Impregnation of Synthetic Saponites with Aldehydes: A Green Approach in the Intercalation of Bioactive Principles

Synthetic saponite clay was impregnated with either linear saturated or unsaturated aldehydes through an incipient-wetness deposition approach. To increase the aldehyde loading, saponite was also intercalated with positively charged cetyltrimethylammonium (CTA+) species, aiming to expand the clay gallery and to increase the hydrophobic character of the host solid. A multitechnique, physicochemical investigation was performed on the organic-inorganic hybrid solids. The analyses revealed that the aldehydes are mainly adsorbed on the clay particles' surface, with a small fraction inside the interlayer space. In CTA+-modified saponites, the concentration of saturated aldehydes was higher than the one observed in the pure clay. These features are quite promising for the development of novel layered solids containing bioactive molecules for ecocompatible and economically sustainable applications, especially in agriculture, for the development of innovative hybrid materials for crop protection.