Facile Hydrothermal Synthesis of Size-Controlled Silicalite Crystals from Rice Husk Ash

抄録

This study is the first one to yield the controllable size of highly crystallized silicalite from rice husk ash, one of the most accessible agriculatural byproducts. Moreover, this silicalite was successfully obtained through the simplest hydrothermal method with these materials as the silica source, i.e., rice husk ash (RHA), sodium silicate and potassium silicate, prepared by dissolving RHA with NaOH and KOH. Its crystal size could be easily tuned from 3 to 23 µm by adjusting the molar ratio of NaOH : SiO₂ or KOH : SiO₂ in the system of SiO₂–TPABr–NaOH/KOH–H₂O through the synthesis process with the temperature at 187°C for 6 h. The synthesized samples were then characterized by infrared spectroscopy, X-ray powder diffraction and scanning electron microscopy. Thus, the significant outcomes of the research come in the forms of controllable size of crystallized silicalite, cost effectiveness and accessibility of its silica sources, RHA.