Active aluminum oxide desiccant is a porous material with adsorption properties and catalytic activity, characterized by high dispersion and a large specific surface area. It is suitable for drying various gases and liquids and is used as an adsorbent, desiccant, catalyst, and carrier in many reactions in petroleum, fertilizers, and chemical industries. This product is produced from high-purity aluminum oxide through scientific formulation and catalytic refinement. It has high compressive strength, long service life, and can be reused repeatedly through regeneration methods. The principle of defluorination is that fluoride is adsorbed on the surface of the adsorbent to form insoluble fluorides, while the SO42– on the adsorbent can exchange F- and HCO3ˉ and other anions in water. The adsorbent can be placed in a filter tank, with a thickness generally between 700 and 1000 mm, a particle size of 0.5 to 2.5 mm, and a filtration speed of 1.5 to 2.5 m/n. The support layer is made of pebbles, with a thickness of 400 to 700 mm, and the pH of the raw water is adjusted to 5.5 to 6.5 with acid. Using small particle activated alumina, which has a large specific surface area, can enhance the defluorination effect and reduce water production costs. When the defluorination capacity of the activated alumina adsorbent does not meet the standards, an aluminum solution of 1% to 2% can be prepared and passed through the filter column at a flow rate of 0.6 m/n for 6 to 8 minutes for regeneration, after which it can be reused. This method has a strong defluorination capacity and is an excellent technology for removing fluoride and other inorganic ions. Typically, activated alumina is produced by calcining aluminum hydroxide at 400℃ to 600℃ or burning general aluminum oxide with alkaline metal ions at 400℃ to 500℃ to form white granular porous adsorbents. //// Adsorption Function of Activated Alumina Desiccant Activated alumina desiccant is a multi-microporous spherical substance with strong adsorption capabilities, a large specific surface area, high compressive strength, long service life, and can be reused through regeneration methods. This product is a white, spherical porous substance that is non-toxic, odorless, does not powder, and is insoluble in water. It is widely used in the petroleum and chemical industries, textiles, metallurgy, and other sectors for instrument air drying and pressure swing adsorption separation devices, with an adsorption dew point reaching above -41 degrees. It can also be utilized for deep drying of liquid and gas phases in steel, petroleum cracking gas, ethylene, and propylene. Activated alumina, also known as reactive alumina, is referred to in English as Activated Alumina or Reactive alumina; activated alumin(i)um oxide. When aluminum oxide is used in catalysts, it is usually specifically called "activated alumina." It is a porous, highly dispersed solid material with a large surface area and possesses the characteristics required for catalytic activity, such as adsorption properties, surface activity, and excellent thermal stability. Therefore, it is widely used as a catalyst and catalyst carrier in chemical reactions. Spherical activated alumina for pressure swing adsorption is a white spherical porous particle with uniform particle size, smooth surface, high mechanical strength, strong hygroscopicity, and does not swell or crack after absorbing water, is non-toxic, odorless, and insoluble in water. Activated alumina is an efficient desiccant for deep drying of trace water and is particularly suitable for non-thermal regeneration devices. //// Main Factors Affecting the Adsorption Performance of Activated Alumina: (1) Particle size: The smaller the particle size, the higher the adsorption capacity, but the smaller the particle size, the lower the particle strength, which affects its service life. (2) pH value of raw water: When the pH value is greater than 5, the lower the pH value, the higher the adsorption capacity of activated alumina. (3) Initial fluoride concentration of raw water: The higher the initial fluoride concentration, the larger the adsorption capacity. (4) Alkalinity of raw water: A high concentration of bicarbonate in raw water will reduce the adsorption capacity. (5) Chloride ions and anions. (6) The impact of arsenic: Activated alumina has an adsorption effect on arsenic in water, and the accumulation of arsenic on activated alumina reduces the adsorption capacity for fluoride ions and makes it difficult to elute arsenic ions during regeneration.