Green Surfactant-Free Synthesis of Mesoporous Silica Materials via a Biomass-Derived Carboxylic Acid-Assisted...

This study presents a novel approach for synthesizing porous silica materials using various biomass-derived carboxylic acids as non-surfactant, eco-friendly porogens. Different carboxylic acids were selected, and their influence on the properties of the final materials was systematically investigated. The silica synthesis was performed using only the intrinsic acidity of carboxylic acids without pre-hydrolysis of the silica precursor - tetraethyl orthosilicate (TEOS). Citric and tartaric acids had a favorable effect on the formation of mesoporous silica, whereas the oxalic, ascorbic, maleic, and mandelic acids led to the formation of microporous silica. The optimal synthesis compositions and parameters were thoroughly investigated. A mesoporous silica with a uniform pore size was prepared using tartaric acid, and the pore size was controlled by the drying temperature. Template removal via water extraction yielded silica materials with superior textural properties compared to conventional high-temperature calcination, while allowing the recovery and reuse of organic acids. Our results confirm that using carboxylic acids can be efficiently and economically applied for the controlled synthesis of mesoporous silica suitable for different applications, such as adsorption, drug delivery, and catalysis.