Adsorption of petroleum sulfonate TRS 10‐80 on a mineral sand

Abstract

A BSTRA CT Adsorption of petroleum sulfonate TRS 10-80 on a mineral sand, characterized by chemical analysis and infrared spectra to be silica, has been studied under conditions relevant to the practical field. The adsorption is significantly affected by the age of the sulfonate solutions. A new mechanism of adsorption involving sulfonate monomers and multimers has been proposed. The adsorption behavior is best characterized by Langmuir and Freundlich models. At higher temperatures, the mineral surface seems to be capable of forming chemical bonds with the sulfonate anions. Micelles are not considered to be the species favored for adsorption. The adsorption, depending upon the concentration of added electrolyte, either reaches a saturation value or decreases abruptly after a fixed surfactant concentration has been reached. The apparent surfactant loss at higher salt concentrations seems to be due to salting-out of the sulfonate rather than its adsorption. NOMENCLATURE= Langmuir constant representing intensity of adsorption = depletion in surfactant concentration after adsorption = equilibrium surfactant concentration (wt%) b AC ce CMC = critical micelle concentration D = sulfonate dimer K