Pushing Chemical Filtration Technology Towards The Future: Low Concentrations

The filtration/removal of gaseous emissions and vapor phase contaminants is a rapidly growing market and is becoming a critical part of many industrial processes and applications. Although, some of this growth can be attributed to tightened regulatory standards, much of it can be attributed to a growing concern about the air we breath at work and at home, as well as the concern regarding the purity of the air used in manufacturing processes. Examples of a few key areas in which chemical filtration can make a significant impact to the breathing and/or manufacturing process air quality are: 1) indoor air; 2) auto cabin air; 3) disk drives, and 4) cleanroom air. In all four of these areas, the environment is typically quite complex and the contaminant Levels very low, making the adsorbent material choice an extremely critical step. Although, an experimental and theoretical understanding of chemical filtration at relatively high vapor phase contaminant concentrations is quite well developed; at extremely low concentrations, there is essentially no information to draw upon to make conclusive decisions about a particular material or approach. In essence, applications operating in this concentration regime open a new arena for chemical filtration technology. Whether physical or chemical adsorption mechanisms are being employed, it is crucial that the overall application environment be fully understood in order to design an optimum chemical filter. In this paper, we will address chemical filtration basics, theoretical predictions at low concentrations, methods of analyzing a specific application environment, and the testing and development of adsorbents for application at low contaminant concentrations.