Toray is discontinuing the production of some of their reverse osmosis (RO) membranes. These membranes are being replaced in Sterlitech's line-up by the new 70HA, 70AC, 72U, and 82V membranes will be overtaking some of Toray's newly obsolescent membranes.  The table below lists the specifications of the new and obsolete membranes for easy comparison.  To browse our complete selection of RO membranes or to place an order with us, click here.

Sterlitech is shaking up our flat sheet membrane offerings with the addition of new nanofiltration, ultrafiltration, and microfiltration membranes from Synder Filtration. These new membranes encompass a variety of materials and applications.

First established in 1989, Synder Filtration has grown into an international supplier of high quality membrane technology.  Emphasizing technical expertise, and reliable products, Synder Filtration's membrane technology is ideal for solving industrial and environmental challenges.

The table below lists the new membranes and their specs.  To browse the complete list of Sterlitech's flat sheet membranes or to place an order, click here.

Synder Nanofiltration Membranes

Ultrafiltration Membranes

Microfiltration Membranes

We're looking forward to showcasing our latest microbiology and life science equipment at the ASM 2014 General Meeting at the Boston Convention Center! Bring all of your burning questions about filtration or lab equipment over to booth #1047, and we'll do our to show you how we can help.

Sterlitech Corporation is adding the EZWaste Safety Vented Carboy to its roster of ergonomic, compact fluid storage and transport equipment.  These new, specially vented carboys are designed to help scientists create a safer laboratory environment by reducing the risks of spills and preventing hazardous solvent vapors from infiltrating the lab.

“Many organic solvents common to laboratories, like acetonitrile, can give off hazardous vapors, while others, like dimethyl sulfoxide, can easily permeate through the skin when airborne.” says Mark Spatz, founder and President of Sterlitech.  “The EZWaste carboy creates a closed waste collection system, preventing spills and minimizing the risks of exposure to personnel from volatile organic compounds.”

The EZWaste Safety Vented Carboys are a direct descendent of the EZgrip Carboys currently offered by Sterlitech, which mean they share the same efficient, ergonomic design.  What sets the EZWaste apart the normal carboy is a special VersaCap with integrated tubing connections and an activated carbon exhaust filter.  Each EZWaste system comes with extra plugs for any unused ports in the cap, and a sulfur-cured EPDM gasket to ensure a tight, chemically resistant seal.  Once waste collection is complete, the vented cap is easily replaced with a standard cap for storage or transport to a designated waste facility.

By their very nature, laboratories are expected to handle and store potentially harmful chemicals used in techniques such as high-performance liquid chromatography (HPLC).  Solvents like acetonitrile, methanol, and tetrahydrofuran, may be necessary to conduct research, but exposing laboratory personnel to the risk of spills and harsh vapors can now be minimized.

Aquaporin A/S and their Aquaporin Inside Membrane were featured last month in CNN's series, Make Create Innovate.  As you may recall from this article here, Aquaporin is a customer of ours which is working to perfect membranes made with aquaporins, a protein pore which is found in all living things and only allows water molecules to pass through it.

In the video from CNN, we get to see the Aquaporin Inside membrane at work inside of an acrylic CF042 FO cell as it's used to draw water out of coffee.  This is a great video to watch if you want to see forward osmosis in action and check out an amazing innovation.

Have you ever wondered what goes in on inside one of Sterlitech's crossflow testing cells? Most of our cells are opaque, being made of stainless steel or tough, white polymers. Our clear acrylic CF042 cells offer a view of the cell's inner workings, but, as you can see in this video, even that is difficult to watch without some kind of dye in the feed.

So how can we show you how our cells work if even video can't capture it clearly?  Our answer to that question comes from Ulf Aslak of Aslak Animations, who created the computer simulation of our CF042 FO cell below.

Another computer-generated flow diagram of our CF042 by Ulf Alsak can be found here.

Sterlitech Corporation is adding new product options to its line of silt density index (SDI) testing devices. Sterlitech is offering these all-in-one units in response to the industry’s demand for a convenient and durable on-site tool for measuring the fouling capacity of the feed water used in reverse osmosis systems.

Silt density index testing quantifies the amount of particulate contamination in a water source and is used to estimate the rate at which membrane fouling will occur, particularly in applications employing reverse osmosis membranes. The SDI of a feed source is measured by running a stream of feed water through a 0.45 micron filter at a constant pressure and calculating the rate at which the flow slows down (ASTM Test Method 4189-07).

“Accurate and reliable SDI testing is key to maintaining good efficiency in membrane purification facilities and to help keep operating costs down, especially when dealing with sources like seawater which have a highly variable SDI,” notes Mark Spatz, founder and President of Sterlitech. “This can be an extremely valuable measurement when performed regularly.”

Unlike previous automatic SDI kits, the SimpleSDI kit is uniquely suited for testing in the field due to its lightweight structure and rechargeable battery, which allows up to 13 hours of use between charges. Accurate and repeatable SDI measurements are automatically calculated by means of the integrated microprocessor at 5, 10, or 15 minute increments. Replacement filter membranes, booster pumps, and a manual version of the kit are also available through Sterlitech.

Sterlitech Corporation provides superior laboratory products, specializing in flat sheet filter membranes and bench scale testing equipment for a variety of industries, including the occupational health and safety, petrochemical, fossil fuels and biotech industries. For precision and accuracy, Sterlitech’s membrane disc filters, filter holders, silt density index test kits, and syringe and capsule filters consistently relied upon to assure exceptional results.

Sterlitech Corporation is adding the EZWaste Safety Vented Carboy to its roster of ergonomic, compact fluid storage and transport equipment. These new, specially vented carboys are designed to help scientists create a safer laboratory environment by reducing the risks of spills and preventing hazardous solvent vapors from infiltrating the lab. The EZWaste Safety Vented Carboys are a direct descendent of the EZGrip Carboys currently offered by Sterlitech, which means they share the same efficient, ergonomic design. What sets the EZWaste apart from the normal carboy is a special VersaCap with integrated tubing connections and an activated carbon exhaust filter. Each EZWaste system comes with extra plugs for any unused ports in the cap, and a sulfur-cured EPDM gasket to ensure a tight, chemically resistant seal. Once waste collection is complete, the vented cap is easily replaced with a standard cap for storage or transport to a designated waste facility. “Many organic solvents common to laboratories, like acetonitrile, can give off hazardous vapors, while others, like dimethyl sulfoxide, can easily permeate through the skin when airborne,” says Mark Spatz, founder and President of Sterlitech. “The EZWaste carboy creates a closed waste collection system, preventing spills and minimizing the risks of exposure to personnel from volatile organic compounds.” By their very nature, laboratories are expected to handle and store potentially harmful chemicals used in techniques such as high-performance liquid chromatography (HPLC). Solvents like acetonitrile, methanol, and tetrahydrofuran may be necessary to conduct research, but exposing laboratory personnel to the risk of spills and harsh vapors can now be minimized.

Since 2007, the Southern California Coastal Water Research Project has been monitoring the impact of fecal indicator bacteria (FIB) on public health at Doheny, Avalon, and Surfrider beaches in California (just when thought it doesn't get worse than peeing in the pool).  They explain and summarize their tracking efforts in a neat video below.

Sterlitech also offers analytical funnels, Grade F glass fiber filters, manifolds, and microbiological monitors that are similar to the ones you see in the video.  If you are also working with or involved in microbiological monitoring, we are also developing a new microbiological monitor that uses a polycarbonate membrane filter in place of the usual MCE filter.  You can contact us here, if you would like to learn more.

If you were to spend a little time perusing Sterlitech’s selection of membrane disc filters, one thing we’re very proud of might just jump out at you: we have a lot of pore sizes. So many that you might wonder if it’s a little excessive that we carry both 0.2 and 0.22 micron pore sizes. After all, both are used to sterilize fluid passed through them. Can the tiny difference of 0.02 microns really change a filter’s performance characteristics that much?

To answer that question, we must first take a look at one of the methods used to test a filter’s performance: the bubble point test1. Standard tests to verify a filter’s stated pore size usually entail a bubble point test. This test pushes air under pressure through a submerged membrane (either in water or alcohol) to the point where air bubbles first begin to come through the filter membrane2. The largest pore, or pores, in the membrane will bubble first, and the air pressure required to push the bubbles through these pores can be mathematically correlated to pore size. The irregular and tangled nature of the pores of most membrane filters makes it impossible to directly measure the size of an individual pore, so the bubble point test is used to determine the smallest particle that the filter can sieve out of a fluid.

In other words, the stated pore size of filter isn’t literally the size of the pores. It’s a rating of what can’t pass through them. Obviously, when sterilizing solutions, the object is to physically remove bacteria suspended in the solution. Before 0.2 and 0.22 micron filters became standard, it was thought that filters with an absolute rating of 0.45 micron were thought to be sufficient to strain out even the smallest bacteria. However, the discovery of Brevundimonas diminuta, showed that there were still bacteria capable of passing through a 0.45 micron filter in large quantities. After the discovery, researchers and labs competed to create the new filtration standard, arbitrarily defining their filters to be either 0.2 or 0.22 micron in pore size, roughly half the size of the old standard.

What that means is, for the purpose of sterilization, 0.2 micron and 0.22 micron filters are indistinguishable. Their performance is the same, only the difference being the designation of their pore size rating. The real measure of filter’s ability to sterilize fluid is passing the test described in ASTM F838-05, Standard Test Method for Determining Bacterial Retention of Membrane Filters Utilized for Liquid Filtration. Basically, if the filter can retain a minimum of 1 x 107 colony forming units (cfu) per cm2 of a challenge bacteria (usually B.diminuta5), then the filter is suitable to use for sterilization.

Even with the contraction of the standard pore size for sterilization, it turns out that simple size selection is not a sufficient method to fully contain all particles. Jornitz6 et al. showed adsorptive effects also change the manner in which different filter media capture different particles. Influences such as pH, pressure, bacterial load, and the liquid medium itself influence the size of bacteria. However, as long as the filters could capture the required number of challenge bacteria per square centimeter of membrane, then it is a valid sterilizing filter - whatever the stated pore size. Sterlitech Corporation is both a manufacturer and a reseller of different membrane filters, so you will see 0.2 micron and 0.22 micron in our filter offerings; but for sterile filtering, both are suitable based on the above information.

References:
1. ASTM International. F838-05 Standard Test Method for Determining Bacterial Retention of Membrane Filters Utilized for Liquid Filtration (2005); http://webstore.ansi.org/ansidocstore/product.asp?sku=ASTM+F838-05.

2. Cheryan, Munir. Ultrafiltration and Microfiltration Handbook. Boca Raton: CRC Press, Technology & Engineering. Jan 26, 1998. Print

3. “Pharmaceutical Filtration: The Management of Organism Removal.” Parenteral Drug Association (PDA) Online Bookstore. Accessed online 28 May, 2014. https://store.pda.org/TableOfContents/Pharm_Filtration_Ch01.pdf

4. Bowman, F.W., Calhoun, M.P., and White, M. “Microbiological Methods for Quality Control of Membrane Filters”, J. Pharm. Sci. 1967, 56: 222-225.

5. Segers P, Vancanneyt M, Pot B et al. “Classification of Pseudomonas diminuta Leifson and Hugh 1954 and Pseudomonas Vesicularis Busing, Doll, and Freytag 1953 in Brevundimonas gen. nov. as Brevundimonas diminuta comb. nov. and Brevundimonas vesicularis comb. nov., respectively.” Int J Syst Bacteriol 1994; 44: 499–510.

6. M.W. Jornitz, J.P. Agalloco, J.E. Akers, R.E. Madsen, and T.H. Meltzer “Filter integrity testing in liquid applications, revisited. Part II.” Pharmaceutical Technology, 2001, vol. 25, no. 11, pp. 24-35.

We’d like to extend our congratulations to a young scientist, Alec Isaacman, who’s been making waves at California’s science fairs with his experiments with osmotic power.  Alec’s experiment, which was conducted in a fish tank his friend was no longer using, examined the effect salinity had on the production of osmotic power to determine the best locations in the world to place an osmotic power plant.

The tank was divided into two chambers separated by a ACM5 RO membrane and were filled with equal amounts of water. One side was filled with fresh water and the other side was filled with salt water. Alec then determined the absorption rate of the salt water as it pulled fresh water through the membrane.

The salt water was mixed to represent the three most common salinity levels found in the ocean: Polyhaline (18-29 parts per thousand), Mixoeuhaline (30-39 parts per thousand), and Metahaline (40-49 parts per thousand).   Alec predicted that the metahaline water would absorb the most fresh water, and would have the most potential to produce osmotic power.

The fresh water side of the tank was pressurized to 50 PSI with a bicycle pump and, after 20 minutes, the water levels on both sides of the tank were measured to determine how much fresh water was drawn through the membrane.  The tank would then be emptied and cleaned for the next test.  Five tests were run for each salinity level.

Alec's results ultimately proved his hypothesis.  He found, on average, the polyhaline water absorbed 32.1 cubic inches of fresh water, the mixoeuhaline water absorbed 34.4 cubic inches of fresh water and the metahaline water absorbed 37.4 cubic inches of fresh water during the 20 minute intervals.

For determining that steeper salinity gradients have more potential energy, Alec won 1st prize at the Irvine District Science Fair, 2nd place at the Orange County Science Fair and was nominated for the Broadcom MASTERS program.  In addition, he won $200 dollars from the Irvine Ranch Water District.  Congratulations from Sterlitech, Alec!

Sterlitech's offices will be closed on Friday, July 4, in observance of Independence Day. We'll be back on Monday, July 7 to help you find the best solution to your laboratory filtration questions.

Sterlitech Corporation is now offering fully customizable membrane and process development systems which provide users with complete experimental control over the system’s flow parameters to simulate the dynamics of larger membrane systems.  Sterlitech first began building custom-made crossflow systems in 2011 and has since improved and expanded their capabilities to cover a wide range of applications in reverse osmosis, nanofiltration, ultrafiltration and microfiltration.

These units can be individually tailored to meet the specific testing needs for off-the-shelf or custom membrane designs. Customizable factors include: membrane size, the number of cells in operation (up to 6), and whether the cells are run in sequence or in parallel.  Some of the new features built into the new testing units include a NEMA-standard waterproof touchscreen HMI panel and new back pressure regulators for better testing performance. This previously unattainable degree of flexibility is responsible for greatly improving operational efficiency.

According to Sterlitech President Mark Spatz, “The biggest difference between an off-the-shelf test system and one built to match a customer’s flow specifications is how much time is saved between membrane tests.  This advantage is further compounded by the system’s ability to evaluate up to six membrane samples simultaneously.”

Custom systems have already been created to assist in applications such as materials research and batch production of microbiological supplies.  Organizations with several different interests can quickly adjust the parameters to meet an assortment of testing needs. Each system ships with its own specially made instruction manual for easy reference.

To explore the options that can be added to one of our customizable crossflow testing systems, click here.

To view examples of crossflow testing systems that have been built for past customers, click here.

Over the years, we have received a number of questions about the optical clarity of some of our membrane filters, usually of the polycarbonate variety. Optically clear membranes are used in numerous applications such as culturing cells for immunofluorescence studies or even unmanned biology missions into space. All of our polycarbonate membrane filters are made by the same process, track-etching, but the clarity of our filters varies.  To shed some light on (or through) the matter of our filters' optical clarity we put together a handy infographic that you can check out.

To learn more about Sterlitech's polycarbonate filters, check out some of our other blog articles below:

• Totally Tubular: Polycarbonate Membranes as Templates for Nanotubes
• Etching the Tracks in a Track-etched Membrane Filter

To browse our complete selection of polycarbonate membrane filters, click here.  You can also contact us to learn even more about how our track-etched filters could help you with your application.

As first time exhibitors, we had a great time meeting everyone who stopped by our booth at the 41st Annual NAOSMM Conference and Trade Show! Indianapolis is a great city and it was great having the chance to meet you there.

Thanks to all of you who stopped by our booth during the show! Look for us again at next year's NAOSMM trade show, which will be hosted in Long Beach, CA.

Our friends at Foxx Life Sciences put together a short video demonstrating the various features of the ergonomically designed and space-saving EZgrip Carboy.  Check it out below:

The NF245 line of nanofiltration membranes from Dow Filmtec is being discontinued. At this time, these membranes do not have any direct replacements, although we still carry other DOW membranes which may be suitable for your application.  We've listed the specifications of the NF245 below to aid comparison with other flat sheet membranes:

*GFD = Gallons per square foot of membrane per day

The following products are longer being offered:

• YMNF2453001
• YMNF2451905
• YMNF245425
• YMNF245475

If you need assistance finding a suitable replacement product, please contact us.  You can also click here to browse the other nanofiltration membranes that Sterlitech carries.

Sterlitech is proud to announce that it is adding Synder Filtration’s polymeric membranes to its stable of products.  These additional products increase the selection of available molecular weight cut-offs and include membrane filters with surface charges.

“We have seen a steady increase in customer demand for our membrane process testing equipment, and correspondingly, a wider demand for a greater variety of flat sheet membranes,” explains Sterlitech President Mark Spatz.  “The addition of Synder Filtration products illustrates our desire to support the wide-ranging needs of our customers and facilitate the development of new applications.”

Synder’s flat sheet membranes characteristically yield stable flux, consistent rejection, and high mechanical strength and integrity. In addition to an optimal balance of flux and rejection, their ultrafiltration PES membranes offer one of the widest ranges of molecular weight cut-offs available, excellent resistance to pH, temperature, and fouling. A family of ultrafiltration elements that meet the USP Class VI certification requirements for use in pharmaceutical production are also available. All of the new Synder flat sheet membranes are offered individually as sheets or conveniently pre-cut for use with Sterlitech’s HP4750 stainless steel stirred cell, CF042 test cell, and SEPA CF cross-flow cell.

Sterlitech’s membrane and process development equipment is used by major universities and large corporations worldwide.  Common uses for its systems include research on desalination, water reclamation, membrane development, pharmaceutical processing, food and beverage processing, and protein separation.

About Sterlitech:

Sterlitech Corporation provides superior laboratory products, specializing in flat sheet filter membrane and membrane process and development equipment for a variety of industries, including the occupational health and safety, petrochemical, fossil fuels and biotech industries. For precision and accuracy, Sterlitech’s membrane disc filters, filter holders, silt density index test kits, and syringe and capsule filters consistently relied upon to assure exceptional results.

About Synder Filtration:

Synder Filtration manufactures spiral wound ultrafiltration (UF) membranes, nanofiltration (NF) membranes, and flat sheet NF and UF membranes. Synder has developed the widest range of ultrafiltration membrane pore sizes of any polymeric membrane manufacturer. Applications of these membranes include: protein concentration, protein separation, protein fractionation, and many other sanitary and industrial purposes.

Our friends at Foxx Life Sciences have a new video demonstrating the features and innovations incorporated into the design of the Autofil Bottle-top Filtration System. Check it out below:

You can also click here to browse Sterlitech's entire selection of Autofil systems and accessories.

The CQ line of ultrafiltration membranes from GE is being discontinued. At this time, these membranes do not have any direct replacements, although we still carry other GE membranes which may be suitable for your application.  We've listed the specifications of the CQ membrane line below to aid comparison with other flat sheet membranes:

*GFD = Gallons per square foot of membrane per day

The following products are no longer being offered:

• YMCQSP3001
• YMCQSP1905
• YMCQSP425
• YMCQSP475

If you need assistance finding a suitable replacement product, please contact us.  You can also click here to browse the other ultrafiltration membranes that Sterlitech carries.