RO / NF / UF

Wider Chemical Stability Than Conventional Materials

Ionomr’s polymers have much wider chemical stability than conventional materials with properties that are highly tunable, making them attractive for development of next generation advanced filtration products. Our materials are stable in strong alkaline and strong acid solutions used for cleaning, which allows for harsher, more frequent chemical treatment. Additionally, Ionomr’s materials have increased resistance to common oxidants used in traditional water treatment such as chlorine and its positive surface charge makes it naturally resistant to bacteria and biofouling.


Reverse osmosis (RO) is a water purification process that uses a semi-permeable membrane to remove ions and particles from water. In RO, applied pressure is used to overcome the osmotic pressure driven by the chemical potential differences caused by differences in salinity.

The semi-permeable membrane is typically a multi-layered polymeric membrane that will allow certain particles including water to pass through it by diffusion, while leaving behind the solutes such as salt. Being the finest level of filtration available, RO is often used to achieve ultra-pure water levels for applications such as semiconductor industry, power industry (boiler feed water), and medical/laboratory procedures. It is also the preferred method of seawater desalination.


Nanofiltration (NF) is essentially a membrane separation process with a pore size cut-off between that of reverse osmosis and ultrafiltration. The separation is done by diffusion through a membrane, under pressure differentials that are considerably less than those for reverse osmosis, but still significantly greater than those for ultrafiltration.

The key difference between nanofiltration and reverse osmosis is that the latter retains monovalent salts (such as sodium chloride), whereas nanofiltration allows them to pass, and then retains divalent salts such as sodium sulfate. This is beneficial in the production of drinking water because no additional salts are needed to be added after the filtration process.


Ultrafiltration (UF) systems use semi-permeable membranes, which are characterized by their nominal molecular weight cut off above 10 kDa. Typically, these membranes are suitable for separating biomolecules, bacteria and viruses, while allowing dissolved salts to pass through. They have an average pore diameter between 10 nm and 100 nm. Above this pore size, the next class of filtration is referred to as microfiltration (MF).

Ultrafiltration applications consist of wastewater treatment, chemical and pharmaceutical manufacturing as well as food and beverage processing. In the case where membranes come in contact with alkaline solutions, integration of Aemion™ polymers can increase the stability and lifetime of your membranes.