Publications by authors named "Sara Morandi"

12 Publications

  • Page 1 of 1

Nanosized SnO Prepared by Electrospinning: Influence of the Polymer on Both Morphology and Microstructure.

Polymers (Basel) 2021 Mar 23;13(6). Epub 2021 Mar 23.

Department of Chemistry, University of Torino, Via P. Giuria 7, NIS and INSTM Reference Centres University of Torino, 10125 Torino, Italy.

An electrospinning (ES) procedure of polymeric solutions containing metal oxide precursors, followed by thermal treatments, was exploited to obtain SnO nanofibers. Attention was focused on the effect of different templating polymers (polyvinyl pyrrolidone (PVP), polyethylene oxide (PEO) and polyvinyl acetate (PVAc)) on the morphologies and particle size distributions of SnO. We demonstrated that with different polymers, the final oxide's morphology and crystallite size change. Defined fibers, with homogeneous diameter, were obtained with each polymer, but, after calcination, the morphology of the oxide changes, leading to fibers, "flakes" or "sphere-shaped" particles when PVP, PEO or PVAc were used, respectively, as evidenced by SEM images. Data from HR-TEM and XRD measurements confirm that SnO samples consist of crystalline cassiterite, with small mean particle dimensions calculated by Debye-Scherrer equation, i.e., 30, 11 and 25 nm with PVP, PEO and PVAc, respectively. TEM measurements put in evidence lower average particle sizes and for SnO obtained with PEO average size of 8.5 nm with a standard deviation of ±4.9 nm was evidenced. By applying different calcination temperatures on fiber mat obtained by the same polymer, i.e., PEO, the influence of polymer not only on the final shape of the oxide particles but also on the crystallite size was definitively demonstrated.
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http://dx.doi.org/10.3390/polym13060977DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8004968PMC
March 2021

Growth Mechanisms of ZnO Micro-Nanomorphologies and Their Role in Enhancing Gas Sensing Properties.

Sensors (Basel) 2021 Feb 13;21(4). Epub 2021 Feb 13.

Istituto di Scienze e Tecnologie per l'Energia e la Mobilità Sostenibili (CNR-STEMS), Via Canal Bianco 28, 44124 Ferrara, Italy.

Zinc oxide (ZnO) is one of the main functional materials used to realize chemiresistive gas sensors. In addition, ZnO can be grown through many different methods obtaining the widest family of unique morphologies. However, the relationship between the ZnO morphologies and their gas sensing properties needs more detailed investigations, also with the aim to improve the sensor performances. In this work, seven nanoforms (such as leaves, bisphenoids, flowers, needles, etc.) were prepared through simple wet chemical synthesis. Morphological and structural characterizations were performed to figure out their growth mechanisms. Then, the obtained powders were deposited through screen-printing technique to realize thick film gas sensors. The gas sensing behavior was tested toward some traditional target gases and some volatile organic compounds (acetone, acetaldehyde, etc.) and compared with ZnO morphologies. Results showed a direct correlation between the sensors responses and the powders features (morphology and size), which depend on the specific synthesis process. The sensors can be divided in two behavioral classes, following the two main morphology kinds: aggregates of nanocrystals (leaves and bisphenoids), exhibiting best performances versus all tested gases and monocrystal based (stars, needle, long needles, flowers, and prisms).
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http://dx.doi.org/10.3390/s21041331DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7918259PMC
February 2021

(Ti,Sn) Solid Solution Based Gas Sensors for New Monitoring of Hydraulic Oil Degradation.

Materials (Basel) 2021 Jan 28;14(3). Epub 2021 Jan 28.

Istituto di Scienze e Tecnologie per l'Energia e la Mobilità Sostenibili (CNR-STEMS), 44124 Ferrara, Italy.

The proper operation of a fluid power system in terms of efficiency and reliability is directly related to the fluid state; therefore, the monitoring of fluid ageing in real time is fundamental to prevent machine failures. For this aim, an innovative methodology based on fluid vapor analysis through metal oxide (shortened: MOX) gas sensors has been developed. Two apparatuses were designed and realized: (i) A dedicated test bench to fast-age the fluid under controlled conditions; (ii) a laboratory MOX sensor system to test the headspace of the aged fluid samples. To prepare the set of MOX gas sensors suitable to detect the analytes' concentrations in the fluid headspace, different functional materials were synthesized in the form of nanopowders, characterizing them by electron microscopy and X-ray diffraction. The powders were deposited through screen-printing technology, realizing thick-film gas sensors on which dynamical responses in the presence of the fluid headspace were obtained. It resulted that gas sensors based on solid solution TiSnO with x = 0.9 and 0.5 offered the best responses toward the fluid headspace with lower response and recovery times. Furthermore, a decrease in the responses (for all sensors) with fluid ageing was observed.
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http://dx.doi.org/10.3390/ma14030605DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7865283PMC
January 2021

Development of an easy portable procedure for on-site determination of mercury and methylmercury.

Food Chem 2021 Apr 12;342:128347. Epub 2020 Oct 12.

Department of Chemistry, University of Torino, Via Pietro Giuria 5, 10125 Torino, Italy. Electronic address:

A portable measurement and speciation procedure for inorganic mercury (Hg) and methylmercury (CHHg) was developed. A portable sample pretreatment was optimized to determine total mercury content. A new home-made sorbent (CYXAD, CHYPOS 101 modified Amberlite XAD), was prepared to separate Hg and CHHg. Mercury species were determined using square wave anodic stripping voltammetry (SW-ASV) with a solid gold electrode (SGE) and using a portable potentiostat. A certified reference material, five freeze-dried samples and three fresh samples were analysed with conventional voltammetric analyzer, after dissolution of the samples in microwave oven, and with a portable potentiostat after the mild eating procedure. The results obtained by SW-ASV were compared with those obtained using Direct Mercury Analyser (DMA). The quantification with the portable method is comparable to that obtained with the DMA. Retention tests showed the selectivity of CYXAD for Hg, its stability and the possibility to re-use the same aliquot of resin.
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http://dx.doi.org/10.1016/j.foodchem.2020.128347DOI Listing
April 2021

High-Throughput Preparation of Metal Oxide Nanocrystals by Cathodic Corrosion and Their Use as Active Photocatalysts.

Langmuir 2017 11 9;33(46):13295-13302. Epub 2017 Nov 9.

School of Chemistry, University of Birmingham , Edgbaston, Birmingham B15 2TT, United Kingdom.

Nanoparticle metal oxide photocatalysts are attractive because of their increased reactivity and ease of processing into versatile electrode formats; however, their preparation is cumbersome. We report on the rapid bulk synthesis of photocatalytic nanoparticles with homogeneous shape and size via the cathodic corrosion method, a simple electrochemical approach applied for the first time to the versatile preparation of complex metal oxides. Nanoparticles consisting of tungsten oxide (HWO) nanoplates, titanium oxide (TiO) nanowires, and symmetric star-shaped bismuth vanadate (BiVO) were prepared conveniently using tungsten, titanium, and vanadium wires as a starting material. Each of the particles were extremely rapid to produce, taking only 2-3 min to etch 2.5 mm of metal wire into a colloidal dispersion of photoactive materials. All crystalline HWO and BiVO particles and amorphous TiO were photoelectrochemically active toward the water oxidation reaction. Additionally, the BiVO particles showed enhanced photocurrent in the visible region toward the oxidation of a sacrificial sulfite reagent. This synthetic method provides an inexpensive alternative to conventional fabrication techniques and is potentially applicable to a wide variety of metal oxides, making the rapid fabrication of active photocatalysts with controlled crystallinity more efficient.
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http://dx.doi.org/10.1021/acs.langmuir.7b02465DOI Listing
November 2017

Micro-sized TiO as photoactive catalyst coated on industrial porcelain grès tiles to photodegrade drugs in water.

Environ Sci Pollut Res Int 2018 Jul 27;25(21):20348-20353. Epub 2017 Apr 27.

GranitiFiandre SpA, Via Radici Nord 112, 42014, Castellarano, Italy.

Pharmaceutical compounds and their metabolites raise worrying questions because of their continuous release and lack of efficient removal by conventional wastewater treatments; therefore, they are being detected in groundwater, surface water and drinking water in increasing concentrations. Paracetamol and aspirin are two of the most commonly used drugs employed as fever reducer, analgesic and anti-inflammatory. They and their metabolites are very often found in river water, so their degradation is necessary in order to render water suitable for human consumption. The present work is focused on the comparison of the photocatalytic performance of industrial active grés porcelain tiles covered with a commercial micro-sized TiO by industrial process using either conventional spray deposition or innovative digital printing methods. The photodegradation of two commonly used drugs, namely aspirin and paracetamol, was investigated both individually and as a mixture, in both deionized and tap water. The results reveal the full conversion of the drugs and the significant role of the photocatalytic tiles in the mineralization processes leading to harmless inorganic species. In particular, the digitally printed tiles exhibited better photodegradation performance for both drugs compared to the spray deposited tiles. No deactivation was observed on both photocatalytic tiles.
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http://dx.doi.org/10.1007/s11356-017-9066-6DOI Listing
July 2018

Aspirin and paracetamol removal using a commercial micro-sized TiO catalyst in deionized and tap water.

Environ Sci Pollut Res Int 2017 May 21;24(14):12646-12654. Epub 2016 Oct 21.

GranitiFiandre SpA, Via Radici Nord 112, 42014, Castellarano, Italy.

Micro-sized TiO catalyst was employed to degrade pharmaceutical compounds, i.e. aspirin and paracetamol, two of the most widely used drugs, purchasable without prescription. Their active agents, acetylsalicylic acid and acetaminophen, are characterized by different substituent groups, linked to the aromatic ring, which affect both the photodegradation and mineralization processes. The experimental conditions highlight the relationship between the nature of the pristine molecules, their degradation mechanisms, their mutual interference and the water's role. The research started from model systems with a single pollutant to the mixture of them and finally by moving from deionized water to tap water.
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http://dx.doi.org/10.1007/s11356-016-7781-zDOI Listing
May 2017

Copper NPs decorated titania: A novel synthesis by high energy US with a study of the photocatalytic activity under visible light.

Ultrason Sonochem 2016 Jul 15;31:295-301. Epub 2016 Jan 15.

GranitiFiandre SpA, Castellarano (MO), Italy.

The most important drawback of the use of TiO2 as photocatalyst is its lack of activity under visible light. To overcome this problem, the surface modification of commercial micro-sized TiO2 by means of high-energy ultrasound (US), employing CuCl2 as precursor molecule to obtain both metallic copper as well as copper oxides species at the TiO2 surface, is here. We have prepared samples with different copper content, in order to evaluate its impact on the photocatalytic performances of the semiconductor, and studied in particular the photodegradation in the gas phase of some volatile organic molecules (VOCs), namely acetone and acetaldehyde. We used a LED lamp in order to have only the contribution of the visible wavelengths to the TiO2 activation (typical LED lights have no emission in the UV region). We employed several techniques (i.e., HR-TEM, XRD, FT-IR and UV-Vis) in order to characterize the prepared samples, thus evidencing different sample morphologies as a function of the various copper content, with a coherent correlation between them and the photocatalytic results. Firstly, we demonstrated the possibility to use US to modify the TiO2, even when it is commercial and micro-sized as well; secondly, by avoiding completely the UV irradiation, we confirmed that pure TiO2 is not activated by visible light. On the other hand, we showed that copper metal and metal oxides nanoparticles strongly and positively affect its photocatalytic activity.
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http://dx.doi.org/10.1016/j.ultsonch.2016.01.015DOI Listing
July 2016

Effect of water and ammonia on surface species formed during NO(x) storage-reduction cycles over Pt-K/Al2O3 and Pt-Ba/Al2O3 catalysts.

Phys Chem Chem Phys 2013 Aug;15(32):13409-17

Dipartimento di Chimica and NIS, Centre of Excellence, Università di Torino, via P. Giuria 7, 10125 Torino, Italy.

The effect of water, in the temperature range 25-350 °C, and ammonia at RT on two different surface species formed on Pt-K/Al2O3 and Pt-Ba/Al2O3 NSR catalysts during NO(x) storage-reduction cycles was investigated. The surface species involved are nitrates, formed during the NO(x) storage step, and isocyanates, which are found to be intermediates in N2 production during reduction by CO. FT-IR experiments demonstrate that the dissociative chemisorption of water and ammonia causes the transformation of the bidentate nitrates and linearly bonded NCO(-) species into more symmetric species that we call ionic species. In the case of water, the effect on nitrates is observable at all the temperatures studied; however, the extent of the transformation decreases upon increasing temperature, consistent with the decreased extent of dissociatively adsorbed water. It was possible to hypothesize that the dissociative chemisorption of water and ammonia takes place in a competitive way on surface sites able to give bidentate nitrates and linearly bonded NCO(-) that are dislocated, remaining on the surface as ionic species.
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http://dx.doi.org/10.1039/c3cp51195bDOI Listing
August 2013

Photoreduction of mesoporous In2O3: mechanistic model and utility in gas sensing.

Chemistry 2012 Jun 16;18(26):8216-23. Epub 2012 May 16.

University of Paderborn, Faculty of Science, Department of Chemistry, Warburger Strasse 100, 33098 Paderborn, Germany.

A model is proposed for the drop in electronic resistance of n-type semiconducting indium oxide (In(2)O(3)) upon illumination with light (350 nm, 3.5 eV) as well as for the (light-enhanced) sensitivity of In(2)O(3) to oxidizing gases. Essential features of the model are photoreduction and a rate-limiting oxygen-diffusion step. Ordered, mesoporous In(2)O(3) with a high specific surface area serves as a versatile system for experimental studies. Analytical techniques comprise conductivity measurements under a controlled atmosphere (synthetic air, pure N(2)) and temperature-resolved in-situ Fourier transform infrared (FTIR) spectroscopy. IR measurements reveal that oxygen vacancies form a donor level 0.18 eV below the conduction band.
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http://dx.doi.org/10.1002/chem.201103905DOI Listing
June 2012

Evaluating the clinical accuracy of GlucoMen®Day: a novel microdialysis-based continuous glucose monitor.

J Diabetes Sci Technol 2010 Sep 1;4(5):1182-92. Epub 2010 Sep 1.

A. Menarini Diagnostics, Florence, Italy.

Background: The objective of this work was to determine the clinical accuracy of GlucoMen®Day, a new microdialysis-based continuous glucose monitoring system (CGMS) from A. Menarini Diagnostics (Florence, Italy). Accuracy evaluation was performed using continuous glucose-error grid analysis (CG-EGA), as recommended by the Performance Metrics for Continuous Interstitial Glucose Monitoring; Approved Guideline (POCT05-A).

Methods: Two independent clinical trials were carried out on patients with types 1 and 2 diabetes mellitus, the glycemic levels of whom were monitored in an in-home setting for 100-hour periods. A new multiparametric algorithm was developed and used to compensate in real-time the GlucoMen®Day signal. The time lag between continuous glucose monitoring (CGM) and reference data was first estimated using the Poincaré plot method. The entire set of CGM/reference data pairs was then evaluated following the CG-EGA criteria, which allowed an estimation of the combined point and rate accuracy stratified by glycemic ranges.

Results: With an estimated time lag of 11 minutes, the linear regression analysis of the CGM/reference glucose values yielded r = 0.92. The mean absolute error (MAE) was 11.4 mg/dl. The calculated mean absolute rate deviation (MARD) was 0.63 mg/dl/min. The data points falling within the A+B zones of CG-EGA were 100% in hypoglycemia, 95.7% in euglycemia, and 95.2% in hyperglycemia.

Conclusions: The GlucoMen®Day system provided reliable, real-time measurement of subcutaneous glucose levels in patients with diabetes for up to 100 hours. The device showed the ability to follow rapid glycemic excursions and detect severe hypoglycemic events accurately. Its accuracy parameters fitted the criteria of the state-of-the-art consensus guideline for CGMS, with highly consistent results from two independent studies.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2956803PMC
http://dx.doi.org/10.1177/193229681000400517DOI Listing
September 2010

Association of sugar-based carboranes with cationic liposomes: an electron spin resonance and light scattering study.

Biochim Biophys Acta 2004 Jul;1664(1):53-63

Dipartimento di Chimica, Laboratorio di Chimica Fisica delle Interfasi, Università di Firenze, 50019, Sesto Fiorentino no, Florence, Italy.

The possibility of cationic (di-oleoyltrimethylammonium propane, DOTAP)/(L-alpha-dioleoylphosphatidyl-ethanolamine, DOPE) liposomes to act as carriers of boronated compounds such as 1,2-dicarba-closo-dodecaboran(12)-1-ylmethyl](beta-D-galactopyranosyl)-(1-->4)-beta-D-glucopyranoside and 1,2-di-(beta-D-gluco-pyranosyl-ox)methyl-1,2-dicarba-closo-dodeca-borane(12) has been investigated by Electron Spin Resonance (ESR) of n-doxyl stearic acids (n-DSA) and Quasi-Elastic Light Scattering (QELS). Both these carboranes have potential use in Boron Neutron Capture Therapy (BNCT), which is a targeted therapy for the treatment of radiation resistant tumors. They were shown to give aggregation both in plain water and in saline solution. Carborane aggregates were, however, disrupted when DOTAP/DOPE liposome solutions were used as dispersing agents. The computer analysis of the ESR spectra from carborane-loaded liposomes allowed to establish an increase of the order degree in the liposome bilayer with increasing carborane concentration, together with a decreased mobility. The same discontinuities of both correlation time and order parameter with respect to temperature variations were observed in carborane-containing and carborane-free liposomes. This suggested that a homogeneous dispersion of nitroxides and carboranes occurred in the liposome bilayer. The ESR line shape analysis proved that no dramatic changes were induced in the liposome environment by carborane insertion. QELS data showed that the overall liposome structure was preserved, with a slight decrease in the mean hydrodynamic radius and increase in polydispersity caused by the guest molecules.
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http://dx.doi.org/10.1016/j.bbamem.2004.04.002DOI Listing
July 2004
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