In the Taihu Lake of the south of the Yangtze River, the original watercolor is 17 degrees in the early spring, while the traditional water treatment process, ie reaction, sedimentation, filtration, liquid chlorine disinfection can only decolorize 4 degrees, that is, reach 14 degrees, and when adding dioxide When chlorine is used, the chromaticity is significantly reduced. For example, when pre-dosed with chlorine dioxide 0.5mg/L, the chromaticity can be reduced to 11 degrees; when pre-dosed with chlorine dioxide 1.0mg/L, the chromaticity can be reduced by 10 degrees. When pre-dosed with chlorine dioxide 1.5mg / L (or greater than 1.5mg / L), the chromaticity can be reduced to 9 degrees, that is, the traditional water treatment process, its decolorization efficiency can only reach 23.5%, while dioxide Chlorine has a decolorization efficiency of 47.0% for low-color raw water.
Chlorine dioxide is currently recognized as the latest generation of high-efficiency, broad-spectrum, and safe disinfectants. The World Health Organization (WHO) has classified chlorine dioxide as an A1 safe and highly effective disinfectant. Chlorine dioxide is favored because of its strong bactericidal ability, no harm to humans and animals, and no secondary pollution to the environment. Chlorine dioxide kills many pathogens such as Escherichia coli and Staphylococcus aureus at very low concentrations (0.1 ppm or 10 parts per million). Even under the interference of organic matter, all microorganisms such as bacterial propagules, hepatitis viruses, bacteriophages, and bacterial spores can be completely killed when the concentration is used at several tens of ppm. Compared with the chlorine gas phase: when the concentration of chlorine dioxide in water is 0.5-1 mg/L, 99% of the bacteria in the water can be killed in one minute, and the sterilization effect is 10 times that of chlorine. Chlorine dioxide also has a fast sterilization rate and a wide pH range (6-10). It is not affected by the hardness and salt content of water. It does not produce chlorinated phenols and trihalomethanes. It can oxidize many organic substances, thus reducing the toxicity of water. Mutagenic properties.
As early as 1811, American scientist H. Davey used the KClO3 aqueous solution to react with hydrochloric acid to synthesize and collect ClO2 gas for the first time. However, it was not until the 1930s that ClO2 was able to be produced on a safe and economic scale and began to be widely used in industrialization. In 1944, ClO2 was first used as a disinfectant to treat drinking water in Niagara Falls, New York, USA. In the late 1970s, chlorine dioxide was widely used as a disinfectant and bleaching agent in pulp bleaching, food processing, and disinfection and water purification.
Chlorine dioxide has long been widely used as a bleaching agent in the paper industry of industrialized countries. Compared with the bleaching powder and chlorine gas, it not only improves the whiteness, but also prevents the fiber strength from being lowered, simplifies the production process, and more importantly, eliminates the use of bleaching powder and chlorine gas to generate free chlorine, resulting in the production of a large number of carcinogens. The bleaching process can also kill microorganisms, effectively disperse the mucus and inorganic precipitates in the pulp, thereby eliminating the formation of solid blocks in the pulp and improving the quality of the paper.
The control of algae by chlorine dioxide is mainly because it is very similar to the benzene ring, and chlorine dioxide can also act on the pyrrole ring. Thus, chlorine dioxide oxidizes chlorophyll, and plant metabolism is terminated, causing disruption of protein synthesis. The result of this reaction is that the damage to the plant lies in the dehydration of the protoplasm and the hyperosmotic contraction (plasma separation), which is an irreversible process leading to algae death.
Chlorine dioxide can be used as an effervescent tablet, and a single component solid chlorine dioxide can be prepared by using sodium chlorite, an activator, a filler, a foaming agent, a binder and a lubricant as main raw materials. The stabilizer may be sodium chloride or magnesium sulfate; the blowing agent is sodium carbonate followed by sodium carbonate; and polyvinylpyrrolidone is an adhesive. Not only in the aquarium industry, but also in the aquaculture sector, chlorine dioxide can be used for water conservation and for the treatment of bacterial and viral diseases such as fish, shrimp, crab, turtle, and frog.