Preparation of nano-pyrophyllite: Comparative study of sonication and grinding Original Research Article

In this work, we propose the use of ultrasonic treatment for the preparation of pyrophyllite (Al4Si8O20(OH)4) nanoparticles. Effect of treatment time on the resulting particles is studied. Samples are characterized in terms of their specific surface area, particle size distribution, particle morphology, particle thickness and structural modifications. It has been observed that there is a practical limit of 80 m2 g−1 in the specific area after 20 h of treatment, thus longer sonication times do not produce further increase in specific surface area. The particle size analysis shows a bimodal distribution where the amount of the small size particles increases as the sonication time increases. Pyrophyllite particles retain the plate-like particles and the crystalline structure after the sonication treatment. Ultrasonic treatment results are compared with those obtained by mechanical grinding. This comparative study shows that ultrasonic treatment yields smaller particles and higher specific surface areas than grinding. Additionally, grinding produces significant structural degradation and morphological deformation.