fumed silica colloidal silica

Sealants and adhesives are important products that are widely used in production and life. They are widely used in the fields of construction, transport, electronic instruments and components, etc. Fumed silica is the preferred material for adhesive and sealant modification. Adding fumed silica to silicone sealants and adhesives can significantly increase the bonding strength and ensure free flow, prevent caking and hanging during curing, collapsing, denting, maintaining transparency, reinforcing, anti-shear and other roles. The mechanism is when it is dispersed in the sealant and adhesive, different particles through the surface of the silica hydroxyl hydrogen bonding, the formation of a silica aggregate network, so that the fluidity of the system is limited, viscosity increases, play a thickening effect; in the role of shear silica network is damaged, resulting in a decrease in system viscosity, thixotropic effect occurs, to facilitate the construction. Once the shear force is removed, this network structure can be re-formed, effectively preventing the adhesive from sagging during the curing process. The hydrophilic Geseesil A-200 fumed silica produced by Geseesil has good thickening thixotropic and anti-settling properties, and is widely used in adhesives and sealants, coatings and paints, silicone rubber, and unsaturated resins.

Grout sealer is a decorative material applied directly into the gaps between tiles after they are adhered, addressing the issues of unsightly and dirty black tile seams. It is an upgraded version of traditional grout, offering superior decorative and practical benefits compared to colored fillers. The raw materials consist of a uniform mixture of epoxy resin, curing agents, fillers, pigments, and additives, presenting a ceramic-like texture and semi-liquid state with rich, natural, and delicate colors. It is waterproof and mold-resistant.  In the composition of grout sealer, there are incompatible components with significantly different densities, which can lead to sedimentation during storage, affecting the performance of the sealer. Particularly when applied on vertical or overhead surfaces, the system must not flow or drip. During application, the material requires a certain level of fluidity and should not cure too quickly to maintain its shape. These requirements necessitate the use of a thixotropic agent, fumed silica.  Fumed silica has silanol groups on its surface that tend to form hydrogen bonds, leading to the creation of a three-dimensional network structure within the system. This network increases the system's viscosity, but once shear force is applied, the structure is disrupted, and the viscosity rapidly decreases. When the shear force is removed, the three-dimensional network reforms, and the viscosity increases again. Epoxy resin, containing various polar functional groups such as epoxy and hydroxyl groups, has good wettability on inorganic surfaces, and a certain amount of fumed silica can achieve excellent thixotropy.    Due to these characteristics of fumed silica, it serves to thicken and provide thixotropic effects in grout sealer, effectively solving problems such as flow, drip, and collapse during application. For more information, visit our website at www.geseesiltech.com.

In recent years, stringent environmental regulations and the growing demand for cleaner fuels have made oxidative desulfurization (ODS) a key research focus due to its high efficiency and low energy consumption. Fumed silica, a high-performance nanomaterial with unique physicochemical properties, has shown great potential as a catalyst support and adsorbent in ODS. This article explores the application of fumed silica in desulfurization, along with recent advancements and future trends. 1. Recent Developments in Fumed Silica Technology   Fumed silica is produced via high-temperature hydrolysis of silicon tetrachloride (SiCl₄), resulting in nanoscale amorphous silica with high surface area (100-400 m²/g), low bulk density, excellent chemical stability, and tunable surface properties. Recent progress in nanotechnology has expanded its applications in catalysis, composites, energy storage, and environmental remediation. Improved Surface Modification: Silane coupling agents and metal oxide coatings enhance hydroxyl group density, improving interaction with catalytic active sites.  Enhanced Dispersion: Advanced synthesis methods (e.g., plasma-assisted processes) optimize dispersibility, making fumed silica more stable in liquid-phase catalytic systems.   Greener Production: Some manufacturers are adopting low-carbon synthesis methods to reduce environmental impact and costs.,      2. Applications of Fumed Silica in Oxidative Desulfurization ODS converts sulfur compounds (e.g., thiophene, benzothiophene) in fuels into sulfones/sulfoxides under mild conditions, followed by extraction/adsorption. Fumed silica contributes in the following ways:   Catalyst Support   Its high surface area and abundant silanol (Si-OH) groups make it ideal for anchoring metal oxides (e.g., TiO₂, MoO₃, WO₃) and heteropolyacids (e.g., phosphomolybdic acid): TiO₂/SiO₂ composites: TiO₂ supported on fumed silica exhibits enhanced photocatalytic ODS efficiency due to improved charge separation and active site exposure.   Heteropolyacid-silica hybrids: Immobilizing phosphotungstic acid (HPW) on modified fumed silica improves catalyst stability and reusability while minimizing leaching.   Adsorbent Enhancement   Post-oxidation, sulfones must be removed via adsorption/extraction. Fumed silica’s porosity and modifiable surface enable: Functionalized molecular sieves/activated carbon for selective sulfur adsorption. Ionic liquid composites for integrated extraction-adsorption systems.   Oxidant Stabilization   In H₂O₂/O₃-based ODS, fumed silica acts as a stabilizer, preventing rapid oxidant decomposition and prolonging reactivity. 3.Future Perspectives Advanced Catalyst Design: Precise control of surface chemistry to optimize metal/heteropolyacid loading for higher activity and durability. Integration with Green Processes: Combining photocatalysis, electrocatalysis, or biocatalysis with fumed silica-based systems for energy-efficient desulfurization. Scale-up Challenges: While lab-scale results are promising, industrial adoption requires cost-effective production and long-term stability. 4. Conclusion   Fumed silica’s tunable properties position it as a versatile material for next-generation ODS technologies. Continued research on nanoengineering and catalytic mechanisms will drive the development of efficient, sustainable desulfurization solutions, supporting global clean energy goals.