Silicon (Si) in Water Treatment

Quick Answer

Silicon (Si) is a metalloid with atomic number 14. PubChem lists its standard state as solid and its relative atomic mass as 28.085.

Silicon is commonly encountered as dissolved silica, silicate or colloidal silica. It is a major concern in boilers and high-recovery membrane systems because it can form difficult deposits; speciation determines whether coagulation, adsorption, ion exchange or RO is suitable.

Interesting Facts

• Water analyses usually report silica, not elemental silicon; “reactive,” colloidal, and total silica are not the same measurement.
• Quartz and glass are built largely from silicon–oxygen networks, which helps explain why polymerized silica deposits can be stubborn.
• In high-recovery RO, concentrating dissolved silica can cross a solubility or polymerization threshold even when the feed seems harmless.

Water-treatment Design Implications

An element name alone is not enough to select treatment equipment. Confirm chemical form or speciation, total and dissolved concentration, pH, alkalinity, competing ions and the product-water target. Send the water-analysis results to Watermart to identify additional testing and shortlist processes before equipment is specified.

Summary Data Sources

• PubChem — Silicon
• IUPAC Periodic Table of Elements
• WHO — Chemical hazards in drinking-water

Practical Reference for a Water Analysis

Ask what chemical form was measured. Total and dissolved results should be distinguished, and oxidation state or compound class may also be essential. Different species can carry different charge, toxicity, solubility, and affinity for treatment media.

Validate treatment on the actual matrix. A process name is not a performance guarantee. Competing ions, organic ligands, redox conditions, pH, suspended solids, and required recovery can change removal sharply. Use bench or pilot testing for unusual industrial streams, and make a mass balance for concentrate, sludge, regenerant, or spent media.

Do not invent a drinking-water limit from the periodic table. A health value applies only to the specified substance, route, averaging period, and jurisdiction. Check the current Indonesian requirement and the intended reuse or discharge permit before setting the design target.