Separation of Particles in Suspensions by Contact With Gas Phase

Web Published:

Princeton Docket # 16-3249-1

Researchers at Princeton in the Department of Mechanical and Aerospace Engineering have developed a method for concentrating suspended particles in suspensions that could be used to attract/repel particles to/from a surface.


Methods for concentrating particles suspended in a liquid are useful for many industrial and scientific applications, especially when the particles are small and their concentration is low. Current methods use external forces such as gravity and electric fields for concentration and separation of particles in suspensions and are generally limited to particles that are tens of microns or larger in size. Techniques of the current invention concentrate suspended particles by bringing the suspension into contact with a soluble gas phase. Exposure of the suspension to the gas induces either attraction of the suspended particles to the gas-liquid interface or repulsion from it depending on the selected gas, the properties of the particles, and the design of the process. The present method is not only able to selectively move particles in different directions, but is also effective for use on submicron sized particles.


Overall, this invention represents a promising way to improve the removal of particles such as from wastewater, prevent fouling of filters and membranes or for other end-uses.



•       Prevention of fouling of filters and membranes

•       Wastewater treatment

•       Mining operations

•       Preconcentration of biomolecules

•       Ultrapure water production



•       Concentrate dilute suspensions

•       Effective for submicron sized particles

•       Movement of particles in different directions



Howard A. Stone, Donald R. Dixon and Elizabeth W. Dixon Professor in Mechanical and Aerospace Engineering and Department Chair

Howard Stone is the Donald R. Dixon '69 and Elizabeth W. Dixon Professor in Mechanical and Aerospace Engineering at Princeton University. His research has been concerned with a variety of fundamental problems in fluid motions dominated by viscosity, so-called low Reynolds number flows, and has frequently featured a combination of theory, computer simulation and modeling, and experiments to provide a quantitative understanding of the flow phenomenon under investigation. Prof. Stone is the recipient of the most prestigious fluid mechanics prize, the Batchelor Prize 2008, for the best research in fluid mechanics in the last ten years. He is also a Fellow of the American Academy of Arts and Sciences and is a member of the National Academy of Engineering and the National Academy of Sciences.


Orest Shardt is a lecturer in fluid mechanics and transport processes in the newly-launched Bernal Institute at the University of Limerick in Limerick, Ireland. He was previously a postdoctoral research fellow in Howard Stone's Complex Fluids Group at Princeton University, holding a fellowship from the Natural Sciences and Engineering Research Council of Canada. He received his PhD in Chemical Engineering from the University of Alberta in 2014. His research focuses on interfacial and electrokinetic phenomena in multiphase flows.


Sangwoo Shin is an associate research scholar in the Department of Mechanical and Aerospace Engineering at the Princeton University under the supervision of Prof. Howard A. Stone. He received his B.S. and Ph.D. in Mechanical Engineering from Yonsei University in 2005 and 2012, respectively. His primary research interest lies in the field of thermofluids and transport phenomena in small-scale systems.


Suin Shim is a PhD candidate in the Department of Mechanical and Aerospace Engineering at the Princeton University under the supervision of Prof. Howard A. Stone. Her research focuses on the complex fluids phenomena in small scales such as migration of particles driven by CO2 dissolution in water, coalescence of liquid drops, and building a cooling wall using thin film evaporation of water.


Patrick B. Warren is a staff scientist at Unilever’s R&D facility in Port Sunlight, near Liverpool in the UK.  He obtained a PhD in Physics from the University of Cambridge.  His domain expertise includes statistical and condensed matter physics.  He is a member of the American Physical Society (since 1990), and is currently an Editorial Board member for Physical Review E.


Intellectual Property & Development status

Patent protection is pending.

Princeton is currently seeking commercial partners for the further development and commercialization of this opportunity.



Michael R. Tyerech

Princeton University Office of Technology Licensing • (609) 258-6762•

Sangeeta Bafna

Princeton University Office of Technology Licensing • (609) 258-5579•


Patent Information:
For Information, Contact:
Tony Williams
Princeton University
Orest Shardt
Sangwoo Shin
Suin Shim
Howard Stone
Patrick Warren