Abstract
It is well known that alkaline earth metallic ions in aqueous solution influences to detergency.
In this report, an investigation was made on the detergency of LAS to triglycerides in the presence of Ca ion. It was found that there is a concentration of Ca ion to give the maximum detergency, which increases in proportion to the concentration of LAS.
Namely, there is an optimum ratio between the concentration of Ca ion and Na ion in LAS on detergency, and it is independent of the concentration of LAS.
This fact suggests us that Na salt of LAS and Ca salt formed by double decomposition of a part of LAS with Ca ion in aqueous solution form a kind of complex micell, which may increase the adsorption of LAS on soil.
It is considered that LAS is not only adsorbed on the surface of soil but penetrates into the soil to form a sort of liquid crystal, and that the adsorption of LAS to soil decreases the adhesive energy between soil and glass to lower the interfacial tention between soil and aqueous solution of LAS, and may improve the detergency of the system.
