Porous materials derived from industrial by-products for titanium dioxide nanoparticles capture

The aim of this paper was the evaluation of hybrid porous materials, named SUNSPACE (“SUstaiNable materials Synthesized from by-Products and Alginates for Clean air and better Environment”), realized with raw materials such as silica fume (SUNSPACE SF) and bottom ash derived from municipal solid waste incineration (SUNSPACE BA), compared to cement and leaf for particulate matter (PM) entrapment. SUNSPACE BA was synthesized to overcome the limited applicability of the original material due to its dark grey color. The modification of raw materials used for its realization allows one to obtain a light color in comparison to the corresponding SUNSPACE SF, more suitable to be used as a coating on the buildings’ facades for aesthetic reasons. Moreover, another great advantage was obtained by the synthesis of SUNSPACE BA in the frame of circular economy principles; indeed, it was obtained by using a waste material (derived from waste incineration), opening new possibilities for its reuse. Experimental tests to evaluate the particles entrapment capability of the material were realized for the first time by using a nanoparticles generator. TiO2 suspension with a size of 300 nm and a concentration of 3 g/L was used to simulate a monodisperse nanoparticles flux. To compare the quantity of TiO2 adsorbed by each specimen, both the exposed and the pristine samples were digested and then analyzed by total X-ray fluorescence (TXRF). The results showed a high adsorption capacity of SUNSPACE BA (3526 ± 30 mg/kg).