Removal of heavy metals from a contaminated soilusing tartaric acid

【Abstract】 This study reports the feasibility of remediation of a heavy metal (HM ) contaminated soil using tartaric acid, an environmentally-friendly extractant. Batch experiments were performed to test the factors influencing remediation of the HM contaminated soil. An empirical model was employed to describe the kinet ics of HM dissolution/desorption and to predict equilibrium concentrations of HM s in soil leachate. The changes of HMs in different fractions before and after t artaric acid treatment were also investigated. Tartaric acid solution containing HMs was regenerated by chestnut shells. Results show that utilization of tartar ic acid was effective for removal of HMs from the contaminated soil, attaining 5 0%—60% of Cd, 40%—50% of Pb, 40%—50% of Cu and 20%—30% of Zn in the pH ra nge of 3.5—4.0 within 24 h. Mass transfer coefficients for cadmium (Cd) and lead (Pb) were much higher than those for copper (Cu) and zinc (Zn). Sequ ential fractionations of treated and untreated soil samples showed that tartari c acid was effective in removing the exchangeable, carbonate fractions of Cd, Zn and Cu from the contaminated soil. The contents of Pb and Cu in Fe-Mn oxide fra citon were also significantly decreased by tartaric acid treatment. One hundred milliliters of tartaric acid solution containing HMs could be regenerated by 10 g chestnut shells in a batch reactor. Such a remediation procedure indicated tha t tartaric acid is a promising agent for remediation of HM contaminated soils. H owever, further research is needed before the method can be practically used for in situ remediation of contaminated sites.更多还原