Papers by Luca Bernazzani
Clay nanotubes for designing eco-compatible smart materials
Evaluation of physicochemical properties of Type-II deep eutectic solvents/Water mixtures based on choline chloride and calcium/magnesium chloride hexahydrate
Journal of Molecular Liquids
Langmuir, Aug 16, 2006
The interaction of lithium perfluorononanoate (LiPFN) with poly(ethylene glycol) (PEG) molecules ... more The interaction of lithium perfluorononanoate (LiPFN) with poly(ethylene glycol) (PEG) molecules of different molecular weights (300 < MW < 20000 Da) has been investigated in water at 298.15 and 308.15 K by isothermal titration calorimetry (ITC). Density, viscosity, and conductivity measurements were also performed at 298.15 K. The aggregation process of this surfactant on the PEG polymeric chain was found to be very similar to that exhibited by cesium perfluorooctanoate (CsPFO) and appears to be consistent with the necklace model. ITC titrations indicated that a fully formed LiPFN micellar cluster can be wrapped by a PEG chain having a molecular weight (MW) of ∼3200 Da, longer than that required by the shorter perfluorooctanoate (MW ∼ 2600 Da), and also suggested a stepwise mechanism for the aggregation of successive micelles. Viscosity data indicate that the formation of polymer-surfactant complexes between PEG and LiPFN involves a conformational change of the polymer. The aggregation of preformed micelles of LiPFN or CsPFO or SDS on the PEG polymeric chain always gives rise to further stabilization.
In situ microwave assisted extraction of clove buds to isolate essential oil, polyphenols, and lignocellulosic compounds
Industrial Crops and Products, Mar 1, 2021
Abstract Clove buds is a spice of relevance in food, traditional medicine, pharmaceutics and cosm... more Abstract Clove buds is a spice of relevance in food, traditional medicine, pharmaceutics and cosmetics and, among the spices, they have the highest content of total polyphenols with exceptional antiviral and antimicrobial properties. Various approaches have been reported for the isolation of essential oil from clove buds. Nonetheless, the qualitative and quantitative analysis of hydrosoluble polyphenols and solid residues simultaneously yielded during the extraction process has not been explored yet. This work is focused on the analysis of some variables effect on yield and composition of the clove buds essential oils on a green microwave assisted extraction, and the characterization and quantification of the different compounds obtained from the extraction process. A versatile coaxial dipole antenna, to directly apply the electromagnetic energy inside the extraction medium, was used to thermally activate the hydrodistillation. The composition profiles of clove buds essential oil and hydrosoluble polyphenols obtained during in-situ microwave assisted extraction (IMWAE) were analysed and quantified by head space gas chromatography mass spectrometry (HS-GC–MS) and liquid chromatography with UV/visible diode array/fluorescence detector (HPLC-DAD-FD). The solid residue was characterized by Fourier Transform Infrared (FTIR) spectroscopy and its composition in term of lignin, cellulose and hemicellulose was predicted. The green IMWAE process was compared with the conventional hydrodistillation (CH) in terms of yield and quality of isolated products. Thermogravimetry coupled to FTIR analyses of the evolved gases from the solid residue evidenced that the solid residue obtained from IMWAE of clove buds is richer in cellulose-hemicellulose than the residue obtained from CH. This can be because of microwaves that allow to remove a higher amount of phenolic compounds/lignin oligomers. The enthalpy of combustion values (ΔcH) (kJ/g) of IMWAE and CH residues were determined by calorimetric combustion and were compared with the –ΔcH (kJ/g) values calculated using the hemicellulose, cellulose and lignin compositions predicted by partial least square chemometrics. The ΔcH highlighted the energetic features of solid residues from IMWAE and CH for their potential uses as alternative biomass for fuel production and here firstly reported for this kind of biomass. The extraction approach here presented is environmentally friendly, highly flexible, easily controllable, time saving, and enables to break the scale-up barrier in microwave assisted industrial processes aimed to valorise aromatic herbs and eventually to exploit vegetable wasting materials. This leads to a lowering of production costs and, therefore, of the market price of isolated extracts from aromatic herbs.
I2HET: Development of an Iodine-Fed Hall Effect Thruster
Absorption-based Laser Mass Flow Meter for Iodine Feeding System for Electric Propulsion
Iodine came up recently as a feasible alternative to xenon and krypton to be used in space electr... more Iodine came up recently as a feasible alternative to xenon and krypton to be used in space electric propulsion applications. Iodine presents good ionization properties and a high atomic mass, which allow it to yield a good propulsive performance. Iodine is stored in a solid state, allowing to achieve higher storage densities, useful in volume-constrained applications. Nevertheless, the condensible nature and the reactivity of iodine prevents the use of propellant management systems and components used in noble gas-based systems. The University of Pisa is developing an iodine feeding system for electric propulsion applications, which controls the mass flow rate through the thermal control of the sublimation process and a thermal throttle. The article presents the main results of an ongoing activity aimed at the development of a laser-based mass flow meter to be used in the feeding system. The device measures the light absorbance of the iodine flow in a region upstream of the thermal throttle. Upon an integral-measurement calibration procedure, the spectrophotometric device allows to infer the mass flow rate instantaneous value. The measurement procedure and the underlying theory are described, as well as the calibration methodology and experimental setup.
Scientific Reports, May 19, 2023
In this work we propose the use of isothermal thermogravimetry to evaluate the oxidative stabilit... more In this work we propose the use of isothermal thermogravimetry to evaluate the oxidative stability of a lipid and to evaluate how the glyceride composition affects the entire oxidative process, to quantify the oxidation undertaken by the lipid, and numerically compare the oxidative behaviour of different lipids. The innovative aspect of the present method lies in the acquisition of a prolonged "oxygen uptake" curve (4000-10,000 min) of a lipid under oxygen and in the development of a semi-empirical fitting equation for the experimental data. This provides the induction period (oxidative stability), and allows to evaluate the rate of oxidation, the rate and the magnitude of oxidative degradation, the overall mass loss and the mass of oxygen taken by the lipid upon time. The proposed approach is used to characterize the oxidation of different edible oils with different degrees of unsaturation (linseed oil, sunflower oil, and olive oil) as well as chemically simpler compounds used in the literature to model the autoxidation of vegetable oils and lipids in general: triglycerides (glyceryl trilinolenate, glyceryl trilinoleate and glyceryl trioleate) and methyl esters (methyl linoleate and methyl linolenate). The approach proves very robust and very sensitive to changes in the sample composition. Lipids, when exposed to atmospheric oxygen, are subject to a complex series of reactions which may evolve toward two main competitive pathways: oxidative degradation-resulting in the formation of polar species, including volatile compounds (such as short chain carboxylic acids, aldehydes and ketones), and cross-linkingresulting in the formation of higher molecular weight species 1. Oxidative degradation is one of the most common degradative pathways of lipids-based drug formulations 2,3 and it leads to the so-called rancidity of lipid-rich food, which is characterised by the development of unpleasant smells, as well as a decrease in nutritional value 4. In oil-based paints, a curing process dominated by oxidative degradation can negatively affect the painting stability and favour the rising of degradation phenomena upon time 5,6. Polymerization reactions, on the other hand, are fundamental in the case of drying and semi drying oilbased paints, as they are responsible for the gradual conversion of the liquid paint into a solid painting layer 7. Oxidative stability is also one of the most important quality parameters set by European and American standards for biodiesels 8. The oxidative behaviour of a lipid is strictly related to its chemical composition in terms of the degree of unsaturation and the methylene bridge index (MBI: the mean number of bisallylic methylene positions), stereospecific positional distribution of fatty acids in the TAG molecules, lipid class (alkyl ester, triglyceride, phosphoglyceride, etc.), the presence of antioxidants and other trace components (enzymes, metals) 9. In addition to the nature of the lipid, environmental factors (i.e. storage conditions), processing, and product formulations also affect its oxidation rate 9. Several methods are routinely used to assess if an oil can be considered oxidized or not, and to rank the degree of stability to oxidation among different oils. Induction time, peroxide value, presence of free fatty acids and conjugated dienes and trienes, are commonly tested by means of automated methods, such as Rancimat (Metrohm, model 743, Herisau, Switzerland) and Oxitest-Oxidation Test Reactor (VELP, Usmate, MB, Italy), spectroscopy, and gas chromatography 10-13. Alternatively, mass changes upon oxidation are also recorded, either using a scale before and after the oxidation event has taken place 14-17 , or using isothermal thermogravimetry (TG) under air flow 18-24 .
Optimized preparation, thermal characterization and microwave absorption properties of deep eutectic solvents made by choline chloride and hydrated salts of alkali earth metals
Journal of Molecular Liquids, Feb 1, 2023
Quantitative Structure−Property Relationship (QSPR) Prediction of Solvation Gibbs Energy of Bifunctional Compounds by Recursive Neural Networks
Journal of Chemical & Engineering Data, Jul 21, 2010
ABSTRACT In this paper we apply a recursive neural network (RNN) model to the prediction of the s... more ABSTRACT In this paper we apply a recursive neural network (RNN) model to the prediction of the standard Gibbs energy of solvation in water of mono- and polyfunctional organic compounds. The proposed model is able to directly take as input a structured representation of the molecule and to model a direct and adaptive relationship between the molecular structure and the target property. A data set of 339 mono- and polyfunctional acyclic compounds including alkanes, alkenes, alkynes, alcohols, ethers, thiols, thioethers, aldehydes, ketones, carboxylic acids, esters, amines, amides, haloalkanes, nitriles, and nitroalkanes was considered. As a result of the statistical analysis, we obtained for the predictive capability estimated on a test set of molecules a mean absolute residual of about 1 kJ·mol−1 and a standard deviation of 1.8 kJ·mol−1. This results is quite satisfactory by considering the intrinsic difficulty of predicting solvation properties in water of compounds containing more than one functional group.
Thermodynamics of the Solvation Process of Organic Molecules in Solvents belonging to the "Critical Quartet
Development of an Iodine Propellant Feeding System for Electric Propulsion
Interaction of Surfactans with Macromolecules. Calorimetric Investigation of Bile Salts with Human Serum Albumin
Overview of the Unipi & Sitael Activity on Iodine-Fed Hall Effect Thrusters
Journal of Thermal Analysis and Calorimetry
The valorization of poultry feathers wastes is very important to reduce the environmental polluti... more The valorization of poultry feathers wastes is very important to reduce the environmental pollution deriving from their disposal. In this frame, we present the production process of completely natural, biodegradable, biocompatible and ecofriendly composites made by non-soluble keratin (NSK) and poly(lactic acid) (PLA). NSK was obtained as by-product of a microwave assisted keratin extraction from poultry feathers and it was added to PLA pellets without adding additional compatibilizers or plasticizers, differently from the other works reported in the literature until now. The mixture was used to obtain homogeneous NSK-based PLA filaments by means of hot-melt extrusion technology. The filaments were subsequently 3D printed to explore applications in the additive manufacturing field. All the samples presented unaltered thermal stability, but reduced toughness with respect to neat PLA. Other tested parameters (water adsorption, glass transition, crystallinity) were dependent from NSK content and from the fabrication technology. Besides, Fourier Transform Infrared Spectroscopy (FTIR) highlights the differences in the structure of the NSK-based PLA filaments and 3D printed samples.
Metal-organic frameworks (MOFs) that display step-shaped adsorption isotherms, i.e., phase-change... more Metal-organic frameworks (MOFs) that display step-shaped adsorption isotherms, i.e., phase-change MOFs, represent a relatively small subset of all known MOFs. Yet, they are rapidly emerging as promising sorbents to achieve excellent gas separation performances with little energy demand. In this work, we assessed F4_MIL-140A(Ce), a recently discovered phase-change MOF adsorbent for CO2 capture in two scenarios using a pressure-vacuum swing adsorption process, namely a coal-fired power plant flue gas (12.5 %mol CO2), and a steel plant flue gas (25.5 %mol CO2). Four CO2 and three N2 adsorption isotherms were collected on F4_MIL-140A(Ce) over a range of temperatures and modelled using a bespoke equation for step-shaped isotherms. We accurately measured the heat capacity of F4_MIL-140A(Ce), a key thermodynamic property for a sorbent, using a method based on differential scanning calorimetry that overcomes the issues associated with the poor thermal conductivity of MOF powders. We then us...
Guidelines for a correct evaluation of Deep Eutectic Solvents thermal stability
Current Research in Green and Sustainable Chemistry
Desarrollo de Propulsor Hall Alimentado a Iodo
X Congreso Argentino de Tecnología Espacial, 2019
20 years of microwave technology developments using a coaxial antenna: From human health to green chemistry applications
Current Research in Green and Sustainable Chemistry
Scientific Reports
In this work we propose the use of isothermal thermogravimetry to evaluate the oxidative stabilit... more In this work we propose the use of isothermal thermogravimetry to evaluate the oxidative stability of a lipid and to evaluate how the glyceride composition affects the entire oxidative process, to quantify the oxidation undertaken by the lipid, and numerically compare the oxidative behaviour of different lipids. The innovative aspect of the present method lies in the acquisition of a prolonged “oxygen uptake” curve (4000–10,000 min) of a lipid under oxygen and in the development of a semi-empirical fitting equation for the experimental data. This provides the induction period (oxidative stability), and allows to evaluate the rate of oxidation, the rate and the magnitude of oxidative degradation, the overall mass loss and the mass of oxygen taken by the lipid upon time. The proposed approach is used to characterize the oxidation of different edible oils with different degrees of unsaturation (linseed oil, sunflower oil, and olive oil) as well as chemically simpler compounds used in t...
From volatiles to solid wastes: Towards the full valorization of lavender and rosemary by simultaneous in situ microwaves and ultrasounds irradiation extraction
Industrial Crops and Products
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Papers by Luca Bernazzani