Activated alumina desiccant is a porous, high-dispersity, and large specific surface area aluminum oxide with excellent adsorption and catalytic properties. It is suitable for drying various gases and liquids, serving as an adsorbent, desiccant, catalyst, and carrier in many reaction processes in industries such as petroleum, fertilizers, and chemicals. This product is made from high-purity aluminum oxide through scientific formulation and catalytic fine processing. It has high compressive strength, long service life, and can be regenerated for repeated use.
The principle of defluorination is that fluorine is adsorbed onto the surface of the adsorbent, forming insoluble fluorides, while the SO42– on the adsorbent can exchange with F- and HCO3ˉ and other anions in the water. The adsorbent can be placed in a filter bed, typically with a thickness of 700 to 1000 mm and a particle size of 0.5 to 2.5 mm, with a filtration speed of 1.5 to 2.5 m/n. The support layer uses gravel, 400 to 700 mm thick, and the pH of the raw water is adjusted to 5.5 to 6.5 with acid.
Using small particle activated alumina increases the specific surface area, improving defluorination efficiency and reducing water production costs. When the defluorination capacity of the activated alumina adsorbent fails to meet the standard, an aluminum solution of 1% to 2% can be prepared and passed through a filter column at a flow rate of 0.6 m/n for 6 to 8 minutes for regeneration, allowing for repeated use. This method has a strong defluorination capacity and is an excellent technology for removing fluorides and various inorganic anions.
Typically, activated alumina is produced by calcining aluminum hydroxide at 400°C to 600°C or burning ordinary aluminum oxide with alkaline metal ions at 400°C to 500°C to form white granulated porous adsorbents.
//// Adsorption Function of Activated Alumina Desiccant
Activated alumina desiccant is a multi-microporous spherical substance with strong adsorption capabilities, high specific surface area, high compressive strength, and long service life, and it 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 industries such as petrochemicals, textiles, and metallurgy for instrument air drying and in pressure swing adsorption air separation devices, with dew points reaching above -41 degrees. It can also be used for deep drying of liquid and gas phases in steel, petroleum cracking gas, ethylene, and propylene.
Activated alumina, also known as reactive alumina, has the English names Activated Alumina or Reactive alumina; activated alumin(i)um oxide. In catalysts, the aluminum oxide used is commonly referred to as "activated alumina." It is a porous, high-dispersity solid material with a large surface area, and its microporous surface possesses the characteristics required for catalytic activity, such as adsorption capacity, surface activity, and excellent thermal stability. Therefore, it is widely used as a catalyst and catalyst carrier in chemical reactions. The spherical activated alumina pressure oil adsorbent consists of white spherical porous granules, with uniform particle size, smooth surface, high mechanical strength, strong moisture absorption, and retains its original shape without swelling or cracking after absorbing water. It is non-toxic, odorless, and insoluble in water. Activated alumina is an efficient desiccant for deep drying of trace water. It is especially suitable for non-thermal regeneration devices.
//// Main Factors Affecting the Adsorption Performance of Activated Alumina:
⑴ Particle size: The smaller the particle size, the higher the adsorption capacity, but the lower the particle strength, which affects its service life.
⑵ Raw water pH value: When the pH value is greater than 5, the lower the pH, the higher the adsorption capacity of activated alumina.
⑶ Initial fluoride concentration in raw water: The higher the initial fluoride concentration, the larger the adsorption capacity.
⑷ Alkalinity of raw water: High concentrations of bicarbonate in raw water will reduce the adsorption capacity.
⑸ Chloride ions and anions.
⑹ Influence 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, making it difficult to elute arsenic ions during regeneration.
