Activated carbon is one of the most powerful purification agents in the world, and it is used in countless industries for purification purposes. There are several types of activated carbon varieties with varying properties used in diverse purification processes. Knowing these varying properties and their specific applications is extremely important when it comes to choosing the right kind of activated carbon for your particular demands. To understand the quality of activated carbon, there are certain quality standards, and in this article, we are going to discuss these parameters in detail.
Activated carbon
Activated carbon is a very porous form of carbon produced industrially to be used in purification processes. Water treatment, sewage treatment, air purification, solvent recovery, medicine, and metal purification are some of the most important applications of activated carbon. Also referred to as activated charcoal, activated carbon can be made from different raw materials, but the most popular raw materials are coconut shells, wood, peat, lignite, and coal.
Carbonization and activation are the two main processes used to produce activated carbon from these raw materials. The divergence in these two processes, along with the type of raw material used, can produce various results. For example, steam-activated carbon and chemical-activated carbon are different products even though their core properties are the same, and they are used in different industries based on their qualities; furthermore, modification processes such as impregnation transform activated carbon to be used in very specific applications.
An exceptionally porous surface, a large surface area, and adsorption are the core properties of activated carbon. The presence of millions of microscopic pores creates massive surface space in activated carbon, and this huge surface adsorbs toxins and pollutants. The surface area of 50 grams of activated carbon is almost the surface area of 10 football fields, to put it into perspective.
Properties and values for evaluating activated carbon quality
Activated carbon, whether it is granular activated carbon (GAC) or powdered activated carbon (PAC), has several distinct properties and characteristics, and these properties are quality parameters for activated carbon. Certain test values that measure these properties are used to evaluate the quality of activated carbon around the globe. Let’s take a look at those values and properties.
Iodine number: We know that adsorption is a core property of activated carbon, and the iodine number is a measurement referring to the adsorption capacity and surface area of activated carbon. It measures the amount of iodine adsorbed using one gram of activated carbon.
CTC value: Like the iodine value, the CTC value is a denominator used to express the adsorption capacity of different types of activated carbon. The amount of carbon tetrachloride adsorbed by activated carbon under ideal test conditions is the CTC value.
Methylene blue value: The methylene blue number is another evaluating parameter of the adsorption capacity of activated carbon. The methylene blue value is the amount of methylene blue absorbed by one gram of activated carbon.
Butane value: The butane activity test measures the butane value, which cites the porosity of activated carbon. It tests the ability of activated carbon to adsorb butane from a mixture of butane and dry air under specific conditions.
Surface area: Surface area, like we mentioned before, is an important parameter in determining the quality of activated carbon. Surface area can vary in different types of activated carbon based on the raw materials used in the production and activation processes, and the Brunauer-Emmett-Teller test, also known as the BET test, is generally used to measure it.
Pore diameter: We know that activated carbon is full of pores of varying sizes, and the diameter of these pores is another crucial factor that determines the quality and specific use of the carbon. Based on the size of these pores, the specific application of activated carbon can change.
Particle size: Particle size is a huge factor that determines the performance of activated carbon. Typically, smaller particles offer a larger surface area, increasing the number of active sites available for adsorption. So activated carbon with smaller particle sizes tends to be more efficient, but still, specific applications demand specific characteristics, so we cannot generalize.
Ash content: Ash content is another important value that can determine the effectiveness and specific use of activated carbon. The term ash content refers to the non-combustible inorganic substance present in the activated carbon after carbonization. A high ash content value generally reduces effectiveness and might even hinder the adsorption process, whereas a low ash content ensures the reliability, purity, and efficiency of the activated carbon.
Mesh size: The mesh size of activated carbon refers to the particle size distribution of powdered or granular activated carbon. Generally, smaller particles possess a higher surface area, which can increase the adsorption capacity but potentially lead to a greater pressure drop and slower flow rates. Mesh size is an important value to consider when you choose your activated carbon for any particular application because it influences the pressure drop, flow rate, and adsorption capacity of the activated carbon bed for purification.
Molasses number: The molasses number measures the efficiency of activated carbon in removing large molecules. A high molasses number generally indicates better efficiency in the adsorption of large molecules.
Quality tests of activated carbon
Like we have already discussed, there are many tests to measure the properties of activated carbon. The quality of activated carbon and its specific applications are determined by analyzing these test values. The iodine adsorption test, carbon tetrachloride (CTC) adsorption test, methylene blue (MB) test, phenol adsorption test, butane activity test, Molasses number, benzene adsorption test, chlorine test, and BET (Brunauer-Emmett-Teller test) nitrogen adsorption test are some of the most prominent quality tests that measure the properties and quality standards of activated carbon.
As we have discussed before, each specific production process produces a different type of activated carbon used in specific kinds of applications, so judging solely by one test or a specific quality is not feasible when it comes to activated carbon. Remember that the purpose of the product is an extremely crucial factor when selecting your activated carbon.
Southern Carbon
Southern Carbon is one of the premier activated carbon manufacturers in Kerala, distributing activated carbon across the globe. With more than 23 years of industrial expertise and high-end customized products, we have created a revolution in environmental industries in India and all around the world. We are one of the top suppliers of granular activated carbon in Korea and in many other markets in Asia. connect with us to learn more about our specialized products and be part of our global family.