Adsorption of Nonionic Oxyethylated Sulfonamides onto Sand and Kaolin from Aqueous Solution

Abstract

AbstractNonionic surfactants continue to be used as soil conditioners, principally as wetting agents, but optimum surfactant chemical structure has not as yet been completely established. This research using nonionic surfactants, alkyl substituted polyoxyethylated phenylsulfonamides, has determined the effect of varying the ethoxy content and the alkyl side chain on three surfactant characteristics, i.e., adsorption, wetting, and dispersion. It was found that surfactant adsorption on sand and kaolin, two soil components, at a constant pH of 6.0 decreased with higher surfactant ethoxy content. Changing the alkyl side chain from C6 to C8 to C10 increased the apparent surfactant attraction for the adsorbent surface but not the total amount of surfactant adsorbed. The amount of surfactant adsorbed determines the final nature of the adsorbent's surface and its hydrophobic or hydrophilic character. Thus, the wetting and dispersing properties of soil components can be set by the amount of surfactant adsorbed.