Sorption Mechanisms Of A Nonionic Surfactant Onto Soils

The distribution of Triton X-100 (TX, a typical nonionic surfactant) between sediments/inorganic components samples and water as a function of sediment composition and the adsorption kinetics of TX on to sediments samples were systemically studied. The adsorption capacity does not correlate well with the fraction organic carbon of the sediment, the amount of swelling clay and the hydrophobic index of organic matters may affect the uptake capacity. All the adsorption isotherms are nonlinear. Freudlich isotherms represent the data well. The adsorption kinetics demonstrates there are two different property sorption domains contained in sediments. Addition of CaCl₂ negatively affects adsorption capacity for S1 and S2 for the entire observed concentration rang, yet certain amount of CaCl₂ promotes the affinity for TX for S3 and S4. This discrepancy may result from competitive adsorption and conformational flexibility or rigidity of humic components. And also the adsorption of the widely used nonionic surfactant Triton X-100(TX) onto three model inorganic soil components (silica powder, γ-alumina, and calcite) was investigated in a series of batch experiments in which the aqueous phase equilibrated with solid, under different solution conditions. TX did not show discernable adsorption on γ -alumina (25℃ 3.845°C), indicating that the adsorption is exothermic. The calculated enthalpy of adsorption (¹0kJ/mol) demonstrates that the uptake at solid-liquid equilibrium pH (6.1) was largely due to physisorption.