(84d) Depth Filter Membranes of Biodegradable Biomass Plastics

Depth filter membranes retain particles in water in the filter media to avoid the formation of filter cakes (particle layers on membrane surfaces) which cause a large increase in membrane resistance. However, depth filter membranes of conventional synthetic polymers have problems at disposal after their uses. Recently biodegradable biomass plastics, such as poly(lactic acid), poly(1,4-butylene succinate), have received increased attention as key materials for sustainable technologies because they are produced from a renewable resource, biomass, and degradable in natural environments and composting processes. Membranes of biodegradable biomass plastics can be degraded in composting machines to reduce industrial wastes in biochemical and food industries. In this study we developed microfiltration membranes of poly(L-lactic acid) (PLLA). The asymmetric porous structures of the membranes were formed via thermally and nonsolvent-induced phase separation process [1-3]. The membranes retained bacterial cells in a manner of depth filters.

REFERENCES [1] T. Tanaka and D.R. Lloyd, Formation of poly(L-lactic acid) microfiltration membranes via thermally induced phase separation, J. Membr. Sci., 238 (2004) 65-73. [2] Tanaka et al., Microfiltration membranes of polymer blend of poly(L-lactic acid) and poly(epsilon-caprolactone), Desalination, 193 (2006) 367-374. [3] T. Tanaka et al., Formation of microporous membranes of poly(1,4-butylene succinate) via nonsolvent and thermally induced phase separation, Desal. Water Treat., 17 (2010) in press.