Frequently Asked Questions (FAQs)

About Thin-Film Nanocomposite (TFN) Technology

What does the term “thin-film nanocomposite” mean?

The term “thin-film nanocomposite” was first used by researchers at University of California, Los Angeles (UCLA) who found that by encapsulating benign nanomaterial into the thin-film polyamide layer of a traditional thin-film composite membrane, they were able to increase membrane permeability compared to conventional RO membranes. LG Chem leverages nanotechnology to further change the structure of the thin-film of a conventional RO membrane and enhance membrane performance. Benign nanoparticles are introduced during the synthesis of a traditional polymer film and are fully encapsulated when the nanocomposite RO membrane is formed.

How do nanoparticles increase membrane performance?

LG Chem’s encapsulation of benign nanoparticles changes the structure of the thin-film surface of a conventional RO membrane, allowing more water to pass through while rejecting unwanted materials such as salt. LG Chem membranes are 50-100% more permeable than conventional membranes while still meeting best-in-class salt rejection.

Do nanoparticles pose any potential risks to water quality?

No. LG Chem membrane elements are completely safe for the treatment of potable water. The LG SW 400/440 ES, LG SW 400/440 SR, LG SW 400/440 GR and LG SW 400/440 R are all NSF Standard 61 certified, which means that they have been independently evaluated by NSF International, the global organization that provides standards development, product certification, auditing, education and risk management for public health and safety. NSF Standard 61 certification attests to the safety and viability of LG Chem membrane elements when used in the production of drinking water.

Does LG Chem use a nanoparticle coating applied to another manufacturer’s membrane?

No. LG Chem introduces nanostructured materials into the monomers that form the polymer film manufactured solely at its facility in Cheong-ju (Republic of Korea). The nanoparticles are encapsulated into LG Chem patented and patent-pending thin-film polyamide formulation, which makes up the top layer of the thin-film nanocomposite membrane.


LG Chem Product Specifications

Are LG Chem membranes similar in construction to other thin-film composite membranes?

Yes. Thin-film composite membranes consist of a layer of non-woven polyester, a cast layer of polysulfone and a 100 to 200 nanometer thin-film layer. LG Chem membranes encapsulate benign nanoparticles into the polyamide thin-film of a composite membrane. This technology enhances the performance and permeability of a traditional thin-film composite membrane.

Are LG Chem membrane elements NSF Standard 61 Certified?

Yes. Currently, all LG Chem SWRO membranes are certified by NSF according to Standard 61. LG Chem will continue to obtain NSF certification for future RO membrane elements developed for the treatment of potable water.


Installation and Use

Do LG Chem elements fit into standard pressure vessels?

Yes. LG Chem membrane elements are available in 8-inch spiral-wound configurations, making them easy to retrofit into standard pressure vessels.

Can LG Chem elements tolerate chlorine in the feedwater?

Similar to other conventional thin-film composite membranes, LG Chem membranes demonstrate some resistance to short-term chlorine (hypochlorite) exposure. The free chlorine tolerance of the membrane is < 0.1 ppm. Continuous exposure, however, may damage the membrane and should be avoided. Under certain conditions, the presence of free chlorine and other oxidizing agents will cause premature membrane failure. Since oxidation damage is not covered under warranty, LG Chem recommends removing residual free chlorine or other oxidants like permanganate by pretreatment prior to membrane exposure. For more information on free chlorine in feedwater, please consult the Technical Manual.

What is the temperature range that LG Chem modules can tolerate?

Zero to 45°C. The normal operating temperature of seawater is from 8° to 35°C.

What is the average membrane life of LG Chem membrane?

Membrane life is directly related to a system’s feed water quality, along with the frequency and type of chemicals employed in the membrane/system cleaning process. LG Chem membranes have the same average membrane life as any other polyamide membrane operating under standard conditions. LG Chem membranes have been repeatedly tested to confirm they can be cleaned with pH from 2 to 12 pH and, in some case, pH 13 when necessary.



Will the nanoparticles within the membrane require any special considerations regarding membrane cleaning?

No. LG Chem membrane elements require the exact same cleaning procedures as do conventional thin-film composite membrane modules. Specific guidelines regarding the use of biocides, along with membrane element flushing procedures, are outlined in the Technical Manual.

How long can LG Chem elements be stored (or what is the “shelf life”)?

LG Chem modules can be stored at ambient temperature, protected from direct sunlight, for up to 12 months. After 12 months the modules should be inspected, and if mold or other discoloration is observed, the modules can be re-soaked in sodium bi-sulfate (SBS) and repackaged for another 12 months.


Product Availability & Service

Where are LG Chem membranes manufactured?

LG Chem membranes are formulated, developed, cast, rolled and wet-tested at the LG Chem manufacturing facility in Cheong-ju, Republic of Korea.

Does LG Chem wet test each membrane element before it is shipped?

Yes. LG Chem wet tests each element at industry standard test conditions – 54 Bar, 32,000 ppm NaCl, 25°Celsius – before shipping the membrane elements to the customer facility.

Are LG Chem elements packaged and shipped in a preservative?

Yes. After wet testing and Quality Assurance inspection, the elements are soaked in a 1% solution of sodium metabisulfite (SBS), drained and packaged in oxygen barrier bags.

What is the availability of LG Chem elements?

For product lead-time and availability, contact your local Sales Office or

Does LG Chem offer a 41 m2 (440 ft2) element?

Yes. LG Chem offers 440 square foot elements (see Product Listing for more details).

Does LG Chem have projection software?

Yes, please click on the following link to download LG Chem’s Q+ Projection Software.

Does LG Chem have a service department to assist users?

LG Chem has a team of Application Engineers and Field Service Technicians who are available to support our customers’ needs. Please click HERE for contact information.



Can I use LG Chem elements for food and dairy or other specialty applications?

LG Chem membrane modules are currently available 8-inch spiral wound configurations designed specifically for seawater (SWRO) and brackish water (BWRO) applications. These modules are wrapped in a fiberglass shell and are not suitable for use in food and dairy applications requiring sanitary element construction. However, the inherent properties of the membrane sheet make it ideally suited for a variety of applications, including dairy processing. Contact LG Chem today and ask about high-flux LG Chem membranes for other water and process treatment applications.

Which LG Chem element will work best for my application?

As there are variances from system to system, the “right” membrane element for your application depends on many factors. LG Chem’s product line is grouped into two categories: high flux and high rejection.
LG Chem’s high flux seawater ES membrane elements, delivering 52 m3/d (13,700 gpd), are ideal for low temperature, low salinity water and are designed to lower energy consumption, or increase production, or decrease a plant’s footprint by reducing the number of elements required at specified operating conditions. Our high rejection R, GR and SR membrane elements are designed for high temperature, high salinity water and ideal in applications requiring high quality permeate and minimized second pass. The full line of low-energy and high rejection brackish water membranes are perfectly suited for applications ranging from watewater reuse to industrial process water applications.

Please complete the Application Questionnaire and send it to us with the information about your specific application. LG Chem Application Engineers can then recommend the right membrane(s) best suited for your needs.

Where are LG Chem membranes installed?

LG Chem membranes operate in hundreds of installations across 50 countries. Customers around the globe have come to trust the reliability and dependability of LG Chem’s NanoH2O RO membranes.