Tesi di Dottorato
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Item Advanced functionalized materials for multipurpose applications(Università della Calabria, 2021-03-21) Pantuso, Elvira; Andò, Sebastiano; Nicoletta, FioreItem Study of physical, mechanical and transport properties of polymeric membranes for gas separation(Università della Calabria, 2022-01-31) Longo, Mariagiulia; Cipparrone, Gabriella; Giorno, Lidietta; Carolus Jansen, JohannesThe work in this thesis is organised in different main topics. The first part is devoted to present Atomic Force Microscopy (AFM), carried out in force spectroscopy mode, as a powerful alternative to the more commonly used tensile tests for the analysis of the mechanical properties of polymers, and MMMs in particular. AFM force spectroscopy measurements are carried out with nanometric and micrometric tips on dense membranes of neat Pebax®1657 and on mixed matrix membranes of Pebax®1657 with different concentrations of an ionic liquid. This offers good perspectives for the analysis of samples where traditional tensile tests cannot be used, for instance composite membranes or particularly small samples. The second part of the research is focused on the relationship, between the transport properties and Young’s modulus for films of polymers of intrinsic microporosity (PIM) and on the effect of physical aging, investigated using pure gas permeability and atomic force microscopy (AFM) measurements in force spectroscopy mode. In the third part, the transport properties of polymer blend membranes are evaluated. In the last part, using a computational approach, it is possible to predict missing values for permeability starting with a collection of existing permeability values for other polymers. The data are estimated by means of machine learning models that correlate the behaviour of different gases. Thus, this thesis is structured as follows: Chapter 1 and Chapter 2 provide a general introduction on membrane technology and characterization methods used in this thesis, as well as the theoretical background and the description of all experimental techniques used; Chapter 3 describes the mechanical study on MMMs of blends of Pebax® and the ionic liquid ([BMIM][BF4]); Chapter 4 describes mechanical and gas transport studies on PIMs; Chapter 5 presents the gas transport analysis on Matrimid®5218/AO-PIM blend membranes; Chapter 6 discusses the results of the machine learning model. Chapter 7 presents the overall conclusions of the work and gives a brief future outlook of possible and desired developments in the field.Item Use of submerged membrane technology for the treatment of olive mill wasterwater: fouling study and process performance(2017-07-21) D'Agostino, Napoleone; Carbone, Vincenzo; Giorno, LidiettaThe objective of this research work was to study the performance of an immersed (or submerged) membrane system for the treatment of vegetative waste water, coming from the production of olive oil (or Olive Mill WasteWater OMWW). To this end, a prototype has been built up on a bench‐scale capacity of 5 L, which employs a bundle of polymeric hollow fiber membranes. The approach of the study has been to divide the survey on three fronts: the first aimed at studying the waste water matrix in order to identify a pre‐treatment method capable of favoring the membrane filtration processes limiting the fouling (fouling ); the second involved the study of fouling by adsorption of the components present in the waters using different polymeric membranes, in order to identify the most suitable materials for the process; the third and final concerned the construction of the immersed membranes system and to the study of its performance as‐a‐function‐of‐process‐parameters. The chemical/physical analysis on the vegetation water evidenced range of values affected by different parameters related to the production of olive oil. Parameters such as the collection period, maturation of the fruit, the climate and soil can significantly vary the chemical concentration of a compound, which can become more than double in certain condition. This means that the effluent to be treated needs a flexible process to cope with such variations. One of the properties of the waste water that does not vary is the Z potential of the solution. The post production vegetation waters have a potential value of about ‐30 mV, which defines a stable solution, and the inability of the particles in solution to undertake processes of aggregation and or flocculation. On the basis of this finding it has been studied a treatment that provided for the destabilization of the solution to values of Z potential between ± 5 mV, in such a way as to favor the attraction between the particles in solution and subsequent sedimentation. Once removed the deposit of material, is obtained an effluent easier to treat with the processes of submerged membrane filtration compared to the original effluent. The interaction of the components that cause fouling on the membrane surface was studied using different membranes, which differed in composition of material and pore size. In order to understand the behavior of fouling, three different systems to put in contact vegetation water with membrane surface were used. The three different systems were intended to verify the different contributions to fouling by adsorpition of molecules on the surface of membranes and/or the intrusion of molecules within the pores due to the even minimum values of the hydrostatic pressure of the liquid column which is in contact with the membrane. By means of membrane ultrapure water permeability measurements, before and after contact with the waste water, and by morphological analysis of the surfaces of the same membranes, by atomic force microscopy (AFM), it was possible to define the degree of fouling and the mechanism for‐different‐types‐of‐membranes. The construction of a system immersed membrane system on a banch‐scale was obtained using hydrophilized polymeric hollow fiber membranes. The study of the influence of operating conditions on the efficiency of the process permitted to identify the parameters that make competitive the treatment of vegetable waste by means of immersed‐hollow‐fiber‐microfiltration. The membrane module was constructed with a bandle of about 50 polymeric hollow fibers of polyethylene having 0.4 μm pore diameter and the length of 20 cm. At the base of the module a system for the production of air bubbles was inserted connected to an air line with adjustable flow. The membrane module was installed inside a cylindrical tank with a capacity of 5 L and connected to an adjustable peristaltic pump. The lumens of the hollow fibers is occluded from the upper and immersed in the solution (in which the fibers are free to sway) while it is open from the end secured to the base of the module. The peristaltic pump creates a depression inside the fibers, which promotes the permeation of water through the membrane. A pressure gauge positioned along the connection line between the module and diaphragm pump measured the pressure downstream the fibers. The intent was to find a modus operandi that would allow the system to work continuously at a constant flow for 8 hours (the equivalent of a working day). The operating conditions studied include the influence of the transmembrane pressure, frequency and flow rate of air and the frequency of back‐flushing on the progress‐of‐the‐permeation‐flux‐over‐time. The studies have been conducted with various vegetative waters differing in pH and solids content. Results confirmed that a flexible system for the treatment of vegetative waste water was identified. In fact, the immersed membranes system was efficient in clarifying these waters in terms steady state permeate flux, product quality and reusability. It should be noted that the low transmembrane pressures employed determine a permeate flow through the immersed membranes lower compared to that usually obtained with side‐stream membranes. However, the lower power consumption and less tendency to fouling of immersed polymeric membranes makes the latter competitive for the first stage of water treatment with high pollutant load such as the vegetative waste water.Item Functionalized polymeric membranes for development of biohybrid systems(2016-02-26) Vitola, Giuseppe; Giorno, Lidietta; Drioli, Enrico; Molinari, RaffaeleLe proprietà di superficie di una membrana sono di grande importanza per la sua funzione. Mediante tecniche di funzionalizzazione chimica è possibile ottenere membrane con gruppi funzionali in grado di adempiere nuove e diverse funzioni che rendono la membrana funzionalizzata un dispositivo in grado di svolgere funzioni multiple trovando applicazione in vari impieghi. Le membrane funzionalizzate, infatti, trovano impiego nei processi di separazione, nei settori che richiedono l’uso di membrane biocompatibili, e nell’immobilizzazione di biomolecole che a sua volta trova applicazione nella preparazione di biosensori e bioreattori a membrana. Questi ultimi sono particolarmente interessanti poiché sfruttano l’alta superficie specifica della membrana e permettono di integrare il processo di separazione con quello catalitico. Il presente lavoro di tesi ha riguardato lo sviluppo di membrane polimeriche biofunzionalizzate per la decontaminazione di acque da sostanze tossiche quali i pesticidi organofosfati. Il lavoro è stato focalizzato sullo studio di diverse tecniche per l’ingegnerizzazione di membrane polimeriche aventi differenti caratteristiche chimico-fisiche. L’impatto dei diversi tipi di funzionalizzazione è stato valutato considerando il grado di legame e le proprietà catalitiche di biomolecole immobilizzate sulle membrane funzionalizzate. I polimeri utilizzati per l’immobilizzazione delle biomolecole sono stati il fluoruro di polivinilidene (PVDF) e il polietersulfone (PES), materiali ampiamente usati in sistemi di filtrazione. La proteina sieroalbumina bovina (BSA) e l’enzima lipasi da candida rugosa (LCR) sono state selezionate quali biomolecole modello per lo studio della capacità di legame e le proprietà catalitiche delle membrane ingegnerizzate. Le condizioni ottimali di funzionalizzazione e immobilizzazione sono state poi impiegate per lo sviluppo di sistemi bioibridi contenenti l’enzima fosfotriesterasi (PTE), un enzima in grado di operare la detossificazione di organofosfati. Al fine di migliorare le performance degli enzimi immobilizzati sul PVDF è stato sviluppato un nuovo approccio di ingegnerizzazione. Esso ha riguardato la sintesi di nanoparticelle colloidali a base di poliacrilammide e il loro utilizzo, dopo opportuna funzionalizzazione, come vettori per l’immobilizzazione covalente di enzimi sul PVDF. La nuova strategia di immobilizzazione ha permesso di mantenere il microambiente idrofilo a livello dell’enzima immobilizzato migliorandone di conseguenza le proprietà catalitiche. La strategia allo stesso tempo ha consentito di preservare l’idrofobicità della membrana. Tale proprietà è necessaria per lo sviluppo di sistemi operanti nella decontaminazione di aria. I risultati hanno mostrato che l’enzima fosfotriesterasi immobilizzato sul PES mantiene un’attività residua maggiore rispetto a quella dell’enzima immobilizzato sul PVDF. La membrana biocatalitica in PES è risultata idonea per la decontaminazione di organofosfati in fare acquosa.Item Evaluation of thermal polarization and membrane characteristics for membrane distillation(2014-11-11) Alì, Aamer; Drioli, Enrico; Aimar, Pierre; Bouzek, Karel; Fila, Vlastimil; Molinari, RaffaeleThe current PhD work emphasizes on various aspects of membrane distillation for approaching zero liquid discharge in seawater desalination. In broader sense, two themes have been discussed in detail: (i) correlation between membrane features and their performance in MD (ii) understanding and control of thermal polarization in MD. Introduction and state-of-the-art studies of MD including progress in membrane development, understanding the transport phenomenon, recent developments in module fabrication, fouling and related phenomenon and innovative applications have been discussed in introductory part of the thesis. The effect of operating conditions and dope compositions on membrane characteristics and correlation between membrane features and their performance has been discussed in subsequent section. It has been established that membrane morphology plays a crucial role in performance of the membrane for real applications. Furthermore, it has been demonstrated that the effect of membrane morphology is different for direct contact and vacuum configurations. Theoretical and experimental aspects of thermal polarization in direct contact membrane distillation have also been investigated. Thermal polarization phenomenon in a flat sheet membrane has been studied by using a specifically designed cell. The effect of operating conditions and solution concentration on thermal polarization has been explored experimentally. It has been observed that increased solution concentration favors the thermal polarization due to resulting poor hydrodynamic at the membrane surface and increase in diffusion resistance to the water vapors migrating from bulk feed phase to the membrane surface. Some active and passive techniques to decrease thermal polarization and possible fouling in membrane distillation have also been discussed in the current study. Thermal polarization can be greatly reduced by inducing secondary flows in the fluid flowing inside the fiber. The induction of secondary flows in the current study has been realized by using the fibers twisted in helical and wavy configurations. Due to improvement of thermal polarization coefficient on up and downstream, the undulating fiber geometries provide high flux and superior performance ratio. Application of intermittent and pulsatile flow to control thermal polarization in MD has also been discussed. It has been inferred that these flows have positive impact on performance ratio and volume based enhancement factors without compromising on packing density of the system. The application of MD for treatment of produced water has also been studied. The effect of membrane features on their performance for the treatment of this complex solution has been discussed. The desirable membrane features for successful application of MD for such treatment have been distinguished. It has been inferred that MD possesses the capability to produce a distillate of excellent quality and is an interesting candidate to recover the minerals present in the produced water. The fouling tendency of the membranes with different characteristics towards different types of feed solutions has also been discussed in this study. It has been shown that the porosity enhanced through the introduction of macrovoids in non-solvent induced phase separation technique creates problems related with wetting and pore scaling during practical application of such membranes. The fouling related issues are less severe in the membranes with sponge like microstructure but the overall porosity of such membranes is relatively less. Thus it has been concluded that there should be an optimum between the high throughput and stable performance of the membranes synthesized through phase inversion techniques. Conclusions of the study and future perspectives have been discussed in the last section of the study.Item Preparation and characterisation of polymerisable bicontinuous microemulsion membranes for water treatment application(2013-12-02) Galliano, Francesco; Bartolino, Roberto; Gabriele, Bartalo; Figoli, Alberto; Veltri, LuciaClimate changes, population growth and urbanization are some of the causes of water shortage in many countries of the world. Water is essential to the life of all living organisms and its preservation and responsible use are some of the challenges that humanity will face in the near future. In particular, the possibility of treating and re-using municipal and industrial wastewaters can represent an important solution to water scarcity. Technological breakthroughs have led to the development of a number of technologies that can be efficiently applied in wastewater treatment. Among them, membrane applications are receiving an increasing attention thanks to their versatility, low environmental impact, easy scale-up and high product quality. Aim of this thesis was to produce polymeric membranes obtained through the polymerisation of a polymerisable bicontinuous microemulsion (PBM). Bicontinuous microemulsions consist of an interconnected network of oil and water channels stabilised by a surfactant. Oil channels can be polymerised, forming the membrane matrix, while water channels remain unaffected, forming the pores. In the present work, for the first time PBM membranes were applied, by polymerisation, as coating material for commercial polyether sulfone (PES) membranes. In the first part of the work, the polymerisable surfactant acryloyloxy undecyltriethylammonium bromide (AUTEAB) was synthesised and used for microemulsion formulation. The possibility of using a non-polymerisable surfactant such as dodecyltrimethylammonium bromide (DTAB) was also evaluated. In the second part of the work, novel membranes prepared by microemulsion polymerisation were characterised in order to select the proper membrane with suitable characteristics and properties. Characterization tests carried out on PBM membranes showed the great potential that these membranes could have on wastewater treatment in membrane bioreactor (MBR) applications. In particular, the very smooth surface, the relatively high hydrophilicity and the channel-like structure (typical of the bicontinuous microemulsion) make PBM membranes less prone and highly resistant to fouling. This aspect is the key point if we consider that fouling is one the major drawbacks affecting almost all membrane processes. Fouling is mainly due to the deposition of organic and/or inorganic matter on the surface of the membrane, causing therefore a decline in membrane performance, an increase in energy consumption and (in severe cases) damage of the membrane structure. Furthermore, PBM membranes, due to the presence of a cationic surfactant, present an interesting antimicrobial activity. The possibility of having membranes with antimicrobial properties prevents the phenomenon of biofouling caused by the adhesion and the accumulation of microorganisms at membrane surface. PBM coated membranes were, then, successfully applied to the MBR process for the treatment of wastewater from textile dying. PBM coated membranes, when compared with commercial PES membranes, showed superior results for a long time (6 months) in terms of permeability and dye rejection. Moreover, less cleaning efforts were required leading to lower costs. Novel PBM coated membranes developed can be, thus, also applied to other membrane processes for wastewater treatment.Item Biodegradable polymeric membrane systems for tissue engineering applications(2013-11-12) Messina, Antonietta; De Bartolo, Loredana; Curcio, Efrem; Molinari, RaffaeleItem Graphene and titanium based semiconductors in photocatalytic hydrogen and oxygen generation and hydrogenation of organics also in membrane reactors(2013-11-12) Lavorato, Cristina; Molinari, Raffaele; Argurio, Pietro; Garcia, HermenegildoThe development of graphene (G)-based materials as photocatalysts has become in the last years of high interest due to their sustainability and flexibility in the modification and design, particularly in the field of photocatalytic generation of hydrogen. Carbon based materials are sustainable when they are derived from renewable biomass feedstocks. G is a versatile material allowing different modification strategies to improve its activity. Thus, the present thesis reports that inserting heteroatoms, adding semiconductors or changing the layers size, the activity of the materials prepared can be improved for different applications. Sun light is one of major renewable energy resource. The use of light as driving force for chemical reactions has attracted much attention of organic chemists. Heterogeneous photocatalysis is a discipline which includes a large variety of reactions, in particular hydrogen (considered the perfect renewable energy source in the future) and oxygen generation from water and hydrogenation of multiple bonds are the target of this PhD thesis. Photocatalytic reductions represent an alternative to conventional catalytic hydrogenation and it represent a more sustainable method to synthesize organic compounds under mild conditions in the presence of affordable photocatalysts. Photocatalytic processes in membrane reactors represent a technology of great scientific interest because it allows chemical reactions and separation processes to be accomplished in one step, which in turn results in lower processing cost and minimum environmental impact. The preparation and characterization of G-based semiconductors has been carried out in the first part of the Thesis and their photocatalytic activity for hydrogen and oxygen generation from water was determined in the second part. Graphite was oxidized to graphene oxide (GO) and its photocatalytic activity for hydrogen generation from water/methanol mixtures with visible or solar light was enhanced by the presence of dyes, in the absence of any noble metal. The most efficient tested photocatalyst was the one containing a tris(2,2-bipyridyl) ruthenium(II) complex incorporated in the interlayer spaces of a few layers of GO platelets with a moderate degree of oxidation. This photocatalyst was two orders of magnitude more efficient than a titania based photocatalyst containing Au, when the reaction is performed under 532 nm laser as excitation light. Doping G with nitrogen by pyrolysis of chitosan leads to a material that behaves as a semiconductor and exhibits high efficiency for the photocatalytic generation of hydrogen from water-methanol mixtures with similar efficiency using UV or visible light. This similar photocatalytic activity wis due to the fact that, in contrast to GO, N-doped G exhibits an almost “neutral” absorption spectrum. The main parameter controlling the residual amount of nitrogen and the resulting photocatalytic activity is the pyrolysis temperature that produces an optimal material when the thermal treatment is carried out at 900 °C. Furthermore, N-doped G was able to generate hydrogen also upon illumination of simulated sunlight. The use of G as co-catalyst of metal oxides semiconductors to enhance their photocatalytic activity has been extensively reported. Using alginate, a natural polysaccharide from algae, simultaneously as G precursor and as ceria nanoparticles template agent, a series of materials consisting of highly crystalline ceria nanoparticles embedded on a few layers G matrix has been prepared. Varying the weight percentage of ceria/alginate and the pyrolysis temperature, it was possible to prepare a ceria/G photocatalyst that exhibits about three times higher photocatalytic activity for water oxidation to oxygen than commercial ceria. Pyrolysis at 900 °C under inert atmosphere of alginate renders a graphitic carbon that upon ablation by exposure to a pulsed 532 nm laser (7 ns, 50 mJ pulse−1) in acetonitrile, water, and other solvents leads to the formation of multilayer graphitic quantum dots. The dimensions and the number of layers of these graphitic nanoparticles decrease along the number of laser pulses leading to G quantum dots (GQDs). Accordingly, the emission intensity of these GQDs increases along the number of laser shots, the maximum emission intensity appearing at about 500 nm in the visible region increasing in intensity along the reduction of the particle size. Transient absorption spectroscopy has allowed detection of a transient signal decaying in the microsecond time scale that has been attributed to the charge separation state. During the second part of the present thesis the photocatalytic hydrogenation of acetophenone by using titanium based semiconductors in batch and membrane reactors under UV and visible light has been studied. Different photocatalytic tests have been performed using ethanol or water and formic acid in a batch reactor in order to optimize the reaction parameters before to be applied in membrane reactors with different substrate addition mode. The use of a membrane reactor system for the photocatalytic hydrogenation of acetophenone in water solution with formic acid as hydrogen and electron donor was found to improve the efficiency of the photocatalytic system with respect to the use of batch reactor. The most efficient system for photocatalytic hydrogenation of acetophenone in terms of productivity, amount of phenylethanol produced and extraction of desired product was found to be the membrane reactor in which acetophenone was used as both organic phase and substrate. The presence of palladium enhances the visible light photocatalytic activity of TiO2 photocatalyst, that is not active alone. The productivity by using Pd/TiO2 photocatalyst under visible light increases five times more than using TiO2 under UV lightItem Development of membrane bioreactor (MBR) process applying novel low fouling membranes(2013-11-12) Deowan, Shamim Ahmed; Drioli, Enrico; Molinari, Raffaele; Figoli, Alberto; Hoinkis, JanWater is a part and parcel of human life. Water contaminated from industry and agriculture with heavy metal ions, pesticides, organic compounds, endocrine disruptive compounds, nutrients (phosphates, nitrates, nitrites) has to be effi-ciently treated to protect humans from being intoxicated with these compounds or with bacteria. Clean water as basis for health and good living conditions is too far out of reach for the majority of the population in the world (Bionexgen, 2013). Water recycling is now widely accepted as a sustainable option to re-spond to the general increase of the fresh water demand, water shortages and for environmental protection. Water recycling is commonly seen as one of the main options to provide remedy for water shortage caused by the increase of the water demand and draughts as well as a response to some economical and environmental drivers. The main options for wastewater recycling are industri-al, irrigation, aquifer recharge and urban reuse (Pidou, M., 2006). Among the industrial wastewaters, the textile industry is long regarded as a water intensive sector, due to its high demand of water for all parts of its pro-cedures. Accordingly, textile wastewater includes quite a large variety of con-tents, chemicals, additives and different kinds of dyestuffs. The main environ-mental concern with this waste water is about the quantity and quality of the water discharged and the chemical load it carries. To illustrate, for each ton of fabric products, 20 – 350 m3 of water are consumed, which differs from the color and procedure used. The quality of the textile wastewater depends much on the employed coloring matters, dyestuffs, accompanying chemicals, as well as the process itself (Brik et al., 2006). MBR technology is recognised as a promising technology to provide water with reliable quality for reuse. It provides safely reuse water for non-potable use. But the treated textile wastewater by MBR technology alone can’t comply with the reuse or discharge standard in many countries due to its colouring matters and dyestuffs remained in the effluent, if otherwise, MBR is associated with other technology like NF, RO, other processes or the applied membrane is modified or a novel MBR is applied. Fouling is another limiting factor for worldwide application of MBR technology especially in high-strength industri-al wastewater like textile wastewater. Moreover, membrane fouling is regarded as the most important bottleneck for further development of MBR technology. It is the main limitation for faster development of this process, particularly when it leads to flux losses that cleaning cannot restore (Howell et al. 2004). In this thesis work, a novel membrane bioreactor (MBR) process was devel-oped by modifying a applied commercial PES UF membrane in MBR module by nano-structured novel coating through polymerisable bicontinuous micro-emulsion (PBM) process with the purpose of having higher hydrophilicity and low fouling propensity. Before starting the MBR experiments, some characteri-sation tests such as SEM, AFM images analysis, roughness measurements, pore geometry, contact angel, standard salt rejections, model textile dye rejec-tions were performed. In addition, fouling tests using two laboratory cross flow testing units were conducted as well. To reach the ultimate goal of research, 6 sheets of novel coated membranes with size of 30 cm × 30 cm were prepared and these were used to prepare a three-envelope MBR module of 25 cm × 25 cm in size (total membrane area 0.33 m2) similar to that of a commercially available three-envelope PES UF MBR module. This novel MBR module was tested in a submerged lab-scale MBR pilot plant (tank volume ca. 60 L) for about 6 months using model textile dye wastewater (MTDW) as test media for all experiments with the aim of having uniform compositions with respect to time. The tests were done based on carefully selected operation conditions. Prior to testing of the novel membrane module MBR, experiments were carried out with a commercial PES UF MBR module using the same pilot plant set up and the same selected operating conditions for about 10 months. After comple-tion of trials with the novel coated MBR module, similar experiments were carried out again with a commercial PES UF MBR module to check the simi-larity of the biological sludge conditions and other operation conditions as well. In short, the sequences of the experiments were as follows: Commercial PES UF MBR (10 months) →novel membrane coated MBR (6 months)→PES UF MBR (1.5 months) The ultimate goal of the experiments was to compare the results between the commercial MBR and novel coated MBR module in order to demonstrate im-provement regarding fouling propensity and permeate water quality. The performance analysis shows that the novel coated MBR module compared to the commercial MBR module has 7% points higher COD removal efficien-cy, 20% points higher blue dye removal efficiency, high antifoul-ing/antimicrobial properties, resulting in a very low-fluctuating and highly ro-bust MBR process which looks promising with regard to economic viability. Since the newly developed MBR module worked excellent on laboratory scale it consequently should be deployed at an industrial site to be tested with real ii wastewater. Therefore, this novel three-envelope MBR module is on the way to be tested with real wastewater in a textile factory in Tunisia. The findings of these on-site pilot trials will serve as a basis for further improvement and even-tually pilot trails with larger membrane area will be addressedItem Total and parial oxidation reactions in photocatalytic membrane reactors(2008-11-11) Caruso, Angela; Molinari, Raffaele