SURFACTANT ENHANCED DESORPTION OF TNT FROM SOIL

Surfactant enhanced desorption of 2,4,6-trinitrotoluene (TNT) from con taminated soils at a military site was investigated. Anionic (SDS and DOWFAX 8390), cationic (CTAC and CTAB), and nonionic (Tween 80 and Bij 35) surfactants were first tested at concentrations ranging from 0.1 to 1%. The anionic and nonionic surfactants were further tested at con centrations of up to 10%. Anionic surfactants, particularly SDS, provi ded the best desorption of TNT from the soil. There was not any increa se in TNT desorption for both the nonionics and cationics at concentra tions ranging between 0.1 to 1% and the extent of desorption was found to be lower than the TNT desorption only by water. The competition of the negatively charged soil surfaces for the positively charged catio nics and the neutral nonionic surfactants may constitute the underlyin g reason. TNT was significantly desorbed when the concentrations of Tw een 80, DOWFAX 80 and SDS were increased up to 10%.