ROLE OF SURFACTANT PRECIPITATION AND REDISSOLUTION IN THE ADSORPTION OF SULFONATE ON MINERALS.

This study on the precipitation of sulfonates with various inorganic ions (Na, K, NH//4, Ca, Mg, and Al) and the subsequent redissolution when the surfactant concentration is increased shows a precipitation maximum to occur in the same surfactant concentration range where an adsorption maximum is obtained. Simultaneous abstraction, precipitation, and adsorption experiments have been conducted using chromatographically purified dodecylbenzenesulfonate and Nakaolinite, and the results show the 'abstraction vs. surfactant concentration' curves to exhibit a much more pronounced maximum than the real adsoprtion (abstraction minus precipitation) maximum.