64 research outputs found

    Influence of the catalyst support on the steam reforming performance of toluene as tar model compound

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    The large amount of tar produced along with the syngas during biomass gasification is one of the major obstacle for the diffusion of gasifiers at industrial scale. Catalytic cracking and reforming are the most suitable processes for the transformation of tar into lighter gases. The selection of suitable catalysts is a critical step. The catalysts must own high activity and high resistance to deactivation for coke deposition. In this work the effect of two different supports, mayenite and aluminium oxide, on the activity of the nickel was investigated in the steam reforming of toluene that was used as tar model compound. In particular, the performed experimentations aimed to test the mayenite in terms of improvement of resistance to carbon deposition in conditions similar to those of gasification reactors. The obtained results indicate that Ni /mayenite catalyst needs higher temperature to activate and leads to lower value of toluene conversion with respect to Ni / alumina. However, mayenite, which is known from literature to have higher resistance to coke deposition due to the presence of free oxygens in the lattice which oxidize the coke deposited on the catalyst surface showed higher resistance to deactivation especially for low steam to carbon ratios

    Waterborne Acrylate-Based Hybrid Coatings with Enhanced Resistance Properties on Stone Surfaces

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    The application of coating polymers to building materials is a simple and cheap way to preserve and protect surfaces from weathering phenomena. Due to its environmentally friendly character, waterborne coating is the most popular type of coating, and improving its performance is an important key of research. The study presents the results regarding the mechanical and photo-oxidation resistance of some water-based acrylic coatings containing SiO2 nanoparticles obtained by batch miniemulsion polymerization. Coating materials have been characterized in terms of hydrophobic/hydrophilic behavior, mechanical resistance and surface morphology by means of water-contact angle, and scrub resistance and atomic force microscopy (AFM) measurements depending on silica-nanoparticle content. Moreover, accelerated weathering tests were performed to estimate the photo-oxidation resistance of the coatings. The chemical and color changes were assessed by Fourier-transform infrared spectroscopy (FTIR) and colorimetric measurements. Furthermore, the nanofilled coatings were applied on two different calcareous lithotypes (Lecce stone and Carrara Marble). Its properties, such as capillary water absorption and color modification, before and after accelerated aging tests, were assessed. The properties acquired by the addition of silica nanoparticles in the acrylic matrix can ensure good protection against weathering of stone-based materials

    Antibacterial effect of zinc oxide-based nanomaterials on environmental biodeteriogens affecting historical buildings

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    The colonization of microorganisms and their subsequent interaction with stone substrates under different environmental conditions encourage deterioration of materials by multiple mechanisms resulting in changes in the original color, appearance and durability. One of the emerging alternatives to remedy biodeterioration is nanotechnology, thanks to nanoparticle properties such as small size, no-toxicity, high photo-reactivity, and low impact on the environment. This study highlighted the effects of ZnO-based nanomaterials of two bacteria genera isolated from the Temple of Concordia (Agrigento’s Valley of the Temples in Sicily, Italy) that are involved in biodeterioration processes. The antimicrobial activities of ZnO-nanorods (Zn-NRs) and graphene nanoplatelets decorated with Zn-NRs (ZNGs) were evaluated against the Gram positive Arthrobacter aurescens and two isolates of the Gram negative Achromobacter spanius. ZNGs demonstrated high antibacterial and antibiofilm activities on several substrates such as stones with different porosity. In the case of ZNGs, a marked time- and dose-dependent bactericidal effect was highlighted against all bacterial species. Therefore, these nanomaterials represent a promising tool for developing biocompatible materials that can be exploited for the conservation of cultural heritage. These nanostructures can be successfully applied without releasing toxic compounds, thus spreading their usability

    Soil Biocementation via Enzyme Induced Carbonate Precipitation (eicp) Method Employing Soybeans as a Source of Cheap Enzyme

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    In this work, the soil improvement technique via Enzyme Induced Carbonate Precipitation (EICP) was investigated by employing, as an alternative to expensive pure enzymes, enzymes extracted from agro-food wastes (tomato, apple, and soybean) such that the process is economically viable and fully embraces the concept of the circular economy. The feasibility of the process was evaluated by monitoring calcium carbonate precipitation in a sand sample. The effect of selected operative parameters was investigated during the injection into different grain size sand samples. The optimal operating conditions in terms of sand grain size, temperature, Urea/Calcium concentration were found. Results demonstrated the effectiveness of this alternative solution for EICP method in term of acquired material strength and the possibility to operate sand consolidation through an economically sustainable process

    Hydrothermal Liquefaction of Waste Biomass Model Compounds: a Study to Unravel the Complexity of Interactions in Biocrude Production from Mixtures of Cellulose-Albumin-Lipids

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    Hydrothermal liquefaction is a promising technology for liquid biofuel production from a wide range of organic wastes. Waste biogenic feedstocks with a high moisture content are particularly suitable for this purpose due to the possibility to feed wet materials and to obtain high liquid yields in hydrothermal liquefaction (HTL). Although, yields and quality of the obtained liquid products are usually strongly dependent on the composition of the feedstocks, and due to their variability, it is often difficult to have reliable predictions. However, biogenic waste can be easily schematize based on their content of organic macro-components, mainly polysaccharides, proteins, and lipids. This work tries to summarize the effect of the variation of feedstock’s composition on yields and the quality of HTL products, with a particular focus on binary interactions between the macro-components. Cellulose, egg albumin and sunflower oil are used as model compounds to represent polysaccharides, proteins, and lipids, respectively. HTL tests are carried out in micro autoclaves of 10 mL using these model compounds alone and in binary and ternary mixtures as feedstocks, at 330°C and 10 minutes of retention time. Results showed that the biocrude yields did not follow the behaviour predicted by the linear combination of the three compounds but an increase of biocrude production and a reduction of solid residue is obtained for the mixtures. GC-MS results showed the presence of compounds related to Maillard reactions and amides formation. Some general reaction pathways were summarized to explain these results. The comprehension of these interactions can guide the future research to obtain a prediction model for biofuel production through a HTL process

    Effect of carbon nanostructures and fatty acid treatment on the mechanical and thermal performances of flax/polypropylene composites

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    Four different strategies for mitigating the highly hydrophilic nature of flax fibers were investigated with a view to increase their compatibility with apolar polypropylene. The effects of two carbon nanostructures (graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs)), of a chemical modification with a fatty acid (stearic acid), and of maleated polypropylene on interfacial adhesion, mechanical properties (tensile and flexural), and thermal stability (TGA) were compared. The best performance was achieved by a synergistic combination of GNPs and maleated polypropylene, which resulted in an increase in tensile strength and modulus of 42.46% and 54.96%, respectively, compared to baseline composites. Stearation proved to be an effective strategy for increasing the compatibility with apolar matrices when performed in an ethanol solution with a 0.4 M concentration. The results demonstrate that an adequate selection of surface modification strategies leads to considerable enhancements in targeted properties

    ChAracterization of ItaliaN severe uncontrolled Asthmatic patieNts Key features when receiving Benralizumab in a real-life setting: the observational rEtrospective ANANKE study

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    Background: Data from phase 3 trials have demonstrated the efficacy and safety of benralizumab in patients with severe eosinophilic asthma (SEA). We conducted a real-world study examining the baseline characteristics of a large SEA population treated with benralizumab in clinical practice and assessed therapy effectiveness. Methods: ANANKE is an Italian multi-center, retrospective cohort study including consecutive SEA patients who had started benralizumab therapy ≥ 3 months before enrolment (between December 2019 and July 2020), in a real-world setting. Data collection covered (1) key patient features at baseline, including blood eosinophil count (BEC), number and severity of exacerbations and oral corticosteroid (OCS) use; (2) clinical outcomes during benralizumab therapy. We also conducted two post-hoc analyses in patients grouped by body mass index and allergic status. Analyses were descriptive only. Results: Of 218 patients with SEA enrolled in 21 Centers, 205 were evaluable (mean age, 55.8 ± 13.3 years, 61.5% females). At treatment start, the median BEC was 580 cells/mm3 (interquartile range [IQR]: 400-850); all patients were on high-dose inhaled controller therapy and 25.9% were on chronic OCS (median dose: 10 mg/die prednisone-equivalent [IQR: 5-25]); 92.9% experienced ≥ 1 exacerbation within the past 12 months (annualized exacerbation rate [AER] 4.03) and 40.3% reported ≥ 1 severe exacerbation (AER 1.10). During treatment (median duration: 9.8 months [IQR 6.1-13.9]; ≥ 12 months for 34.2% of patients), complete eosinophil depletion was observed; exacerbation-free patients increased to 81% and only 24.3% reported ≥ 1 severe event. AER decreased markedly to 0.27 for exacerbations of any severity (- 93.3%) and to 0.06 for severe exacerbations (- 94.5%). OCS therapy was interrupted in 43.2% of cases and the dose reduced by 56% (median: 4.4 mg/die prednisone-equivalent [IQR: 0.0-10.0]). Lung function and asthma control also improved. The effectiveness of benralizumab was independent of allergic status and body mass index. Conclusions: We described the set of characteristics of a large cohort of patients with uncontrolled SEA receiving benralizumab in clinical practice, with a dramatic reduction in exacerbations and significant sparing of OCS. These findings support benralizumab as a key phenotype-specific therapeutic strategy that could help physicians in decision-making when prescribing biologics in patients with SEA. Trial registration ClinicalTrials.gov Identifier: NCT04272463

    Benralizumab in Patients With Severe Eosinophilic Asthma With and Without Chronic Rhinosinusitis With Nasal Polyps: An ANANKE Study post-hoc Analysis

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    Background: Severe eosinophilic asthma (SEA) in the presence of chronic rhinosinusitis with nasal polyps (CRSwNP) indicates the presence of a more extensive eosinophilic inflammation. Post-hoc analyses from a pivotal clinical trial have demonstrated the enhanced efficacy of benralizumab on asthma outcomes in patients with CRSwNP as a comorbidity. Methods: This is a post-hoc analysis from the Italian multi-center observational retrospective ANANKE study. Patients were divided into two groups based on self-reported CRSwNP. Baseline clinical and laboratory features in the 12 months prior to benralizumab prescription were collected. Data of change over time of blood eosinophils, annualized exacerbations rates (AER), asthma control, lung function, oral corticosteroids (OCS) use, and benralizumab discontinuation were collected during the observation period. Results: At baseline, the 110 patients with CRSwNP were less frequently female (50.9% vs 74.2%) and obese (9.1% vs. 22.6%) with higher eosinophils (605 vs. 500 cells/mm3) and OCS use when compared to patients without CRSwNP. Similar reductions of AER were seen (-95.8% vs. -91.5% for any exacerbation and -99.1% vs. -92.2% for severe exacerbations in patients with and without CRSwNP, respectively). During benralizumab treatment, comorbid SEA+CRSwNP was associated with a lower risk of any exacerbation (p = 0.0017) and severe exacerbations (p = 0.025). After a mean ± SD exposure of 10.3 ± 5.0 months, half of the SEA+CRSwNP patients eliminated OCS use. No discontinuation for safety reasons was recorded. Conclusions: This study helped to confirm the baseline clinical features that distinguish patients with and without CRSwNP being prescribed benralizumab. Numerically enhanced OCS reduction and lower exacerbation risk were observed in patients with SEA and comorbid CRSwNP treated with benralizumab
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