(107a) Adsorption of Nonionic Polyethoxylated Surfactants on Mineral Oxides At High Salinity

Nonionic surfactants possess low critical micelle concentration and high brine tolerance. In this study, the adsorption behavior of a polyethoxylated octylphenol and a polyethoxylated nonylphenol on silica in various aqueous solutions was investigated. Adsorption isotherms were used to study the effects of increasing salinity and hardness concentrations on the mechanism of adsorption and the overall adsorption density. The effect of solution temperature and its relation to the phase separation boundary, the cloud point temperature, on adsorption was analyzed by comparing overall adsorption at various temperatures. This is the first step in a multiple phase study that will investigate the adsorption behavior of nonionic/anionic surfactant mixtures. Nonionic surfactants are of interest to those studying chemical enhanced oil recovery because of their potential to decrease anionic surfactant adsorption and chromatographic separation in oil reservoirs, thus increasing the economic feasibility of enhanced oil recovery.