Analytical challenges in the fields of Nanobioscience and Nanobiotecnology: integrated methods for separation and characterization

Nano(bio)science and nano(bio)technology play a growing and tremendous interest both on academic and industrial aspects. They are undergoing rapid developments on many fronts such as genomics, proteomics, system biology, and medical applications. However, the lack of characterization tools for nano(bio)systems is currently considered as a major limiting factor to the final establishment of nano(bio)technologies. Flow Field-Flow Fractionation (FlFFF) is a separation technique that is definitely emerging in the bioanalytical field, and the number of applications on nano(bio)analytes such as high molar-mass proteins and protein complexes, sub-cellular units, viruses, and functionalized nanoparticles is constantly increasing. This can be ascribed to the intrinsic advantages of FlFFF for the separation of nano(bio)analytes. FlFFF is ideally suited to separate particles over a broad size range (1 nm-1 μm) according to their hydrodynamic radius (rh). The fractionation is carried out in an empty channel by a flow stream of a mobile phase of any composition. For these reasons, fractionation is developed without surface interaction of the analyte with packing or gel media, and there is no stationary phase able to induce mechanical or shear stress on nanosized analytes, which are for these reasons kept in their native state. Characterization of nano(bio)analytes is made possible after fractionation by interfacing the FlFFF system with detection techniques for morphological, optical or mass characterization. For instance, FlFFF coupling with multi-angle light scattering (MALS) detection allows for absolute molecular weight and size determination, and mass spectrometry has made FlFFF enter the field of proteomics. Potentialities of FlFFF couplings with multi-detection systems are discussed in the first section of this dissertation. The second and the third sections are dedicated to new methods that have been developed for the analysis and characterization of different samples of interest in the fields of diagnostics, pharmaceutics, and nanomedicine. The second section focuses on biological samples such as protein complexes and protein aggregates. In particular it focuses on FlFFF methods developed to give new insights into: a) chemical composition and morphological features of blood serum lipoprotein classes, b) time-dependent aggregation pattern of the amyloid protein Aβ1-42, and c) aggregation state of antibody therapeutics in their formulation buffers. The third section is dedicated to the analysis and characterization of structured nanoparticles designed for nanomedicine applications. The discussed results indicate that FlFFF with on-line MALS and fluorescence detection (FD) may become the unparallel methodology for the analysis and characterization of new, structured, fluorescent nanomaterials.

Catalytic liquid- and gas-phase oxidations for the synthesis of intermediates and specialty chemicals: some examples of industrial relevance

Nowadays, it is clear that the target of creating a sustainable future for the next generations requires to re-think the industrial application of chemistry. It is also evident that more sustainable chemical processes may be economically convenient, in comparison with the conventional ones, because fewer by-products means lower costs for raw materials, for separation and for disposal treatments; but also it implies an increase of productivity and, as a consequence, smaller reactors can be used. In addition, an indirect gain could derive from the better public image of the company, marketing sustainable products or processes. In this context, oxidation reactions play a major role, being the tool for the production of huge quantities of chemical intermediates and specialties. Potentially, the impact of these productions on the environment could have been much worse than it is, if a continuous efforts hadn’t been spent to improve the technologies employed. Substantial technological innovations have driven the development of new catalytic systems, the improvement of reactions and process technologies, contributing to move the chemical industry in the direction of a more sustainable and ecological approach. The roadmap for the application of these concepts includes new synthetic strategies, alternative reactants, catalysts heterogenisation and innovative reactor configurations and process design. Actually, in order to implement all these ideas into real projects, the development of more efficient reactions is one primary target. Yield, selectivity and space-time yield are the right metrics for evaluating the reaction efficiency. In the case of catalytic selective oxidation, the control of selectivity has always been the principal issue, because the formation of total oxidation products (carbon oxides) is thermodynamically more favoured than the formation of the desired, partially oxidized compound. As a matter of fact, only in few oxidation reactions a total, or close to total, conversion is achieved, and usually the selectivity is limited by the formation of by-products or co-products, that often implies unfavourable process economics; moreover, sometimes the cost of the oxidant further penalizes the process. During my PhD work, I have investigated four reactions that are emblematic of the new approaches used in the chemical industry. In the Part A of my thesis, a new process aimed at a more sustainable production of menadione (vitamin K3) is described. The “greener” approach includes the use of hydrogen peroxide in place of chromate (from a stoichiometric oxidation to a catalytic oxidation), also avoiding the production of dangerous waste. Moreover, I have studied the possibility of using an heterogeneous catalytic system, able to efficiently activate hydrogen peroxide. Indeed, the overall process would be carried out in two different steps: the first is the methylation of 1-naphthol with methanol to yield 2-methyl-1-naphthol, the second one is the oxidation of the latter compound to menadione. The catalyst for this latter step, the reaction object of my investigation, consists of Nb2O5-SiO2 prepared with the sol-gel technique. The catalytic tests were first carried out under conditions that simulate the in-situ generation of hydrogen peroxide, that means using a low concentration of the oxidant. Then, experiments were carried out using higher hydrogen peroxide concentration. The study of the reaction mechanism was fundamental to get indications about the best operative conditions, and improve the selectivity to menadione. In the Part B, I explored the direct oxidation of benzene to phenol with hydrogen peroxide. The industrial process for phenol is the oxidation of cumene with oxygen, that also co-produces acetone. This can be considered a case of how economics could drive the sustainability issue; in fact, the new process allowing to obtain directly phenol, besides avoiding the co-production of acetone (a burden for phenol, because the market requirements for the two products are quite different), might be economically convenient with respect to the conventional process, if a high selectivity to phenol were obtained. Titanium silicalite-1 (TS-1) is the catalyst chosen for this reaction. Comparing the reactivity results obtained with some TS-1 samples having different chemical-physical properties, and analyzing in detail the effect of the more important reaction parameters, we could formulate some hypothesis concerning the reaction network and mechanism. Part C of my thesis deals with the hydroxylation of phenol to hydroquinone and catechol. This reaction is already industrially applied but, for economical reason, an improvement of the selectivity to the para di-hydroxilated compound and a decrease of the selectivity to the ortho isomer would be desirable. Also in this case, the catalyst used was the TS-1. The aim of my research was to find out a method to control the selectivity ratio between the two isomers, and finally to make the industrial process more flexible, in order to adapt the process performance in function of fluctuations of the market requirements. The reaction was carried out in both a batch stirred reactor and in a re-circulating fixed-bed reactor. In the first system, the effect of various reaction parameters on catalytic behaviour was investigated: type of solvent or co-solvent, and particle size. With the second reactor type, I investigated the possibility to use a continuous system, and the catalyst shaped in extrudates (instead of powder), in order to avoid the catalyst filtration step. Finally, part D deals with the study of a new process for the valorisation of glycerol, by means of transformation into valuable chemicals. This molecule is nowadays produced in big amount, being a co-product in biodiesel synthesis; therefore, it is considered a raw material from renewable resources (a bio-platform molecule). Initially, we tested the oxidation of glycerol in the liquid-phase, with hydrogen peroxide and TS-1. However, results achieved were not satisfactory. Then we investigated the gas-phase transformation of glycerol into acrylic acid, with the intermediate formation of acrolein; the latter can be obtained by dehydration of glycerol, and then can be oxidized into acrylic acid. Actually, the oxidation step from acrolein to acrylic acid is already optimized at an industrial level; therefore, we decided to investigate in depth the first step of the process. I studied the reactivity of heterogeneous acid catalysts based on sulphated zirconia. Tests were carried out both in aerobic and anaerobic conditions, in order to investigate the effect of oxygen on the catalyst deactivation rate (one main problem usually met in glycerol dehydration). Finally, I studied the reactivity of bifunctional systems, made of Keggin-type polyoxometalates, either alone or supported over sulphated zirconia, in this way combining the acid functionality (necessary for the dehydrative step) with the redox one (necessary for the oxidative step). In conclusion, during my PhD work I investigated reactions that apply the “green chemistry” rules and strategies; in particular, I studied new greener approaches for the synthesis of chemicals (Part A and Part B), the optimisation of reaction parameters to make the oxidation process more flexible (Part C), and the use of a bioplatform molecule for the synthesis of a chemical intermediate (Part D).

SMO inhibitor specifically targets the Hedgehog Pathway and reverts the drug-resistance of Leukemic Stem Cells

Abnormal Hedgehog signaling is associated with human malignancies. Smo, a key player of that signaling, is the most suitable target to inhibit this pathway. To this aim several molecules, antagonists of Smo, have been synthesized, and some of them have started the phase I in clinical trials. Our hospital participated to one of these studies which investigated the oral administration of a new selective inhibitor of Smo (SMOi). To evaluate ex vivo SMOi efficacy and to identify new potential clinical biomarkers of responsiveness, we separated bone marrow CD34+ cells from 5 acute myeloid leukemia (AML), 1 myelofibrosis (MF), 2 blastic phases chronic myeloid leukemia (CML) patients treated with SMOi by immunomagnetic separation, and we analysed their gene expression profile using Affimetrix HG-U133 Plus 2.0 platform. This analysis, showed differential expression after 28 days start of therapy (p-value ≤ 0.05) of 1,197 genes in CML patients and 589 genes in AML patients. This differential expression is related to Hedgehog pathway with a p-value = 0.003 in CML patients and with a p-value = 0.0002 in AML patients, suggesting that SMOi targets specifically this pathway. Among the genes differentially expressed we observed strong up-regulation of Gas1 and Kif27 genes, which may work as biomarkers of responsiveness of SMOi treatment in CML CD34+ cells whereas Hedgehog target genes (such as Smo, Gli1, Gli2, Gli3), Bcl2 and Abca2 were down-regulated, in both AML and CML CD34+ cells. It has been reported that Bcl-2 expression could be correlated with cancer therapy resistance and that Hedgehog signaling modulate ATP-binding (ABC) cassette transporters, whose expression has been correlated with chemoresistance. Moreover we confirmed that in vitro SMOi treatment targets Hedgehog pathway, down-regulate ABC transporters, Abcg2 and Abcb1 genes, and in combination with tyrosine kinase inhibitors (TKIs) could revert the chemoresistance mechanism in K562 TKIs-resistant cell line.

Comparison of affinity chromatography supports for separation of protein

Chromatography is the most widely used technique for high-resolution separation and analysis of proteins. This technique is very useful for the purification of delicate compounds, e.g. pharmaceuticals, because it is usually performed at milder conditions than separation processes typically used by chemical industry. This thesis focuses on affinity chromatography. Chromatographic processes are traditionally performed using columns packed with porous resin. However, these supports have several limitations, including the dependence on intra-particle diffusion, a slow mass transfer mechanism, for the transport of solute molecules to the binding sites within the pores and high pressure drop through the packed bed. These limitations can be overcome by using chromatographic supports like membranes or monoliths. Dye-ligands are considered important alternatives to natural ligands. Several reactive dyes, particularly Cibacron Blue F3GA, are used as affinity ligand for protein purification. Cibacron Blue F3GA is a triazine dye that interacts specifically and reversibly with albumin. The aim of this study is to prepare dye-affinity membranes and monoliths for efficient removal of albumin and to compare the three different affinity supports: membranes and monoliths and a commercial column HiTrapTM Blue HP, produced by GE Healthcare. A comparison among the three supports was performed in terms of binding capacity at saturation (DBC100%) and dynamic binding capacity at 10% breakthrough (DBC10%) using solutions of pure BSA. The results obtained show that the CB-RC membranes and CB-Epoxy monoliths can be compared to commercial support, column HiTrapTM Blue HP, for the separation of albumin. These results encourage a further characterization of the new supports examined.

Advances in methods to detect, isolate and quantify foodborne pathogens

Foodborne diseases impact human health and economies worldwide in terms of health care and productivity loss. Prevention is necessary and methods to detect, isolate and quantify foodborne pathogens play a fundamental role, changing continuously to face microorganisms and food production evolution. Official methods are mainly based on microorganisms growth in different media and their isolation on selective agars followed by confirmation of presumptive colonies through biochemical and serological test. A complete identification requires form 7 to 10 days. Over the last decades, new molecular techniques based on antibodies and nucleic acids allow a more accurate typing and a faster detection and quantification. The present thesis aims to apply molecular techniques to improve official methods performances regarding two pathogens: Shiga-like Toxin-producing Escherichia coli (STEC) and Listeria monocytogenes. In 2011, a new strain of STEC belonging to the serogroup O104 provoked a large outbreak. Therefore, the development of a method to detect and isolate STEC O104 is demanded. The first objective of this work is the detection, isolation and identification of STEC O104 in sprouts artificially contaminated. Multiplex PCR assays and antibodies anti-O104 incorporated in reagents for immunomagnetic separation and latex agglutination were employed. Contamination levels of less than 1 CFU/g were detected. Multiplex PCR assays permitted a rapid screening of enriched food samples and identification of isolated colonies. Immunomagnetic separation and latex agglutination allowed a high sensitivity and rapid identification of O104 antigen, respectively. The development of a rapid method to detect and quantify Listeria monocytogenes, a high-risk pathogen, is the second objective. Detection of 1 CFU/ml and quantification of 10–1,000 CFU/ml in raw milk were achieved by a sample pretreatment step and quantitative PCR in about 3h. L. monocytogenes growth in raw milk was also evaluated.

Essays in the Economics of the Family and Cultural Transmission

My research aims at identifying the role cultural-ethnic traits play in marriage choices and at uncovering the implications of marital sorting on consequent intra-household decisions. From different perspectives, this thesis focuses on intermarriages, within the Italian marriage market. In the first chapter, I explore the role of ethnic endogamy on marital instability. I document the existence of a positive differential in marital instability of interethnic marriages compared to homogeneous ones and I demonstrate that genetic and ethnolinguistic measures of cultural diversity are informative about the incidence of marital dissolution. The second chapter investigates a novel channel, which explains the differential in household stability and investments across family types: cultural socialization of children. I propose a marital matching model along cultural-ethnic lines, to study the process of family formation and intra-household decision making in a context where ethnic differences between spouses potentially matter both in terms of preferences and technologies for household production. The observed intermarriage, fertility, separation and socialization rates are in line with theoretical predictions and they are consistent with strong preferences of parents toward cultural socialization of children to their own ethnic identity. In the third chapter, I propose and estimate a marital matching model along ethnic lines. I argue that gains to intermarriage depend on both cultural preferences and legal status motives. Taking advantage of the exogenous EU enlargements to East European countries in 2004 and 2007, I show that gains to intermarriage of East European migrants significantly decrease in response to the acquisition of the legal status. The final chapter aims to understand whether judicial decisions respond to the ethnic identity of spouses and what incentives those judgments are guided, by looking at separation and divorce sentences. Studying the legal custody assignment of children, I document a significant differential interacting mothers’ ethnicities with the family type.

I controlli sulla tutela interinale della crisi della famiglia

La tesi affronta il tema dei controlli avverso i provvedimenti nell’interesse della prole e dei coniugi resi nell’ambito dei procedimenti di separazione e di divorzio, dapprima fornendo un inquadramento storico della problematica, attraverso la disamina delle posizioni dottrinali e giurisprudenziali formatesi con riferimento alla natura ed al regime impugnatorio di tali provvedimenti dall’entrata in vigore del codice di rito del 1865 ad oggi, dopodiché analizzando le numerose questioni interpretative cui l’attuale quadro normativo, risultante dalla stratificazione legislativa operata dalla L. 14 maggio 2005, n. 80 e dalla L. 8 febbraio 2006, n. 54, dà origine. In particolare la tesi, dopo aver delineato la struttura del reclamo di cui all’art. 708 c.p.c., cercando di fornire una soluzione ai dubbi che la scarna disciplina contenuta nella menzionata norma solleva, si occupa dei rapporti tra gli istituti del reclamo alla Corte d’appello e della revoca e modifica ad opera del giudice istruttore, riepilogando le varie teorie elaborate dalla dottrina e dalla giurisprudenza sul tema e cercando di individuare quale sia l’ambito di applicazione di ciascuno strumento di controllo. La tesi affronta poi, a fronte della mancata previsione di una forma di riesame avanti ad un organo superiore avverso i provvedimenti resi dal giudice istruttore ai sensi dell’art. 709, ultimo comma, c.p.c., la questione della reclamabilità di tali provvedimenti, cercando di individuare quale sia lo strumento più idoneo cui fare ricorso per colmare la lacuna che si dovesse ritenere esistente nel dato normativo. Il lavoro si conclude con la disamina, in una prospettiva de iure condendo, dei progetti di riforma che sono stati elaborati con riferimento al tema dei controlli avverso i provvedimenti temporanei e urgenti.

I fondi comuni di investimento: Aspetti inerenti alla separazione patrimoniale

Il presente lavoro mira a una ricostruzione della condizione giuridica del fondo comune di investimento, definito come “patrimonio autonomo e distinto”, su cui il legislatore non ha preso alcuna posizione espressa sul piano della titolarità, lasciando all’interprete il relativo (e tormentato) compito. A tal fine, l’esame critico della disciplina, alla luce di ulteriori forme di separazione patrimoniale rinvenibili nell’ordinamento giuridico, richiede un approccio metodologico teso sì a una ricostruzione in retrospettiva della questione ma anche a una sua analisi sistematica. La prima parte prende avvio dall’analisi della disciplina dei fondi comuni di investimento e della gestione collettiva del risparmio, ripercorrendo i tratti salienti della normativa al fine di acclararne la ratio. Rifuggendo da una redazione meramente compilativa, tale analisi risulta necessaria ai fini dell’esame degli aspetti problematici concernenti la natura giuridica dei fondi comuni di investimento, che non può essere avulso dal relativo contesto normativo. La seconda parte è dedicata al tema della qualificazione giuridica del fondo e della relativa titolarità alla luce della risalente dottrina, dell’evoluzione normativa e della giurisprudenza pronunciatasi sul punto. Sotto questo profilo, la prospettiva di indagine mira ad approfondire alcuni degli spunti emergenti dalle riflessioni teoriche concernenti la natura e la titolarità del fondo, avendo riguardo non solo alla classiche categorie civilistiche ma anche alla reale essenza della struttura e della disciplina dei fondi comuni di investimento e alle specifiche finalità di tutela degli interessi degli investitori perseguite dalla disciplina. Seguendo questo percorso, l’ultima parte volge uno sguardo doveroso alle tematiche concernenti le funzioni della separazione dei patrimoni nell'ambito dei mercati finanziari e del diritto positivo, senza pretermettere le categorie civilistiche, di diritto interno e di diritto straniero, sottese alle fattispecie considerate.

Design of biobased additives for tuning the properties of biopolymers

This work mainly arises from the necessity to support the rapid introduction of different biobased polymers that the industrial sector has been facing lately. Indeed, while considerable efforts are being made to find environmentally and economically sustainable materials, less attention is paid to their need to be properly compounded to fulfil increasingly rigorous technical and quality requirements. Therefore, there is a strong demand for the development of a novel generation of compatible additives able to improve the properties of biobased polymers while respecting sustainability. With this in mind, a new class of biobased plasticizers is herein proposed. Five different ketal-diesters were selectively synthesized starting from levulinic acid, a promising renewable chemical platform. These molecules were added to poly(vinyl chloride) as model polymer to test their plasticizing effectiveness. Complete morphological, thermal and viscoelastic characterizations showed a clear correlation between the structural features of the ketal-esters and the properties of the material. In addition, no significant leaching was found in both hydrophilic and lipophilic environments. Importantly, the proposed ketal-diesters performed comparably and, in some cases, even better than commercial plasticizers. The same molecules were then added to bacterial poly(3-hydroxybutyrate), a semicrystalline polyester characterized by poor thermal and mechanical properties. Morphology assessments showed no phase separation and the plasticizing effectiveness was confirmed by thermal and viscoelastic analyses, while leaching tests showed low extraction values. Readily usable fractions with controlled structure and tailored properties were obtained from highly heterogeneous industrial grade Kraft lignin. These fractions were then added to poly(vinyl alcohol). Promising preliminary results in terms of compatibility were achieved, with thermograms showing only one glass transition temperature. Finally, a fully biobased glycerol-trilevulinate was successfully synthesized by means of a mild and solvent-free route. Its plasticizing effectiveness was evaluated on poly(vinyl chloride), showing a significant decrease of the glass transition temperature of the material.

Theoretical and Experimental Study of the Magnetic Separation of Pollutants from Wastewater

This Thesys reports the study of a HGMS (High GradientMagnetic Separation) process for the treatment of industrialwastewaters that considers an assisted chemical-physical pre-treatment for the removal of heavy metals through the bound by adsorption with added iron-oxide particulate matter (hematite). The considered filter, constituted by ferromagnetic stainless steel wool and permanent magnets, is studied with a new approach based on a statistical analysis that requires the study of the trajectories of the particles. Experimental activity on a laboratory device has been carried out in order to test the model.

Development and characterization of micromachined devices for separation techniques

Nowadays microfluidic is becoming an important technology in many chemical and biological processes and analysis applications. The potential to replace large-scale conventional laboratory instrumentation with miniaturized and self-contained systems, (called lab-on-a-chip (LOC) or point-of-care-testing (POCT)), offers a variety of advantages such as low reagent consumption, faster analysis speeds, and the capability of operating in a massively parallel scale in order to achieve high-throughput. Micro-electro-mechanical-systems (MEMS) technologies enable both the fabrication of miniaturized system and the possibility of developing compact and portable systems. The work described in this dissertation is towards the development of micromachined separation devices for both high-speed gas chromatography (HSGC) and gravitational field-flow fractionation (GrFFF) using MEMS technologies. Concerning the HSGC, a complete platform of three MEMS-based GC core components (injector, separation column and detector) is designed, fabricated and characterized. The microinjector consists of a set of pneumatically driven microvalves, based on a polymeric actuating membrane. Experimental results demonstrate that the microinjector is able to guarantee low dead volumes, fast actuation time, a wide operating temperature range and high chemical inertness. The microcolumn consists of an all-silicon microcolumn having a nearly circular cross-section channel. The extensive characterization has produced separation performances very close to the theoretical ideal expectations. A thermal conductivity detector (TCD) is chosen as most proper detector to be miniaturized since the volume reduction of the detector chamber results in increased mass and reduced dead volumes. The microTDC shows a good sensitivity and a very wide dynamic range. Finally a feasibility study for miniaturizing a channel suited for GrFFF is performed. The proposed GrFFF microchannel is at early stage of development, but represents a first step for the realization of a highly portable and potentially low-cost POCT device for biomedical applications.

Polymeric membranes for CO2 separation: effect of aging, humidity and facilitated transport

Polymeric membranes represent a promising technology for gas separation processes, thanks to low costs, reduced energy consumption and limited waste production. The present thesis aims at studying the transport properties of two membrane materials, suitable for CO2 purification applications. In the first part, a polyimide, Matrimid 5218, has been throughout investigated, with particular reference to the effect of thermal treatment, aging and the presence of water vapor in the gas transport process. Permeability measurements showed that thermal history affects relevantly the diffusion of gas molecules across the membrane, influencing also the stability of the separation performances. Subsequently, the effect of water on Matrimid transport properties has been characterized for a wide set of incondensable penetrants. A monotonous reduction of permeability took place at increasing the water concentration within the polymer matrix, affecting the investigated gaseous species to the same extent, despite the different thermodynamic and kinetic features. In this view, a novel empirical model, based on the Free Volume Theory, has been proposed to qualitatively describe the phenomenon. Moreover, according to the accurate representation of the experimental data, the suggested approach has been combined with a more rigorous thermodynamic tool (NELF Model), allowing an exhaustive description of water influence on the single parameters contributing to the gas permeation across the membrane. In the second part, the study has focused on the synthesis and characterization of facilitated transport membranes, able to achieving outstanding separation performances thanks to the chemical enhancement of CO2 permeability. In particular, the transport properties have been investigated for high pressure CO2 separation applications and specific solutions have been proposed to solve stability issues, frequently arising under such severe conditions. Finally, the effect of different process parameters have been investigated, aiming at the identification of the optimal conditions capable to maximize the separation performance.

Synthesis, Modification and Characterization of Polymeric Membranes for CO2 Separation

This doctorate focused on the development of dense polymeric membranes for carbon capture, mostly in post combustion applications, and for natural gas sweetening. The work was supported by the European Project NANOMEMC2 funded under H2020 program. Different materials have been investigated, that rely on two main transport mechanisms: the solution-diffusion and the facilitated transport. In both cases, proper nano-fillers have been added to the matrix, in order to boost the mechanical and permselective properties of the membranes. Facilitated transport membranes were based on the use of was polyvinylamine (PVAm), as main matrix with fixed-site carriers, and L-Arginine as mobile carrier; the filler, used mostly as reinforcer, was carboxymethylated nanocellulose (cNFC). Humid test showed interesting results, and especially the blend made of PVAm/cNFC/Arg in weight ratio 27,5/27,5/45 crossed the Robeson CO2/N2 upper bound, representing current state of the art membranes, with a CO2 permeability of 271 Barrer and CO2/N2 selectivity of 70. Solution diffusion membranes were based on Pebax®2533 matrix which was added with three different graphene oxide (GO)-based materials, namely pristine GO, Porous Graphene Oxide (PGO) and a GO functionalized with polyetheramine (PEAGO). All of them provided a modest but clear increment of permeability of the Pebax matrix, from plus 2% (GO) to plus 8% (PGO), with no change in selectivity. The gas tested with this type of composites were CO2 and N2, for Post combustion capture applications. Pebax®2533 was also chemically modified, obtaining the product called “Benzoyl-P2533”, that was fully characterized, and tested in term of permeation using five gas: CO2, N2, CH4, O2, and He. Modified material showed an increment of the overall permeability of the material of a fair 10% for all gases tested, apart from helium, that increased of almost 50%.

Design and evaluation of aerosol and liquid separation systems

Conventional chromatographic columns are packed with porous beads by the universally employed slurry-packing method. The lack of precise control of the particle size distribution, shape and position inside the column have dramatic effects on the separation efficiency. In the first part the thesis an ordered, three-dimensional, pillar-array structure was designed by a CAD software. Several columns, characterized by different fluid distributors and bed length, were produced by a stereolithographic 3D printer and compared in terms of pressure drop and height equivalent to a theroretical plate (HETP). To prevent the release of unwanted substances and to provide a surface for immobilizing a ligand, pillars were coated with one or more of the following materials: titanium dioxide, nanofibrillated cellulose (NFC) and polystyrene. The external NFC layer was functionalized with Cibacron Blue and the dynamic binding capacity of the column was measured by performing three chromatographic cycles, using bovine serum albumin (BSA) as target molecule. The second part of the thesis deals with Covid-19 pandemic related research activities. In early 2020, due to the pandemic outbreak, surgical face masks became an essential non-pharmaceutical intervention to limit the spread. To address the consequent shortage and to support the reconversion of the Italian industry, in late March 2020 a multidisciplinary group of the University of Bologna created the first Italian laboratory able to perform all the tests required for the evaluation and certification of surgical masks. More than 1200 tests were performed on about 350 prototypes, according to the standard EN 14683:2019. The results were analyzed to define the best material properties and masks composition for the production of masks with excellent efficiency. To optimize the usage of surgical masks and to reduce their environmental burden, the variation of their performance over time of usage were investigated as to determine the maximum lifetime.