Exchange Exhibition
What are the roles of the pore structure of activated carbon in water treatment applications?
The activated carbon adsorbed using chemical activation is very porous, mostly in the micropore and mesopore range. However, compared to steam-activated carbon, the pore surface of chemically activated carbon has less hydrophobicity and more negative charges.
The role of the pore structure of activated carbon in water treatment applications:
Activated carbon adsorption is often applied to adsorb molecules. The adsorption capacity of activated carbon determines its applicability, which is related to the pore size distribution of various types of carbon. For example, peat-based, lignite-based, and coconut shell-based powdered activated carbons activated by steam: peat-based activated carbon has micropores and mesopores, making it suitable for various applications; lignite-based carbon has more mesopores and larger mesopores, providing excellent accessibility; coconut shell-based activated carbon mainly has micropores, suitable only for the removal of low molecular weight substances.
The activated carbon adsorbed using chemical activation is very porous, mostly in the micropore and mesopore range. However, compared to steam-activated carbon, the pore surface of chemically activated carbon has less hydrophobicity and more negative charges. Taking extruded and crushed granular activated carbons as examples: peat-based extruded activated carbon can be made into varieties with different pore size distributions. Varieties mainly composed of micropores are primarily used for gas-phase applications such as gold recovery. Varieties with both micropores and mesopores are mostly used for liquid-phase applications, such as adsorbing impurities from small and large molecules in water purification.
Crushed coal-based activated carbon has both micropores and mesopores, suitable for various applications. Granular activated carbons made from lignite or coconut shells have the same micropore and mesopore structure as powdered carbons. The technical indicators of activated carbon are very important: the performance indicators of activated carbon products can be divided into physical performance indicators, chemical performance indicators, and adsorption performance indicators. These three performance indicators play a very important role in the selection and application of activated carbon. The main physical performance indicators of activated carbon include: shape, appearance, specific surface area, pore volume, specific gravity, mesh number, particle size, abrasion resistance, floatability, etc.
The main chemical performance indicators of activated carbon include: pH value, ash content, moisture content, ignition point, uncarbonized materials, sulfides, chlorides, cyanides, sulfates, acid-soluble substances, alcohol-soluble substances, iron content, zinc content, lead content, arsenic content, calcium and magnesium content, heavy metal content, phosphates, etc. The main adsorption performance indicators of activated carbon include: methylene blue adsorption value, iodine adsorption value, phenol adsorption value, carbon tetrachloride adsorption value, caramel adsorption value, sulfuric acid quinine adsorption value, saturated sulfur capacity, breakthrough sulfur capacity, water capacity, chloroethane vapor protection time, ABS value, etc.