ExcellPureRO™ High Silica Rejection RO Elements
High Silica Rejection Membrane Elements
Many potable waters from surface sources contain naturally low levels of silica (4-8 ppm), but volcanic areas like Japan and Mexico and groundwater sources in the Middle East normally contain 20-100 ppm. This causes problems when purifying water. Hence, membranes with high rejection of soluble silica (SiO2) are valuable for producing ultrapure water.
Standard and low energy (LE) reverse osmosis (RO) membranes do not reject silica well, often only 97-98%. Special membranes (ExcellPureRO™) have been developed to reject silica over 99.2%.
SnowPure’s ExcellPureRO™ membranes are uniquely designed for high rejection of silica. Achieving low silica values from the RO is important for many applications, including providing feedwater for electrodeionization (EDI) systems. We have matched these SXR™ membrane elements to specific Electropure™ EDI modules. An article is published here on successfully operating RO-EDI in a high-silica environment.
Key properties to be successful rejecting silica:
- flat sheet membrane must be designed for silica removal (SnowPure’s is)
- operation must be at the correct flux/pressure (SnowPure has an element for each EDI model)
Avoiding silica scale:
SnowPure recommends using Avista Vitec® 4000 with ExcellPureRO™ membranes to prevent silica scaling. With Vitec® 4000, you can achieve up to 325 ppm SiO2 in the RO concentrate.