Activated Alumina

Activated alumina, also known as activated aluminum oxide, is a highly porous and adsorbent material derived from the dehydroxylation of aluminum hydroxide (Al(OH)3). Its exceptional porous structure provides an extensive surface area, exceeding 200 square meters per gram, making it a valuable material for various applications, including moisture adsorption, filtration, and catalysis.

Key Properties of Activated Alumina

• High Surface Area: The extensive surface area facilitates efficient adsorption of molecules onto the alumina surface.
• Porosity: The porous structure allows for deep penetration of molecules, enhancing adsorption capacity.
• Chemical Stability: (Al(OH)3 exhibits high chemical stability, making it suitable for various environments.
• Regenerability: The material can be regenerated by thermal treatment, extending its lifespan.

Applications of Activated Alumina

Catalysis

• (Al(OH)3 serves as a catalyst support in numerous chemical reactions. Its high surface area and porosity provide a large contact area for catalysts, promoting reaction rate and yield.
• Petroleum Refining: Employed as a catalyst support in processes like catalytic cracking and hydrodesulfurization.
• Chemical Production: Used in the production of chemicals like polyethylene, polypropylene, and ethylene glycol.
• Flue Gas Treatment: Supports catalysts for flue gas cleaning, removing pollutants like NOx and SOx.

Moisture Adsorption

• (Al(OH)3 is highly effective in drying gases and liquids by removing moisture.
• Compressed Air Drying: Eliminates moisture from compressed air in industries like pharmaceutical, food, and chemical.
• Natural Gas Drying: Removes moisture from natural gas prior to transportation and consumption.
• Solvent Drying: Dehydrates solvents in industries like paint and resin, pharmaceutical, and chemical.
• Liquid Drying: Removes moisture from liquids like oils, chemicals, and pharmaceuticals.

Purification

• Activated alumina’s high surface area and adsorption capacity enable it to purify gases, liquids, and wastewater.
• Gas Purification: Removes contaminants like hydrogen sulfide, sulfur dioxide, nitrogen oxides, and VOCs from gases.
• Liquid Purification: Eliminates impurities like heavy metals, fluoride, arsenic, and organic compounds from liquids.
• Wastewater Treatment: Purifies industrial wastewater by removing various pollutants.

Fluoride Adsorption

• Activated alumina effectively removes fluoride from water sources.
• Drinking Water Treatment: Reduces fluoride levels to meet drinking water standards.
• Industrial Water Treatment: Removes fluoride from industrial wastewater to comply with environmental regulations.
• Dental Applications: Used in fluoride prophylaxis treatments to prevent tooth decay.

Other Applications

• Deodorization: Eliminates odors from gases and liquids.
• Carrier Material: Supports active ingredients in various applications.
• Desiccant: Dries air and gases in industrial and laboratory settings.
• Activated alumina’s versatility and effectiveness make it an indispensable material in various industries, contributing to cleaner processes, improved product quality, and environmental protection.

Physical Properties of Activated Alumina

(Al(OH)3 is available in a variety of sizes, with the most common being 5-3 millimeters. It is also categorized into different grades for specific applications.

• Appearance: Activated alumina can be found in either purple or yellow hues. The purple variety is a combination of alumina and potassium permanganate, while the yellow form is a blend of alumina and zeolite (molecular sieve).

Interesting Facts about Activated Alumina

1. Discovery: Activated alumina was first discovered by French scientists in the 1800s.
2. Unusual Applications: Aside from its conventional uses, activated alumina finds applications in wastewater treatment for spacecraft, diver breathing apparatus, and even in some cosmetics.
3. Environmental Friendliness: Activated alumina is an eco-friendly material due to its recyclability and non-toxicity.
4. Exceptional Adsorptive Capacity: Activated alumina stands as one of the strongest moisture adsorbents, capable of removing up to 99% of humidity from air.