Geopolymers are a new class of binders based on alkali activation of natural and by-products raw materials. Their properties and eco-compatibility highly depends on the reaction system. The (Na,K)₂O-Al₂O₃-SiO₂-H₂O system shows a distinguishing pseudo-zeolitic network structure, but reaction requires a high amount of activators. The aim of this work is to investigate how the use of forest biomass ash (FBA), as partial replacement material in the production of metakaolin (MK) based geopolymeric mortar, and affect its properties. FBA is a by-product of the combustion process of forest biomass in thermal power plants. Mortars with a FBA content of 0%, 10%, 20%, and 30% wt have been tested for workability, flexural, and compressive strength. Capillary absorption, micro-morphological features, thermal, and shrinkage behavior have been investigated. The addition of FBA allowed for a decrease in the use of alkaline activator up to 20%, while preserving the characteristic broad hump centered at approximately 28° 2θ Mechanical properties of the geopolymeric mortars decrease proportionally with metakaolin replacement, even if a compression strength of more than 35 MPa is still obtained with a FBA content of 30% wt. After thermal cycles of up to 700 °C, all of the mortars still retain their cohesiveness, with an overall loss of mechanical strength of about 80% of the initial value that can be attributed to the formation of microcracks as a consequence of the network strain and distortion due to dehydration and shrinkage.

The aim of this project was to study the treatment of industrial waste using ETS-10 zeolite. The pollutants that must be removed were metals sourced from zinc ferrite, a processing waste derived from the use of mineral-containing zinc. The first phase of the work involved the characterization of the industrial waste, zinc ferrite, in order to deepen the knowledge regarding its nature and composition. The second phase involved the removal of the metals released by the zinc ferrite in aqueous systems using the ETS-10 phase as an ion exchanger. Different chemical and physical techniques were used: plasma mass spectrometry, X-ray diffraction, scanning electron microscopy, microanalysis, and thermal analyses. A comparison between ETS-10 and commercial zeolite A performance, in the same aqueous systems, was carried out. The results showed that the metal removal efficiency of ETS-10 phase is higher than that obtained by commercial zeolite A, especially towards dangerous heavy metals such as Pb, Zn and Mn.

Most of the dyes used today by the textile industry are of synthetic origin. These substances, many of which are highly toxic, are in many cases not adequately filtered during the processing stages, ending up in groundwater and water courses. The aim of this work was to optimize the adsorption process of carbon nanotubes to remove an azo-dye, called Reactive Black-5, from aqueous systems. Particular systems containing carbon nanotubes and dye solutions were analyzed. Furthermore, the reversibility of the process and the presence of possible degradation phenomena by the dye molecules were investigated. For this purpose, the influence of different parameters on the adsorption process, such as the nature of the carbon nanotubes (purified and nonpurified), initial concentration of the dye, stirring speed, and contact times, were studied. The solid and liquid phases after the tests were characterized by chemical-physical techniques such as thermogravimetric analysis (TG, DTA), UV spectrophotometry, BET (Brunauer, Emmett, Teller), and TOC (total organic carbon) analysis. The data obtained showed a high adsorbing capacity of carbon nanotubes in the removal of the Reactive Black-5 dye from aqueous systems. Furthermore, the efficiency of the adsorption process was observed to be influenced by the stirring speed of the samples and the contact time, while purified and nonpurified nanotubes provided substantially the same results.

The aim of this project is to investigate the behaviour of several special types plasters specifically designed to degrade the most common pollutants which are present in the atmosphere. In particular, specific additives have been added to these plasters, in order to obtain a broad spectrum of active and synergic response, each of which have peculiar functions: - microporous materials, such as clinoptilolite, a natural zeolite, that promotes the adsorption of air pollutants thanks to its porous nature; - nano-fillers, such as carbon nanotubes, that behave both as reinforcing agents as well as adsorbent materials; - photochemical agents, such as titanium oxide, that degrade air pollutants, previously adsorbed on carbon nanotubes and zeolites, thanks to the action of light that activates photodegradation reactions. All the samples were also characterized in terms of mechanical properties, adhesion to supports and water absorption. Furthermore, photodegradation tests were carried out by exposing plaster surfaces, wetted with a Rodamine solution, to Ultraviolet rays (UV) for different times. Plasters photodegradative capacity was evaluated and the results highlighted the fact that the designed admixtures showed an important photodegradative action, strictly dependent on the types and specific ratios of the selected additives.

Adsorbent columns, containing different amounts of multi-walled carbon nanotubes (MWCNTs), in a semicontinuous process were studied. The optimal conditions for the discoloration of water contaminated by an azoic organic textile dye were investigated. In particular, as representative of contaminated water, a highly concentrated solution of Reactive Black 5 (RB5) equal to 37 mg/L was utilized. A predetermined volume of dye solution, equal to 100 mL, was subjected to repeated cycles of adsorption until the eluted solution became colorless. This adsorption operation was carried out for different types of columns. Adsorbent performances as a function of characteristics of each column were investigated. For each column, the optimum quantity of MWCNTs, maximum volume of treatable solution, carbon usage rate (CUR), empty bed contact time (EBCT), and adsorption capacity were determined. The permeate was characterized by UV-VIS analysis and TOC analysis, while adsorbent material (MWCNTs) was characterized by thermogravimetric TG-DTA analysis. The column containing 2.5 g of carbon nanotubes was revealed to be the best one for the total amount of Reactive Black 5 adsorbed, i.e., 55 mg/g_(MWCNTs) The research has shown the high adsorption efficiency of carbon nanotubes toward RB5 dye, highlighting the degradation of the dye molecule and the stratification, inside the columns, of the adsorbed compound.