Preparation of functional nanostructured materials by facile and green methods

A challenging goal of Chemistry is its sustainability towards a circular no-waste approach. This statement has been the mainstream of this PhD work, applied to innovative functional materials based on inorganic hosting substrates. The experimental work has used synthetic strategies, optimization tools and characterization methods to identify and pursue materials with facile, rapid and green preparations for functional photoactive materials, improving durability and performances. A part of the work dealt with the study and optimization of the preparation of tailored inorganic hosts, as synthetic layered clay-like materials (saponite), with a study of the synthetic conditions and the thermal treatment features to achieve high yield, morphological and compositional quality with a reduced energetic payload. Aside, in a waste-reduction strategy, a highly innovative approach was carried on using biomasses (i.e. rice husk and straw) as sources of inorganics for materials with controlled composition. The preparation of functional materials via host-guest architectures was targeted on photoactive systems using anionic (i.e. DyeA) and neutral (GAM2-35) photoactive dyes, to be incorporated in hydrotalcite and synthetic saponite clay respectively. A mechanochemical methodology of intercalation of DyeA into hydrotalcite based on the Liquid Assisted Grinding (LAG) was fully optimized using statistical tools as factorial design and Simplex. Intercalating neutral optically active dyes in saponite was then pursued using a quasi-solid state co-intercalation of GAM2-35 and a proper cationic surfactant (CTAB), avoiding the use of harsh conditions of temperature and pH. To fulfill an approach to sustainable hotoactive host-guest materials, a full asset of high throughput characterization techniques, as in situ XRPD and Uv-Vis methods and chemometric methodologies, was applied to an established fully thermal process coming from the past, the Maya Blue formation from palygorskite and indigo.