Evaluating filtration media: A comparison of polymeric membranes and nonwovens

Filtration efficiency depends greatly upon selecting the proper media, a de cision that requires the careful consideration of the advantages/disadvanta ges of each. The four major criteria for evaluating filtration media are: p ermeability, filtration efficiency, filtration capacity (or life) and filtr ation cost. In this article, Dr. Ernest Mayer and Jennifer Warren of E.I du Pont de Nemours and Company, USA compare the major characteristics of the two most commonly used filtration media groups: microporous/PTFE (polytetra fluoroethylene) membranes and nonwoven materials; and discuss ways of evalu ating them. A new nonwoven material, Tyvek(R) SoloFlo(TM), formulated by Du Pont for use specifically in the filtration industry is also introduced.