Activated alumina’s large pores and surface area enable it to adsorb a range of liquids, gases, and vapours – making it an excellent material for water treatment, gas purification, drying agents or any other purpose. This versatility makes activated alumina an invaluable choice in many fields including water purification.
Assuring safety when working with activated alumina requires using personal protective equipment (PPE). This may include safety goggles or face shields, chemical-resistant gloves and a dust mask.
Adsorption
Activated alumina is a porous, granular material made of aluminum hydroxide by way of thermal treatment known as calcination in a rotary kiln. Heating alters its crystalline structure, leading to network of pores which make activated alumina highly absorbent and therefore ideal for purifying gases, air, and liquids.
Granular activated alumina has numerous applications in industries like petroleum refining and chemical manufacturing, including natural gas dehydration, compressed air systems and the removal of impurities such as moisture, hydrogen sulfide or any other contaminants from gasses or liquids such as compressed air or compressed gas systems. Furthermore, it can also be used to remove impurities such as moisture or hydrogen sulfide that contaminates them – something granular activated alumina is adept at doing.
Granular activated alumina’s large pores and surface area make it ideal for absorbing contaminants from gases, liquids and vapors. Adsorption may be achieved using different types of activated alumina granules with various sizes of pores or in combination with silica or zeolite materials depending on its application.
Activated alumina desiccants are non-toxic and chemically stable, making them safe options for use in food industries. With minimal dust production, activated alumina desiccants are also an ideal choice in areas where dust contamination may be an issue. Furthermore, their adsorption capabilities can be further adjusted by altering its pore size or surface chemistry through various manufacturing processes.
Catalysis
Activated alumina can be utilized as a catalyst in various applications, from defluoridation and water purification, to defluoridation and water defluoridation. Furthermore, its desiccant properties make activated alumina an indispensable addition in natural gas and industrial air dryers for maintaining optimal performance and function.
Granular activated alumina’s surface is highly porous with an average specific surface area exceeding 200 m2/g, making it an excellent adsorbent and catalyst material. Due to this porosity, granular activated alumina is also capable of retaining chemicals it adsorbs so well that in certain applications, such as silica replacement applications, it may even serve as an ideal replacement material.
To achieve the catalytic properties of alumina, it must first undergo a process known as calcination in a rotary kiln. Calcination dehydrates aluminum hydroxide while altering its surface structure resulting in porous alumina material by creating pores or etching away at it surface structure.
Granular activated alumina produced through this process must be free from sodium admixtures. To accomplish this goal, the decomposed product of hydration must be filtered and washed until sodium content does not exceed 0.02 percent by weight (Na2O). Granulated activated alumina produced in this fashion can then be acid treated to achieve its gamma-activated characteristics.
Defluoridation
Activated alumina is like the magnet of water filtration; its porous structure and large surface area attract impurities that would otherwise enter our drinking water and become trapped there, where they cannot escape. Thanks to its chemical inertness and ionic strength, activated alumina stands tall as the undisputed champion of potable drinking water purification, filtering out fluoride, arsenic metals, and other organic contaminants such as fluorine to help ensure our safety while drinking pure drinking water.
Heat expands hydrated alumina, and its crystal lattice fractures along lines of structural weakness to produce an ordered pore structure with a large surface area. Adsorption capacity of activated alumina increases with temperature due to release of bound water molecules that leave high-energy al3+ sites exposed.
After being subject to adsorption, activated alumina undergoes a regeneration procedure using specific chemicals in order to restore its active surface and remove any biofilm formation that might occur – in accordance with GMP (Good Manufacturing Practice) and HACCP principles.
FEECO Innovation Center is an advanced testing facility that provides both batch thermal processing and continuous process loop testing of agglomeration in a pilot-scale kiln, to gather production data and develop agglomerates with desired characteristics for specific applications. For instance, activated alumina desiccants may be tested in an atmosphere controlled by temperature, humidity and light conditions for moisture absorption capabilities.
Water Treatment
Activated alumina is often employed as a desiccant, to remove moisture vapor and impurities from gases and liquids, as well as air and liquid purification for fluoride, arsenic, color odor phosphate removal from drinking water supplies. Alumina can be effectively regenerated at regular intervals to maintain its capacity to remove contaminants ensuring users receive tasteless, odorless water supplies.
Thermal processing of alumina involves dehydration through calcination in a rotary kiln. Calcination dehydrates aluminum hydroxide source material (gibbsite) by extracting bound water molecules and dehydrating its high energy Al3+ sites of Gibbsite without binding them with water molecules, creating highly porous forms with an average pore diameter of 4nm.
FEECO Innovation Center can conduct batch and pilot scale thermal processing and agglomeration trials to gather data and simulate production conditions to optimize a process that will yield highly performant granular activated alumina products tailored to individual application requirements. Customers have the opportunity to test their material under their own process in order to meet rigorous NSF and California Proposition 65 standards set for water industry use.