Preparation of SiO2 Photocatalyst via Electron-Assisted Thermal Decomposition of Rice Husks and its Application for Chromium (VI) Determination

Rice husk ash (RHA), obtained through pyrolysis of rice husk (RH), is primarily composed of silicon dioxide (SiO₂). However, a conventional thermal treatment produces harmful byproducts, that can pollute the environment and harm biological health. Meanwhile, energy consumption hinders scaling up a conventional producing technique. Here, an electron-assisted thermal decomposition (EATD) technology was developed to obtain silicon dioxide (SiO₂), which included two mixed crystal phases: cristobalite and tridymite. The influence of temperature on the SiO₂ structure was examined through the various structural characterizations. Based on the experimental findings, we emphasized that the EATD process induced specific structural phase and glass transition owning to the radiated heat system. Notably, the prepared samples displayed the ability as a chemical sensor for Cr⁶⁺ and photocatalyst for methylene blue (MB) degradation. This unique characteristic improved the detection signal for Cr⁶⁺ by at least twofold, resulting in a streamlined detection technique that reduced the risk of secondary pollution.