Mechanochemical Treatments of Commercial Vermiculites

This study investigates the mechanochemical transformation of commercial vermiculites from Uganda and China, processed for 30 minutes (30 min), 8 hours (8 h), and 24 hours (24 h). Structural and textural modifications were analyzed using X-ray diffraction (XRD), thermogravimetric analysis (TGA), BET surface area measurements, and scanning electron microscopy (SEM). Characterization via X-ray diffraction (XRD), thermogravimetric analysis (TGA), BET surface area measurements, and scanning electron microscopy (SEM) revealed substantial structural and textural modifications. Crystallinity decreased significantly, from 66.37% to 3.47% in the Ugandan sample, whereas the three mixed-phase Chinese samples exhibited greater structural resilience, with final crystallinity ranging from 3.82% to 6.30%. Mechanochemical treatment induced mineral phase transformations, including hydrobiotite formation in the Ugandan sample and Fe3Si, quartz, moganite, and NaMgH3 in the Chinese samples. Particle size reduced significantly, reaching submicrometric dimensions after 24 h, with C1 showing the smallest mean size (0.39 µm). BET analysis showed an initial increase in specific surface area, peaking at 31.83 m2/g for C1 after 8 h, followed by a decrease due to pore collapse. The optimal treatment time varied by sample, with 30 min maximizing adsorption in C2 and C3, while 8 h was most effective for C1. These findings highlight mechanochemical treatment as a viable method for tuning vermiculite properties for applications in adsorption, catalysis, and composite materials.