Sumitomo Chemical has developed a new high-performance alumina technology designed to significantly improve the permeance of ceramic separation membranes without sacrificing their separation performance.
The breakthrough targets a longstanding trade-off in membrane technology: increasing the flow of fluid through a membrane can come at the expense of separation efficiency, thus opening new possibilities for wastewater treatment and other demanding applications.
The company said its newly developed alumina increases the density of “through-pores” within the membrane structure, creating more pathways for fluid to pass through.
The results could have implications for industries where membrane fouling—the adhesion and accumulation of contaminants—can rapidly reduce filtration performance. Potential applications include food processing, biotechnology, fermentation, chemicals and wastewater treatment.
Researchers compared the internal three-dimensional structures and filtration performance of multilayer α-alumina tubular membranes using yeast suspensions.
Although the membranes had nearly identical average pore sizes, those produced with Sumitomo Chemical’s newly developed alumina had a much higher through-pore density.
That higher density distributed permeate flow across a greater number of flow paths. The result was lower localized loading, reduced contaminant intrusion into membrane pores and a lower likelihood of internal pore blockage.
The high-through-pore-density membranes achieved more than three times the steady-state permeance of the comparable membranes while maintaining similar separation performance.
The findings challenge the traditional emphasis on average pore size as a primary indicator of membrane performance. According to the research, the way flow is distributed through the membrane’s internal structure can be equally important.
Ceramic separation membranes are widely used because of their mechanical strength, chemical resistance and heat resistance. They are particularly valuable in processes involving suspensions, emulsions and other fluids where contaminants can readily accumulate inside membrane pores.
As fouling builds up, however, membrane permeance can fall, reducing throughput and potentially increasing cleaning requirements and operational instability.
Sumitomo Chemical’s research points to through-pore density and internal flow-path structure as important design parameters for addressing this problem.
The company said its high-performance alumina can help control that internal structure, providing a new route to higher-performance ceramic separation membranes.
For membrane manufacturers, the technology could support the development of differentiated, higher-value ceramic membranes with improved filtration characteristics.
For filtration-system manufacturers, the improved permeance could translate into higher throughput, less frequent cleaning and more stable operation.
Sumitomo Chemical plans to further develop alumina-based structural-control technologies and strengthen collaboration with membrane and filtration-system manufacturers.
The company also intends to expand material solutions for applications in food processing, fermentation, biotechnology, chemicals and wastewater treatment, particularly where contaminant adhesion and accumulation cause declining permeance.
The research was published in the Journal of Membrane Science Letters under the title “Role of through-pore density in governing filtration performance and fouling of α-alumina microfiltration membranes.”
The authors are Hana Hosokawa, Tooru Kitagawa, Shuji Nakatsuka, Setsuaki Murakami and Hideto Matsuyama.
