Sterlitech Newsletter - September 2011

 In This Issue…

• What's New in September?
• Sterlitech Corporation Recognized on Inc. 5000 List
• September Promotion - Savings on Disposable Vacuum Filters and Sterile Nylon Syringe Filters
• FAQ: Transforming Hydrophilic PCTE Membranes into Hydrophobic
• Recovering Ionic Liquids from Wastewater by Nanofiltration

What's New in September?

This month we expanded our selection of Hollow Fiber Membranes with the Explorer series of cartridge filters for larger volume samples between 500 mL and 5 liters. Also making their way into the Sterlitech catalog are Reusable and Disposable Spin Columns (ultrafiltration holders) for separating or purifying small volume samples (< 2mL).

Additionally, we've updated our website's ordering system so that now you can enter your own shipping account information (UPS, FedEx, or DHL) for any of your online orders!

Sterlitech Corporation Recognized on Inc. 5000 List

This month Sterlitech Corporation was named one of the Top 5000 fastest growing private companies in America by Inc. Magazine! Thank you to all of our customers for making our continued success possible! In addition to being ranked #2373 overall, we also came in at #74 for Manufacturing and #60 for companies in the Seattle area.

FAQ - Transforming Hydrophilic PCTE Membranes into Hydrophobic

Polycarbonate is a naturally hydrophobic membrane renowned for its nearly transparent properties, distinct pores, and versatility. It is most commonly found coated in Polyvinlypryrrolidone (PVP) to create a hydrophilic surface, spanning a vast range of pore sizes, while its natural counterpart is supplied in a more limited scope. Not seeing the hydrophobic pore size you need?
 
There is an easy method to revert the hydrophilic membrane back to its hydrophobic natural state. Simply flush the hydrophilic membrane with deionized, ultra-pure, hot water for at least one hour and then allow to air dry. Repeat steps until desired level of hydrophobicity is achieved.

Recovering Ionic Liquids from Wastewater by Nanofiltration

Experiments with ionic liquids have become increasingly popular due to their potential use in industrial applications. A study recently published in the Journal of Membrane Science & Technology by the UFT-Centre for Environmental Research and Sustainable Technology at the University of Bremen in Germany addressed possible environmental concerns of using ionic liquids by setting out to determine if they could be removed from wastewater through nanofiltration.
 
An ionic liquid can be defined as a salt that exists in a liquid state below 100 C. One of the most frequent applications for these liquids is in cellulose processing as a solvent to help transform the cellulose into a useful concentration for production. Currently ionic liquids can be extracted from wastewater using evaporation, but that method is costly and inefficient. Some experiments have been conducted to remove hydrophilic ionic liquids through filtration, but the University of Bremen study is likely the first to examine the filtration of hydrophobic ionic liquids from wastewater.
 
For this experiment the researchers performed dead-end and cross-flow experiments using the FilmTec NF-90 and NF-270 nanofiltration membranes from Dow Chemical as well as the Desal DK designation from GE Osmonics. Performing the dead-end nanofiltration tests involved using an HP4750 stirred cell with the stir bar assembly and standard couplings. Other necessary equipment included a magnetic stirrer and pure nitrogen for gas pressure.
 
Membranes were placed in deionized water for two days for complete swelling. Then, they were conditioned with DI water until a pressure of 40 bar was reached. The feed was placed in the cell at a fixed pressure of 35 bar. For a complete description of this experiment and the cross-flow NF experiment, take a look at the published report.
 
The researchers concluded that nanofiltration could be used to recover hydrophilic and hydrophobic ionic liquids effectively, the latter was accomplished by including synthetic solutions. The scientists note that it would be ideal if future efforts to incorporate ionic liquids into industrial processes focused on zero waste production, but it’s good to know that in the meantime there may be a viable option for treating this type of wastewater by nanofiltration.
 
Read the full study by here
See Also: http://pubs.acs.org/doi/abs/10.1021/jp0112368

Handy filter term to know: Extractables: Substances that may leach or otherwise come off the filtration system and into the fluid being filtered.