Comparison of six surfactants in removing toluene and trichlorobenzene from a sandy soil under laboratory conditions

The effectiveness of four food-grade and two industrial surfactants to remove toluene or 1,2,4-trichlorobenzene added to an Iowa soil was evaluated in batch and column experiments. One of the anionic food-grade surfactants, disodium n-hexadecyl diphenyloxide disulfonate (Dowfax 8390), was more effective than the other surfactants in shaken batch experiments. The maximum recoveries of the added toluene (57%) or 1,2,4-trichlorobenzene (71%) were obtained with one surfactant wash plus two water rinses. Dowfax 8390 also yielded the highest recovery of toluene (75%) or 1,2,4-trichlorobenzene (83%) in columns of soil flushed with 1250 mL of 4% surfactant solutions. Synergism in a mixture of 2% Dowfax 8390 (anionic) and 2% T-Maz 60 (nonionic) did not occur, in contrast to enhanced recoveries exhibited by a similar mixture of the two industrial surfactants, Sandopan JA36 (anionic) and Pluronic L44 (nonionic).