The aim of this work was to obtain cobalt nanoparticles through a physical method, which could be formed simultaneously during the Catalytic Chemical Vapour Deposition (CCVD) synthesis of carbon nanotubes, under conditions suitable for both carbon nanotube synthesis and Co-nanoparticle formation. Co nanoparticles were prepared by Physical Vapour Deposition (PVD) using a 0.05 m3 magnetron on two different substrates, SiO2/Si and C, followed by a reduction treatment in an H2 atmosphere. Transmission Electron Microscopy (TEM) and Field Enhanced Scanning Electron Microscopy (FE-SEM) were used to characterize the Co nanoparticles. On the SiO2/Si substrate, cobalt silicate is formed, which stabilizes the Co nanoparticles, while the nanoparticles obtained on the C-substrate are sometimes surrounded by a layer of Co3O4, which deactivates the cobalt nanoparticles. To obtain suitable Co nanoparticles for carbon nanotube synthesis, the optimal Co-layer thickness is between 20 and 30 Å, and the optimal reduction temperature is 800 °C and 450 °C for SiO2/Si and C substrates, respectively.

The primary aim of this research was to identify the optimal experimental conditions for obtaining aligned carbon nanotubes, temporarily leaving aside aspects such as the purity of carbon nanotubes, which is nonetheless crucial for potential applications in the field of nanoelectronics. The predefined alignment of CNTs can significantly influence the performance and efficiency of electronic components. In this study, two different catalytic supports based on cobalt nanoparticles, Co/SiO2/Si and Co/C, have been utilized and compared in the catalytic chemical vapor deposition (CCVD) synthesis of CNTs. Various parameters have been examined, including the nature and thickness of the catalyst, the reaction temperature, and the pressure of the acetylene mixture entering the reactor. The results indicate that the optimal temperature for the Co/SiO2/Si catalyst is 800 °C, while for the Co/C catalyst, it is 450 °C. The optimal Co layer thickness should be between 20 and 30 Å. CNT growth occurs from the top in the Co/C system, whereas bottom-up growth is characteristic of the Co/SiO2/Si catalyst, making the latter more suitable for the synthesis of CNTs intended for nanoelectronic devices.

Mechanical properties of carbon nanotubes (CNTs) are very interesting for the nanocomposite field. The possibility to use these nanomaterials as fibers in polymeric matrix is one of the most important applications of the last years. This study recognised the mechanical properties of CNTs and the obtained composites with polymeric matrix. The second part of chapter presents a short characterisation of an epoxy-CNTs-based composite. This study verified the hypothesis made concerning a different tensile strength of these materials as a function of presence of structure defects.

An experimental research has been done investigating the effects of the addition of multi-walled Carbon Nanotubes (CNTs) on the rheological behaviour of bitumen and its microstructure. two different types of CNT have been tested, consisted of a product obtained by laboratory synthesis through Catalytic Chemical Vapour Deposition (CCVD) technique and a commercial one, hereinafter are called type 1 and type 2, respectively. Both types of CNTs were completely characterized in terms of morphological, chemical, and structural properties. In addition, the rheological analysis were also conducted on bitumen blends containing CNT providing a complete study understanding the effectiveness of introduced CNT compared to those of commercial ones as for bitumen modification. For this purpose the experimental plan consisted of Trasmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM), micro-Raman spectroscopy, and rheological analysis in oscillatory regime.

This article displays an efficient and cost effective technique for the removal of unleaded gasoline from water. Multi-walled carbon nanotubes (MWCNTs) were used as the sorbent material. Nanotubes were synthesized according to a well-known procedure and successfully used avoiding cumbersome purifications from traces of catalyst. A series of lab-scale experiments was performed on dispersions of commercial unleaded gasoline (20 mL) in water (30 mL), which were subjected to the action of variable amounts of MWCNTs at room temperature. Physicochemical characteristics and sorbent capacity of nanotubes were investigated by thermal analysis and FT-IR spectroscopy. The highest percentage of removed unleaded gasoline was obtained using small amounts (0.7 g) of MWCNTs, over very short stirring times (5 min). The composition of residual organic materials in water was investigated by 1H and 13C high-resolution NMR spectroscopy, which confirmed the almost complete removal of unleaded gasoline hydrocarbon components from polluted waters.

Abstract The present work aims to experiment the action of carbon nanotubes (MWCNTs) in the removal of sodium chloride from aqueous systems, not using them as a membrane but dispersing them directly in solution, in order to evaluate possible applications in the desalination of brackish water. For this purpose, different aqueous systems have been prepared by varying the sodium chloride concentration and the amount of carbon nanotubes dispersed therein. The systems were stirred for scheduled times and then the amount of residual sodium chloride was measured by drying, after filtration, the systems and weighing the dry residue. In the final part of the experimentation, after having identified the best system, the tests were carried out directly on sea water and using different types of carbon nanotubes such as not oxidized (MWCNTs) and oxidized (MWCNTS-ox) ones.

The main purpose of this work was to prepare and optimize glues consisting primarily of natural components. The fundamental component was the laricio pine resin to which different additives were added, varying their nature and quantity. The additives used were: charcoal, activated carbon and carbon nanotubes (MWCNTs). The optimization of the systems continued to identify and select suitable solvents, in order to improve dispersion and solubilization of the phases and to obtain glues in the fluid phase at room temperature. The best results were obtained with ethyl alcohol which, moreover, represents a solvent with a limited environmental impact. The evaluation of the adhesive capacity of the glues was carried out by cutting, tensile and flexural tests on prepared wooden specimens. Furthermore, the specimens and the same glue were subjected to thermal cycles and observed by Scanning Electron Microscope (SEM). The carbon nanotubes, used in very low percentages (1%, in a system consisting mainly of natural origin products) in the presence of an adequate solvent, such as ethyl alcohol, make it possible to obtain a glue that is easy to apply, with an excellent adhesive capacity.

In the aim to get high quality graphene films, with large domains and free from impurities, minimizing also the manufacturing costs, we investigate the graphene grown on copper (Cu) foil by chemical vapor deposition at ambient pressure conditions, by using methane (CH4) as carbon source, diluted in a suitable mixture of argon (Ar) and hydrogen (H-2). Several graphene samples were synthesized, for variable exposure times to hydrocarbon precursor, in the range from 1min to 1hr. The quality of the graphene films and their structural, morphological, and electronic properties were evaluated by micro-Raman spectroscopy and other techniques, including, scanning tunneling microscopy, atomic force microscopy, and scanning electronic microscopy. In particular, samples obtained with shorter growth time (less than 10min) exhibit a non-uniform coverage of the Cu surface, whereas those synthesized with exposure time between 10 and 30min show a prevalence of well-ordered monolayer graphene domains. For longer deposition, the amount of disordered domains increases, as revealed by Raman analysis, and the resulting film shows a nonself-limiting growth behavior for chemical vapor deposition at atmospheric conditions. In addition, we observed 2 kinds of monolayer graphene, in terms of coupling with the Cu surface, for the samples synthesized between 10 and 30min. To the best of our knowledge, coupled and decoupled graphene regions have never been reported at the same time on Cu surface. Furthermore, a Raman statistical analysis has been performed on the G and 2D bands measured in both the kinds of regions, gaining evidence of a bimodal behavior for the graphene spots, corresponding to coupled and decoupled configurations. This difference, which is appreciable also by the optical microscopy inspection, could be related to the local Cu oxidation and to oxygen intercalation after graphene growth.

The data presented in this work has been obtained from experimental research aiming towards the usage of natural resources of the National Park of Sila in Calabria, Southern Italy. Such resources are: "Laricio" pine resin, beeswax, mineral inert and charcoal to make natural glues. Furthermore, research has been done to find out if by using small quantities of carbon nanotubes, the strength of adhesion of prepared glues improves. Raw materials were characterized by physico-chemical techniques. In particular, the "Laricio" pine resin was characterized through the NMR techinique. The data obtained have shown that each utilized component plays a specific role: the pine resin on the fundamental binding properties, the beeswax on the plasticity of the material, the coal and the mineral inert on raising the melting temperature, the carbon nanotubes on improvement of the adhesion resistance.

MWCNTs are considered as high performance adsorption materials. In this paper these materials are tested in the adsorption treatments of reactive Blue 116, Red 159 and Yellow 81, used in textile applications. The evaluation of kinetic behavior and the study of adsorption isotherms permits to define nanotubes as suitable for potential industrial application for depuration of wastewaters.

The development of advanced functional membranes with tailored properties is a key issue to be addressed in order to better exploit the potentialities of membrane-based separations processes. An important approach toward this aim is the realization of composite systems in which an organic and an inorganic phase coexist in order to have synergic effects on membrane properties. In this study functionalized multiwalled carbon nanotubes (MWCNT) and polyvinylidene fluoride (PVDF) are combined to produce composite porous membranes by solution casting and phase separation. The main goal is to gain more insight into the role of MWCNT functional groups on the interface-controlled properties of the composite films. The results show that the interactions between the polymeric matrix and the MWCNT are tailored by the nanotubes functionalization. In fact, Raman analysis support a better interaction of the PVDF polymer with the MWCNT functionalized with nitrogen containing groups (aminated and amidated) than with oxidized samples, thanks to the cooperative formation of hydrogen bonds and charge transfer complexes. The composite films, in particular that containing amidated MWCNT, show improved thermal, mechanic and transport properties in comparison with pure polymeric films.

The paper deals with the application of multiwall carbon nanotubes(CNTs) to the adsorption of dyes from wastewater. Textile dyes are dangerous and diffused pollutant in wastewater, and the paper results confirmed the good adsorption ability of CNTs, with respect to classic active carbon, even for different dye types. The effect of surface treatments of CNTs was primarily investigated, revealing that neither the presence of residual catalyst nor common surface treatment(oxidation) affects the CNT’s performances. Therefore less expensive nonpurified CNTs were assessed as good and economically convenient alternative for the process. In order to gain in generality in adsorption kinetic modelling, the parameters of the "best fitting" pseudo-second order model have been correlated to the main process variables(the dye initial concentration and the specific mass of CNTs.) setting-up a predictive kinetic model useful design new application of these materials in currently operating industrial operations for adsorption. In addition, isothermal data were used to screen all the relevant adsorption isotherms models and the Temkin model was confirmed as the more effective to accurately fit equilibrium data for any of the considered different dye types.

Membrane operations are promising tools for efficient and environmentally friendly separations. However, the development of advanced membranes with tailored properties is a key issue to be addressed in order to better exploit the potentialities of membrane-based separations. An important approach toward this aim is the development of mixed matrix membranes in which an organic and an inorganic phase coexist in order to have synergic effects on membrane properties. The peculiar properties of carbon nanotubes (CNTs) such as high electrical and thermal conductivity, high strength and unique transport properties, has motivated a considerable effort to produce CNT-polymer composites in order to engineer membrane properties. In this work the roughness, wettability, morphology, crystalline phase and pore size of polyvinylidenefluoride (PVDF) membranes were tailored working on the membrane preparation conditions, as well as, by blending the polymer with multiwalled carbon nanotubes (MWCNTs). A study on the effect of concentration of the polymer, use of pore forming additives, type and concentration of MWCNTs (pristine and functionalized), was carried out. The results highlighted interesting relationships between membrane microstructure and composition, as well as, MWCNTs distribution, on transport and wettability properties, in the perspectives of a more efficient application of PVDF membranes in liquid phase separations.

Carbon nanotubes are very interesting materials, with a wide range of applications. Their use as adsorbents represents a method of gas purification which can find various applications; an example is the industrial processes for the production of methane (CH4), where the purification of the same from the carbon dioxide (CO2) and/or nitrogen (N2) has always been one of the main objectives. In this work, carbon nanotubes (CNTs) produced through a process of catalytic chemical vapor deposition (CCVD) are analyzed in view of this application. For this reason, the initial physical–chemical properties of the as-made, purified and oxidized CNTs, together with CH4, N2 and CO2 adsorption/desorption tests at room temperature, have been considered to optimize the best material and the best operative condition for a potential application in adsorption and/or purification processes.

Due to the well-known adsorption properties of titanosilicates (ETS-4 and ETS-10) and aluminotitanosilicates (ETAS-4 and ETAS-10), it was considered particularly interesting to investigate their efficiency in adsorbing ammonia from a gaseous phase. Prior to testing their adsorption capacity, materials thus synthesized have been analyzed by appropriate characterization techniques. Afterward, the adsorption capacity of microporous materials toward ammonia has been evaluated by measuring the corresponding adsorption isotherms through batch experiments. Experimental measurements were best fitted by a linear constant relationship. From the experimental results, high adsorption capacity values were found for all microporous materials in correspondence of high gaseous ammonia concentration values. In particular, ETAS-10 attained the maximum value of adsorption potential, equal to 7.647 mg of NH 3 per g of material. This was likely due to the presence of the acid site linked to the Al atom in its structure with respect to the ETS structure. In addition to that the greater pore size characterizing the phase 10 compared to phase 4 might have entailed a more selective sorption of ammonia molecule. Overall, both titanosilicates and aluminotitanosilicates showed a great adsorption potential toward ammonia. However, materials achieved their maximum capacity at high pollutant loading.

From hydrophobic to hydrophilic PVDF membranes by a combination of functionalization by blending chemical additives and selection of manufacturing procedure.

ETS-10 and ETS-4 microporous materials were synthesized in presence of tetralkylammonium (TAA) ions from gels of molar composition w Na2O–0.10 TAABr–1 SiO2–z TiO2–0.6 KF–1.28 w HCl–39.5 H2O with TAA = tetramethyl-, tetraethyl-, tetrapropyl- and tetrabutyl-ammonium in hydrothermal conditions at 190 °C. The TAA ions enter the microporous channel of ETS-10, while they cannot penetrate the void spaces of ETS-4. The ETS-10 microcrystals are all cubic, while the ETS-4 crystals are laminar and irregular. The microporous volume of ETS-10 is equal to 0.11–0.13 cm3 g−1, the microporous volume of ETS-4 is very small, 0.002–0.008 cm3 g−1. The ion exchange of Cs+, Cd++, Pb++ and Hg++ ions using their corresponding nitrates show kinetic effects, i.e. the efficiency of ion exchange is higher at 1 than 2 h, the thermodynamic equilibrium. For ETS-10, partially dehydrated cations intervene in the ion exchange, while for ETS-4 well dehydrated ions can only penetrate the available pores.

This paper reports a study of ETS-4 based self-bonded pellets, with several amounts of Zr moles in initial gel. The following gel composition is used: xNa2O–0.6KF–1.28xHCl–yZrO2–0.2TiO2–1.49SiO2–39.5H2O with 0.5 ≤ x ≤ 2.5 and 0.015 ≤ y ≤ 0.12. The characterisation of obtained samples is carried out by XRD, thermal analysis, EDX and SEM. The results point out the possibility to synthesise ETS-4 zeotype with Zr in self-bonded pellets form. The importance of the amount and composition of the amorphous phase is underlined as binder of the ETS-4 crystals. Its amount is bigger at the outer face of the pellets, showing that the crystallisation occurred from the inner to the external face. Zirconium replaces titanium in the structure and its presence reinforces the mechanical resistance of the pellets.