Abstract
Chemical solubilization of lipids is an process in soil removal from textiles. This study reports a real time observation of a modelistic removal process of solid lipids : namely, the removal of tripalmitin (TP), palmitic acid (PA) and lard by sodium dodecyl benzenesulfonate (DBS), dodecyl heptaethyleneoxide and two commercial detergents, was traced with a quartz crystal microbalance method (QCM). The variations in the frequency 9 MHz QCM and the admittance were recorded. Those variations were interpreted as changes in the apparent weight and viscosity of the lipids on QCM. The conclusions are as follows : 1) The removal process comprises the swelling of lipids by water and detergent and the following removal with different rates depending on the detergent type, concentration and the pH of the solution; 2) With DBS and nonionic surfactants, the removal takes place below the cmcs. With DBS, the removal rate increases with the concentration until it levels off over the cmc, while with the nonionic surfactants, the removal rate increases with the concentration even over the cmcs. These two facts imply that the micelles of DBS do not participate in the removal process, while the micelles of the nonionic surfactants do; 3) Lard shows a removal behavior similar to PA rather than to any mixture of TP and PA; 4) The removal of PA and lard by the two commercial detergents was slow and incomplete compared to the cases where surfactant solution were used.
