Abstract

The feasibility of using cationic surfactants to desorb lead (Pb) from contaminated soil was investigated by a two-phase batch-test program. In phase I, Pb desorption from the Slaughterville sandy loam was measured as a function of surfactant concentration for 10 cationic surfactants. In Phase II, Slaughterville sandy loam and Teller loam soils were used to measure the impact of pH on surfactant desorption of Pb. During this part of the investigation, pH was varied over the range of 4 to 9, while the initial surfactant concentration was kept constant at 0.025 mole/L.

Phase I results indicate that 3 of 10 screened surfactants, Isostearamidopropyl Morpholine Lactate (ISML), Lapyrium Chloride (LC), and Dodecyl Pyridinium Chloride (DPC), are clearly better in desorbing lead. At solution concentration of 0.1 mole/L, ISML, LC, and DPC desorbed 82, 59, and 50% of Pb, respectively, from Slaughterville sandy loam. Data from phase II show that Pb desorption by 0.025 mole/L surfactant solutions is pH dependent. As pH decreased, desorption of lead increased. At a pH of 4, ISML, LC, and DPC desorbed 83, 78, and 68% Pb, respectively, from Slaughterville sandy loam along with 36, 32, and 29% Pb, respectively, from Teller loam. These test results support the feasibility of using cationic surfactants in the removal of lead and other heavy metals from fine-grained soil.