A.A. 2022-23
Research activity in the Academic Year 2022-23 of PhD students is below briefly summarized.
As regards to the activity of students at their first year (38th cycle):
- The research activity developed in this first year of the PhD on “Calcium batteries: a “New challenge”” involved two steps. (i) Electrochemistry of Calcium Ions in Aprotic Electrolytes. Preliminary studies were conducted on two intercalation materials, specifically analogs of Prussian blue and anatase nanotubes. These materials were synthesized and experimentally and characterized using chemical-physical and electrochemical techniques. In addition to evaluating the electrolytes, alternative strategies to replace metallic calcium were explored, such as the utilization of pseudocapacitive cells. Two research manuscripts have been drafted and will be submitted for publication in the near future. (ii) Development of New Aprotic Electrolytes (NAE) for Calcium-ion Batteries. The primary objective of this activity was to identify new formulations of aprotic electrolytes (aprotic solvents, aprotic Ca salts, and additives) and to characterize them chemically and physically, including thermal properties, conductivity, and electrochemical stability window. Particularly, two innovative calcium salts, CaB12H12 and Ca-FPB, were synthesized during this step. One research manuscript has been drafted and will be submitted for publication in the near future.
- As part of the industrial PhD thesis “Chemical-physical and biological remediation processes combined with hydraulic groundwater handling systems”, two lines of work in parallel were carried out. The first area of work concerned the monitoring and analysis of chemical and hydraulic data on the contaminated sites of Manfredonia, Gela and Livorno in order to calibrate and optimize the remediation work in progress. A collaboration in the drafting of technical documentation on the Manfredonia, Gela and Ferrandina sites (work progress reports, instruction manual for plant use and maintenance, Front End Engineering Design) was also carried out. A second area of work concerned the study of literature and laboratory tests on the possibility of distributing materials in groundwater for contaminants’ immobilization. Specifically, the work aimed at the formulation of a colloidal suspension containing biochar stabilized with biopolymers and biosurfactants for the in-situ adsorption of organic contaminants.
- During the first year of the doctoral program on “Stochastic modeling of intracellular biochemical processes with applications to lipid nanoparticles' transport and reaction”, the following activities were carried out: 1. Introduction to Stochastic Analysis of Biological Processes: study of the literature and developed a formalism in terms of derivatives of Poisson processes for the mathematical representation of processes. 2. Introduction to Anomalous Transport Analysis: study of the anomalous diffusive processes and the relationship between mean square displacement and Gaussianity. 3. Laboratory work at the Faculty of Pharmaceutical Technologies: preparation and characterization of liposomes using the thin-film technique and extrusion. 4. Collaboration with the Faculty of Medicine and Pharmaceutical Technologies and Techniques: analysis of the effects of valproate (with and without liposomes) on the vitality of tumor cells.
- In the framework of the thesis: “Polymeric cryogels and extrusion-based 3D bioprinting”uring the first year of research an accurate bibliographic research on both polymeric cryogels and bioinks was carried out as well as laboratory activities. Regarding the research activity focused on these polymeric scaffolds, cryogels based on dextran methacrylate were prepared and optimized. These highly elastic and porous polymeric structures can be used both for the modified release of drugs and as scaffolds for 3D cell cultures. The research activity involved the study of the cross-linking kinetics of these systems, optimizing the ratio of millimoles of reactant/millimoles of methacrylic groups. The obtained cryogels were subjected to in-depth mechanical and morphological characterization. Release studies were carried out using vitamin B12 as a model molecule. The resulting release data, although preliminary, show clearly an "anomalous" behaviour characterized by a non-Fickian scaling at short/intermediate time scales, attributable to a complex interaction between microporous and macroporous zones that characterize the cryogels. These data will be subjected to modeling in the second year of activity. As regards extrusion-based 3D bioprinting, the work was centered on the formulation, optimization and rheological characterization of bioinks based on methacrylate gelatin and gellan gum using laponite as a thickening agent. These bioinks were used for printing polymer scaffolds and for the development of salivary swabs, with promising results.
- The activity on “Valorisation of waste biomasses via thermochemical processes: optimization of yield and quality of the biocrude obtained from Hydrothermal Liquefaction for the production of an advanced biofuel” was initially focused on hydrothermal liquefaction of cellulose, egg albumin and sunflower oil as model compounds of carbohydrates, proteins and lipids respectively, that are the main macro-components of waste biomasses as secondary sewage sludge from wastewater treatment plants and food wastes. The first part was of such activity was focused on the study of the interactions between those compounds and their effect on the yield and composition of the obtained bio-oil and solid residue, which resulted in a lecture at the ICheap16 conference of may 2023 and in a publication in “CET” journal. A second part was focused on the effects of the heating rate on the yield and composition of the products, which resulted in a paper submitted to “Fuel” journal. Moreover, in collaboration with Federico II university of Naples, the bio-oil production from hydrothermal liquefaction of an agricultural waste and two secondary sludges, from municipal and paper mill facilities is under investigation. This collaboration resulted in a participation with an extended abstract at the conference “Proceedings of the Belgian and Italian Sections of the Combustion Institute, 2023”.
- During this year experimental tests on methane cracking have been carried out, analyzing the conversion of reagent, the formation of benzene and PAHs and the characteristics of carbon obtained by varying the operating parameters. The tests were conducted in quartz tubular reactors introducing methane via capillary (dcap= 0.25 mm). In particular, the effect of temperature in the range T = 875 - 1070 °C and the methane inlet flow rate (QCH4,0= 30 - 60 mL/min) were studied. The conversion was studied downstream of the reactor using a mass spectrometer (QGA - Hidden); the study on carbon precursors was conducted by injection into GC/MS and GC FID of gas samples taken at the reactor exit. The process was conducted in two different types of systems: in empty reactors and in reactors filled with molten Tin. This was used for the purpose of heat exchange improvements and in order to optimize (thanks to density difference) the separation of the carbon product. The experimental results were subsequently compared with detailed kinetic simulations well-known in literature for the description of the processes of soot formation in flames, shock tubes and deposition of carbon on surfaces (CVD - Carbon Vapor Deposition). The experimental results were satisfactorily consistent with those predicted by the models. The highest conversion was achieved at the highest temperature (approximately 65% at 1070 °C) and for the lowest flow rate, i.e. longer mean residence time. Residence time was found to be a fundamental parameter for the preliminary comparison between the process conducted in an empty reactor and that one in the molten metal. The carbon obtained through the latter was found to be morphologically different from that obtained in empty reactors: this probably because of the way it is formed. In fact it would seem that carbon is formed at the interface of the bubble with the fluid metal surface and takes on a shape sheets that distinguishes it from that deposited on the walls of the reactor (pyrocarbon) and from that originating in the gaseous bulk (aggregated spheres).
- The research activity developed in this first year of the PhD “Development of a novel-continuous feeding process for the production of polyhydroxyalkanoates (PHAs) with mixed microbial coltures (MMCs) focused on the optimization of the main operating parameters of an innovative continuous process for the production of biopolymers (i.e., polyhydroxyalkanoates, PHAs). The PHA production with MMC requires a microbial selecton stage, obtained setting up the “feast and famine” conditions, which consist of the alternance of excess and lack of carbon external source. These conditions are conventionally established in a Sequencing Batch Reactor (SBR) in which the feast and famine phases are temporally separated. In this novel process, there is a spatial separation instead. This approach considerably allows to simplify the operating assessment and to improve the economy of the process. More specifically, during the first year, two operating parameters, identified as key parameters, the Organic Load Rate (OLR) and the Recirculation factor (Rc) were studied and optimized. The recirculation factor is defined as the ratio between the volumetric flow rate of recirculation (Qr) and the volumetric feeding flow rate (Qe). The tested conditions were at the values of 4,250 gCOD/Ld and 8 for the OLR and Rc respectively. The results showed that this combination between the two key parameters is the best tested until now in terms of PHA intracellular content, which after the accumulation batch tests, reached a value around 80% (wt,wt).
- In the framework of the thesis project: “Valorization of phosphogypsum (PG) containing rare earths by hydrometallurgical processes: process optimization at laboratory scale and validation at pilot scale”, a thoroughly literature review focused on getting essential insights regarding the recovery of Rare Earth Elements (REE) from phosphogypsum waste was conducted. Building on this knowledge foundation, the upcoming plan involves simulating and optimizing an innovative and economically viable method in the laboratory that will also be validated at pilot scale. The main activities performed are as follows: 1. Conducting an extensive literature review on REE recovery from phosphogypsum waste. 2. Extract key insights and methodologies from existing research. 3.Formulation of an innovative REE recovery approach based on literature findings. 4. Analysis of potential challenges and devised strategies to overcome them. 5. Setting up a sustainable and efficient REE recovery process. 6. Preliminary feasibility assessments considering both technical and economic aspects.
As regards to the second year (37th cycle) students activity:
- During the second year of the thesis: “Green hydrogen production through molten carbonate electrolysis”, in the first part of the year, the 2D model of an MCEC developed the previous year was completed. Model predictions were compared with experimental data provided by the ENEA Casaccia research center (RM) to assess its ability to accurately describe the cell's behavior. The model proved effective in describing both the relationship between applied voltage and current flow and the composition of the outlet gas. From February to July, experimental activities on MCECs at the ENEA laboratories was carried out, aiming to perform a detailed parametric study of the chemical and physical phenomena influencing the cell's operation under steady-state conditions. Electrochemical performance were evaluated using galvanostatic polarization tests and impedance spectra. Two different experimental setups were employed: 3 cm2 button cells with reference electrodes, providing electrochemical data for both the entire cell and individual components, and planar cells of 100 cm2, in which we were able to analyze gas composition both entering and exiting the anodic and cathodic compartments. Impedance spectra obtained for the button cell were deconvoluted using the Distribution of Relaxation Times (DRT) technique to identify the primary processes affecting cell performance.
- In the context of the thesis: “Development and characterisation of a bioelectrochemical reactor for the simultaneous treatment of oxidisable and reducible contaminants from contaminated groundwater”, the PhD work in the second year was focused on the development and optimization of a MET prototype for the treatment of groundwater containing complex mixtures of oxidizable and reducible contaminants. While during the 1st year, the treatment of synthetic groundwater containing toluene and chlorinated solvents (i.e., trichloroethylene or chloroform) was successfully investigated, in the 2nd year theresearch work has addressed the challenging issue of groundwater contamination by toluene and heavy metals (i.e., copper). Through the application of a comprehensive suite of experimental approaches as well as analytical, microscopy and biomolecular techniques, the proposed MET-based approach allowed the simultaneous anodic bioelectrochemical oxidation of toluene and cathodic (abiotic) electrodeposition of copper in the form of CuO. In a follow-up investigation the viability of METs in the treatment of a “real” groundwater from a petrochemical site containing a hard-to-degrade compound (i.e., dichlorodiisopropyl ether, DCIPE) along with aromatic and chlorinated hydrocarbons was investigated. However, due to the recalcitrance of DCIPE to biodegradation, it is under evaluation the possibility to develop a combined process, including an initial Electro-Fenton oxidation step.
- In the context of the thesis: “Decarbonization of hard-to-abate sectors: testing, simulation and CFD analysis of pre- and post-combustion CO2 reduction and sequestration methods “, the research activity conducted has focused on studying solutions to decarbonize "hard to abate" sectors. In particular, innovative process schemes have been analyzed from an energy, economic, and environmental perspective, with the aim of producing alternative steel using green methods. A model of a direct reduction furnace for the production of iron sponge has been developed. The model is based on a kinetic approach and has been validated with plant data. The model allows for the assessment of the impact of using reducing agents obtained from different sources and the integration of a CO2 capture plant into the process. In detail, the use of syngas from methane reforming, syngas and hydrogen from municipal solid waste gasification, and hydrogen from water electrolysis have been analyzed. Furthermore, in collaboration with the Max Planck Institute, an experimental study on steel production through hydrometallurgical process has been initiated.
- During the second year of PhD on Characterization of different synthetic and natural surfactants for applications in contaminated aquifers remediation using SEAR (Surfactant Enhanced Aquifer Remediation) technology, the experiment activity regarded the evaluation of surfactants ability in mobilization of organic pollutants form real polluted matrices, in the operative context of SEAR (Surfactant Enhanced Aquifer Remediation). In particular, the investigated matrix is a marine sediment affected by and historical contamination of polycyclic aromatic hydrocarbons (PAHs) with an advanced state of aging in which there is an immobile residual fraction of contaminants with a high persistence. Used surfactants are non-ionic, both synthetic and natural surfactants, belonging to alkyl-polyglucosides (APGs), sophorolipids (SLs) and rhamnolipids (RLs) families. The study has been started with a series of batch experiments to evaluate the performances of each surfactant in PAHs removal for the sediment through a screening of several experimental conditions (multiple washes, surfactants concentration, temperature). Based on the results, the optimal operative conditions for PAHs mobilization were selected and a sediment flushing process was simulated by a setting up a continuous configuration column test in order to evaluate the effective surfactant’s ability to mobilize PAHs.
- In the context of the PhD project focused on the development of a bioelectrochemical process for the conversion of CO2 into acetate, during the second year, in chronological order, an enriched mixed culture obtained in the 1st year was tested, under bioelectrochemical conditions in typical H reactors. The study was conducted continuously, setting an HRT based on the kinetics of the microorganisms of interest (acetogenic ), to evaluate the efficiency of the process in terms of overcoming competitions with competing organisms (methanogens). The study was conducted at two cathode potentials (-0.7 V and -0.9 V vs SHE) and, furthermore, the effect of bioaugmentation, i.e. the addition of a pure culture in the inoculum, was evaluated. Subsequently, preliminary studies of pure cultures of extremophiles, i.e. an alkalophile and a haloalkalophile, capable of growing under extreme growth conditions in terms of salinity and pH were carried out. The study was conducted in batches both in hydrogenophilic conditions, i.e. in serum bottles in which hydrogen was manually inserted into the headspace, and in bioelectrochemical conditions, at a cathode potential of -0.9 V vs SHE. In parallel, an estimation of the kinetic parameters of the biomass used for the experiments using Matlab as programming software, was performed. The objective was to develop simple mathematical models that allow us to predict the competition between acetogens and methanogens, and optimize the process once the kinetic parameters have been estimated. Finally, the last experimental activity was carried out in the Netherlands, at the TU Delft university, for a period of 7 months (April-November). The experimental work consisted of the study of four continuous laboratory-scale reactors, at controlled pH and temperature, evaluating the effect of the thermal treatment of the inoculum and the co-presence of organic substrates for the start-up phase.
- In the context of the thesis: Inorganic Nanostructured materials for environmental and biomedical Application”, during the second year of my PhD studies, I engaged in an in-depth review of literature and bibliography focusing on nanomaterials and nanofibers fabrication using diverse techniques, notably electrospinning. Additionally, practical applications involved the utilization of a Spinning Disc Reactor for producing inorganic composite nanostructured oxides, particularly for environmental applications such as organic dye and antibiotic degradation.
- During the 2nd year of the PhD work on “Innovative electrochemical processes for methane upgrading”, the research activity was carried out from January to March in Sapienza’s labs supervised by Prof. Marianna Villano, then from April to October, at “Le Laboratoire de Gènie Chimique” supervised by Dr. Bejamin Erable, Toulouse (France).
During the first period in Rome, I studied the performance of two different cathode electrode materials in a microbial electrolysis cell (MEC) aimed at upgrading biogas to biomethane. The reactor consists of a two-chamber continuous MEC. The oxidation of COD occurs at the anode which provides part of the reducing power necessary for the production of H2 at the cathode. H2 produced at the cathode is used by hydrogenophilic methanogenic microorganisms for the biological reduction of CO2 to CH4. To optimize the process two different cathode electrode materials were tested: stainless steel and mixed metal oxides. Furthermore, the effect of MOFs (Metallic Organic Frameworks) in the storage of H2 and consequent transformation into CH4 in the presence of hydrogenophilic methanogenic microorganisms using CO2 as a substrate was investigated. During the six months spent abroad at “Le Laboratoire de Gènie Chimique (LGC)” in Toulouse the effect of different electrode materials (graphite, “foaming” stainless steel, carbon felt and carbon brush) in combination, or not, with magnetite was studied. The materials were tested for 1) the formation of a bio-anode in a single-chamber MEC for the acetate oxidation reaction and 2) as a cathode in a single-chamber MEC for the hydrogen evolution reaction (HER). In both cases the addition of magnetite at different concentrations was tested. Furthermore, I applied several electrochemical techniques based on the study of capacitive and faradic currents to determine the difference between the electrochemically accessible surface electrode area (EASA) and the projected electrode surface area (PSA) of the above-mentioned materials.
- As part of the project "Conversion of plastic waste into biopolymers", the aqueous residual fraction from hydrothermal liquefaction (HTL) of polymers such as: cellulose, polyurethanes and PET, also identified as the single components mostly characterizing the mixture of waste resulting from the mechanical recycling treatments of plastic (better known as Plasmix), have been tested for their biodegradability. This, in particular, has been tested with mixed microbial cultures (MMCs) under either aerobic conditions to obtain polyhydroxyalkanoates, or under anaerobic conditions (trough acidogenic fermentation tests) to obtain organic acids. In addition, at the Instituto de Agroquímica y Tecnología de Alimentos (Spain), the possibility of creating new materials consisting mainly of a commercial poly (3-hydroxybutyrate-co-3-hydroxyalerate) and Plasmix, was investigated with this latter used as filler in compositions from 1% up to 10% (on weight basis), so as to reduce the market cost of the biological polymer.
- In the second year of the work on „Sustainable green process to extract bioactive compounds from food byproducts and whole cells with natural atoxic solvents”, the aim of the research was to obtain and divide biological fractions present in biomass of microalgae, focusing on fractionation of major classes of compounds in a possibly simple and sustainable way, using nontoxic solvents, with respect to the principles of Green Chemistry and Green Engineering. Using previously screened and tested methodologies, the work was focused on processes of extraction of high value biomolecules from chosen microalgal biomasses: Arthrospira platensis and Haematococcus pluvialis based on utilization of switchable solvents for efficient extraction and separation of the fraction of interest. Experimental work was performed partially at the Department of Chemical Engineering Materials Environment and continued during the research period abroad in the company Algreen B.V. from Wageningen, The Netherlands.
- In the context of the work on “Immobilization of industrial lipases on graphene oxide nanosheets for biodiesel production”, the use of graphene oxide (GO) nanosheets as a promising nanomaterial for the covalent immobilization of commercial lipases for the realization of a biocatalyst of industrial interest was investigated. To this end, Candida rugosa lipase (CRL) was covalently immobilized with an EDC/sulfo-NHS coupling system on amine-functionalized graphene oxide (GO-NH2) (CRL@GO-NH2). The GO based nano-supports have been characterized by thermogravimetric analysis and Fourier transform infrared spectroscopy (FTIR) which show a high resistance to high temperatures and a correlation between the catalytic behavior of the immobilized enzymes with the α-helical content, respectively. The obtained CRL@GO-NH2 exhibited an improvement in esterase activity with an immobilization efficiency of 89 %, under the optimal conditions. Finally, biocatalyst was employed in the transesterification reaction from POME (palm oil mill effluent) in the presence of methanol (or ethanol) for the production of biodiesel and glycerin as a by-product.
- The research activity conducted during the second year of the Ph.D. program on “Simulation, CFD modelling and advanced control of innovative waste-to-chemicals plants in the circular economy: Gasification of Refuse Derived Fuel” was focused on modeling thermochemical processes for waste and biomass treatment. In particular, the modeling study of the gasifier continued, based on technology licensed by NextChem, through the development of a one-dimensional fluid dynamic model. This model was also implemented in the simulation software Aspen Custom Modeler to create a model that could be used for co-simulation with Aspen Plus in an integrated flowsheet. To complete the gasifier modeling, a 3D model of the upper section of the reactor is currently under development. Furthermore, during the research period at the University of Glasgow (UOG, Scotland), an experimental study was conducted on the pyrolysis of lignocellulosic biomass, plastics, and RDF. Finally, during the second year of the Ph.D. program, a simulation study was carried out on the modeling of reaction mechanisms for the formation of dioxins and furans (chlorinated pollutants and toxic compounds) in a reducing environment, typical of thermochemical treatment processes such as gasification and pyrolysis.
- In the context of the thesis on: “Development of in situ treatment processes for the sustainable remediation of groundwater contaminated by PFAS”, During the second PhD year (January-November 2023), the research activity concerned the prosecution of adsorption tests on waters added with Per- polyfluoroalkyl substances (PFASs) using a biochar derived from date seeds, setting batch tests already carried out for the other adsorbent materials previously selected (pinewood biochar, graphene). Subsequently, adsorption tests were carried out using a flow-through column configuration, in order to obtain greater robustness of the experimental data. In this type of experimental set, columns were packed with date seeds biochar together with an inert material (glass sand), in which water contaminated by PFAS was constantly recirculating. In the last period, the research activity has focused on the study of the date seeds biochar functionalization in order to increase its adsorbent capacity towards the selected PFAS substances, especially for the short-chain ones which have demonstrated a lower adsorbent-adsorbate interaction.
- In the framework of the thesis: “Eco-sustainable processes for the production of monomers for synthesis of innovative biodegradable polyesters, with particular reference to PBS (polybutylene succinate)”, on this year, the zero-waste HTL experimentation tests performed on the catalytic activity of red mud (RM) in pinewood liquefaction reactions, by recycling both the water and solid phases at the laboratory of the chemical engineering department. Tests were performed on reduced RM (RRM), as-received (FRM) and calcinated RM (CRM) samples. The recycling of both the water solid phase (WP) in HTL tests with the RRM and CRM for consecutive runs demonstrated that the proposed strategy maximizes the bio-crude yield (increasing 20% compared to the test without recycling). Also, the amounts of inorganics and especially Fe includes in RM samples immigrated to the oil, water, and solid phases were detected. Among the red mud tested, the highest Fe concentration in liquid phases was recognized with RRM. The results are under review in a peer review journal. Moreover, in the second part of the year, the experimental data were used to simulate an Aspen plus model and initial results presented in an AIDIC conference. Thereafter, the techno-economic analysis (TEA) of the process to produce biofuel equivalent carried out. Two schemes were designed in the Aspen plus simulation model. The first scheme involves the integration of co-units, producing the required H2 from the by-products of HTL reaction for hydrotreating of the bio-oil. In the second scheme, the required H2 was purchased from an external source. The TEA analysis was conducted to identify the minimum fuel selling prices (MFSP) of two proposed schemes. The MFSP for first and second schemes confirmed that the profitability of first scheme compared to second one.
- In the context of the thesis “Development of methodologies for the remediation of contaminated sites following accidental events, including significant ones, relating to lithium batteries“, based on the experimental tests carried out in November 2022, regarding the fire extinguishing of lithium-ion batteries, data processing and chemical analyzes of the samples found were carried out. In particular, the data processing was completed with the writing of an optimization model aimed at calculating the most efficient extinguishant among the various tests performed. Regarding the chemical analyzes of the post-test liquid and solid residual samples, the Gas Chromatograph-mass spectrometer instrument was used for the purpose of qualitative identification of any volatile compounds present. This analytical phase was carried out at the Chemistry laboratory of the National Fire Brigade of Rome Capannelle. In April 2023, a new experimental campaign was carried out, again regarding the fire extinguishing of lithium-ion batteries. Data processing and chemical analysis activities of the collected samples followed. In particular, these experimental tests involved the sampling of the fumes produced by the fire via an extraction and storage system in Bag gas. The sizing of this system was carried out in the weeks preceding the experimentation. Subsequently, tests were conducted using a DSC instrument on samples of lithium ion cells. The experimentation involved the opening of these cells, in an inert atmosphere, and the study of samples taken from the cathode, anode and separator of the cell. This study was conducted in order to determine and understand the thermal behavior of the components of lithium ion cells, "pouch" type. Between August and November 2023, the first period of working activity abroad was completed at the DTU in Copenhagen. In this period, a laboratory prevention and safety course was carried out, the test procedures were written, the experimental activities were programmed, and familiarity was acquired with the instrumentation to be used (in particular the H-tris instrument, with all the attached extraction system, and the Combusted Gas Analysis tool for calculating the Heat Realease Rate). The experimental activity carried out in the months of October and early November involved the study of the thermal behavior of lithium ion cells subjected to radiation produced by H-tris.
As regards to the third year students (36th cycle) activity:
- In the framework of the thesis: “Development of strategies in order to control contamination in heterotrophic microalgae cultures “, during the last year multiple simulations with MATLAB have been carried out, using the new hybrid growth model for non-axenic microalgal cultures, developed in the previous year. In these simulations, three inputs were varied: initial biomass concentration, maximum fattening factor and contamination ratio. Then, four outputs have been analyzed: total biomass productivities, total produced biomass, process duration and efficiency in the use of glucose by microalgae. Then, a validation experiment has been conducted in the best conditions identified with the simulations. Other than that, six months have been spent in Wageningen University & Research, where the heterotrophic cultivation of Gladieria sulphuraria has been studied, on different sugars: glucose, fructose, glucose + fructose and sucrose. Exponential growth rate, volumetric productivity and yield were determined on each sugar. Since Galdieria sulphuraria is an extremophile, these studies will provide useful information to evaluate the integration between its cultivation and the wastewaters treatment.
- As regards to the thesis on “Evaluation and Optimization of technologies for treatment of contaminated sites (SIN) with advanced Target and Non-Target analytical techniques”, in the third year, after finishing the characterization of 8 different surfactants (synthetic or natural, but both biodegradable) through preliminary, washing and concentration tests, a new study, by varying the temperature (Room Temperature, 40°C, 50°C and 60°C) of a water bath, was conducted to evaluate if changing the temperature there is an enhancing in water solubility of Polycyclic Aromatic Hydrocarbons (PAHs) from the marine sediment. Later, three column tests in continuum were conducted to simulate a soil-flushing process and evaluate the mobilization capacity of our surfactants on PAHs in a different experimental setup. Two solutions, one with APG2 (Alkyl polyglucoside) and the other with SL (Sophorolipid), both at 1% w/w, were used because of they resulted to be the best synthetic and natural surfactant in the previous experiments in batch.
- In the context of the thesis: “The use of SDR technology for the production of nanoparticles of industrial interest”, the research activity developed during this year involved a first phase of producing nickel ferrite nanoparticles using the Spinning Disc Reactor (SDR). More in detail, the operating parameters of the disc that influence the size and size distribution of the particles were studied. The size of such particles also influences other properties such as magnetic, optical and active surface. The photocatalytic activity of the produced particles was tested against methylene blue solutions in different concentrations and illumination conditions, and also against an antibiotic (tetracycline) whose concentration in wastewater has increased in recent years. The same reactor was used for the synthesis of liposomes used to evaluate the encapsulation efficiency of a drug and its comparison with the same samples obtained using a microfluidics system. Long-term stability was also evaluated. Again, the dependence of the size of vesicular structures on operational parameters was investigated, and also the lipid composition was optimized.
- The final year of the PhD study on “ Plastic waste management and conversion into biofuels and valuable chemicals through thermochemical reactions involving hydrothermal liquefaction and pyrolysis”, can be divided into two parts. In the first part, I studied the depolymerization of different types of polyurethane to obtain chemicals for reuse in new polyurethane production. I also investigated the effects of temperature and ethanol as a co-solvent in this process.
The second part of the study focused on mixed plastic waste. The aim of this project was to develop a sustainable method for managing plastic waste, as separating mixed plastics can be prohibitively expensive. Initially, we conducted a systematic study to obtain a clear understanding of pure plastics. Subsequently, we expanded the scope of the study to include real-world mixed plastic waste. Based on existing knowledge, the most effective approach involves an HTL pretreatment step to remove impurities and obtain pure polyolefins. These polyolefins are then pyrolyzed to produce higher quality oil. Notably, the water phase from the HTL process was used for microbial fermentation to achieve polyhydroxyalkanoate (PHA).
- During the third year of the thesis focused on the development and analysis of the techno-economic feasibility and carbon footprint of process schemes aimed at the valorization of waste streams through pathways belonging to the waste-to-energy and waste-to-chemical philosophies., two completely innovative process cycles were developed and analyzed. As a result of the studies conducted in the first two years, focused on comparing the two philosophies, it was possible to assess that the waste-to-chemical philosophy seems to have more advantages, both economically and environmentally. Therefore, the last year was devoted exclusively to developing process cycles from this strand. The first study involved the recovery of bioactive compounds from waste coffee grounds, with the simultaneous production of green hydrogen through a solid oxide electrolyzer. As part of this work, first a simulation was conducted of the entire process in the Aspen Plus environment, so as to highlight the technical feasibility of the process, and then conducted energy, exergy, economic and carbon footprint analyses, so as to analyze the impact this process could have in the current energy transition scenario. In this work, in fact, the two waste-to-energy and waste-to-chemical pathways are integrated into one completely innovative process cycle. Each equipment was simulated and evaluated to estimate the OpEx and obtain the outputs needed to solve the material, energy, exergy, and carbon balances.
The second study examined the production of biodiesel, green hydrogen and pyridine through an innovative process of gasification of municipal solid waste using syngas as an intermediate. The study considered the valorization of the undifferentiated and organic fraction of waste. Again, after simulating the entire process in the Aspen Plus environment, environmental, thermodynamic and economic analyses were conducted to assess whether the work done could represent a real alternative to the traditional biodiesel production method.
- In the third year of the Ph.D. program on “Synthesis, characterization, and testing of photocatalytic nanomaterials for the removal of trace pollutants from water and wastewater”, the experimental work focused on simplifying the "solid-state" synthesis of a photocatalytically active material based on iron-doped titanium oxide. The material was characterized, and its photocatalytic performance was studied. Subsequently, the material was supported on macroscopic polystyrene pellets (1-3 mm) through a dry thermal process, aiming to eliminate the need for a costly industrial-scale separation of the catalyst from the treated effluent. Optimization of the material quantity, support dimensions, and pellet count, along with demonstrating material reusability for up to ten cycles, facilitated the development of a continuous treatment system on a laboratory scale. The last phase involved studying the material's photocatalytic performance while varying the pH and in the presence of commonly found inorganic ions in the effluents to simulate a situation closer to real-world conditions.
- The research activity during the third year of the work on “Use of bioelectrochemical systems in the multi-stage process for polyhydroxyalkanoates production with mixed microbial cultures.”, a lab-scale Sequencing Batch Reactor (SBR) was operated under F/F conditions and fed with a fermented substrate of reground pasta (RP), a by-product of farinaceous industry, collected by a pilot scale digestor placed in Verona (North Italy). Two different organic loading rates (gCOD (Chemical Oxygen Demand)/Ld) were tested at a fixed cycle length of 6 h. The main activity was performed during an exchange period at the Queensland, where a mixed electro-active microbial culture was used as inoculum in four bioelectrochemical systems equipped with graphite electrodes serving as working electrodes, and batch fed with a synthetic growth medium amended with acetic acid as the carbon and energy source. During the incubations, the electrodes of bioelectrochemical systems were polarised at different electrochemical potentials ranging between +0.20 V to -0.30 V (vs. the Ag/AgCl reference electrodes), tested as such to investigate the effects of the electrode potential on the storage capacity of the microbes.
- During the third year of the Ph.D. program on New positive electrode materials for next generation lithium-ion batteries, an in-depth analysis of the processes occurring during extended electrochemical cycling of Co-free lithium-rich layered oxide materials was conducted. As part of a collaborative effort at the ALBA synchrotron in Barcelona, within the research group led by Dr. Laura Simonelli, analyses were carried out to characterize variations in the electronic structure of these materials. This was accomplished using X-ray absorption spectroscopy techniques, employing in-operando methods where the spectral data acquisition was synchronized with the galvanostatic cycling of the cathodic materials. Furthermore, the same technique was employed to analyse the temperature dependence of these materials, assessing their structural disorder in relation to fine structural fluctuations. The collected data were then subjected to analysis using multivariate curve resolution (MCR) techniques, a form of multivariate statistical analysis.
- The third year activity of the PhD project on “Fire risk management of Li-ion batteries” focused on the study of the fire risk due to the thermal abuse of lithium-ion batteries (LIBs). For this purpose, over the previous years, a test reactor was developed to apply thermal abuse on the LIBs, optimizing the best test conditions and drawing up a test procedure for the complete characterization of the residues, such as gas, solid, and liquid. In the last year, thermal abuse tests were completed, heating at 5 °C/min, on cylindrical cells, 18650, with different internal chemical composition, such as NCA, LTO, LFP, INR and ICR, and at different states of charge, such as 50 and 100 %. Residue analyzes were carried out using different analytical techniques depending on the nature of the sample. Specifically, the gases were analyzed in line, by FT-IR (Spectrum 3, PerkinElmer), to identify and quantify the gases throughout the test time. The solid and liquid residues were analyzed using different analytical techniques at the end of the tests. The organic composition was investigated by ART-FTIR analysis while the metallic composition was identified and quantified by ICP-OES, ASS-OES and SEM-EDS analyses. By combining the different results obtained it was therefore possible to determine the thermal behavior as function of the state of charge and the internal chemical composition, not only in terms of fire temperatures but also of the compounds emitted, which can have negative impacts on human health. The last period of the work was spent at INERIS to evaluate the thermal behavior, the risk of explosiveness and the eco-toxicity of some nanomaterials under investigation for the next generation of LIBs.
Tutti i dottorandi in corso hanno inoltre partecipato alle attività formative proposte dal dottorato nell’A.A. 2022-23.
I corsi del primo modulo (TOPICS IN CHEMICAL ENGINEERING - 4 CFU) sono stati erogati dal 27 giugno al 1 luglio 2022:
Facing the intermittency problem of renewable energies: a chemical engineering perspective - Part 1, Pro.sse Annesini e Murmura, docenti ENEA: Turchetti, Moreno, seminario F. Bassetti (Magaldi Green Energy.
Facing the intermittency problem of renewable energies: a chemical engineering perspective - Part 2, Prof. Bubbico, Prof. Celeste
I corsi del secondo modulo (TOPICS IN CHEMICAL, BIOCHEMICAL and ENVIRONMENTAL PROCESSES - 4 CFU) sono stati erogati tra il 26 giugno 2023 e il 6 luglio 2023:
1) Chemical and (Bio) chemical approaches to biopolymers synthesis and degradation (6 ore), Prof.sse Cleofe Palocci e Marianna Villano
2) Novel biobased biomaterial for industrial applications (6 ore), Prof.ssa Laura Chronopoulou
3) Electrified biotechnologies for environmental applications (6 ore), Prof. Marco Zeppilli
4) Development of selective bioprocesses for microorganisms with high accumulation ability for bio-compounds (6 ore), Fabrizio di Caprio
I corsi del modulo di Methods for Research and Technology Transfer - 3 CFU, sono stati erogati dal 12 al 14 settembre 2023.
Tali corsi sono stati: Nonlinear dynamics of chemical processes (1 CFU), Prof. Altimari e prof. Brasiello; Conceptual Chemical Process Design and Control (1 CFU), Prof. Bildea (University Polytechnica of Bucharest); Life cycle assessment and environmental footprint of processes (1 CFU), Prof. Moreschi, Università di Genova.
I dottorandi hanno inoltre partecipato a seminari, convegni e workshop su argomenti inerenti alla loro attività di ricerca, conseguendo i crediti formativi previsti dal piano formativo.