Activated carbon is a specially treated carbon. Organic raw materials (fruit shells, coal, wood, etc.) are heated under air-tight conditions to reduce non-carbon components (this process is called carbonization), and then react with gas, the surface is eroded, and a microporous structure is produced (this process is called activation). So activated carbon has an adsorption effect, but do you know what factors affect the adsorption effect of activated carbon? Today we will explain the answer.
The factors that affect the adsorption of activated carbon mainly include:
· Properties of activated carbon: Its physical and chemical properties, such as particle size, specific surface area, pore size distribution, surface chemical functional groups, etc., have an important influence on the adsorption effect. Activated carbon with large specific surface area and rich pore size has a higher adsorption capacity.
· Properties of adsorbate: including molecular size, polarity, concentration, solubility, etc. of the solute. Generally speaking, substances with large molecular weight and low polarity are easier to be adsorbed.
· PH value of the solution: pH value affects the dissociation and solubility of the solute, thereby affecting the adsorption effect. Under different pH values, the adsorption effect of activated carbon on certain ions will be different.
· Temperature: The effect of temperature on adsorption depends on the type of adsorption (physical or chemical adsorption). In liquid phase adsorption, the effect of temperature changes on adsorption capacity is relatively small.
· Coexisting substances: Other substances in the solution may compete for adsorption sites and affect the adsorption capacity of activated carbon for a specific substance.
· Contact time: The contact time between activated carbon and adsorbate is important to fully utilize the adsorption capacity.
· Chemical properties of activated carbon: Chemical functional groups on its surface, such as acidic or basic compounds, affect the adsorption of specific types of adsorbates.
· Coexistence of multi-component solutes: Activated carbon usually does not adsorb a single pollutant, and multiple pollutants may affect each other when they coexist.