Sterlitech Blog

Your source for new information on filtration equipment applications and processes.

  1. DURAMEM® and PURAMEM® for Organic Solvent Nanofiltration

    DURAMEM® and PURAMEM® for Organic Solvent Nanofiltration

    DuraMem® and PuraMem® membranes are now available as a valuable addition to our Chemically Resistant Membranes product line. Duramem® and Puramem® polymeric membranes, made by Evonik, are market leaders for Organic Solvent Nanofiltration (OSN).

    Organic Solvent Nanofiltration, i.e. separation of molecules dissolved in organic solvents through a semipermeable membrane, has gained great traction over the last decade. Advantages of OSN over conventional separation processes include lower energy requirements, conservation of expensive materials, and system robustness.

    DuraMem® offers long term stability in most polar and polar aprotic solvents (acetone, tetrahydrofuran, dimethylformamide, isopropanol, acetonitrile, methylethylketone, ethyl acetate, and more), while PuraMem® series is stable in apolar hydrocarbon-type solvents (toluene, heptane, hexane, methylethylketone, methyl-isobutylketone, ethyl acetate, and more).

    Technical Specs

    • Material: P84® polyimide

    • Molecular weight cutoff range:

      • Duramem®: 150 to 900 Da

      • PuraMem®: 280 to 600 Da

    • Recommended maximum temperature: 50°C (122°F)

    • Recommended maximum operating pressure: from 20 to 60 bar (290 to 870 psi)

    Main Application Areas for DuraMem® and PuraMem® Membranes1

    • Removal of impurities or product purification

    • Monomer/dimer separation

    • Molecular fractionation

    • Room temperature solvent exchange

    • Catalyst recovery and recycle

    • Color removal

    • Solvent recycling

    Both DuraMem® and PuraMem® series are available in a flat sheet format as well as spiral wound elements. For more information about these membranes and their applications, contact a Membrane Process Specialist at Sterlitech: E: or T: 253.437.0844.

    1 Source: Evonik Corporation:

  2. Tipping Back An “Interesting” Pint

    Tipping Back An “Interesting” Pint

    How about a nice tall glass of ice-cold beer… made from recycled sewage water?

    Did you hesitate? Well, now let’s think about it: most breweries use some combination of hops, malted barley, yeast, and…. well… clean water! But beer from recycled wastewater? That’s exactly what took place March 19-10 at the 2017 WateReuse California Annual Conference in San Diego. The City of San Diego’s Pure Water San Diego program hosted a fun competition event at the conference, where they asked homebrewers to concoct their favorite pale ales or IPAs using water exclusively sourced from the reuse program, and then offer samples of the created goods to attendees.

    In addition to the competition, local San Diego breweries such as Stone Brewing and Ballast Point also showed off a few specialty brews made from water sourced from the program and offered samples to attendees. So how did this process work?

    The program in San Diego uses what is known as “Title 22” water, which is secondary effluent collected from specified wastewater treatment plants. The water is treated in much the same way as any other treatment plant, but then is sent through a more in-depth process of ozonation, activated carbon filters, microfiltration (gotta get those bugs out!), reverse osmosis, and UV oxidation. At the end, the water is so pure that minerals must be added back in so it does not corrode the pipes used to transport it. (remember, water is the universal solvent!) So, was the beer any good?

    If attendance was any indicator, the conference event drew a packed exhibitor hall with fans lining up for the homebrewer competition to sample their favorite beer. Three local homebrewers were awarded cash prizes as the winners, based on their frothy works. Bear in mind though, the reclaimed water program is still under development as the full infrastructure is slowly phased in. The city does not yet supply this water as standard product to regular breweries in San Diego. So don’t go sidling up to the bar at one of these breweries in San Diego and yell out to the barkeep for the “Sewage Ale!” or “Commode Stout!” or “Shower Water Pilsner!” If you do, you’ll probably be asked to leave. But fear not, with over 750 craft breweries in California alone, and on the heels of the State’s chronic drought issue, it won’t be long before this program is in full swing and satisfying thirsts up and down the Golden State every Friday & Saturday night.

    Until then, the hard-working folks at Sterlitech Corporation will continue to develop and offer cutting edge filtration technology to help ensure researchers at utilities, university labs, private R&D, and yes microbreweries, have the tools they need to keep water a top priority in our communities.

  3. Looking for filter or product technical data?

    Looking for filter or product technical data?

    You spoke and we listened! Many of you expressed difficulty in finding additional application or technical specifications while viewing a product page on Thanks to your feedback, each tab is now individually outlined and highlights when moving your mouse cursor over a given tab; information is just one click away! Simply place your mouse curser over the “Application/Specification” tab near the middle of the page (example shown to the left) and click. This will open the tab, and you will then have all pertinent information on your screen.

    When you are ready to select a product, simply place your mouse curser back over the “Ordering Information” tab and click. You will return to the ordering information tab without leaving the product page and can select the items needed.

    Still have questions? Contact a Sterlitech representative directly via, or reach us via chat.

  4. Focus on Microfiltration: Filter Longevity

    Focus on Microfiltration: Filter Longevity

    For consumers using disk, syringe, and capsule filters it is a common FAQ: How long will my filter last? Or, to put it another way: How much fluid can I expect to pass through my filter before it clogs? This seems to be a simple and reasonable question for a filter consumer: Would any of us purchase a product without an understanding of its service life? However, this apparently simple question is deceivingly complex as a multitude of factors influence filter service life. Service life can be defined as the total volume of fluid that is passed through a normal flow filter until it becomes clogged; this is commonly referred to as total throughput. It is nearly impossible to predict total throughput, even with a good understanding of the application. So, as a filter manufacturer, how would we suggest approaching this challenge?

    Most laboratory filtration applications involve limited volumes of fluid that are filtered on a batch basis. For these applications, the appropriate filters are not operated to the point of clogging. With reasonable amounts of expertise, technical assistance, or even educated guesses, users can confidently select appropriately sized filters and not worry about clogging.

    For applications where the filters are used to the point of clogging, it may not be possible to predict total throughput, but it is possible to estimate it through experimentation. The experiment may be as simple as trialing a filter and directly observing how long it takes to clog. Clogging can be quantified by measuring changes in differential pressure and/or by measuring changes in flow. The results can be used to develop filter replacement strategies, or to select more appropriately sized filters if performance is unsatisfactory. Sterlitech offers a variety of sample filters to facilitate trials.

    For applications requiring higher flows, small-area filters may be used to perform service life studies. The results are used to estimate the size of the larger filters (usually capsules or cartridges) required for the full-scale flow to ensure acceptable replacement intervals. Using small scale filters helps minimize the cost of, and reduces the volume of fluid required for, the experiments. It is important to realize there is usually variability in feed stream particle loading. When scaling up results, it is a good idea to consider a safety factor so that feed steam variability can be mitigated.

    There are additional strategies that filter consumers can employ to maximize total throughput in continuous use applications, including selection criteria, use of prefilters, and modification of flow dynamics. Selecting and operating filters for optimal service life can be challenging. Our goal at Sterlitech is to provide you with the products and resources to meet these challenges. Over the next few months, we’ll be discussing these strategies in detail; so stay tuned!

    For technical guidance on selecting the best filters and parameters for your application, please contact Sterlitech’s membrane experts at or 253.437.0844.

  5. New White Paper from Sterlitech – A Solution for Waste Disposal of VOCs to improve Health in the Laboratory

    New White Paper from Sterlitech – A Solution for Waste Disposal of VOCs to improve Health in the Laboratory

    In order to provide a safe work environment, better control of vapor wastes needs to be implemented. EZ waste technology has become readily available to improve the containment of volatile liquids and prevent vapors from escaping into laboratory air. Learn about how to prevent the dangers of hazardous waste and the technology behind the closed waste system with an activated carbon filter, such as the EZ waste system. Download EZwaste whitepaper for more detail and additional instruction.

     EZ waste Whitepaper

    Explore EZ Waste Solvent Waste System product line at Sterlitech


  6. Celebrating World Water Day with Sterlitech!

    Celebrating World Water Day with Sterlitech!

    Do you know today, there are over 663 million people, who do not have safe water supply and suffering with health problems from use of dirty water?

    Here are some facts about wastewater:

    1. Globally, over 80% of the wastewater generated by society flows back into the ecosystem without being treated or reused. (Sato et al, 2013)

    2. 1.8 billion people use a source of drinking water contaminated with feces, putting them at risk of contracting cholera, dysentery, typhoid and polio. Unsafe water, poor sanitation and hygiene cause around 842,000 deaths each year. (WHO/UNICEF 2014/WHO 2014)

    3. The opportunities from exploiting wastewater as a resource are enormous. Safely managed wastewater is an affordable and sustainable source of water, energy, nutrients and other recoverable materials.

    What options do we have to make a difference for the people of the global population who are currently suffering from water related problems:

    1           WASTE + WATER = WASTEWATER

                  WATER - WASTE = WATER

    2. We can treat more wastewater and safely reuse it:

    For cleaning vehicles and city streets

    For irrigating fields

    For heating and cooling system

    3. Donation: Help Vulnerable Children Get Access to Clean Water (UNICEF: USA)


    Inspired by United Nation. (

  7. Nanomaterials to the Rescue!

    Nanomaterials to the Rescue!

    Sterlitech is proud to announce the availability of Alumina Oxide (Al2O3) inorganic microporous membrane filters. These filters are finding use in several specialty applications, ranging from nanomaterials synthesis (where they perform best), graphene synthesis (Buckypaper) and testing, HPLC mobile phase filtering, liposome filtering, environmental monitoring, and more! The Sterlitech alumina membranes are also a suitable alternative to Whatman Anodisc© filters.

    These anodized alumina filters are distinguished by swift filtration speed owing to their high pore density, efficient separation, and high purity. The inorganic material is constructed of numerous, narrowly distributed pores in the form of honeycombs yielding a high degree of open space.

    Adding to their features, these membranes become almost completely transparent when wet, and display minimal auto-fluorescence, making them well-suited for epifluorescent light microscopy. As particles are retained on the smooth surface, the alumina membrane is eminently suitable for microscopic analyses. The material is not cytotoxic and also offers a good surface substrate for cell culture applications. Alumina does not contain organic extractable components and displays only minimum adsorption. Pore sizes available are 0.02 µm, 0.1 µm, or 0.2 µm.

    For more background on the unique properties of this inorganic filter, please contact at technical representative at Sterlitech Corporation at 1-877-544-4420 or to learn more.

  8. Single-Cell RNA Sequencing in a fast and inexpensive format

    Single-Cell RNA Sequencing in a fast and inexpensive format

    Sterlitech Corporation’s unique track-etch polycarbonate membrane filters are helping MIT Researchers pioneer a faster and less expensive means of identifying key genes turned on in response to infection or diseases, as featured in the February 13 issue of Nature Methods from the Shalek and Love Labs at Massachusetts Institute of Technology.

    Most cells in the human body only express a tiny portion of all genes coded in their DNA. Those genes are copied into messenger RNA, also known as RNA transcripts, which direct the cells to build specific proteins. Each cell's gene expression profile (all genes turned “on” at any given moment) varies depending on its function or response to outside factors. Sequencing the RNA from individual cells of a blood or tissue sample offers a way to identify cells based on patterns of gene expression, allowing researchers to study what cells are doing in response to infection or treatment. But how can so many tiny cells be sorted, tracked, and sequenced in an easy manner?

    One of the main hurdles to overcome in identifying single cell transcripts in a large population of cells (think of how many cells are in that blood draw from your doctor’s office), is in keeping track of which mRNA comes from which cell – be it a B-cell, T-cell, macrophage, or more! Early on, this process relied on laborious cell sorting (flow cytometry/FACS), but FACS uses expensive equipment, is not portable, and requires a tremendous amount of time to yield only a few small populations of cells.

    The lead author at the Shalek Lab at MIT, Todd Gierahn, used Sterlitech’s 10nm pore size, 62mm x 22mm polycarbonate membrane filters to develop a chitosan-functionalized PDMS array (see the 3 glass slides in the image above). The researchers first prepared the polycarbonate membranes by plasma treatment (as described via the protocol at the Shalek Lab) and then used a process to isolate single cell suspensions from complex tissue. The cells released from the tissue are then mixed with barcoded mRNA-capture beads previously placed into the PDMS array. The array is then sealed using the prepared Sterlitech polycarbonate membrane that, upon addition of a chemical lysis buffer, confines cellular mRNAs within wells while allowing efficient buffer exchange.

    Love's lab is now using this approach to analyze immune cells from people with food allergies, which could help researchers determine why some people are more likely to respond well to therapies designed to treat their allergies. "There are still a lot of unknowns in chronic diseases, and these types of tools help you uncover new insights", Love says.

    To order these, or custom polycarbonate membrane filters, or discuss your application with a Microfiltration Expert, contact Sterlitech at 1-877-544-4420 or

  9. Introducing: Sepa Cell Assembly Support

    Introducing: Sepa Cell Assembly Support

    Sterlitech has developed a new support for the Sepa Cell Assembly to improve ease of handling and facilitate safe operation when assembling the cell or changing membrane coupons and O-rings.

    The unique design of the Sepa Cell Assembly Support allows users to safely slide the cell body out of the holder onto a sturdy shelf, minimizing the risk of dropping the body and causing bodily injury. A convenient lower shelf serves as storage for the cell top, spare membranes, or O-rings. The Support can easily be integrated into existing systems configured with the Sepa Cell.

    To obtain more information about the Sepa Cell Assembly Support, contact a Membrane and Process Development Expert at Sterlitech: 1-877-544-4420 or

  10. Introducing: The Air Gap Membrane Distillation (AGMD) Cell

    Introducing: The Air Gap Membrane Distillation (AGMD) Cell

    Continuing demand for low energy solutions to separation challenges have fueled Sterlitech’s latest product release: an Air Gap Membrane Distillation Cell. The first commercially available bench-scale tangential flow test cell of its kind, it mimics conditions representative of large-scale systems with minimal use of membrane or product. The AGMD cell offers researchers fast and accurate performance data to easily evaluate the performance of membranes and/or the efficiency of a given process with respect to their application.

    How it works: liquid to be treated is circulated in direct contact with the feed side of the membrane in the AGMD cell. A cold liquid solution is circulated in direct contact with a cooling plate on the permeate side of the membrane. Both the feed and the cooling solutions are circulated tangentially while using pumps at low or no hydrostatic pressures. An air gap is created between the permeate side of the membrane and the cooling plate where permeate is condensed and collected through a permeate collection tube at the bottom of the gap.

    Membrane Distillation (MD) is widely applied in desalination, concentration in food processing, acid manufacturing, removing organic and heavy metals, and in treating radioactive waste. The MD process offers advantages such as:

    • Low operating temperatures

    • Low hydrostatic pressures

    • Less susceptibility to fouling

    • Ability to use renewable energy or waste heat

    This all translates into lower energy requirements, compared to high pressure or high temperature processes.

    To obtain more information about Sterlitech’s AGMD cellor MD membranes, contact a Membrane and Process Development expert at Sterlitech at 1-877-544-4420 or