Abstract:

The contamination caused by industrial dyes is harmful to soil ecology. Nonionic surfactants exhibit high desorption ability towards dyes but leave a high residual content in soil， and anionic surfactants present lower elution efficiency on dyes other than cationic ones but remain less in soil. The combination of these two types of surfactants could retain the advantages of both， whereas the anionic-nonionic surfactant that combines the structural characteristics of both requires further exploration for its elution and remediation effect in dye-contaminated soil remediation. In this experiment， the hydrophobic/hydrophilic dye-contaminated soil models were established using methyl orange and alizarin red， and the performance of a novel anionic-nonionic surfactant， sodium nonylcyclohexanol ethoxysulfate（NCEO₅S） in dye elution from contaminated soil was investigated， with a classic surfactant sodium laureth sulfate （SLES） as a control. The results indicate that the elution efficiency for methyl orange and alizarine red from contaminated soil reached 94.34% and 97.66% respectively， with 1% of NCEO₅S solution and solid-liquid mass ratio of 1∶10（g/g） at pH 8 and 25 ℃. Under the same conditions， the elution efficiencies of SLES were 88.61% and 91.23%， respectively. The results reveal that NCEO₅S exhibited slightly better ability to elute dyes from contaminated soil than SLES， with less residue remaining in soil.

Key words: Sodium nonylcyclohexanol ethoxysulfate, Sodium laureth sulfate, Dye, Soil, Elution