Abstract
The behavior of kaolin which was coated with palmitic acid in a detergent solution was discussed in terms of the ζ-potential and the potential energy of interaction. The detergent was composed of 20% sodium dodecyl sulfate (SDS), 20% zeolite, 5% sodium silicate, 3% sodium carbonate, 1% sodium carboxymethyl cellulose, and 51% sodium sulfate. The ζ-potentials of kaolin coated with palmitic acid ineach aqueous solution of SDS, various builders, and the detergent were measured by an electrophoretic mass-transfer method. The potential energies of interactions between the coated kaolin and fabrics (nylon and cellulose), between the coated kaolin and zeolite, and between the coated kaolin and the other particulate soils (carbon black, coated carbon black, and kaolin) were calculated by the use of the theory of heterocoagulation and that between coated kaolin particles by the use of the DLVO theory. It is suggested from the total potential energy curves thus obtained that in SDS solution the coated kaolin may deposit onto fabrics or may coagulate with the other particulate soils more easily than kaolin, but in the detergent solution the deposition of the coated kaolin onto fabrics may take place with difficulty and the behavior of coated kaolin may be similar to kaolin.
