What makes powdered carbon different
Powdered activated carbon (PAC) is activated carbon ground to a fine powder — typically below 75 microns (200 mesh) or finer. This small particle size means two things: an extremely short diffusion path from the carbon surface to the adsorption site, and the ability to dose the carbon as a slurry and then remove it by filtration.
These characteristics give PAC a speed and flexibility advantage over granular carbon in many applications. Where GAC requires contact time in a fixed bed measured in minutes, PAC begins adsorbing immediately on contact, and dose rate can be adjusted in real time.
Water treatment
PAC is dosed into the water treatment process — either in the rapid mix stage or ahead of clarification — to address taste, odour, and trace organic contamination events. It is particularly effective for seasonal events like algal blooms, which produce geosmin and 2-MIB — compounds detectable at parts per trillion that are notoriously difficult to remove.
Pharmaceutical applications
In pharmaceutical manufacturing, PAC is used to decolorise API (active pharmaceutical ingredient) solutions. The active ingredient is dissolved in solvent; the carbon is added, stirred for a defined contact time, and then filtered out, leaving a clear, colourless solution ready for crystallisation or formulation. Acid-washed grades are used where the solution is pH-sensitive.
Rajindra’s UCI UW series (22, 24, 26, 32) and DL Premium grades are purpose-designed for pharmaceutical decolorisation — with BP/USP test reports and batch-specific certificates of analysis.
Food and beverage
PAC decolorises liquid sugar, glucose syrups, citric acid, and other food ingredients. It removes colour compounds formed during processing without affecting the chemical composition of the product. For food applications, food-contact certification and low heavy metal content are essential.
Industrial decolorisation
Many industrial organic chemistry processes produce coloured intermediates or byproducts. PAC treatment at various stages — before or after reaction steps — removes these colour bodies and improves the quality of the final product. The flexibility to adjust dose without capital investment makes PAC the standard tool for this application.