Sterlitech Newsletter - February 2012
Sterlitech February Newsletter
In This Issue…
- What's Going On in February?
- Custom Membrane Filter and Flat Sheet Membrane Packs
- HP4750 Stirred Cell Use in Membrane Development/Pesticide Research
- 25% off Glass Fiber Filters Through March!
- FAQ: What is the Function of a Binder in a Glass Fiber Filter?
We’ve enhanced our line of Laboratory Equipment products and introduced PTFE Vent Filters to the Sterlitech catalog. The lab equipment comes to us courtesy of Scilogex and adds to our collection of Mini Centrifuges, Hotplates & Stirrers, Shakers, Mixers & Rockers, Vortex Mixers, and Overhead Stirrers. These new additions allow us to offer a premium alternative to customers looking for added features such as digital displays and advanced monitoring systems.
PTFE Vent Filters function like standard syringe filters but they include built-in connection options so they can be easily hooked up as part of a venting process, which makes it easier to perform autoclave venting and venting of holding tanks. Sterile and non-sterile PTFE vent filters are available in a variety of sizes and connection fittings.
Next month we will be exhibiting at Pittcon in Orlando, FL (Booth #1929) and then making our first company trip to the United Arab Emirates for ArabLab (#477) in Dubai! Let us know if you’d like to meet up at either event!
Custom Membrane Filter and Flat Sheet Membrane Packs
Did you know that you can create a custom sample pack of membrane disc filters and assortment packs of flat sheet membranes through the Sterlitech website? For membrane filter samples, choose from a dozen different materials and build a 10 pack of filters with any pore size/diameter combinations for complete testing coverage.
The Flat Sheet Membrane Assortment packs are organized by separation range and membrane size. Select any 5 designations for your evaluation.
If you are looking for an option that isn’t shown on the website you can still contact one of our representatives for further assistance.
HP4750 Stirred Cell Use in Membrane Development/Pesticide Research
The new book, “Sustainable Membrane Technology for Energy, Water, and Environment” includes a good example of how the HP4750 Stirred Cell can assist in membrane research. In it, author Mohammed Ismail introduced a study on how post-treatment of nanofiltration (NF) membranes can improve pesticide removal by filtration. As part of the experiment, custom-manufactured NF membranes were treated with three different substances (methanol, ethanol and 2-propanol) and then evaluated on a solution containing 0.01 M atrazine using the HP4750 in dead-end filtration mode with 1 to 5 bars of operating pressure. The NF membranes were made with a combination of PES, NMP and water. After the membranes were cast, post-treatment was done by soaking them in one of the three solutions for three hours.
The study concluded that the atrazine rejection rates of NF membranes can be increased through post-treatment. Of the three materials evaluated, the membranes treated with 2-propanol had the highest percentage of atrazine rejection, between 40-70%. The reasoning for this is that the propanol post-treatment formed smaller pores on the membrane, which in turn led to increased atrazine rejection and lower flux.
Atrazine is one of the most commonly used herbicides in the world, despite currently being banned in the European Union. While atrazine is an effective weed killer, it can find its way into drinking water and can lead to cancer or birth defects. In the United States, the EPA regulation is a maximum of 3 parts per billion of atrazine in drinking water, although there are some reports to suggest it may be biologically active at levels as low as 0.1 parts per billion!
For more information on atrazine you can read this article from the NY Times, or check out this interview with UC Berkley Professor Tyrone Hayes about its potential environmental hazards.
What is the Function of a Binder in the Glass Fiber Filter?
The purpose of a binder on a glass fiber filter is to increase strength and dirt-loading capacity while decreasing fiber slough. Binders are most often seen in filters designed to accommodate applications which require long durations of filtration under pressure., and are typically an acrylic material added to the borosilicate glass fibers.
Binderless glass fiber filters have the advantages of being autoclavable with higher maximum operating temperatures. Because most analytical and gravimetric determinations favor a binderless filter, most of our glass fiber filter grades do not contain binders.
Handy filter term to know: Retention:"The ability of a filter to retain particles (total number or those of a specific size) suspended in a gas or liquid. In the case of ultrafiltration, retention refers to the ability to concentrate molecules in a solution. Expressed as percent of particles or molecules originally present."