Silica removal

Silica is present in almost all surface waters and reacts with oxygen to silicon dioxide (SiO2). It needs to be removed from process water to protect industrial equipment.




  • Silica Removal Package uses hollow-fiber tight ultrafiltration to remove colloidal silica
  • Low energy consumption, low operating costs
  • Dead-end filtration, high system recovery
  • Can be installed upstream of RO and ion exchange (IX) to protect equipment
  • Alternatively it can be installed downstream of existing IX as a polishing step

application areas

Silica in water can cause tough porcelain-like deposits on industrial equipment. The main contributor to the scaling problem is silica. Scaling in boilers and heat exchangers is very hard to remove and results in increasing efficiency losses and potential defects.

The silica deposits can also change the geometry and balance of turbine blades, which can strongly affect performance and even cause turbine failure. Silica removal is a sensible precaution and an absolute necessity for high-quality boiler feedwater.

Silica can be present either in dissolved form (reactive silica) or in particulate form (colloidal silica). Ion exchange will not remove colloidal silica. RO will foul with colloidal silica. Therefor removal of colloidal silica is critical in high purity applications. 

pentair solutions

The removal of polymerized or colloidal silica can avoid equipment failure, increase operational efficiency, and improve plant performance. Tight ultrafiltration removes up to 99.8 percent of colloidal silica, while dissolved silica will pass through. Spiral-wound RO membranes and ion exchange resins remove dissolved silica, but are vulnerable to scaling and fouling by colloidal silica. In order to guarantee very low silica content, a combination of technologies is needed. 

Pentair developed a Silica Removal Package based on hollow-fiber tight ultrafiltration. The Silica Removal Package applies the X-Flow HFS60 module with a molecular weight cut-off (MWCO) of 10.000 Dalton. These membranes do not suffer from carbonate scaling and can be chemically cleaned at high pH-values. A combination of this technology with a downstream RO or ion exchange system creates a high-performance silica removal system. 

If you have any questions, please contact us.

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