Detergents dirt removal action

Detergency involves the action of surfactants to alter interfacial properties and to reduce the energy needed to cause the removal of dirt from solid surfaces. In addi-... 

It Is effective for the removal of grelge mill oil, dirt, ollstalns, waxes, graphite, etc. In any scouring process where a combination of detergent and solvent action Is necessary. The use of this product allows the processor to work with detergents and solvents In the water phase without fire hazards. 

Figure 2.40 Removal of dirt from a solid surface by detergent and mechanical action. Source Shaw.

In the detergency process, fatty materials (i.e. dirt, often from human skin) are removed from surfaces, such as cloth fibres, and dispersed in water. It is the surfactants in a detergent which produce this effect. Adsorption of the surfactant both on the fibre (or surface) and on the grease itself increases the contact angle of the latter as illustrated in Figure 4.7. The grease or oil droplet is then easily detached by mechanical action and the surfactant adsorbed around the surface of the droplet stabilises it in solution. 

In textile literature, any foreign matter present in or on fiber or fabric, i.e., dirt, oil, grease, etc. These are usually removable by the action of soap, synthetic detergents, or organic solvents. 

Figure 2.39 Detergent cleaning action for removing oily dirt from a solid surface. Source Shaw.

Another problem in colloids is detergency, which involves the action of sinfac-tants (originally soaps were used) to alter interfacial properties so as to promote dirt or oil removal from solid surfaces. The detergent s role is to alter interfacial tensions in order to reduce the amount of mechanical energy required to dislodge the dirt. If the dirt is solid then it is a simple matter of wettability alteration. 

Detergent Action of Soap.—The property possessed by soap of removing dirt is one which it is difficult to satisfactorily explain. Many theories, more or less complicated, have been suggested, but even now the question cannot be regarded as solved. 

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