Development of a Novel Particle Classification Technique Using Microfiltration Membranes

A novel particle classification process by utilizing cross-flow microfiltration has been developed. In this process, particles which are smaller than the pores of membranes are collected in the permeate and those larger than the pores are collected in the retentate. This technique has a great potential to classify particles at any cut-off diameter just by choosing an appropriate membrane with a pore size that corresponds to the target classification diameter, even in the sub-micron region. Here we discuss two important issues, how to prevent the deposition of particles onto the membrane surface and the clogging inside the pores, in order to develop this process as a robust and practical one. Some examples of successful particle classification operations are also presented.