Ceramic Nanotools for Green Technology

Coupling nanoparticle sol-gel process technology with textile finishing or spinning techniques let to obtain HIGHLY VERSATILE MULTIFUNCTIONAL MEDIA, easily exploitable in environmental green technology, application. The high scalability and sustainability of the process is guaranteed by the consolidated technologies involved in nanotech / sol-gel / colloidal and textile processes.

ANTIBACTERIAL PROPERTIES _The widely accepted mechanism of antibacterial action is for both TiO2 and Ag nanomaterials a direct interaction of released Ag+ ions or TiO2 photo-induced oxidative radicals with bacteria membrane, leading to an increased permeability that causes free efflux of intracellular contents, accelerating cell death. The immobilization of such nanoparticles into antibacterial active coatings, deposited onto textile substrates, is the best strategy for an industrial scalable exploitation of their catalytic properties (bio-catalytic nanotools), presenting the advantages of heterogeneous catalysis: highly water and gas permeability of support, catalyst recovery by easy separation, minimal costs and environmental impact.

SELF CLEANING PROPERTIES _Coatings based on TiO2 have attracted particularly attention due to their photocatalytic properties exploitable in processes of stain removal when deposited on technological relevant substrates (textile, ceramic, glass). The use of nanometric particles increases the degree of adhesion of the treatment and its functionality. Nanoparticles of metal oxides have a particular affinity for the natural hydrophilic fibers and may be used in the finishing processes of textile (ceramization process) to modify the surface properties and impart new functions to the product. Cotton textiles are ceramized by sol-gel dip-pad-dry-cure method starting from TiO2 commercial nanosols or synthesized "ad hoc", with stabilized characteristics and a guaranteed reproducibility. The photocatalytic performances are evaluated in different experimental settings: particle/dye solution, particle/substrate/dye solution and particle/substrate/organic stain, so to mimic mechanisms playing in homogeneous catalysis, hetero-geneous catalysis and self-cleaning application, respectively. Nanoscale properties such as nanostructure and surface chemistry as well as macroscale properties such as hydrophilicity influenced the photocatalytic activity and their control is fundamental in order to improve the performances.

CATALYTIC PROPERTIES _ Metal nanoparticles are prepared by a patented green synthesis exploiting sugars as reducing agents. This method allows the achievement of particles with tunable size and shape with very interesting properties in terms of time stability, solid content of suspensions, reaction yield and process versatility / scalability. Synthesized metals and bimetals (core-shell structures and alloys) show high catalytic performance both in hydrogenation and oxidation reactions, even if supported on oxide nanopowders (TiO2) or on polymeric membranes. ISTEC-CNR,