Effect of Soil Properties and Addition of Surfactants on the Adsorption of Carbaryl in Soils

Adsorption and movement of carbaryl in absence and presence of aqueous surfactant (cationic, cetyl pyridinium chloride (CPC), non-ionic, polyoxyethylene lauryl ether (Brij-35) and anionic, sodium dodecyl benzene sulphonate (SDBS)) solutions of different critical micellar concentrations (0.5 X CMC, 1.0 X CMC and 2 X CMC) in soils were studied using batch shake and soil thin-layer chromatography (soil TLC) techniques. The measured equilibrium adsorption isotherms were L-shaped and in close agreement to Freundlich isotherms. Higher adsorption of carbaryl in both systems was observed on FRI silt loam (FSL) soil followed by Alampur silt loam (ASL), Kalai loam (KL) and Bhoran sandy loam (BSNL) soils as anticipated from Freundlich constant K_D, K_D* and distribution coefficient K_F, K_F* values. The adsorption of carbaryl in surfactant-soil-water systems followed the order: cationic > anionic > non-ionic at all CMC values studied. The frontal R_f(FR_f) values obtained from soil TLC studies were inversely proportional to K_F, K_F* and K_D, K_D* values. The ratios of (K_D*/K_D) values were used to evaluate remediation efficiency of surfactants. Non-ionic surfactant (Brij-35) is favorable for remediation of carbaryl contaminated soils as K_D*/K_D ratio is less than 1.