Recent Progress on the Development of Engineered Silica Particles Derived from Rice Husk

The development of engineered silica particles by using low-cost renewable or waste resources is a key example of sustainability. Rice husks have emerged as a renewable resource for the production of engineered silica particles as well as bioenergy. This review presents a state-of-the-art process for the development of engineered silica particles from rice husks via a bottom-up process. The first part of this review focuses on the extraction of Si from rice husks through combustion and chemical reactions. The second part details the technologies for synthesizing engineered silica particles using silicate obtained from rice husks. These include technologies for the precipitation of silica particles, the control of morphological properties, and the synthesis of ordered porous silica particles. Finally, several issues that need to be resolved before this process can be commercialized are addressed for future research.