Synthesis of nanoclay from Sidoarjo mud volcano by sonication method: particle breakage kinetics and mechanism

Nanoclay has attracted significant interest in the industrial sector, particularly in biomaterials, pharmaceuticals, and cosmetics. The Sidoarjo mud volcano in Central Java, Indonesia, represents a promising alternative source for nanoclay production, enabling the development of cost-effective biomaterial products while adding value to the abundant mud deposits. This study focuses on synthesizing nanoclay and elucidating the clay particle breakage mechanism under sonication. The synthesis process was optimized by varying NaCl concentration, sonication temperature, and duration. Optimal conditions�2 M NaCl at 60 °C with 240 min of sonication�produced the smallest particle size of 114.1 nm. X-ray diffraction analysis confirmed that the mineralogical characteristics of the clay remained unchanged during sonication, with all samples dominated by clay minerals. The resulting nanoclay exhibited a uniform nanosheet morphology, excellent stability (zeta potential of �51.9 mV), and a swelling capacity of 93 mL/g. These properties indicate that the synthesized nanoclay meets pharmacopeial standards and holds strong potential for pharmaceutical applications. Furthermore, population balance modeling of sonofragmentation revealed that the dominant breakage mechanism was nanosheet fracture. © The Author(s), under exclusive licence to the Institute of Chemistry, Slovak Academy of Sciences 2025.