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Catalysts and cations in the initial silica sols greatly affect the quality of silica gels. This study focused on elucidating the effects of catalysts and mixing ratios of raw silica sources on the textural properties of resulted silica gels. Series of silica gels were synthesized by 2-step acid-base route from Na- and K-silicates with various catalysts. Acid catalysts used in this study were HCI, HNO₃, H₂SO₄ and H₃PO₄, while NH₄OH, KOH, NaOH were employed as base catalysts. Polyvalent acids led to more stable sols and more microporous gels compared with monovalent acids. Higher surface areas were obtained from monovalent acids. On the other hand, the effect of base catalysts were not significant, probably due to excess presence of the salts orignated from raw sources. Similarly, mixing ratios of raw sources, the ratios of Na- and K- silicates in initials sols, exhibited little effects on the textural properties of silica gels. Therefore, the careful selection of acid catalysts plays a crucial role in the qualify of silica gets. Based on the studies, it is clear that cheap inorganic sources could be used for the production of high-quality and tailored silica gels.
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