Development of surface-modified rice husk adsorbents for eco-friendly industrial desiccation

This study examines the potential of rice husk as a natural desiccant material, particularly after treatment with nitric acid (HNO₃). The structural and thermal properties of both untreated and acid-treated samples were analysed using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Thermogravimetric Analysis (TGA). Additionally, the desorption efficiency was evaluated by determining the regeneration temperatures required for moisture release. Results indicate that acid treatment significantly enhances the porosity and moisture absorption capacity of both materials while reducing their regeneration temperature. Specifically, acid-treated rice husk required regeneration temperatures of approximately 150°C. which is much lower than conventional desiccants such as silica gel (120–180°C), zeolites (200–400°C), activated alumina (175–350°C), and molecular sieves (200–400°C). Rice husk demonstrated superior thermal stability and durability, making it a reliable long-term option. These findings highlight the potential of rice husk as a cost-effective, sustainable alternative to synthetic desiccants.