Abstract
Biopharmaceutical processes, membrane pretreatment, water purification and food and beverage applications all require fine filtration. There are many different types of filter media that can be used for these applications. The types of media vary by materials of construction, processing method and performance characteristics. Each process produces a media with unique properties that have advantages in different applications.
These industries have traditionally relied on membranes for their submicron filtration needs. Nonwoven media have not been successful in finer filtration applications due to the relatively large fibers that are produced or the technical and/or operational difficulties in producing fine fiber media. A significant amount of research has been expended over the last few years on developing high efficiency wetlaid media and producing fine diameter synthetic fibers in drylaid operations.
Nonwoven media have begun to compete with membranes and other separation technologies in these fine filtration applications. High efficiency nonwoven media composites have equivalent efficiency as many types of membranes but with significantly higher dirt holding capacity or life.
This paper will discuss the different types of wetlaid, drylaid and membrane media available for submicron filtration and compare their methods of construction, performance and cost.