Hybrid mineral@silsesquioxane particles for water remediation: synthesis, characterization and application as adsorbent of As(V) and other water pollutants

Mineral-coated silsesquioxane particles of approximately 600 nm diameter were synthesized from the hydrolytic co-condensation of N-[3-trimethoxysilyl]-propyl]ethylenediamine (DAS) and tetraethyl orthosilicate (TEOS). The hybrid particles involve nanocomposites with a mineral core (montmorillonite-MMT-or goethite-Gt-nanoparticles) and coated with a silsesquioxane shell containing hydroxyl and amine groups. These particles were specially designed (exposing amino groups) to be highly efficient for the removal of As(V) and to enhance the adsorption properties of the minerals employed in this work. They were characterized by infrared spectroscopy, X-ray diffraction, scanning electron microscopy, zeta potential, dynamic light scattering and thermogravimetric techniques such as dynamic scanning calorimetry and thermogravimetric analysis. The characteristics found in the composite particles compared with pure organosilane DAS/TEOS or with the unmodified minerals proved the effectiveness of the silanization process. As result, hybrid nanocomposite materials were obtained, denoting versatility in their adsorption properties of different types of pollutants. Moreover, all synthesized particles showed a high arsenic retention capacity; experimental results demonstrated that superficial modification of the minerals is the preponderant factor that determines their adsorbent properties, favoring the versatility of these materials making them suitable for the removal of pollutants of diverse charge and nature.