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Hydrochloric acid is one of the important raw materials in the chemical industry, and it is widely used in industries such as chemical manufacturing, dyes, pharmaceuticals, food, printing and dyeing, leather processing, sugar production, and metallurgy. It is also used for the regeneration of ion exchange resins, as well as in electroplating and as a cleaning agent for metal surfaces. Hydrochloric acid is an aqueous solution of hydrogen chloride (HCl). Pure hydrochloric acid is a colorless liquid with a pungent odor, and it is highly corrosive and volatile ； Industrial hydrochloric acid appears yellow due to impurities such as iron and chlorine, and is available in concentrations of 30% and 36%. Industrial hydrochloric acid is generally produced by burning chlorine and hydrogen in a synthesis furnace to generate hydrogen chloride gas, which is then absorbed by water. The temperature in the furnace is very high; chlorine comes into contact with the furnace walls made of steel and reacts, resulting in hydrogen chloride gas that contains iron trichloride vapor ； This gas also introduces impurities such as iron during pipeline transportation, and the presence of iron causes hydrochloric acid to turn yellow. There are strict **standards** for the iron content in reagent hydrochloric acid: 0.0001 W/% for chemically pure grades, 0.00005 W/% for analytically pure grades, and 0.00001 W/% for ultra-pure grades; it is generally required that such hydrochloric acid be colorless. Reagent hydrochloric acid is usually produced by evaporating hydrogen chloride gas from industrial hydrochloric acid in glass reactors, or by directly purifying and removing impurities from hydrogen chloride gas generated in synthesis furnaces; therefore, removing iron from hydrochloric acid is of great importance in its production. A material that I am aware of exhibits excellent adsorption properties for iron ions in solutions of this type; it allows for large-scale treatment, is easy to regenerate, and requires simple operation. The iron content in highly concentrated hydrochloric acid can be reduced to below 0.1 mg/l using this material. Those who need to resolve this issue please feel free to reach out.