Polymeric Membranes

Polymeric membranes, also known as organic membranes, encompass a family of liquid separation technologies that is industry leading in both performance and efficiency. These membranes are generally identified in four major categories, based on performance characteristics and specific separation attributes. In order of the coarsest separation to the finest, they are: microfiltration, ultrafiltration, nanofiltration and reverse osmosis. The polymers utilized in the production of each membrane category are carefully selected in order to ensure optimal performance in a chosen process environment. Compatibility with the fluid(s) to be processed, as well as with cleaning agents necessary to aid in hygienic and performance stability must be taken into consideration. The scope of polymers may include polyvinylidene fluoride (PVDF), polysulfone/polyethersulfone (PS/PES), polypiperazine and polyamide.

Polymeric Membrane Process
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Microfiltration
Microfiltration

Microfiltration (MF) refers to a category of membranes where separation range (pore size) is expressed in micrometers (µm), and is typically considered to be about 0.1 µm and greater. Separation with MF is largely based on molecular exclusion, however process conditions can be factors in the efficiency of separation. For numerous process applications, organic MF membranes are made using polyvinylidene fluoride (PVDF) polymers. Very often, MF is utilized as a pre-treatment step for other separation processes such as ultrafiltration.

The most common applications for MF membranes are found in the dairy, sugar and sweetener, and industrial bioprocessing industries. In the dairy industry, MF may be used for de-fatting of whey in the production of whey protein isolates, separation of casein and serum proteins from skim milk, as well as clarification of cheese brines. In the sugar and sweetener industry MF is commonly utilized for the clarification of saccharification liquors ahead of further refining processes. In the industrial bioprocessing industry, MF is often used to clarify bulk fermentation streams in order to improve the performance of downstream processing steps.

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Ultrafiltration
Ultrafiltration

Ultrafiltration (UF) refers to a family of membranes where separation range (pore size or molecular weight cut-off (MWCO)) is expressed in Daltons (Da) or kilo-Daltons (kD), and is typically considered to be in a range of 1,000 Da (1kD) to 100,000 Da (100kD). Like MF, separation with UF is largely based on molecular exclusion, however process conditions can again be factors in the efficiency of separation. For numerous process applications, organic UF membranes are made using polyethersulfone (PES) or polysulfone (PS) polymers. UF is predominantly utilized after MF or other pre-filtration as a bulk concentration/fractionation step where the enrichment of macromolecules is desired.

The most common applications for UF membranes are found in the electrocoat (ecoat) paint, dairy, and industrial bioprocessing industries. In the ecoat paint industry, UF is applied to recover as retentate the paint pigment and resin for return to the ecoat tank while producing a permeate stream that is used for pre-rinsing of electrocoated components. In the dairy industry, UF is widely used for concentrating proteins from both milk and whey in the production of milk and whey protein concentrates/isolates. In the industrial bioprocessing industry, UF is often used downstream of MF for the concentration of proteins.

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Nanofiltration
Nanofiltration

Nanofiltration (NF) refers to a category of membranes where separation range is categorized based on rejection characteristics of known solutes such as magnesium sulfate (MgSO4) and sodium chloride (NaCl). The range of rejections may be ~90-99.5% and ~30-70% respectively. Unlike MF and UF, separation with NF is largely based on diffusion of dissolved species through the membrane and can be heavily impacted by pH and chemical charge near or at the membrane surface. For numerous process applications, organic NF membranes are produced via application of a thin film (i.e. polypiperazine) to a polyethersulfone (PES) or polysulfone (PS) UF substrate. NF is predominantly utilized after UF or other pre-filtration as an efficient means of concentrating macromolecules while partially demineralizing via the transmission of monovalent species at the same time.

The most common applications for NF membranes are found in the electrocoat (ecoat) paint, dairy, sugar and sweetener, and industrial bioprocessing industries. In the ecoat paint industry, NF is applied to further treat the UF permeate stream so that the NF permeate may be used for final rinsing of electrocoated components. In the dairy industry, NF is widely used for concentration and partial demineralization of UF permeate streams. Somewhat more recently, NF is also used for the concentration of milk and whey protein concentrates/isolates. For the sugar and sweetener industry, NF may be used for the removal of impurities in processes for enrichment of primary sweetener components. In the industrial bioprocessing industry, NF is often used downstream of UF or ion exchange processes for the partial removal of undesirable mineral components in order to improve product purity.

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Reverse Osmosis
Reverse Osmosis

Reverse Osmosis (RO) refers to a variety of membranes where separation range is categorized based on rejection characteristics of a known solute, traditionally sodium chloride (NaCl). The range of rejections for RO membranes may be ~96-99.8%. Like NF, separation with RO is largely based on diffusion of dissolved species through the membrane and overcoming osmotic pressure of the process fluid. For numerous process applications, organic RO membranes are produced via application of a thin film (i.e. polyamide) to a polysulfone (PS) UF substrate. RO is widely used after UF or NF as an efficient means of concentrating permeate from those processes while producing its own permeate stream that may either be utilized for further processing or reuse.

The most common applications for RO membranes are found in the dairy, sugar and sweetener, and industrial bioprocessing industries. In the dairy industry, RO is commonly used for concentration of milk, whey, as well as UF permeate streams from either of the aforementioned feedstocks. RO is also commonly used as a “polishing” step for recovery and reuse of a variety of feed streams. For the sugar and sweetener industry, RO may be used for the concentration of dilute feed streams as well as for a multitude of water treatment and recovery processes. In the industrial bioprocessing industry, RO again is often used downstream of UF processes for enrichment of valuable feed constituents and/or as a platform for water treatment and recover processes.

NOVEL POLYMERIC MEMBRANES & ELEMENT CONFIGURATIONS

Solecta integrates innovative polymeric membrane chemistries and advanced element designs to accommodate a broad range of installations in our focused market segments. Further, high temperature and high pH tolerant membranes and elements are available where heightened capabilities for cleaning and applications are required.

Our team of applications engineers and domain experts understands the unique challenges of industry and can help select the right membrane solution to keep your operation running smoothly and efficiently.

Solecta’s unique and emerging portfolio includes Microfiltration (MF), Ultrafiltration (UF), Nanofiltration (NF), and Reverse Osmosis (RO) membranes and elements for a diverse range of applications.

Solecta has proven technologies that have been successfully operating more than 20 years.

Contact Us

Headquarters

4113 Avenida de la Plata
Oceanside, CA 92056

760.630.9643

info/at/solectamembranes.com

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