Specialty Applications
ACID & CAUSTIC RECOVERY	BIOTECHNOLOGY & PHARMACEUTICAL	DYE DESALTING
PAPER COATING	TEXTILE SIZE RECOVERY	PIGMENTS
Electrocoat Paint Applications
SelRO®  Applications
BEVERAGE INDUSTRY	DAIRY INDUSTRY	ELECTRONICS INDUSTRY
DYES, OPTICAL BRIGHTENERS	METAL PROCESSING AND FINISHING	PHARMACEUTICAL INDUSTRY
SUGAR INDUSTRY	TEXTILE INDUSTRY	WATER PRETREATMENT

SelRO^® Expands NF To Perform In Hot, Acidic Environments

Most nanofiltration membranes available on the market are limited to aqueous applications within the pH range of 2 to 11. However, many industrial applications require acid/base and solvent stability. The SelRO^® product line was developed to answer the market requirement for high and low pH, high temperature, (up to 158°F) and organic solvents media.

Membrane Characteristics

SelRO® spirals in stainless steel housings

Koch Membrane Systems manufactures this unique class of nanofiltration membranes which are characterized by an outstanding chemical and thermal stability. Two product lines are available: acid/base stable membranes and membranes exhibiting outstanding stability to organic solvents. The stability and separation characteristics of SelRO membranes are shown in the following table:

Product Name	Configuration	Approximate MW Cutoff	pH Range	Solvent Stability	Maximum Temperature °F/ ( °C)
MPS-34 MPS-36	Spiral Spiral	200 1000	0-14 1-13	None	158 (70) 158 (70)
MPS-44	Spiral	250	2-10	excellent	104 (40)

The SelRO acid/based stable membranes can be operated within the pH range of 0-14 and at temperatures up to 158°F (70 °C). Typical applications for this case are: •  Recovery of spent alkaline (NaOH, KOH) streams •  Recovery of spent acid streams •  Decolorization of spent mineral acids •  Removal of heavy metals from acid and basic solutions •  Concentration and demineralization of dyes in acids •  Recovery of spent electroless solutions •  Concentration/Desalination of wastes from dye manufacturing •  COD reduction in pulp and paper waste effluents

Typical Feed Streams for SelRO^® MPS Spiral Elements:

Chemical (in water)	Concentration
Hydrochloric acid (HCI)	5-37 %
Sulfuric acid (H2SO4)	5-15 %
Phosphoric acid (H3PO4)	10-20 %
Acetic acid	5-15 %
Nitric acid (HNO3)	2-5 %
Sodium hydroxide (NaOH)	2-20 %
Potassium hydroxide(KOH)	2-10 %

In some cases, the requirement of cleaning a membrane with aggressive chemicals hampers the use of standard nanofiltration membranes even in standard aqueous applications.  Aggressive cleaning can be performed on the SelRO acid/base stable membranes within the pH range of 0-14 and at temperatures up to 158°F (70 °C).

Typical applications for this case are:
•   Removal of dissolved silica from water.
•   Nanofiltration pretreatment of RO membranes.
•   Humic acid or COD removal from aqueous streams.

For more details please contact Koch Membrane Systems.

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