12064 research outputs found
Sort by
The Effect of Solvent on the Characteristics of FeBTC MOF as a Potential Heterogenous Catalyst Prepared via Green Mechanochemical Process
No full textIn this study, the synthesis of FeBTC (BTC = 1,3,5-benzenetricarboxylate) also known as MIL-100 (Fe) metal organic framework (MOF) has been carried out successfully using green mechanochemical method (neat grinding and liquid assisted grinding). The effect of solvent used in the synthesis was investigated for the first time to elucidate the physicochemical properties of FeBTC including crystal structure, thermal stability, pore size and specific surface area. The physicochemical properties of all FeBTC obtained in this study were compared to commercial FeBTC (Basolite F-300), characterized using powder X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and nitrogen physisorption isotherms. All Fe-BTC MOF synthesized in this study showed improved textural properties compared to commercial Basolite F-300 such as higher crystallinity, higher surface area and larger pore size. It was found that the best synthesis method was by using the mixture of ethanol and water with equal volume ratio as solvent. The highest BET surface area of FeBTC synthesized using this method was 972 m2/g for FeBTC-EtOH/H2O. This value is 2.3 times higher than the surface area of commercial Basolite F-300 (418 m2/g). FeBTC with higher surface area is expected to have higher catalytic activity which makes this FeBTC an excellent candidate as a heterogenous catalyst for many reactions such as aldol condensation or esterification reaction
Evaluating the Energy and Economic Impacts of a Geothermal Heat Pump Installation in Italy
No full textDuring the past years, the need to reduce the consumption of finite resources and mitigate climate change has progressively increased. The building sector is responsible for a substantial portion of energy consumption and emissions. Therefore, the European Union (EU) aims to reduce the energy consumption of existing buildings and achieve climate neutrality. Several national and international programs have been activated to promote energy-saving interventions in the building sector. Researchers have also directed their attention towards energy efficiency initiatives for buildings, especially for Heating, Ventilation, and Air Conditioning systems (HVAC). However, many works on HVAC focus on improving existing systems through control and management, along with mainly considering energy aspects. Thus, this paper aims to investigate the benefits arising from the replacement of a gas-based thermal plant with a geothermal multiuse heat pump, able to simultaneously and independently produce hot and cold water. The intervention is examined from both an energy and economic perspective. The analysis depicts a reduction in energy consumptions and costs thanks to the intervention. This study could assist energy building managers as a preliminary analysis to evaluate potential energy-saving investments
Fermentative hydrogen production enhancement by microbial community selection and enrichment through biostimulation
No full textThis paper presents a novel technique to increase hydrogen production from dark fermentation of cheese whey, conducted using open mixed cultures. Hydrogen (H2)-producing microbial pools were selected and enriched using an innovative biostimulation technique, performed by sequential re-inocula of the interstitial microbial community using porous supports in sequential batch reactors. The supports offered a spatial refuge to the microbial community, facilitated re-inoculum procedures and reduce operational disturbance. Two different re-inoculum times (i.e. 24 h and 96 h) were tested to verify the influence of timing on the selection/enrichment. Results showed that the H2 production rate was up to 80 times higher using a 24 h re-inoculum time than using a 96 h re-inoculum time. Under a 24 h re-inoculum time, a stable H2 production rate was reached after two sequential re-inocula, with values ranging between 4 and 6.1 mLH2 h−1. The cumulative production, detected after the last re-inoculum (8 days), was 2.2 LH2 L-1reactor, corresponding to 42.5 mL gCOD-1. A very low methane (CH4) production was observed and only in the first two re-inocula, as short re-inoculum intervals favoured H2-producing bacteria. Microbiological analyses confirmed that subsequent re-inocula contributed to an increase in total microbial abundance. The proposed approach provides a concentrated inoculum in liquid medium (which is easy to use) exploiting an enrichment technique that is conceptually new and more economical/environmentally friendly than conventional thermal, acid or alkaline enrichment techniques
Study of Seed Layer Growth for Superconducting Fe(Se,Te) Film Deposition
No full textAmong Iron-Based Superconductors (IBS), the development of superconducting films of FeSe1-xTex [Fe(Se,Te)] is looked at with increasing interest due to the high performance in high magnetic fields and low temperatures. In this work, we report on the optimization of the deposition conditions of Fe(Se,Te) films grown on single-crystal CaF2 substrates by pulsed laser deposition (PLD) technique. The deposition of a Fe(Se,Te) bilayer is exploited to control the stoichiometry and the epitaxy simultaneously. The Fe(Se,Te) top layer is deposited at a temperature as low as 250 °C, using a film of the same material deposited at a higher temperature as a seed layer. The seed layer's structural properties and morphology have been studied by varying the deposition temperature between 350 and 470 °C. Seed layers with sharp out-of-plane orientation and smooth surfaces have been obtained at deposition temperatures of about 400 °C. Fe(Se,Te) bilayer (top +seed layer) shows enhanced superconducting properties compared to single-layer films, with a zero-resistance critical temperature of about 19 K and a critical current density above 0.1 MAcm-2 up to 9 T and 4.2 K. These results demonstrate the importance of the fine control of micro-structural and morphological properties of the seed layer to unlock high-performance Fe(Se,Te) films
Synthesis of Photoluminescent 2D Self-Assembled Silver Thiolate Nanoclusters for Sensors and Biomolecule Support
No full textSilver thiolate nanoclusters (Ag NCs) show distinctive optical properties resulting from their hybrid nature, metallic and molecular, exhibiting size-, structure-, and surface-dependent photoluminescence, thus enabling the exploitation of Ag NCs for potential applications in nanobiotechnology, catalysis, and biomedicine. However, tailoring Ag NCs for specific applications requires achieving long-term stability and may involve modifying surface chemistry, fine-tuning ligand composition, or adding functional groups. In this study, we report the synthesis of novel Ag NCs using 2-ethanephenylthiolate (SR) as a ligand, highlight critical points addressing stability, and characterize their optical and structural properties. A preliminary electrical characterization revealed high anisotropy, well suited for potential use in electronics/sensing applications. We also present the synthesis and characterization of Ag NCs using 10-carboxylic 2-ol thiolate (SR’COOH) having a terminal carboxylic group for conjugation with amine-containing molecules. We present a preliminary assessment of its bioconjugation capability using bovine serum albumin as a model protein indicating its prospective application as a biomolecule support
Circular Bioeconomy in the Metropolitan Area of Barcelona: Policy Recommendations to Optimize Biowaste Management
No full textMunicipal biowaste management is at the core of the transition towards a circular bioeconomy in the EU. However, most urban systems are still far from being aligned with these principles. This paper addresses the case of the Metropolitan Area of Barcelona. The current system of biowaste management is compared with a more sustainable alternative scenario. Regulatory and non-regulatory drivers and barriers for the transition from the current state to the alternative scenario are identified and later transformed into policy recommendations using a multi-stakeholder approach. This paper focuses on the separate collection of biowaste and the production of biomethane. Increasing the quantity and quality of separate biowaste collection is a prerequisite for the market-relevant production of biogas from anaerobic digestion that can be converted into biomethane. The results show that more efficient collection systems such as door-to-door or smart bins together with tax incentives such as the pay-as-you-throw principle are key to increasing the amount of collected biowaste, while targeted communication combined with controls and penalties are key to minimizing impurities. In addition to financial incentives for the construction of new anaerobic digestion plants, financial incentive systems are also required for the biomethane sector to ensure competitiveness with fossil fuels
Life Cycle Assessment Based on Primary Data of an Industrial Plant for Microalgae Cultivation
No full textMicroalgae are a potential feedstock for a wide range of final products. However, the commercialization of simple process routes and multi-product biorefinery schemes is hindered by unsatisfactory or uncertain environmental and economic performances. Many life cycle assessment (LCA) studies have evaluated the environmental sustainability of microalgal systems, leading to controversial results. In most cases, they are affected by the use of lab-scale extrapolated or literature data, resulting in qualitative and unreliable projections. This work presents a preliminary evaluation of the environmental profile of an industrial-scale plant by applying the LCA methodology with the use of primary data for the foreground inventory. The analyzed facility is installed in Caltagirone, Sicily (Italy). It has a capacity of 1200 kgDW year–1 (DW = dry weight biomass) cultivating Chlorella vulgaris in vertically stacked horizontal photobioreactors (VSt-PBRs) with a total volume of 40.4 m3. Demineralized water, produced via reverse osmosis of tap water, is used for cultivation and maintenance (cleaning). Centrifugation is used for dewatering the algal suspension from 2 gDW L–1 to ~200 gDW L–1. A cradle-to-gate assessment was performed using primary data on plant operation and poly(methyl methacrylate) (PMMA) usage (the main construction material for the PBRs). The LCA results highlight that (i) cultivation is by far the most impactful process step compared to cleaning and harvesting, and (ii) chemicals (nutrients for cultivation, and cleaning and sterilization agents) and electricity (pumping and agitation, thermoregulation, and LED lighting) are the flows that cause the main environmental hotspots. In contrast, PMMA usage and waste treatment provided lower relative contributions to generating potential impacts, while tap water consumption had negligible effects
Drift wave soliton formation via beat-driven zonal flow and implication on plasma confinement
No full textIn this work, gyrokinetic theory of drift waves (DWs) self-regulation via the beat-driven zonal flow (ZF) is presented, and finite diamagnetic drift frequency due to plasma nonuniformity is shown to play a dominant role in the ZF beat generation. The obtained nonlinear DW equation is a nonlinear Schrödinger equation, in which the linear dispersiveness, linear growth, nonuniformity of diamagnetic drift frequency, and cubic nonlinearity induced by the feedback of beat-driven ZF to DWs are self-consistently included. The nonlinear DW equation is solved numerically in both uniform and nonuniform plasmas. It is shown that the DW envelope soliton may form due to the balance of linear dispersiveness and nonlinearity and lead to turbulence spreading to linearly stable region. It is further found that though the threshold on the DW amplitude for soliton formation is well within the relevant parameter regimes of realistic tokamak experiments, solitons cannot extend beyond the range bounded by the turning points of the wave packet when plasma nonuniformity is self-consistently accounted for
Modeling of Multienergy Polygeneration Hybrid System for the Control Strategies of the Smart Microgrid at the ENEA Research Center in Portici
No full textIn response to the pressing need for sustainable energy solutions amidst escalating climate change challenges, the integration of polygenerative hybrid systems within smart microgrids has emerged as a promising avenue. This article delves into the modeling intricacies of such systems, focusing on the ENEA Research Center in Portici, Italy. Employing advanced simulation techniques and control strategies, the study elucidates the interplay between thermal and electrical components within smart microgrids. By leveraging TRNSYS software, the research assesses the efficacy of various control strategies in optimizing energy utilization and mitigating environmental impacts. Through comprehensive analysis and evaluation of multiple control strategies, the study not only contributes to the field of sustainable energy but also offers practical insights for policymakers and energy planners. Results underscore the significance of control strategies, with certain approaches demonstrating primary energy savings and CO2 emissions avoidance
S.A.P.I.EN.T.E. Hybrid System: An Experimental Test Facility Focused on Energy Generation and Hybrid Storage for Self-Consumption Strategies
No full textThe European Renewable Energy Directive promotes the uptake of Renewable Energy Communities and Jointly Acting Renewable Self-Consumers for the local production and shared consumption of energy, as an alternative to the classic model based on centralized production, transmission, and distribution. In this work, carried out under the MASE - ENEA 2022-2024 program agreement on Electrical System Research, the authors illustrate the hybrid system called S.A.P.I.EN.T.E., a full scale experimental test facility, comprising different energy generation and storage sections, in continuous evolution, and the inherent experimentations that aimed to maximize the selfconsumption of locally produced energy in the context of energy communities. We demonstrate, through experimental activities, the advantages in terms of energy self-consumption and selfsufficiency that such a system architecture can achieve