Removal of Dirt

The task of the detergent is to lower y and y which decreases yju and facilitates the removal of dirt by mechanical agitation. 

Nonionic surfactants are generally less effective in removal of dirt than anionic surfactants. In practice a mixture of anionic and nonionic surfactants are used. 

The addition of detergent increases the contact angle at the dirt/substrate/water interface so that the dirt rolls up and off the substrate. Surfactants that adsorb both at the substrate/water and the dirt/water interfaces are the most effective. If the surfactant adsorbs only at the dirt/water interface and lowers the interfacial tension between the oil and substrate dirt removal is more difficult. Nonionic surfactants are the most effective in liquid dirt removal since they reduce the oil/ water interfadal tension without reducing the oil/substrate tension. 

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Detergency may be defined as the removal of dirt from solid surfaces by surface chemical means [29], and may be related to several surfactant properties, including wetting and rewelting ability, foam generation, and surface and interfacial tension. It has long been observed... 

The removal of dirt and stubborn grease generally requires the use of aqueous-based, heavy-duty industrial cleaners. These cleaners may or may not contain traditional ingredients like caustic or phosphate (which can be replaced by silicates or organic surfactants). 

Detergents aid the removal of dirt. Commercial synthetic detergents were first developed in the 1950s. Detergents act mainly on the oil-based films that trap dirt particles. Most detergents have an oil-soluble portion (usually a hydrocarbon chain), and a water-soluble portion, which is generally ionic. 

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-... 

The role of soaps in removal of dirt and grease is described in Section 15.2. 

HydriseL [Hydrdate] Detergents for removal of dirt, oil and grease during peroxide bleaching, prescouring, and dyeing. 

One of the principal distinction between the liquid-liquid and liquid-gas interface is the possibility to achieve very low interfacial tensions down close to zero. This possibility is realised provided the surfactant is soluble both in the aqueous and hydrocarbon phase, as well as using binary mixtures of water-soluble and oil-soluble surfactants. This phenomenon is of special importance for the formation of emulsions and microemulsions, in the removal of dirt and in the enhanced oil recovery. 

Flattened cuticle cells primarily account for most of the surface properties of mammalian fibers. In Merino wool, cuticle cells are approximately 20 xm x 30 xm x 0.7 xm [35]. Cuticle cells overlap both longitudinally and circumferentially with exposed lips or scale edges pointing toward the distal end of the fiber. The scale edges are thought to aid in the removal of dirt and vegetable matter, but they may also assist in anchoring the fiber to the skin [36]. 

B. Wash components in warm, 43 "C (llO F) maximum, water with a mild detergent or witha cleanerrecommendedby the manufacturer. A stiff bristle (not wire)brush may beused to facilitate the removal of dirt. 

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

The removal of dirt particles, etc. is particular important in pipe extrusion pipe lifetimes under pressure are increased when particular care is taken to purify the polymer. 

The same active materials, powdered zinc metal, electrolytic manganese dioxide, and KOH electrolyte are used in both the standard cylindrical alkaline and the miniature coin cells discussed later. In contrast, the lower-performance, low-cost natural Mn02 in the Leclanche cells is used as it is mined, after the removal of dirt, rocks, and other debris that result from the mining process. It has lower performance but is also at lower cost than EMD. 

The first concern is the removal of dirt and oil used during the manufacturing process of the tubing. If one intends to use an electron-capture detector at any... 

To formulate a good detergent, one has to understand the various processes involved Wetting, removal of dirt, liquid soiling, prevention of redeposition of dirt. 

To be effective as a detergent, a surfactant has to fulfil a number of functions. First, it must effectively wet the fabric, so that the detergent will come into contact with the surface to be cleaned. Second, it should facilitate the removal of dirt from the fabric surface. Third, it should solubilize or disperse dirt, and help to prevent its redeposition. Figure 4.19 summarizes the action of detergent through these processes. 

The mechanism of removal of dirt depends on whether it is particulate or oily/fluid. In the former case, the surfactant must lower the work of adhesion of the dirt particle to the solid fabric surface. If the dirt is a... 

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