Soot, removal from smoke

The removal of soot from smoke is another example of the coagulation of a colloid. When smoke is passed through an electrostatic precipitator (Fig. 17.24), the suspended solids are removed. The use of precipitators has produced an immense improvement in the air quality of heavily industrialized cities. 

One report stated the heavy crude oil processing unit was in normal operation and had not been undergoing repairs. A spokesman indicated the fire produced a visible plume of black smoke and a bucketful of debris was blown into the community. The company offered to wash cars to remove any airborne soot from the fire. [22]... 

Ozone produced in machines like this is used to treat clothing, carpeting, and other materials that have been damaged by smoke and soot from a fire. Hotels also use ozone machines to remove the odor of cigarette smoke from rooms. The reactive ozone oxidizes large, smelly compounds in the smoke and soot into smaller, odorless compounds. 

Sodium bicarbonate is also used in cleaning products on both a household and industrial level. Many householders use commercial baking soda, such as that sold by the Arm Hammer company, to clean kitchen and bathroom appliances, such as sinks, stoves, and toilet bowls. Industries also use sodium bicarbonate filters to remove sulfur dioxide and other pollutants in flu gases released from factory smokestacks. The compound is also used in the treatment of wastewater to maintain proper acidity, remove certain odors (such as those of sulfur dioxide), and destroy bacteria. Some communities have used aqueous solutions of sodium bicarbonate sprayed at high pressure to remove graffiti paint soot and smoke residues and mold from buildings, walls, and other public structures. 

Polyesters burn with a yellow flame with blue edges and produce black smoke with soot in the air. They continue to turn without dripping after the removal of the ignition source and give off a sour cinnamon odor. The specific gravity ranges from 1.30 to 1.50. 

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