Prevention of microparticle blocking in activated carbon membrane filtration with carbon whisker

Abstract

We have developed activated carbon membranes (ACM) that can remove not only particulate matters but also dissolved organic matters. Recently, we succeeded in growing carbon whiskers on activated carbon membranes (W-ACM). We hypothesize that the whiskers prevent the flux from lowering due to particle blocking on the membrane surface. In this study, we compared the filtration properties and blocking characteristics of ACM and W-ACM using an artificial microsphere (polymethyl methacrylate) (PMMA), particle diameter = 0.8, 5, and 10 μm) to estimate the effect of whiskers on particle filtration. We found that the whiskers successfully prevented a reduction of penetration flux in all particle diameters; however, the prevention mechanism seems to be different according to the filtrated particle size. To clarify the mechanism, we performed numerical model analysis using a microfiltration model. In the case of 0.8 μm particle filtration, whiskers seemed to inhibit the packing of particles into the microholes existing at the surface of activated carbon membrane, and with 5–10 μm particle filtration, the packing density of the cake layer accumulated on the membrane would be reduced with the appearance of whiskers.