirical model was employed to describe the kinetics of HM dissolution/desorption.Using the model,we can also obtain two important parameters: the equilibrium HMs concentrations(Ce) and mass transfer coefficients(k).Results show that utilization of saponin was effective for removal of HMs from the contaminated soil,attaining 93.5%of Cd,20.5% of Pb,8.6% of Cu,48.4% of Zn in the pH range of 5.0-5.5 within 12 h.The order of mass transfer coefficient was Cd?Zn?Pb?Cu.Such a remediation procedure indicates that saponin is a promising agent for remediation of HM contaminated soils.However,further research is required before the method can be used for in situ remediation of contaminated sites.