Page 8 - Water and Fluid Separation News
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July 11, 2011
This study from the ACS journal Applied Materials & Interfaces has been making headlines recently for introducing a new way to purify drinking water. Scientists from Rice University have created a new filter material, dubbed “super sand,” by coating regular sand with the nanomaterial graphite oxide. Their tests have shown that this super sand has the potential to be a cheap form of water filtration for developing areas.
The use of sand as a water filter isn’t anything new – it’s actually been done for around 6,000 years. However, by combining this old world technique with cutting edge nanotechnology scientists have made sand filtration at least 5 times more efficient. Their report indicates that the modified sand adsorbed 6 times the amount of liquid mercury and 5 times as much heavy metal and organic dye than regular sand. In addition to the improved filtration capacity, there are other benefits of super sand that increase its prospects for real-world integration. The materials needed
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June 22, 2011
Biogas, a form of renewable energy this is produced through, among other things, animal and human waste (hey, it’s not like you were using it) is one of several developing energy sources whose proponents are exploring membrane separation techniques to improve their purification process. A recent study published in the “Applied Chemistry – A Journal of the Society of German Chemists” experimented with a new method of membrane separation called the “condensing-liquid membrane” (or CLM) in an effort to enrich raw biogas, which typically contains between 50-80% methane, to natural gas quality (at least 95% methane content), with favorable results. Common membrane materials like Cellulose Acetate and Polyimide have been tried for this application with some success, but the problem is that they can be ruined by the aggressive gases that are present in raw biogas, such as carbon dioxide and hydrogen sulfide. The CLM is a liquid (water in this case) layer that condenses on a porous hydrophilic
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June 06, 2011After our last post discussing how experiments with carbon nanotubes (CNT’s) might greatly improve the effectiveness of reverse osmosis desalination now comes a new report from the Institute of Physics that shows researchers are getting closer to making this a reality. Already over a billion people do not have regular access to clean water and the problem will likely get worse as the demand for drinkable water is expected to grow dramatically in the near future. With natural sources increasingly scarce, this urgent need means there is an intense global interest in any potentially viable forms of water purification.
Right now the main issues preventing RO desalination on a large-scale basis are that the membranes used to perform seawater to freshwater separation do not remove salt ions with enough efficiency and they also require great amounts of energy (and therefore expense) in order to purify the water. Jason Reese, a Professor of Thermodynamics and Fluid Mechanics at the University of -
June 01, 2011
One of the most promising new frontiers in filtration technology involves infusing different membrane types with nanomaterials in order to improve performance or to pass along certain material attributes. Here we will look into one prominent example from recent years, the incorporation of carbon nanotubes (CNTs) into ultrafiltration membranes used in water treatment. We’ll also look at how our stirred cells have aided in this specialized membrane manufacturing process. First off, what is there to gain by using CNT’s to manufacture water treatment membranes? While scientists have identified several potential advantages for CNT implementation, since the process is still in the R&D phase they have not necessarily been proven in all cases. One key possible benefit is that membranes made with these materials would be much stronger than traditional membranes, thus reducing instances of membrane breakage and fouling, two problems that contribute significantly to high maintenance costs in water
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May 24, 2011
An increase in salinity levels at the North Reverse Osmosis Water Plant in Kill Devil Hills (yes, that’s the town name) that had been creating stress for some local officials has been explained in a recent study. Researchers from nearby Duke University found that the rising salinity levels at this coastal aquifer are the result of fossil seawater and not seawater intrusion, as had been feared. Since the well’s installation in the late 1980’s salinity has more than doubled from about 1,000 mg/L to about 2,500 mg/L. There was much cause for relief however, when researchers were able to attribute the rise to fossilized seawater and not to seawater leaking in from the coast.
According to the director of the study, Duke Professor Avner Vengosh, knowing the source of the salinity increase is important because fossil seawater raises salinity, “At a relativelyf slow and steady rate that is more manageable and sustainable than the rapid increase we’d see if there was modern-day seawater intrusion.” -
April 25, 2011
Social Media at Work - Isolating the Source. It seems the infamous grotto at the Playboy mansion may be even more sordid than you would have imagined. Over the weekend the Centers for Disease Control released a report detailing their investigation into a February outbreak that infected more than 120 guests of the legendary party locale. They determined that the culprit was none other than the Legionella bacterium – a waterborne pathogen commonly found in spas, showers, and humidifiers which can cause Legionnaire’s Disease or Pontiac Fever. We’ve previously discussed how our polycarbonate membrane filters are used by the CDC to detect samples of the legionella bacterium. In addition to traditional detection methods, the CDC also turned to social media in this case to track down those afflicted and to uncover the source of the problem. Through the use Facebook, Twitter, blogs, and online polling the CDC was able to identify that there was an outbreak and deduce that it likely originated
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March 17, 2011Here’s further evidence that monitoring your company's waste output is something you should probably keep an eye on… Yesterday the former environmental, health & safety manager for AMCAN Beverages, Inc. (A subsidiary of Coca-Cola) pled guilty to falsifying reports about their plant's wastewater discharge. He now faces up to 3 years in prison and/or upwards of $250,000 in fines for directing employees to dilute wastewater samples before they were sent for off-site testing and then reporting on the tampered results. The company was caught when the City of American Canyon’s own wastewater treatment plant staterd experiencing operational problems relating to Biological Oxygen Demand (BOD) and Total Suspended Solids (TSS) measurements and began a covert investigation into industrial discharges in the area, leading them to AMCAN. If only Captain Planet was still around to call on, he'd take pollution down to zero... Read more details on the case here. And yes, we do offer plenty of different
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February 16, 2011The Department of Energy and Savannah River National Laboratory recently published a study regarding their efforts to improve performance on cross-flow filtration for high level waste treatment. Even though the waste being treated in this case is actually radioactive material from nuclear power plants, the process they describe, along with the issues they raise and recommendations for improvement, can be applied to the more common uses for cross-flow filtration.
The stated goal of this DOE research was to improve filter fluxes in their existing cross-flow equipment, a common request of many customers. The study examines the problem of increasing cross-flow filtration efficiency from a number of different approaches: Backpulsing, cake development, scouring, and cleaning were all taken into consideration.
At the end of the study SRNL was able to draw some conclusions to take into consideration when evaluating your own setup.- Higher solids concentration presents a greater challenge to filtration.
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December 02, 2010
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November 01, 2010Scientists at Michigan State University and the PERMEANT Group describes how they are infusing membranes with nanotechnology in order to improve membrane performance, particularly in the field of water purification.While the use of nanotechnology to expand membrane permeability, selectivity, and resistance has grown more frequent over the last 20 or so years, the new research by these groups is taking this approach in interesting directions.For instance, on one project they have demonstrated that by adding silver nanoparticles into the polymer matrix of the membrane that the mixture is effective at reducing intrapore biofouling.Experimentation also shows that this method could also be used to inhibit the biofilm growth on downstream membrane surfaces.Hopefully with every little improvement that these teams make will lead them a step closer to their goal of making the world’s supply of drinking water safer for all of us.You can read more about this research here.
