What is activated charcoal and why is it used in filters?
Charcoal is carbon. Activated charcoal is charcoal that has been treated with oxygen to open up millions of tiny pores between the carbon atoms. These so-called active, or activated, charcoals are widely used to adsorb odorous or coloured substances from gases or liquids.
The word adsorb is important here. When a material adsorbs something, it attaches to it by chemical attraction. The huge surface area of activated charcoal gives it countless bonding sites. When certain chemicals pass next to the carbon surface, they attach to the surface and are trapped.
Before polypropylene was invented, the gaseous waste from oil such as propylene and ethylene were simply burned, because they were useless. Today, these gases are used to produce polypropylene, thus drastically reducing atmospheric pollution. The production process also eliminates the potential polluting of rivers, streams and lakes, due to the use of water in a closed cooling cycle.
The polypropylene used is entirely recyclable and meets the manufacturing requirements of the Environment Commission - these stipulate that there is a minimum use of natural resource, reduced emissions a long working life and optimum re-use.
There is a high demand for polypropylene for recycling purposes as it can be recycled more than 50 times without any reduction in strength. Recycled polypropylene has uses as car parts, furniture, pots and pallets separators.
As well as being the most durable and flexible material for making binders, folders and packaging, polypropylene is far more environmentally and economically sound than rival products such as standard plastics and PVC.
Polypropylene, unlike PVC, does not give off chlorine when burnt. It gives off only water vapour and carbon dioxide, which is converted by photosynthesis (chlorophyll). It is a chemically inert product. To incinerate some materials, extra fuel needs to be added. Polypropylene however, is destroyed simply by burning, because its calorific capacity is similar to that of oil. Thus incinerators economise on fuel and operate more efficiently.
Polypropylene products last much longer than those made from most similar materials. It is easy to wipe clean, hard wearing and will withstand extreme temperatures and ageing. Being more durable than alternative materials, products made from polypropylene don't need to be replaced as often. When used for packaging, boxes and cases often have a second 'life'. Saving cost, resources, our environment and our future.