Silica gel and zeolites: properties and applications
Silica gel and zeolites represent two of the most important classes of industrial adsorbents, without which modern chemical, oil and gas, pharmaceutical and food industries would be inconceivable. Both materials possess a highly developed porous structure and the ability to selectively absorb molecules of various substances, but they differ in chemical nature, pore structure and fields of application.
Silica Gel: Properties and Production
Silica gel (SiO₂·nH₂O) is a dried gel of silicic acid with a porous structure and a highly developed internal surface. It appears as granules or pieces of irregular, spherical or oval shape, white, grey or colourless. Silica gel is characterised by a high specific surface area (up to 700–800 m²/g), chemical inertness, non-flammability and non-explosiveness.
Silica gel production is based on the reaction of sodium silicate solution (water glass) with sulfuric acid or aluminium sulfate, followed by washing and drying of the resulting product. Depending on the shape of the grains, technical silica gel is produced as granular or lump material, and by porosity — as fine-pored or coarse-pored.
According to GOST 3956-76, granular fine-pored silica gel is produced in two grades: KSMG (coarse) and ShSMG (charge). Granular coarse-pored silica gel is produced in four grades: KSKG (coarse), ShSKG (charge), MSKG (fine) and ASKG (activated). Lump fine-pored silica gel is also produced in four grades: KSMK, ShSMK, MSMK and ASMK.
Zeolites: Properties and Production
Zeolites (from Greek ζέω — to boil and λίθος — stone) are crystalline aluminosilicates whose structure is formed by tetrahedral fragments [SiO₄]⁴⁻ and [AlO₄]⁵⁻, joined into a three-dimensional framework permeated by cavities and channels 0.22–1.5 nm in size. These cavities contain water molecules and cations of alkali and alkaline earth metals. The general formula of zeolites is M₂/nO·Al₂O₃·xSiO₂·yH₂O, where M is most often an alkali or alkaline earth metal.
About 40 natural and over 150 synthetic zeolites are known. Synthetic zeolites are produced by precipitation of silicon and aluminium hydroxides followed by crystallisation at high pressures and temperatures up to 200 °C. Sodium zeolites of types A, X and Y are of the greatest industrial importance. Zeolite NaA has an effective pore diameter of 4 Å and is known as molecular sieve 4A. Type X and Y zeolites have larger pores and are used primarily in catalysis.
Applications
Drying and purification of gases and liquids. Silica gel and zeolites are widely used for drying air, natural gas, carbon dioxide, hydrogen and other gases. Zeolites, thanks to their strictly regular pore structure, provide deeper drying and separation of components by molecular size. Zeolites have 6–10 times greater adsorption capacity compared to silica gel or activated aluminium oxide.
Catalysts and their supports. Silica gel is used as a support for catalysts in the chemical and petrochemical industries. Zeolites are among the most important industrial catalysts: they are used in petroleum cracking, isomerisation, alkylation and other petrochemical processes.
Chromatography. Silica gel serves as a stationary phase in chromatographic analysis, used in gas and thin-layer chromatography for separating mixtures of substances.
Ion exchange. Zeolites possess unique ion-exchange properties and are used for water softening, removal of heavy metals from wastewater, and as a component of synthetic detergents.
Drying and clarification of liquids. Silica gel is used for drying and clarifying certain liquids, including petroleum products, oils and organic solvents.
Other applications. Silica gel is used as a moisture absorber in product packaging, to protect electronics, medicines and food products from moisture. Zeolites find application in agriculture for soil improvement and as feed additives, in construction for producing lightweight concrete, in the nuclear industry for radioactive waste treatment, and in medicine and biotechnology.
Global Market
Estimates of the global silica gel market volume vary depending on the methodology. According to Global Information, the market was valued at USD 729.8 million in 2025, projected to reach USD 792.4 million in 2026 and USD 1,208.5 million by 2033 at a CAGR of 6.2%. According to 360iResearch, the market was valued at USD 686.74 million in 2025 and is projected to reach USD 1,031.33 million by 2032 at a CAGR of 5.98%. The Asia-Pacific region dominates the market, accounting for 71.9% of sales in 2025, driven by a developed manufacturing base and high demand from the electronics and pharmaceutical industries.
Estimates of the global zeolite market volume also vary. According to The Business Research Company, the market was valued at USD 19.66 billion in 2025, projected to reach USD 20.6 billion in 2026 and USD 24.86 billion by 2030 at a CAGR of 4.8%. According to Straits Research, the market was valued at USD 9.4 billion in 2025 and is projected to reach USD 15.22 billion by 2034 at a CAGR of 5.5%. The Asia-Pacific region is the largest consumer of zeolites, driven by growing demand for catalysts in petroleum refining and petrochemicals, as well as expanding applications in water treatment and agriculture.
Production in Russia
The Russian silica gel and zeolite market is actively developing. In June 2025, the first industrial production of silica gels and silica sols in Russia with a total capacity of 18,000 tonnes per year was launched in the Kulibin special economic zone in Dzerzhinsk. The project was implemented by RusSilica (part of the Titan Group). The production capacity is 12,000 tonnes of micronised silica gels and 6,000 tonnes of stable silica sols per year.
The largest Russian producer of synthetic zeolites and adsorbents is LLC Ishimbay Specialised Chemical Catalyst Plant (ISCCP). Among the significant players in the natural zeolite market are OJSC Promzeolit (Oryol region) and OJSC Melor, which develop deposits of zeolite-containing tripoli. The Republic of Tatarstan concentrates 13.3% of all natural zeolite reserves in the country, with a production capacity of up to 320,000 tonnes of finished products per year.
Safety and Storage
Silica gel is non-flammable and non-explosive. The maximum allowable concentration of silica gel dust in the working area air is regulated. When working with powdered materials, personal protective equipment must be used: respirators, protective goggles and protective clothing. Storage is carried out in dry, well-ventilated areas, in hermetically sealed containers, away from moisture and heat sources. Zeolites also require protection from moisture, as their adsorption capacity decreases when saturated with water. Spent adsorbents can be regenerated by heating or purging with dry gas.
Conclusion
Silica gel and zeolites remain among the key products of the global chemical industry, providing drying and purification of gases and liquids, catalysis, chromatographic separation and ion exchange. Growing demand for high-purity materials for electronics and pharmaceuticals, the expansion of petroleum refining and petrochemicals, and the development of water treatment technologies create sustained demand for these multifunctional adsorbents. China, the USA and European countries remain the leading players in the global silica gel and zeolite market, and the expansion of production in Russia and the introduction of new synthesis technologies determine the industry's further prospects.