Synthesis and Evaluation of Mesoporous Silica Nanoparticle Catalyst Supports Prepared from South African Coal Fly Ash

Abstract

The development of environmentally sustainable catalytic reaction systems for the oxidation of organic compounds has gained significant interest, with widespread application across various industries. This study investigates the suitability of mesoporous silica nanoparticles, synthesized from coal fly ash, as catalyst supports in the oxidation of veratryl alcohol, a compound that serves as a model to mimic the oxidation behavior of lignin-derived structures commonly found in biomass waste. A Cu(II) salicylaldimine complex was employed as the catalyst, with tert-Butyl hydrogen peroxide as the oxidant. Silica catalyst supports were synthesized from coal fly ash derived Na2SiO3 solutions. The effect of pre-dealumination of coal fly ash during Na2SiO3 preparation, variation of the surfactant in silica nanoparticle synthesis, and storage conditions of the catalyst supports on the performance of the coal fly ash derived silica catalyst supports were evaluated and compared to the performance of MCM-41 and SBA-15. The textural properties of the coal fly ash derived silica catalyst supports were notably influenced by the choice of surfactant used during its synthesis, while storage conditions affected the abundance of silanol groups necessary for successful catalyst immobilisation. Graphical Abstract: (Figure presented.)