New nanostructured hybrid membranes for gas separation have been prepared and characterized for the first time in the literature by using a block copolymer, poly(styrene-b-butadiene-b-styrene) (SBS), and aminated SBA-15. Short mesopore channels, platelet SBA-15 particles with a high surface density of 3-aminopropyl grafts (3.8 nm⁻²) and modest surface area reduction (45%) were prepared, characterized and used as a filler. The gas transport characterization of the hybrid membranes indicates that with a 10 wt% content of aminated filler, outstanding performances in terms of selectivity and permeability for the CH₄/N₂ and the CO₂/N₂ gas pairs can be obtained. In particular, the CH₄/N₂ ideal selectivity of 7.3 is higher than the values of the existing block co-polymers used for this separation and of mixed matrix membranes described to date in the literature. Membranes with such a high separation factor may enable the exploitation of natural gas with high N₂ content and increase the amount of methane that can be economically recovered. The combination of the CO₂/N₂ ideal selectivity of 53 with a CO₂ permeability of 173 Barrer demonstrates that the new hybrid membranes prepared in this study deserve further attention as a practical commercial solution also for the post-combustion capture of carbon dioxide. Finally, the small and flat particles dispersed in the polymer lend themselves to the fabrication of thin industrial membranes with enhanced productivity.

Carbon capture, utilization, and storage (CCUS) is one of the key promising technologies that can reduce GHG emissions from those industries that generate CO₂ as part of their production processes. Compared to other effective CO₂ capture methods, the adsorption technique offers the possibility of reducing the costs of the process by setting solid sorbent with a high capacity of adsorption and easy regeneration and, also, controlling the performance of gas-solid contactor. In this work, an amine-functionalized mesoporous sorbent was used to capture CO₂ emissions in a confined-fluidized bed. The adoption of a confined environment allows the establishment of a homogeneous expansion regime for the sorbent and allows to improve the exchange of matter and heat between gas and solid phase. The results illustrate how the different concentration of the solution adopted during the functionalization affects the adsorption capacity. That, measured as mg of CO₂ per g of sorbent, was determined by breakthrough curves from continuous adsorption tests using different concentrations of CO₂ in air. Mesoporous silica functionalized with a concentration of 20% of APTES proves to be the best viable option in terms of cost and ease of preparation, low temperature of regeneration, and effective use for CO₂ capture.

The synthesis of zeolite membranes and thin films using the secondary growth process is briefly described. In this process colloidal zeolite particles (sols) are prepared hydrothermally and then subsequently deposited on substrates to produce uniform layers of controlled thickness. In order to optimise this process, an understanding of the nature of the sols and an insight into the structure of the consolidated layer so formed, is required. Such studies are illustrated here with silicalite and zeolite A. The formation and growth of silicalite sols has been investigated in situ by small angle neutron scattering (SANS). SANS measurements on sols at progressively higher concentrations have provided details of the colloid interactions which lead to zeolite gel-layer structures which are uniform and free of defects. Several techniques (XRD, small angle X-ray scattering (SAXS), and nitrogen adsorption isotherms) have also been used to characterize colloidal species extracted by ultracentrifugation at progressive stages from solutions during the hydrothermal synthesis of zeolite LTA.