NaOH (sodium hydroxide, caustic soda, etc.) is a clear, colorless liquid. Its strong basicity allows it to turn red litmus paper blue and pinken phenolphthalein solution. When reacting with acidic groups, it forms water and salt.
Applications in daily life and industry:
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Wastewater treatment: Sodium hydroxide is commonly used to adjust the pH of acidic wastewater, to remove heavy metals by forming hydroxides. NaOH helps neutralize and remove scale buildup in water supply systems, and increases pH during processes like cyanide treatment, nitrogen stripping towers, and other applications, thereby improving water quality for the environment.
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Pharmaceutical industry: Liquid caustic soda is used in the production of some pain relievers, fever reducers like aspirin, cholesterol reducers, etc.
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Textile Industry: NaOH is used in the production of rayon and cotton. During the processing of raw fabrics, NaOH can be used to break down pectin and waxes, improving fabric sheen and increasing the efficiency of dye absorption.
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Paper and pulp industry: In the Kraft pulping process, an alkaline mixture containing NaOH and Na2S is used to dissolve lignin and semi-cellulose in raw materials such as straw, bamboo, and wood chips, releasing fibrous cellulose.
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Other industries: Additionally, liquid caustic soda is widely used in the production of soap, sodium percarbonate, sodium perborate, battery production, aluminum ore processing, and more.
