Absorbent powders

Aerosol dry shampoos fill an important market for those unable to tolerate wet hair, such as the sick and infirm. These products are based on oil absorbing powders which include talc, starch, and/or clay. They can be sprayed onto hair and then bmshed off after absorbing soils from the hair. 

The results are shown in Figure 26.58 for two blunt surfaces Knurled aluminum and knurled steel. Aluminum produces a lower abrasion loss than steel. On both surfaces, however, the abrasion was much higher when MgO was used as an absorbing powder than with the mixture of Fuller s earth and alumina. The two compounds examined were an NR compound without antioxidant and one with two parts of Nonox ZA. There is a very clear difference between the two compounds indicating that oxygen plays an important role. 

It may take as much as 12 to 24 hours, especially when using low energy x-rays (e.g. Cr Ka radiation) in combination with a highly absorbing powder and a large camera radius. 

Spray-dry scrubbers are an alternative to conventional wet scrubbers. In this type of scrubber, an alkaline slurry or solution is sprayed in fine droplets into a reaction vessel, along with the flue gas. The droplefs rapidly react with the sulfur dioxide while drying to a fine powder of sulfite salts. This powder is entrained in the gas stream, and is carried to a dust precipitator where it is collected, as shown in Fig. 7. Most of the sulfur dioxide is collected in liquid-phase reactions while the droplets are drying, but 10-15 /o additional sulfur dioxide can be absorbed in gas/solid reactions, as the absorbent powder is swept through the ductwork and particulate collector. These are cocurrent devices, and so the limestone utilization and sulfur removal efficiency are inherently lower than those of countercurrent devices such as wet scrubbers. Partial recycle of the sorbent is often used to improve the sorbent utilization. 

Crystals mp 36-37 . bp 130" Decomposes an contact with moisture or in n warm place Soluble in carbon tetra -chloride. chloroform, ether, oils. Marketed as a mixture with an equnl pari of an absorbent powder Ircompat. Water, alkalies, heat. 

UV/VIS and NIR diffuse reflection spectra are usually measured by an integrating sphere. The inner surface of the so-called Ulbricht sphere (Fig. 5.8) is coated by strongly scattering, non-absorbing powder. After repeated reflections at the inside of the sphere aU radiation will eventually reach the detector. 

Mercury spiU kits available commercially usually include a small pump, sponges impregnated with a material to absorb mercury and which can be used to wipe up the area of a small spill, and a quantity of an absorbent powder that reacts with mercury to form a harmless amalgam. The latter can be spread on cracks and seams in the floor and furniture and is effective in collecting mercury from otherwise irraccessible places. After leavirrg the material on the floor or contaminated surfaces for several hours in order to allow the amalgam to form, the powder can be swept or brushed up and the waste material disposed of as a hazardous waste. 

In case of chemical attack, it is imperative that the war fighter be provided with an effective means of immediate decontamination. The US military currently utilizes kits that contain absorbent powders for this purpose. These powders have some inherent disadvantages and severe limitations, which include but are not limited to ... 

Fine powder with particles <4 tm. Very useful as an absorbent powder... 

An extremely absorbent powder due to its very small size. Can be used to agglomerate Uquids or soft soUds such as nonionic surfactants. Useful as a dusting aid... 

Solid (powders) Diffuse IR reflectance and absorption spectra DRA with powder samples holder For strongly absorbing powders, dilution with KBr or other non IR-absorbing powders is recommended... 

Has a good quahty of static electricity resistance, and will not absorb powder or dust when packing powdery substance. 

Nakamura, K., Kawabata, T, and Mori, Y. (2003) Size distribution analysis of colloidal gold by small angle X-ray scattering and light absorbance. Powder Technology, 131,120-128. 

Wound healing Fluids, sponges, solids, gels, slurries, absorbent powders, sheets, nonwoven fleeces, ropes, and meshes have been used to enhance wound healing. [35, 61-65]... 

Oil absorbers powdered polyurethane foams possess excellent hydrophobic properties and can absorb various types of mineral oils (1 kg of powder can absorb even up to 3.43 dm of oil [58]). Therefore, such reprocessed foams are used for the treatment of scenes of road accidents, in plants involved in the production and trade of petroleum derivatives, and as barriers removing pollution of inland and sea waters. 

---