If you would like to receive more information or would like to know what we can do for you, please feel free to contact one of our specialists:
Marco van den Brand
Adsorption of vapours
Vapours can also be adsorbed to an adsorption material. We work mainly with activated carbon or with zeolites. Activated carbon is a micro-porous carbon matrix with an extremely large internal surface area. This internal surface area is ideal for the adsorption of a large variety of organic hydrocarbons.
Activated carbon has the advantage of being relatively cheap and simple for use in the operations. A number of preconditions are of course attached to this at all times.
With low influent concentrations the loading level is also low. With a correct load the degree of purification can be very good. Activated carbon works the best at certain ranges of temperature and humidity. At a higher temperature the loading level is less, as is the case with (too) much humidity.
Loaded activated carbon desorbs its contamination again. Once loaded, the activated carbon should either be replaced by a new batch or regenerated in situ (e.g. with steam and/or vacuum). Different substances are adsorbed differently by carbon. In general, the more volatile the contamination, the more difficult it is to ‘collect’ using activated carbon. This applies to, for example, alcohols as well. What’s more, substances that adsorb less well can be easily rejected by well adsorbing substances; in other words, mixtures are more difficult to adsorb.
Heat is released during the adsorption process. With excessively high influent concentrations, this can lead to hazardous hotbeds, resulting in possible self-ignition of the activated carbon.
In addition to activated carbon, certain zeolites can also adsorb contamination. Zeolites (mineral origin) have a major advantage in that relatively little adsorption heat is released, which means that the risk of self-ignition is marginal. Zeolite is, however, (much) more expensive, so is only interesting as replacement for activated carbon when this can be cleaned/adsorbed in situ. We mainly use zeolites as a ‘peak shaving’ technique, whereby any high influent peaks are levelled off for the eventual air purification.