From raw to nano: optimized purification and nano-bentonite synthesis for advanced applications

Abstract Bentonite clay, nano-bentonite, and nano-clays are used in many industries such as medical, water purification, food processing, and drilling mud. But because impurities in low-grade bentonite occur, its efficiency is limited; therefore, purification and modification are carried out to enhance its quality. Cetyltrimethylammonium bromide (CTAB), cationic modifier, dispersants, and milling are used in this study’s improved process for synthesizing nano-bentonite and industrial bentonite purification. CTAB was the preferred choice since it possessed the ability to modify further such parameters as surface charge, hydrophobicity, and cation exchange capacity, thus rendering bentonite more effective for its applications. The removal of impurities was mainly facilitated by the dispersants during sedimentation and centrifugation. The best sample, BMP 2 h, has shown a tremendous reduction in the cristobalite and calcite impurities with an increase in the beidellite phase as confirmed by x-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The process reduced particle size from raw bentonite 121.75 μm to 1.07 μm of BMP 2 h, which enabled improved dispersion. The enhanced purity and changed behavior of nano-bentonite reveal its potential for future industrial use in water treatment, catalysis, and drilling mud. This optimized method offers a cost-effective and efficient path to high-quality nano-bentonite, solving the limitations of current purification methods.