Activated alumina desiccant is a porous, high-dispersion, large specific surface area aluminum oxide with adsorption properties and catalytic activity. It is suitable for drying various gases and liquids and is used as an adsorbent, desiccant, catalyst, and carrier in many reaction processes in petroleum, fertilizer, and chemical industries. This product is made from high-purity aluminum oxide that has been scientifically formulated and catalytically refined. It has high compressive strength, long service life, and can be reused repeatedly through regeneration methods.

The defluorination principle involves the adsorption of fluoride onto the surface of the adsorbent, forming insoluble fluorides, while the SO42– on the adsorbent can exchange with other anions such as F- and HCO3ˉ in water. The adsorbent can be placed in a filter bed, with a thickness typically ranging from 700 to 1000 mm, and a particle size of 0.5 to 2.5 mm, with a filtration rate 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 to regenerate it, after which it can be reused. This method has a strong defluorination capacity and is an excellent technology for removing fluoride and various inorganic ions.

Typically, activated alumina is produced by calcining aluminum hydroxide at 400℃ to 600℃ or by burning general aluminum oxide with alkaline metal ions at 400℃ to 500℃ to obtain white, granular, porous adsorbent.

//// 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, non-powdering, and insoluble in water. It is widely used in the drying of instrument air in industries such as petrochemical, chemical, textile, and metallurgy, in pressure swing adsorption air separation devices, with a dew point adsorption capability of over -41 degrees, and can also be used for deep drying in the liquid and gas phases of 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 aluminum oxide. In catalysts, aluminum oxide is commonly referred to as "activated alumina", which is a porous, highly dispersed solid material with a large surface area. Its microporous surface possesses the characteristics required for catalytic activity, such as adsorption capacity, surface activity, and excellent thermal stability, making it widely used as a catalyst and catalyst carrier in chemical reactions. Spherical activated alumina pressure oil adsorbent is white, spherical, porous granules with uniform particle size, smooth surface, high mechanical strength, and strong moisture absorption. After absorbing water, it does not swell or crack and maintains its original state, is non-toxic, odorless, and insoluble in water. Activated alumina is an efficient desiccant for deep drying of trace water. It 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 smaller particles have lower strength, which affects their service life.

2. pH 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 greater the adsorption capacity.

4. Alkalinity of Raw Water: High concentrations of bicarbonate in raw water will reduce the adsorption capacity.

5. Chloride and other anions. 6. Effect 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 the elution of arsenic ions during regeneration more difficult.