Microwave-Assisted Sol-Gel Synthesis of Silica Nanoparticles Using Rice Husk as a Precursor for Corrosion Protection Application

Silica nanoparticles are received significant interest for novel applications owing to inherent characteristics such as porous, resistance to most corrosive conditions, non-toxicity, and stability. In this study, we report a microwave-assisted sol-gel process to synthesize amorphous silica nanoparticles using rice husk as a precursor and CTAB as a surfactant. XRD, FTIR, SEM, EDX, and TEM were employed to study the characteristics of the produced product. Various analyses revealed the formation of amorphous silica nanoparticles with spherical shape of 80-100 nm. CTAB could produce shape-controlled spherical nanoparticles under microwave radiation at the appropriate temperature by forming spherical micelles with silicate anions. From linear sweep voltammetry examination in a 3.5 wt.% NaCl electrolyte, corrosion rate was found to be 2.2261 mm/year and 1.2884 mm/year, for uncoated and silica-coated mild steel plates, respectively. Nyquist plot and Bode plots analysis revealed that the silica coating provides superior protection to mild steel plates against corrosion. Furthermore, silicate ions in the rice husk-derived silica nanoparticle can combine with Fe2+, forming a thin layer that can improve adhesion and provide protection to the mild steel plate in seawater condition. This potential approach is particularly intriguing since it delivers affordable biomass-based corrosion prevention agents.