Activated alumina is a porous material with the capacity to absorb large volumes of water, gases and impurities. Additionally, its high crush strength allows it to withstand extreme temperatures without damage.
Activated alumina is created through low-temperature dehydration of hydrated aluminum oxide, creating an extensive network of pores with high surface area per gram.
Molecular Weight
Activated alumina consists of aluminium oxide with the chemical formula Al2O3, as well as various impurities like silica and iron oxide that may interfere with its adsorption and catalytic properties. Most of these impurities occur naturally in raw material bauxite but can be removed using various purification techniques.
Activated alumina’s high adsorption capacity and porosity make it an ideal candidate for industrial processes, from adsorbent use to catalyst carrier delivery, desiccant applications and removal of contaminants such as fluoride, arsenic and selenium from water sources to natural gas/petrochemical industries that use it to remove moisture, carbon dioxide and trace impurities from gas streams and vapour streams.
Effective use of activated alumina stems from its high surface area and porous nature. Adsorption occurs through interaction between contaminants and activated alumina’s surface, and their molecular weight change, leading to chemical reactions which form networks of pores and channels on its surface structure.
Activated alumina comes in several different forms, from granular, pellet, or spherical shapes – each type has unique properties that influence its performance. Agglomeration and handling capabilities can be enhanced by altering the amount of binder used during manufacturing; additionally, coated activated alumina may offer increased performance as well as resistance against chemicals.
Solubility
Activated alumina is an amphoteric material with dual functions of acting both as an adsorbent and catalyst. Composed mainly of aluminium oxide (Al2O3), commercial production takes place via either calcination or Bayer process; typically it is then agglomerated to improve performance and handling characteristics.
During activation, raw material undergoes thermal decomposition to form partially dehydrated alumina known as gibbsite, followed by formation of highly porous networks with internal surface areas of 150 to 300 square meters per gram and thus can absorb various molecules. Once activated, this material can then be purchased as beads, pellets, granules or powders for various applications or manufacturing processes.
Activated alumina’s water-absorbent properties make it an effective desiccant, capable of extracting moisture from air, gases and liquids. This property makes activated alumina an invaluable material in industrial compressed air systems as well as natural gas and petrochemical industries for preventing corrosion of equipment and products.
Activated alumina is often employed as a fluoride filter in water treatment plants to absorb and remove fluoride from drinking water sources. As it has a specific affinity for fluoride ions, other anions like arsenic or phosphate cannot easily be eliminated using this same mechanism; additionally, activated alumina can be regenerated in the field with dilute NaOH or sulfuric acid solutions in order to effectively filter them away.
Specific Surface Area
Activated alumina boasts an immense surface area of more than 200 m2/g, which allows it to absorb large volumes of water and other liquids. Not only is this material non-toxic and environmentally-friendly; prolonged contact may irritate skin or eyes.
This adsorbent can be utilized for desiccation applications, where it removes moisture from air and other gases to maintain freshness, increase lifespan and mitigate malfunction and degradation risk.
Activated alumina’s ability to absorb moisture and other gases makes it especially valuable in protecting electronics and chemicals from moisture or gasses during shipping, protecting sensitive goods by trapping excess humidity or vapors that might threaten their integrity.
Activated alumina is a commercial porous oxide material available in powder or bead form. Its pores are formed through controlled heating of alumina hydrate crystals to dehydrate them and reform a well-defined porous network structure, producing non-toxic, non-abrasive material suitable for high temperature conditions.
Activated alumina is an effective choice for the removal of arsenic, fluoride and phosphate in fixed bed mode, due to its relatively high capacity. Regeneration can easily be accomplished using dilute aqueous NaOH or sulfuric acid solutions; their anions will depend on pH values between 5.5-6.5 for optimal adsorption capacities.
Reactivity
Activated alumina is an extremely porous substance with hundreds of square meters per gram surface area that absorbs gas and liquid molecules, serving as both catalyst carrier and desiccant. Its high absorbance capabilities have long made it the go-to material in industry; preparation can be achieved via low temperature dehydration of raw materials such as bauxite. Activated alumina adsorption technology is ubiquitously employed today.
This highly reactive adsorbent can bind with water, organic compounds, sulfur compounds, chlorine gas, heavy metals and other chemicals, with its pore structure and surface area being tailored through manufacturing processes to suit specific application needs. Due to its impressive adsorption capacity, thermal stability, regenerability and thermal resilience capabilities it makes an excellent material choice for use in water treatment, gas purification and desiccant applications.
Activated alumina is safe to handle when handled using appropriate precautions and PPE, including eye protection (shield or goggles), chemical-resistant gloves and a dust mask or respirator. Doing this will prevent irritation or respiratory problems caused by exposure to fine powders; in the event of spills occurring immediately contain and clean up should occur in order to reduce exposure or dispersion into the air.