Surfactant Effect On The Distribution Behavior In Soil-water Interface And Degradation Of Phenanthrene

Surfactants have significant effects on the interfacial behavior in solid-liquid system and bioavailability of organic pollutants. For slightly contaminated agricultural soils, cationic-nonionic mixed surfactants-enhanced sorption of organic contaminants onto soils could reduce their transfer to plants, therefore safe-guards the agricultural production. After the plantation, residual surfactants combined with added nonionic surfactant could also promote the desorption and biodegradation of the residual organic pollutants, thus provide a cost-effective pollution remediation technology. The enhanced-sorption and subsequent desorption and biodegradation for phenanthrene by surfactants were introduced and tested in this study. And the main results of this thesis are shown as follows:(1) The cationic-nonionic mixed surfactants could enhance soil retention for phenanthrene, which was about24.5times that of soils without surfactant and1.5times that of soils with individual cationic surfactant. The cationic-nonionic mixed surfactants showed the best capacity on enhanced-sorption of phenanthrene onto soils at ratio of8:2when the concentration of mixture was controlled constantly. And the cost of the cationic-nonionic mixed surfactants for the same effectiveness was approximately reduced by50%.(2) Verify the duration of the mixed surfactant enhanced-sorption of phenanthrene could exactly match the crop growth period. And it did not affect the subsequent removal rates of phenanthrene by nonionic surfactant. After the soil washing, the residual cationic surfactant and nonionic surfactant, respectively, at dose of0-1.0mg/g and0-2.0mg/g had no obvious impact on phenanthrene biodegradation at the end of the experiment. Therefore, the surfactants can be used to regulate the interfacial behavior of phenanthrene in soil-liquid system for the alternative scheme of enhancing sorption or removing organic contaminants, in order to safe-guard the agricultural production and cost-effectively remedy the organic contaminated soils.