In order to overcome the dilemmas of water purification, microbial inactivation, separation and purification of chemical-allied industries, Activated Carbon (AC) is the significant solution. AC has accelerated the remarkable development and expansion of Carbon Science and Nanotechnology in recent years.
It is a highly porous, carbonaceous material produced by carbonizing the organic substances like hardwood, coconut shell, fruit stone, saw dust, coal, cellulose residue, walnut, peach pits, babassu nutshell, palm kernel, petroleum coke or anything and everything having high fixed carbon content & potency of activation.
Historically, 1st world war triggered the tremendous use and production of granular activated carbon for adsorbing poisonous gases. The study of activated carbon requires a massive knowledge of pore volume and surface area.
The porosity enhancement requires efficient activation. The activation involves high temperature with/without using inorganic salts with CO2 & steam. The use of chemical activation agent (ZnCl2 or H3PO4) is optional. The resulting AC has a colossal capacity of adsorption from gases and liquids.
To meet the need for diverse industrial, environmental & miscellaneous sources, various AC is commercialized depending on size, shape & application
Granular Activated Carbon (GAC): The mean particle size is approx 1-5mm and is mainly used for water treatment. A high-quality GAC provides durability, high density & effective carbonaceous material. It is effective against organic contaminant in waste water. It can be used for both gases(4×6, 4×8, 4×10 mesh sieve) & liquid (8×20, 20×40,8×30 mesh sieve). It has marked its bulk application in water treatment, deodorization, decolorization, reduce DBP, allied chlorinated solvents, carcinogenic metals (Pb, Hg) & pesticides.
Powdered Activated Carbon: The average particle size is approx 0.1mm and diameter range from 0.15-0.25mm. Being thoroughly crushed, about 95% of the powdered particle will pass through designated mesh sieve. The enormous adsorption is due to a large surface area to volume ratio and small diffusion distance. The applications include raw water in-take, clarifiers, gravity filters, sugar decolorization, Hg & Dioxin removal from flue gas etc.
Pelletised Activated Carbon: The granular form of AC is given a specific shape (cylindrical) by pelletization. It is well known for its high internal porosity, homogeneous activation & diffusion throughout the particle. It has high density, mechanical strength, hardness & low abrasion index. It is profoundly used in air & gas purification.
Silver Impregnated Activated Carbon: In this, the activated carbon (granular/pelletized) is covered with inorganic metals (silver). Being an excellent disinfectant, silver coupled with AC is used as an adsorbent to tackle various water borne diseases, thus can be used for treating domestic water. The eminent bacteriostatic properties with antimicrobial effects hinder the biofilm growth over filter media, thus prolonging the product’s life.