The figure illustrates crystals on a fouling resistant nano-structured reverse osmosis membrane
Image Source: Figure 3 U.S. Patent Application 20090308804
Fouling and scaling resistant nano-structured reverse osmosis membranes have been created by UCLA Polymers and Separations Research Laboratory Professor Yoram Cohen, along with Myung-Man Kim, Gregory T. Lewis and Nancy Hsiao-Yu Lin (Los Angeles, CA). According to U.S. Patent Application 20090308804, the nano-structured membrane may be used in a reverse osmosis (RO) process, nanofiltration, and ultrafiltration. Particularly the nano-structured RO membranes resist biofouling and mineral salt scaling for saline water desalting which is a main problem in water desalination. The plasma manufacturing process lends itself to large scale commercial production.
Fouling and scaling resistant nano-structured reverse osmosis membranes have been created by UCLA Polymers and Separations Research Laboratory Professor Yoram Cohen, along with Myung-Man Kim, Gregory T. Lewis and Nancy Hsiao-Yu Lin (Los Angeles, CA). According to U.S. Patent Application 20090308804, the nano-structured membrane may be used in a reverse osmosis (RO) process, nanofiltration, and ultrafiltration. Particularly the nano-structured RO membranes resist biofouling and mineral salt scaling for saline water desalting which is a main problem in water desalination. The plasma manufacturing process lends itself to large scale commercial production.
The inventors method of modifying a surface of a membrane includes exposing the surface to an impinging atmospheric pressure plasma source to produce an activated surface, and exposing the activated surface to a solution including a vinyl monomer. Another method of manufacturing a desalination membrane involves treating a surface of the membrane with an impinging atmospheric plasma source for an optimal period of time and with RF power, and exposing the surface to an aqueous solution containing a vinyl monomer. A third method makes a membrane with a surface, and polymer chains terminally grafted onto the surface of the membrane.
According to the research team, graft polymerization that is induced by plasma membrane surface treatment has the advantage of the formation of a high density of membrane surface initiation sites, which allow polymer chain growth directly from the membrane surface, while minimizing bulk polymer growth. The polymer layer formed is a highly dense bush or brush layer with a more uniform distribution of polymer chain sizes than other techniques can produce, primarily due to the suppression of polymer grafting from solution. It is also important to note that plasma membrane surface initiation can be achieved over a short treatment interval to reduce the effects of membrane surface etching.
Use of low pressure plasma (i.e., under vacuum) treatment can limit the potential commercial scale applicability of the approach. Accordingly, the present approach makes use of an atmospheric pressure plasma source, thereby enabling large scale surface treatment for continuous processing for membrane fabrication processes and subsequent surface graft polymerization using either solution or gas phase reaction to create a terminally anchored polymer brush layer on the membrane surface.
Use of low pressure plasma (i.e., under vacuum) treatment can limit the potential commercial scale applicability of the approach. Accordingly, the present approach makes use of an atmospheric pressure plasma source, thereby enabling large scale surface treatment for continuous processing for membrane fabrication processes and subsequent surface graft polymerization using either solution or gas phase reaction to create a terminally anchored polymer brush layer on the membrane surface.
FIG. 1 illustrates a spiral-wound fouling and scaling resistant reverse osmosis membrane made according to U.S. Patent Application 20090308804
FIG. 1 illustrates a spiral-wound membrane element 100. The spiral-wound membrane element 100 includes a reverse osmosis (RO) separation membrane 110, a feed stream port or entrance 120, a permeate tube or exit location 140, and a concentrate tube or exit location 150.
Figure 8 illustrates the RO Process using the nano-structured RO membrane.
Figure 18 is an Atomic Force Microscope Image of the Anti-Fouling Nano-Structured Membrane
Figure 8 illustrates the RO Process using the nano-structured RO membrane.
Figure 18 is an Atomic Force Microscope Image of the Anti-Fouling Nano-Structured Membrane
