We've Moved!

If you're looking for the newest posts from our blog, we've moved the blog and all of the archives over to our main site at: http://www.sterlitech.com/blog

You can still browse through our past posts for now, but please note the change of address for the future. We look forward to continuing the discussion on the new site!

Silver Membrane Filters Play a Part in Antimatter Trapping

If you fastidiously watch “Through the Wormhole” like I do, chances are you’ll find this application for silver membrane filters fascinating – they’re being used to assist in the collection of antimatter! Now if your main reference for antimatter is a certain Dan Brown novel, you should know that separating and collecting antimatter is a much, much more difficult process than the entertainment industry would have you believe. In fact, “If you take all the antimatter produced in the history of the world and annihilated it all at once, you wouldn't have enough energy to boil a pot of tea,” according to Harvard physicist Gerald Gabrielse. Professor Gabrielse is a leader in antimatter trapping methodology and a co-author of the paper Pumped Helium System for Cooling Positron and Electron Traps to 1.2 K, which details how our filters are used to trap antimatter.

Antimatter is composed of the exact opposite particles (particles of the same mass but opposite electrical charges) as its traditional counterpart. So whereas a hydrogen atom is made of one electron and one proton, an antihydrogen atom (called H-Bar) is comprised of a positron and an antiproton. When antimatter comes into contact with matter, even air, both particles annihilate and release energy in the form of photons (light particles) and/or radiation. Because of the extreme instability of antimatter, one of the major challenges with studying it is gathering enough of the material in a lab. To store any amount of antimatter requires an extremely powerful vacuum to prevent it from coming into any contact with matter. To this end, scientists are experimenting with all manner of “traps” in order to separate and analyze the antimatter.

It is one of these traps that pure silver membranes have found a role in the antimatter collection process. The paper referenced above explains how in order to collect antihydrogen the scientists must cool the trap apparatus to temperatures close to absolute zero. To cool the apparatus to such an extreme degree the scientists here use liquid helium (which is about -269°C), this is also where the silver filters come into play. In order to remove any impurities that could cause clogging in the apparatus, the liquid helium is twice filtered through silver filters, first through a 5 micron filter and then a 3 micron filter before continuing through the pumping system.

A popular misconception about antimatter is that it has potential as an alternative energy source. On his website Professor Gabrielse points out that “No antimatter energy source will ever be possible since it takes much more energy to make antimatter than can ever be recovered from antimatter annihilation…Our motivation for trapping antimatter is to study is basic properties and to compare them with the properties of ordinary hydrogen atoms.” So while this research isn’t going to solve our energy problems, it could help physicists answer some of the biggest mysteries regarding the makeup of the universe.

That last part would sound better coming from Morgan Freeman…

Visit here to find the full paper.

To learn more about antimatter trapping, including separating the myths from the facts, see Gabriel Gabrielse’s website.

What the Crap?

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 membrane which then gets regenerated to allow for continuous operation. This support, made from Teflon, gathers water vapor from the biogas on the feed side of the membrane and is partially removed from the permeate side by nitrogen gas, thus allowing for separation to occur in one step as the water is constantly refreshed. One of the more brilliant aspects of the CLM method is that the presence of water in biogas, usually regarded as a disadvantage, suddenly becomes a key component in the process.

Since the membranes are being preserved and not destroyed, the potential exists for this process to be a cost-efficient method of purifying biogas in the future. Researchers will continue to investigate the CLM method in order to find the optimal conditions that will make it even more efficient.

Visit here to read the full report “Effective Purification of Biogas by a Condensing-Liquid Membrane.”

To learn more about biogas, try this site from Alternative Fuels and Advanced Vehicles Data Center and the U.S. Dept. of Energy.

How does a biogas plant work? Watch this animated video to get an idea.

Deadliest Catch: Man-Made Pollution

Cruising around the Scandinavian coastline in November might not sound like the most ideal place to conduct an environmental impact study, but for Norway’s Institute of Marine Research it was necessary in order to investigate the levels of anthropogenic particles in the Skagerrak strait. As you can imagine, this setting presented some unique challenges for the research team. In order to gather and analyze microscopic samples from this body of water, which is located between Norway, Denmark and Sweden, researchers had to come up with some new sampling methods and fashion their own equipment to solve problems that had plagued previous studies.

Norwegian Researchers Hard at Work^

One key obstacle that these scientists needed to overcome was how to distinguish between anthropogenic particles, which are man-made bits of matter that impact the environment (i.e. oil-spill droplets, asphalt, rubber tire wear, fly ash), from those particles with similar characteristics which appear naturally (volcanic ash, peat). To make this distinction, the samples were subjected to morphology analysis of their color and texture to first determine their origin before being counted.

The second major challenge was how to prevent contamination, which is easier said than done considering the harsh and unpredictable nature of the sea. One of the steps the researchers took to solve this was to develop control samples, free of any contaminants, which they could actually bring on board the ship with them. To further reduce the potential of contaminating samples, they also created new methodology and constructed their own customized sampling apparatus.

You can see a schematic of the sampling equipment the Institute researchers built in their published study. Their setup involved a submersible water pump that was positioned inside a waterproof case connected to the sampling filter (10 μm hydrophobic polycarbonate membrane filters, along with a 30 μm square mesh nylon filter as a support) which was placed directly in the sea. To protect the filter from wave turbulence they modified one of our filter holders (this one) with a new outlet fitting and a larger, semi-enclosed inlet with a smooth surface. The filters were also placed in protective holders before and after filtration for protection and to reduce the risk of contamination. As an added protective measure, the filter apparatus was ultrasonically cleaned prior to use. The entire sampling apparatus was held 2 meters outside the boat (to further prevent contamination) and the sampling depth was limited to between 0.1 and 1.5 meters to protect it from large waves.

While it will take many more studies before conclusions can be drawn about the state of this particular body of water, the scientists were encouraged by the results of the new methodology they created. They note in the conclusion how these improvements have standardized the sampling and reduced the risk of contamination. The scientists also suggest that this sampling equipment could be adapted for larger particles.

To read the full study, visit here.
^Image from Survey of microscopic anthropogenic particles in Skagerrak. Lysekil and Flødevigen 2010-11-20, Institute of Marine Research.

Silver, Silver Everywhere!

Check out this interesting article from the NIST Tech Beat explaining how nature may be manufacturing silver nanoparticles all by itself. The article also discusses some ideas as to why it is that silver is such a good antibacterial agent.

Read the NIST article here.

So Will Chemistry Teachers Have to Order New Posters Now?

Move over Copernicium! A collaboration of scientists from the Lawrence Livermore National Laboratory in California (one of our customers - we're so proud!), and the Joint Institute for Nuclear Research in Russia are being recognized today for officially creating two new elements! Scientists first created these elements in 1999 and 2000, respectively, by slamming lighter atoms together to see if they would stick. After a lengthy experimentation and review process by the International Unions of Pure and Applied Chemistry and Physics they are now certified and ready to take their rightful spots as the heaviest members of the periodic table.

Both of these elements are radioactive and exist for less than a second before decaying into lighter atoms. For now the elements are being referred to by their element numbers, 114 and 116, since the discovers are still in the process of submitting their recommendations.

It's probably a good thing that the naming process is limited only to the researchers that actually discovered the elements. Somehow I think if it was left up to an online poll our kids would be learning the atomic weight of "Bieberum."

Read more about the announcement here or here.

Quenching the Thirst for Potable Water Through Nanotechnology

After 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 Strathclyde and also the author of this report, states, “The holy grail of reverse-osmosis desalination is combining high water-transport rates with efficient salt-ion rejection.” Incredibly, these little carbon nanotubes may be able to satisfy both of these requirements for widespread adoption.

Early tests and simulations have shown that CNT membranes could have water permeability that is 20 times greater than today’s materials. Additionally, carbon nanotubes can be chemically tailored to better reject salt ions, thus improving upon the desalination process in multiple key areas.

While it is still early, these features are promising enough that scientists such as Professor Reese feel it is a very real possibility that this application of nanotechnology could be used to curtail our growing water demand.

Read more about this report here.

Enhancing UF Membranes with Carbon Nanotubes

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 treatment. Another unique advantage is that CNTs have antibacterial properties that may reduce biofilm formation and therefore prevent or limit biofouling. Lastly, the process of manufacturing ultrafiltration membranes with CNTs allows the producer to chemically modify the membrane surface which can further reduce fouling by tailoring the membrane for specific organic solutes.

As with standard membrane manufacturing processes, the stirred cell is an ideal piece of equipment for establishing the permeability of the test membranes. For this particular study on the effectiveness of polysulfone ultrafiltration membranes manufactured with CNTs, the cell (an HP4750 in this case) was set to perform dead-end filtration with ultrapure water at 38 bars of pressure (about 551 psi).

The HP4750 Stirred Cell

In order to determine permeability, the HP4750 was directly connected to the pressure regulator of the compressed air tank. Each membrane was compacted at 38 bars until the flow rate was stable (minimum of 30 minutes). Then the flow rate was measured by weighing the permeate as a function of the pressure applied (between 5 and 35 bars). To confirm the results, this test was performed in triplicate.

Permeability is an important test characteristic for determining the membrane’s susceptibility to fouling and its overall efficiency. In the study cited here, researchers found no statistically significant difference in permeability between CNT and non-CNT amended membranes. These findings supported their conclusion that their process for grafting CNTs onto membranes was ineffective. In the conclusion the authors note that because the CNTs only partially dispersed in the host material that they were prevented from taking on the mechanical properties of the CNTs.

While this particular study did not yield the desired results, new methods of integrating nanomaterials onto membranes are constantly being explored and hopefully it’s only a matter of time until these superior membranes become available.

Visit here to read the full study:
http://cohesion.rice.edu/engineering/pedroalvarez/emplibrary/85

Rising Salinity Cause for Concern at North Carolina Desalination Plant

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 relatively slow and steady rate that is more manageable and sustainable than the rapid increase we’d see if there was modern-day seawater intrusion.” As a result of this study the community will be able to rely on this aquifer for decades to come without having to resort to more expensive seawater desalination techniques which require more energy and advanced filtration methods.

Current treatment for groundwater desalination includes the use of reverse osmosis (RO) membranes to separate dissolved salts from potable water. Even with the rising salinity level these membranes remove around 96 to 99 percent of the dissolved salts. RO membranes also remove between 16 and 42 percent of the boron and 54 to 75 percent of the arsenic from the groundwater. Additional treatment following reverse osmosis desalination continues to remove arsenic until it is within safe drinking levels (10 parts per billion, according to the EPA).

Because seawater consistently has more salt than groundwater it requires more energy to treat, and therefore the cost is higher. Per this report on desalination from the Pacific Institute, “Energy is the single largest variable cost for a desalination plant, varying from one-third to more than one-half the cost of produced water.” The report also states, “At these percentages, a 25% increase in energy cost would increase the cost of produced water by 11% (for RO plants).” In looking at these percentages, it’s easy to see why the plant was concerned about seawater intrusion. Thanks to this research, the local citizens can drink easier knowing they have a supply of healthy, affordable water for a long time to come.

Click here to learn more about this case.

Kids Today

If you haven’t taken a look at the semifinalists for the Google Science Fair you still have a few days left to view the submissions and cast your votes! At stake is a $50,000 scholarship from Google, along with an opportunity to apprentice with Google or one of their partner organizations. There are 60 very interesting entries spread across three categories and covering just about every discipline of science. Suffice to say that the projects went beyond the paper-mache volcano. Some examples include:

• A portable solar autoclave for easy sterilization of medical tools in the third world.
• A proposal to utilize gold nanoparticles for the treatment of prostate cancer.
• Building a conductometric biosensor from scratch to detect food-borne illnesses such as Salmonella, using readily available materials.
• A new type of farm implement designed to harvest and thresh crops that requires little to no fuel and can be built from easily available resources and materials.

Impressive stuff indeed! Especially considering all of these submissions came from 13-18 year-olds, a time when a lot of us were just trying to get a grasp on puberty. Kudos to Google and their partners for this project: CERN, the LEGO Group, National Geographic, and Scientific American. And of course, best of luck to all the entrants! Surely there are some incredibly proud parents, teachers, and mentors behind them.

Newsletter Accidentally Resent - Monkeying up the System

It looks like Mailchimp, our email newsletter service, grabbed itself by the tail earlier today and accidentally resent an old newsletter to our subscriber list. Our apologies if you received this blast from the past and were understandably perplexed by it. We're working with them now to make sure it doesn't happen again. Rest assured that the last thing we want to do is overload your already bursting inboxes!

Legionella Sampling Just Got a Whole Lot Sexier

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 from a single source. Further investigation narrowed down the exact source to a particular spa inside the grotto (pictured above).

You do have to wonder if the social media investigation was more effective just because people wanted to brag about having gone to the Playboy mansion. Had this occurred in a local YMCA hot tub I’m not so sure as many people would have put it on their Facebook…

You can view the presentation about the details of the investigation here.

Standard Method and Application Guide

We made a new resource to show you which of our filters and equipment can be used for various Standard Methods and procedures from the likes of the EPA, NIOSH, ASTM and more. These procedures cover applications ranging from detecting pseudomonas in water to aviation fuel testing.

This guide lists the item category as well as precisely which filters to use for each application. We also included the links to particular method whenever possible – to make your research a little easier and because we like you.

Do you have an application that hasn’t been covered yet? Is there a standard we missed? Tell us about it and we’ll make sure to credit you for your righteous knowledge!

New Item - Quartz Fiber Filters

Quartz Fiber Filters for High Temp. Needs

This week we added another new item to our catalog - Quartz Fiber Filters. These filters are especially useful for high temperature filtration applications since they can withstand temperatures over 500°C.

Other nice things about these filters include their indefinite storage life and their high chemical resistance. Right now we have grades QR100 and QR200 available in diameters ranging from 21mm to 150mm.

FAQ: Chemical Compatibility

We all know oil and water don’t mix. Same goes for acids and bases or this guy and gravity. But what about Kerosene and cellulose acetate? Or Trichloroethylene and silver?

To answer these questions we have our frequently referenced Chemical Compatibility Chart for general laboratory filtration products. Since using the correct filter material is vital to the success of a separation process we are constantly expanding our knowledge base of chemicals used with our filtration products. We currently have data on over 70 chemicals and their recommendation level for filtration materials such as Polycarbonate, Nylon and Teflon.                        

Curious about a chemical that isn’t listed yet? Just ask us about it we’ll be happy to help you out.

Shiny New Sterlitech Website!

It's time! After many months of work, we finally launched the new and improved version of our website last week. On our end, this hopefully means no more agonizing over different fonts and button colors.  For you guys, it should mean a user-friendly layout with more services. If you haven't seen it yet, head on over to www.sterlitech.com to look around, then let us know what you think here. We'll reward some lucky commenters with a Sterlitech mug or t-shirt!

Aside from cleaning up the layout and making things prettier, the new site also has some added features to give you a better experience.

• Better Site Search - We made it easier to find what you are looking for, whether it's a particular product or a technical article. You can also search by SKU to quickly pull up the items you want.   
• Organized Resource Documents - Tables, charts, specifications, and other technical data have been organized by product group to make researching a product or application easier.
• FAQs Matched with Products - Our FAQ's have been pulled into the individual product category tabs so you can get answers without having to go back and forth between pages.     
• Accepting Web Purchase Orders -  We added the ability to accept purchase orders over the web to give our customers more ordering options.

For more detailed information on what's changed, we've also put together this guide at http://www.sterlitech.com/website-guide.html.

Here's hoping you like what we've done so far. Of course we're always open to more changes, so if there's something you'd like to see added or changed, don't be shy about letting us know...

How NOT to Handle Wastewater Discharge

Here’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 products for TSS measurements as well as bench scale systems for municipal/industrial waste and wastewater purification.  

Silver Membrane Filters to Collect Wood Dust

A new study by NIOSH found a more effective method for testing occupational exposure to airborne wood dust, which is known to cause cancer. This new practice incorporates silver membrane filters along with a mid-infrared diffuse reflection method for direct on-filter determination of wood dust mass instead of gravimetric analysis and glass fiber filters, creating a more specific test.

To learn more, you can view the article abstract here.

Discount on Water Analysis Filters in March

For the rest of the month we're offering 10% off filters for water analysis! Check out the Sterile MCE Membrane filter as well as the GA-55 and GC-50 Glass Fiber Filters for treating water and wastewater. It's a great opportunity to stock up on any variety of these frequently used models...    

Welcome TriSep to the Sterlitech Family!

Starting this week you can power your process filtration units and membrane test cells with the full line of flat sheet membranes from TriSep Corporation! These membrane elements are designed to provide premium efficiency in water treatment applications. 

What is especially great about this news is that now you can get these membranes in precut sizes to fit the CF042, Sepa CF, and HP4750 membrane test cell (individual sheets are available too)! Performing desalination and wastewater purification just got a lot easier…

See the full announcement here.

EPA Creates 4 New Clean Air Research Centers

Today the Environmental Protection Agency awarded $32 million to 4 universities around the country to study the health impacts of air pollution. These centers will answering questions like, "does air pollution effect a child's learning ability?" "Are obese people more susceptible to health effects of air pollution?" "How does your commute effect your health?"

We work with a number of environmental labs to provide filtration materials, and one of the most common requests we get from them is for our 0.45 micron, 25mm silver membranes to comply with NIOSH methods for testing airborne contaminants such as silica and bromine. 

Here is a breakdown of what the four new centers are focusing on:

• University of Washington - Effects of roadway pollution on on cardiovascular health.
• Michigan State University - The relationships between obesity and air pollution.
• Emory University / Georgia Institute of Technology - Characterize health risks of air pollution mixtures, research how social factors (living location, commute, etc.) impact health. 
• Harvard University - Investigate health effects of short-term and long-term exposure to pollutants on specific health functions, including cognitive function, birth weight, and mortality. 

See also:
"EPA Awards $32 Million to Understand Health Impacts of Air Pollution"

EPA Clean Air Research Centers Home

Bean to Bar at Theo Chocolates

Two weeks ago I had the opportunity to mix business with pleasure during an ACS sponsored event at a local chocolate maker. Based out of Seattle, WA, Theo Chocolates, appropriately named after the chocolate bean bearing tree Theobroma cacao, is the only bean-to-bar, organic, fair trade chocolate factory in the USA. After a delicious round of tastings and an insightful tour of the production line, COO Andy McShea gave an interesting lecture on all things chocolate. Did you know that the antioxidant poly-phenols found in dark chocolate are known to lower blood pressure, reduce oral bacteria, and improve cognition? Still need convincing it’s ok to take one more piece?

At this point, you're probably wondering, but what does chocolate have to do with filtration? And you're right, not nearly as much as you’d find in the beverage industry. But Theo, in an effort to maintain its organic product status, uses only essential oils as opposed to extracts to create the sensational, true to flavor tastes its customers have come to enjoy. That’s where filtration comes in to play. Diatomite filtration has been used for decades in the food and beverage industry to produce essential oils for foods. In recent months, we’ve received several inquiries about the use of cross flow filtration for essential oil extraction as well. Science never smelled so sweet (or tasted this good)!



Visit Sterlitech at the ACS Spring 2011 Exposition in Anaheim, March 27th-31: Booth #313

Theo Chocolates are available at Whole Foods nationwide. For more information, visit www.theochocolate.com

Do You Trust Me?

According to a recent survey from Laboratory Equipment magazine on the usage of meters and monitors in lab experiments, most researchers do in fact trust their instrumentation; only 1% indicated that they were dissatisfied with their existing equipment. Another sign of trust: 71% of respondents plan to purchase direct replacements for their existing products when they buy new equipment.

You can take a look at these charts on what sort of meters and monitors are beings used and what they are being used for.

EPA Increases Funding for Nanotechnology Research

Last week the US Environmental Protection Agency announced that they are awarding $5.5 million to research possible health risks in nanotechnology. The information developed can guide the EPA and other agencies in policy decisions regarding the safety of materials and products made using nanotechnology.

The United Kingdom’s Natural Environment Research Council ($6,000,000) and the Consumer Product Safety Commission ($500,000) are also contributing to this research project. The grants will be divided between three different of researchers in the US and three in the UK.

In related news, the National Institute for Occupational Safety and Health (NIOSH) recently closed public comment on their draft document concerning possible health effects of exposure carbon nanotubes and nanofibers. The NIOSH document recommends:

Employers minimize work-related exposures until scientific studies can fully clarify the physical and chemical properties of carbon nanotubes and carbon nanofibers that define their potential for adverse occupational health effects through inhalation.

At present, NIOSH advises:  

A recommended exposure limit (REL) of 7 micrograms of carbon nanotubes or carbon nanofibers per cubic meter of air as an eight-hour, time-weighted average, respirable mass concentration.

While NIOSH does propose this specific exposure limit, it concedes, “the REL may not be completely health protective but its use should help lower the risk of developing [work-related] lung disease.”

Nanotechnology is the study of small matter called nanomaterials, which are between 1 to 100 nanometers in size. Applications that benefit from nanotechnology include drug delivery, energy storage, and pollution prevention. For more information on nanotechnology research, visit http://www.epa.gov/nanoscience/.

Click here to view the NIOSH document: Occupational Exposure to Carbon Nanotubes and Nanofibers

New Hydrogen Gas Sensing Method Uses Commercially Available Membrane Filters

Scientists 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 in areas such as steel manufacturing and clean energy research.

Performance Improvement of Cross-flow Filtration for High Level Waste Treatment

The 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.
• The presence of a filter cake can improve the solids separation by an order of magnitude as determined by turbidity.
• Scouring a filter without cleaning will lead to improved filter performance.
• Filtrate flux decline is reversible when the concentration of the filtering slurry drops and the filter is scoured.

You can read the full report here to see a detailed description of their setup and complete results.

Sterlitech Bench Scale Customer in the News!

This week the New York Times gave a very nice shout out to one of our customers, Ion Torrent, and their CEO, Dr. Jonathan Rothberg. Ion Torrent is increasing the prevalence of genetic sequencing by developing smaller and more affordable machines. The article compares what they are doing with genetic equipment to what Steve Jobs did with the personal computer – so clearly Ion Torrent has some big, ambitious plans.

They’ve been using our bench scale products for a little while now, and it’s nice to know they are going to good use. My favorite part, “If somebody is to get the Nobel Prize for next-generation sequencing, it should be Jonathan.”

Just make sure to wave to us from Stockholm!

Read the complete article here.

Thomas Graham: Father of Colloid Chemistry

Have you ever wondered where you would be without Thomas Graham? If you are a chemist or membrane scientist, you probably should. Scientists of many disciplines are indebted to Thomas Graham for his groundbreaking studies on gas flow through microporous membranes. His work, which included creating Graham’s Laws of Diffusion to describe the relative permeation rate of two gases, was instrumental in the creation of colloidal chemistry and the advancement of membrane science.

In terms of real world applications, Graham’s efforts are a precursor to inventions ranging from the artificial kidney to the atomic bomb. His feats are even more impressive when you consider that in order to perform his experiments he had to first generate the necessary gases himself, and also that his selection of membrane materials was limited to whatever objects he could find, such as rubber balloons, animal bladders, and thin metal sheets.

Thomas Graham was born in Edinburgh, Scotland in 1805 and enrolled in the University of Glasgow at the tender age of 14! He went on to become Professor of Chemistry at Anderson’s College (now part of Strathclyde University) and then at University College London. In 1854, Graham was named Master of the Mint, a position once held by Sir Isaac Newton. Even though this was considered to be more of an honorary title at the time, Graham invested himself so heavily in its duties that he actually suspended his research for several years. The position was permanently retired following his death in 1869.

Thomas Graham’s influence has grown considerably since his passing. In addition to Graham’s Laws for diffusion and effusion of gases, he introduced the terms gel, sol, colloids, crystalloids, and dialyzer into the scientific lexicon. Other important contributions include his determining the formulas of the PxOy polyatomic ions, and in the 1850’s he hypothesized that a membrane machine could be created that would separate the blood toxins that built up in kidney failure, paving the way for modern kidney dialysis. His tenacity was rewarded with several honors in his lifetime, including the Copley Medal of the Royal Society, the Royal Medal of the Royal Society (twice), and the Prix Jecker of the Paris Academy of Sciences.

Sources:
“Thomas Graham,” D. Lane and J. Solon, Woodrow Wilson Leadership Program in Chemistry, The Woodrow Wilson National Fellowship Foundation, CN 5281, Princeton, NJ 08543; http://www.woodrow.org/teachers/ci/1992/Graham.html.

“Membrane Pioneers: Thomas Graham,” S. Alexander Stern and Richard W. Baker. Membrane Quarterly. Volume 25, Number 1, January 2010, pgs. 17-19.