Detergents and Detergency

摘要: The cleaning of a solid object, i.e., the removal unwanted foreign matter from its surface, is done by methods ranging simple mechanical separation such as blotting or abrasion to solution selective chemical action. term detergency limited systems in which liquid bath present and main component system. action involves more than hydraulic dislodging soil, although both will occur contribute cleaning. enhanced primarily presence special solute, surfactant, that alters interfacial effects at various phase boundaries within Thus, typical detersive system consists object be cleaned, called substrate, soil dirt attached it removed washing process, applied soiled substrate. In turn, each these elements can vary widely properties composition. final benefit results interaction conditions used, temperature, time, energy input (agitation), and, case aqueous baths, hardness ions water. In process system, substrate immersed brought into contact with large excess liquor. Enough used provide thick layer over whole surface During this stage, air displaced surfaces; they are wetted bath. subjected agitation, either rubbing shaking, provides necessary shearing separate disperse Agitation also promotes mass transfer just heterogeneous reaction. carrying drained, wiped, squeezed, otherwise rinsed free remaining This rinsing step determines cleanliness cleaned dried finished. A meaningful discussion requires definition clean. physiochemical sense, clean if contains no molecular species other those interior two adjoining phases. It difficult achieve state even under most exacting laboratory conditions. Practically, has been desired regard upon it, judged agreed-upon criteria. Household linen, for example, considered when visible though may carry starch softening finish. dyehouse textile mill, piece goods would rejected dirty returned scouring because finishes interfere dyeing. Most standards cleanness involve visual optical judgment matter. some systems, desizing cotton, degree specified weight percentage on degreasing metal, per unit area specifies cleanness. dishes glassware, often complete water wettability freedom break, well appearance. Although impossible list all practical might encountered, proportion fall small number classes. classification disregards surfactant structure type (fibrous hard surface) restricted consideration employed, ratio, detergent used. Some commonly encountered classified basis here. Keywords: detergency; detersive systems; surfactants; water hardness; antiredeposition agents; foam; oily soil; solid soil; measurements; laundering; dishwashing; metals; liquid products; solid products; eutrophication