Emerging Technologies
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May 09, 2016
Forward Osmosis has been known and exploited as a separation process for a variety of applications including water and wastewater treatment, food processing, and power generation since the early 1960’s. Can this process also be applied for air de-humidification? Recent publications and patents have demonstrated that combining capillary condensation with osmosis separation through a semi-permeable membrane, introduced as Osmotic Membrane Dehumidification process, can be an efficient de-humidification method.
In the Osmotic Membrane Dehumidification process, a humid air stream is brought into contact with a semi-permeable membrane, which separates the air stream from an osmotic solution, i.e. draw solution (draw solution is generally a salt solution). Water vapors in the air stream condense by capillary condensation in the pores of the membrane and the condensed water is transferred into the draw solution by osmosis.
Unlike the conventional de-humidification processes,
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February 17, 2011Scientists at Northern Illinois University recently published a new approach for fabricating hydrogen gas sensors by depositing palladium onto commercially available filtration membranes. This creates networks of ultrasmall palladium nanowires without the traditional obstacles of nanofabrication (tedious production, potential contamination). Palladium, besides poisoning Iron Man, is highly selective to Hydrogen gas and therefore commonly used in room-temperature solid-state Hydrogen sensors.
The new method involves a network of ultrasmall palladium nanowires (<10nm) being placed on 60 micron thick membranes with a nominal filtration pore diameter of 20nm. The end result is that this new type of fabrication method outperformed traditional hydrogen sensors, such as continuous reference film, by providing higher sensitivity and shorter response times. Better hydrogen sensing can lead to greater efficiency -
October 05, 2010
One of the biggest issues for crossflow filtration is figuring out how to control the loss of permeate flux in the process. Whether using reverse osmosis (RO), ultrafiltration (UF), or microfiltration (MF), the loss due to polarization and membrane fouling prevents many potential users in the biological or chemical processing fields from adopting this method. If you are using crossflow filtration, or considering using it, and fear the effects of permeate loss, then you may want to consider this technique courtesy of North Carolina A&T University and the U.S. National Energy Technology Laboratory. Their study (see here) produced drastically improved results by implementing flow reversal to enhance the membrane flux. They found that by periodically reversing the flow direction of the feed stream at the membrane surface results
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September 22, 2010
We ran across an interesting patent that involves silver membranes – As part of a system designed to detect and identify chemical and biological contaminants in the air! In the proposed sampling method and system, the silver membrane is used to capture liquid, solid, and gas constituents that would then be analyzed by means of spectroscopy for contaminants.
For more versatility, the surface of the membrane can be modified physically or chemically in order to increase the surface area and/or provide specific affinity towards analytes of interest. For instance, a pure length of silver membrane would trap solid particulate materials while a silver membrane treated with a metal oxide such as magnesium oxide would adsorb volatile organic compounds from a gas or liquid state. The suitable thickness for the silver membranes is between 10 - 50 microns, with 30 microns being the preferred thickness. The standard thickness for Sterlitech