एक्टिवेटेड चारकोल / सक्रिय कोयला (Activated charcoal)

Activated charcoal, also called activated carbon, is carbon from sources such as coconut shell, wood or coal that has been treated with steam or chemicals at high temperature. This opens up millions of tiny pores, giving it a huge surface area that traps many organic molecules, smells and colours on its surface (adsorption).

• Main component: carbon (C)
• CAS number: 7440-44-0 (carbon; activated carbon is commonly listed under this number)
• Appearance: fine, odourless black powder
• Solubility: insoluble in water and oils; it stays suspended and settles out
• Surface area: commonly 500 to 1500 square metres per gram, depending on grade

It does not trap everything. Salts, most metals and many very small or water-loving molecules pass through.

Azlok lists activated charcoal powder in its cosmetic raw ingredients range. Fine powder is what soap makers, face pack and scrub makers and hobbyists usually want, because it disperses evenly. The pack size is shown on the product page.

For packed water filter beds, granular carbon is better than powder, as powder clogs and washes through. Check today's price per kg.

Home and DIY

• Odour absorbers in fridges, shoe racks, cupboards and cars, usually in cloth or paper sachets
• Black pigment for handmade soap, bath bombs and candles

Cosmetics

• Colour and texture in face packs, peel-off masks, scrubs and cleansing bars, where it is used for its oil and dirt absorbing feel

Water, air and industry

• Removing chlorine taste, odour and colour in water treatment
• Air and gas filters, and solvent recovery
• Decolourising sugar syrups, oils and chemicals in processing

Lab

• Removing coloured impurities during recrystallisation

Odour sachet. Fill 50 to 100 g into a tight cotton pouch or a paper envelope with small holes. Keep it in the fridge or shoe rack and replace every one to two months. Gently warming it in the sun can refresh it a little.

Soap colour. A little goes a long way. Start with about 1/2 teaspoon per 500 g of melt-and-pour base or soap batter. First mix the powder with a few drops of glycerine or oil to a smooth paste, so you don't get black specks. Too much can leave a grey lather.

Face pack or mask. It is usually a small part of a clay mask. Mix it into the dry clay before adding water, and patch test the finished product on the inner arm 24 hours before wider use.

Lab decolourising. Add a small spatula tip to the hot solution, swirl for a few minutes, then filter it out through filter paper while still hot.

• The fine powder flies easily and stains clothes, grout and counters. Open the pack slowly, away from fans, and work over newspaper.
• Wear a dust mask for large amounts; breathing in fine dust irritates the nose and lungs.
• Keep it away from strong oxidisers such as potassium permanganate, nitrates and chlorates. Carbon dust can burn, and large heaps of fresh powder can self-heat.
• Store in a closed container. Open powder adsorbs smells and moisture from the air and loses its capacity.
• Keep away from children. This pack is not for eating or medical use.
• Used charcoal can go in normal solid waste unless it has adsorbed something hazardous.

For soap colour, face packs and a few odour sachets, a small pack lasts a long time because you use so little at once. Soap and cosmetic workshops making regular batches can buy larger packs and transfer some into a smaller jar for daily use, keeping the main pack sealed.

If you are building a water filter, look for granular activated carbon rather than powder. Finished cosmetics sold in India have to meet BIS and CDSCO requirements, so if you sell products, keep batch records of what you used. For 25 kg and above, use the bulk inquiry form.