Brilliant Young Researchers in Clean Technologies

This paper deals with proton exchange membrane (PEM) electrolyzers directly coupled with a photovoltaic source. It proposes a method to increase the energy delivered to the electrolyzer by reconfiguring the electrical connection of the arrays according to solar radiation. Unlike the design criterion proposed by the literature, the suggested approach considers a source obtained by connecting arrays in parallel depending on solar radiation based on a fixed photovoltaic configuration. This method allows for the optimization of the operating point at medium or low solar radiation, where the fixed configuration gives poor results. The analysis is performed on a low-power plant (400 W). It is based on a commercial photovoltaic cell whose equivalent model is retrieved from data provided by the manufacturer. An equivalent model of the PEM electrolyzer is also derived. Two comparisons are proposed: the former considers a photovoltaic source designed according to the traditional approach, i.e., a fixed configuration; in the latter, a DC/DC converter as interface is adopted. The role of the converter is discussed to highlight the pros and cons. The optimal set point of the converter is calculated using an analytical equation that takes into account the electrolyzer model. In the proposed study, an increase of 17%, 62%, and 93% of the delivered energy has been obtained in three characteristic days, summer, spring/autumn, and winter, respectively, compared to the fixed PV configuration. These results are also better than those achieved using the converter. Results show that the proposed direct coupling technique applied to PEM electrolyzers in low-power plants is a good trade-off between a fixed photovoltaic source configuration and the use of a DC/DC converter. Full article

Energy harvesting is a clean technique for obtaining electrical energy from environmental energy. Mechanical vibrations are an energy source that can be used to produce electricity using piezoelectric energy harvesters. Vibrations and wind in bridges have the potential to produce clean energy that can be employed to supply energy to electronic devices with low consumption. The purpose of this paper was to validate the functioning of an energy harvester and test the electrical power generation potential of a system based on the oscillation of a rod with a tip mass to stimulate piezoelectric transducers by impact. The obtained results showed the electric energy productions for different test conditions. Experimentally, the proposed structure produced 0.337 µJ of energy after 14 s of testing. In addition, after one hour of operation, an estimated production of 10.4 mJ was obtained, considering four stacks of 25 piezoelectric disks each when periodic impacts of 50 N at 5.7 Hz stimulated the transducers. In future work, we will focus on taking advantage of the vibrations produced in the proposed structure induced by the mechanical vibration of bridges and vortex-induced vibration (VIV) through interaction with wind to produce clean energy that is useful for low-power applications. Full article

This investigation presents a new approach for evaluating soil organic carbon (SOC) content in farming soils using a photocatalytic chemical oxygen demand (PeCOD) analyzer combined with geographic information system (GIS) technology for spatial analysis. Soil samples were collected at various sites throughout Canada and were analyzed using sieve analysis, followed by further SOC evaluation using three distinct techniques: loss on ignition (LOI), Walkley-Black, and PeCOD. The PeCOD system, which relies on the photochemical oxidation of organic carbon, showed an exciting correlation between its evaluations and SOC content, making it a prompt and reliable method to evaluate SOC. In this investigation, finer materials such as clayey soils (soil fractions of (<50 µm)) demonstrated high SOC content compared to coarser ones (soil fractions of (>75 µm)) and decreased SOC content with increased soil depth, generally below the 30 cm mark. It should be noted that this investigation revealed that other variables, such as land management practices, precipitation, and atmospheric temperature, have drastic effects on the formation and residence time of SOC. GIS georeferencing еnablеd mapping of the SOC distribution and identification of hotspot areas with high SOC content. The results of this study have implications for sustainable farming, climate change mitigation, and soil health operations by providing farmers with schemes that amplify carbon sequestration while simultaneously improving soil health. Full article

Additive manufacturing (AM) is one of the technologies of Industry 4.0 that has been contributing to the development of different manufacturing industries. The integration of sustainability concepts into additive manufacturing has been gaining attention among researchers. This integration is essential in the development of AM technologies and can be a significant asset in terms of decision making for organizations. This work aims to present a concise literature review on the integration of decision making, especially multi-criteria decision making, and sustainability into the AM environment. The literature on this topic currently possesses a total of fifteen documents, which were analyzed in this work. Some developments on this topic have been achieved in domains such as material selection, process selection and challenges, and drivers’ analysis of sustainable AM. This review shows that even though there has been an effort in recent years to integrate sustainability into additive manufacturing, there is still a long road to the development of this topic for the future, and so some recommendations for future research paths are presented. Full article

As the environment is severely harmed by tobacco (like growing, processing, production, and disposal), the study was set forth to determine the tobacco cultivation status and perceptions of the tobacco farmers toward the environmental and health hazards of tobacco farmers due to tobacco cultivation. We conducted the study in Lama Upazila, Bandarban Hill District, Bangladesh. The survey method was applied to collect the necessary data, utilizing a pre-structured interview schedule, from 242 tobacco farmers who were selected randomly. The study’s results portrayed that the average tobacco cultivation farming experience of the farmers was about 10 years, and the farmers occupied about 0.97 acres of land for cultivating tobacco, while 81% of the tobacco farmers utilized the plain lands for cultivating tobacco, although the study area was a hilly one. A huge amount of fuel wood (average 5390 kg) was required for the curing of tobacco leaves. The farmers produced about 2 MT of tobacco per year and earned about BDT 89,066 (USD 810) from this production. Given that 77% of the tobacco farmers in the research area felt that tobacco production increased the risks to the environment and tobacco farmers health, their opinions ranged from somewhat to highly favorable, which meant they were concerned about the environment and health hazards. The research’s findings provide useful background knowledge on the detrimental effects of Bangladesh’s tobacco farming. Full article

The energy sector is the main source of greenhouse gases, so it has the highest potential for improvement. The improvements can be achieved by generating energy from renewable sources. It is necessary to combine production from renewable sources with storage systems. Thermal energy storage using concentrated solar power systems is a promising technology for dispatchable renewable energy that can guarantee a stable energy supply even in remote areas without contributing to greenhouse gas emissions during operation. However, it must be emphasised that greenhouse gases and other impacts can occur during the production process of concentrating solar system components. This paper analyses the receiver design to produce thermal energy for the existing CSP dish plant at the Energy Center of the Politecnico di Torino. The plant is designed to produce electrical energy in the spring and summer periods. In addition to this energy production, the CSP can be adopted to produce thermal energy, through hot water, during the less favourable periods of the year in terms of global solar radiation. The surface heat flux is calculated in the first part of the analysis to obtain the maximum internal temperature in the receiver, which is 873.7 °C. This value is a constraint for the choice of material for the solar receiver. A life cycle assessment is performed to compare the emissions generated during the production of the main components of the CSP system with the emissions generated by the methane-fuelled water heater to produce the same amount of thermal energy. It can be concluded that the production of the main components of the CSP system results in lower greenhouse gas emissions than the operational phase of a conventional system. Given the assumptions made, the utilization of methane leads to the emission of approximately 12,240 kg of CO₂, whereas the production of the CSP system results in emissions totalling 5332.8 kg of CO₂ equivalent Full article

Solar panels are an environmentally friendly alternative to fossil fuels; however, their useful life is limited to approximately 25 years, after which they become a waste management issue. Proper management and recycling of end-of-life (EOL) solar panels are paramount. It protects the environment because of the high energy consumption of silicon production. We can effectively decrease energy and cost requirements by recovering silicon from recycled solar panels. This is one-third of those needed for manufacturing silicon directly. Moreover, solar panels include heavy metals, such as lead, tin, and cadmium, which pose risks to human health and the environment. Empirical evidence suggests that the costs of mining materials can exceed those of recycled materials, thereby making recycling a more cost-effective means of resource harvesting. This review paper focuses on the techniques developed to delaminate solar panels, which are considered a crucial step in the recycling of EOL solar panels. Initially, various classifications of solar panels are given. Subsequently, an analysis of the diverse methods of solar panel delamination and their efficacy in the retrieval of valued materials is presented. This investigation has identified three primary modes of delamination, namely mechanical, thermal, and chemical. Among these, mechanical delamination is deemed to be a sustainable and cost-effective option when compared to thermal and chemical delamination. The current most popular method of thermal delamination is characterized by its high energy consumption and potential emission, and the chemical delamination generates hazardous liquids that pose their own threat to the environment. This study emphasizes the mechanical delamination techniques, characterized by their environmentally friendly nature, minimal ecological footprint, and capacity to retrieve entire glass panels intact. This paper also discusses the current gaps and potential enhancements for mechanical delamination techniques. For example, some delamination techniques result in crushed materials. Thus, the handling and recovery of materials such as glass and silicon cells require the implementation of an appropriate sorting technique. Also, the value obtained from recovering crushed materials is lower than that of intact glass and silicon cells. Full article

Wastewater discharges from industrial processes typically include elevated concentrations of contaminants, which largely consist of potentially harmful chemicals such as heavy metals. These contaminants are characterized by their slow rate of decomposition. Hence, the removal of these metallic ions from effluents poses a challenge. Among different treatments, the adsorption approach has considerable potential due to its ability to effectively eliminate both soluble and insoluble pollutants from effluent, even at lower levels of concentration. Of various wastes, fly ash (FA) material has been the subject of attention because it is abundant, has favorable qualities, and contains a high percentage of minerals. This review investigates multiple facets, with a specific focus on the application of FA, an industrial byproduct, as an adsorbent in removing heavy metals. A comprehensive examination was conducted on a range of concerns pertaining to the pollution caused by metallic ions, including the underlying causes, levels of contamination, health implications of heavy metals, and removal methods. Multiple factors were found to affect the adsorption process. Of all the factors, the pH value considerably influences the elimination of heavy metals. An acidic pH range of 2.5–4.5 was found to be optimal for achieving the highest possible elimination of As(V), Cu(II), Hg(II), and Cr(VI). The latter elimination rate reached 89% at the optimal pH level. Most heavy metals’ adsorption isotherms conformed to the Langmuir or Freundlich models, while the pseudo-second-order kinetics provided a satisfactory match for their removal. Using a raw FA, adsorption capacities were achieved in the removal of metallic ions, Ni(II), Pb(II), and Cr(VI), that ranged from 14.0 to 23.9 mg g⁻¹. Meanwhile, the FA-zeolite showed a remarkable capacity to adsorb ions Mn(II), Ni(II), Cd(II), Cu(II), and Pb(II), with values ranging from about 31 to 66 mg g⁻¹. The cost analysis showed that the treatment of FA is economically advantageous and may result in significant cost reductions in comparison to commercial adsorbents. In summary, FA is an inexpensive waste material with potential for water treatment applications and several other purposes due to its excellent chemical and mineralogical composition. Full article

This study aims to comprehensively investigate the current advances in water treatment technologies for the elimination of heavy metals using biomass-based adsorbents. The enhancement of adsorption capacity in biomass materials is achieved through surface modification, which increases their porosity and surface area. The study therefore focuses on the impact of different surface modification techniques on the adsorption capacity, as well as the evaluation of adsorptive removal techniques and the analysis of various isotherm and kinetics models applied to heavy metal contaminants. The utilization of kinetic and isotherm models in heavy metal sorption is crucial as it provides a theoretical background to understand and predict the removal efficiency of different adsorbent materials. In contrast to previous studies, this research examines a wide range of adsorbent materials, providing a comprehensive understanding of their efficacy in removing heavy metals from wastewater. The study also delves into the theoretical foundations of the isotherm and kinetics models, highlighting their strengths, limitations, and effectiveness in describing the performance of the adsorbents. Moreover, the study sheds light on the regenerability of adsorbents and the potential for their engineering applications. Valuable insights into the state-of-the-art methods for heavy metal wastewater cleanup and the resources required for future developments were discussed. Full article

Material Flow Cost Accounting (MFCA) is an environmental management accounting method that allocates costs to material and energy flows through a process, thereby enabling a simultaneous reduction in environmental impacts alongside an improvement in business and economic efficiency. This study illustrates the versatility of MFCA beyond its usual application to existing production and manufacturing processes. In this paper, MFCA is used to assess the financial viability of two emerging recycling technologies, IRETA2 (Development and Evaluation of Recycling Routes to Recover Tantalum from Electronic Waste) and ReComp (Development of an Innovative, Economically and Ecologically Sensible Recycling Method for Metallised ABS and PC/ABS Composite Waste). These two projects differ in their process structure. Whilst IRETA2 is a strictly linear recycling process, ReComp consists of two process streams, split according to the treatment of its two material fractions. For both projects, the lab-scale experimental results were used to develop an MFCA model of the recycling process scaled at each project partner’s facilities. MFCA was utilised to calculate the projects’ overall profit or loss, the impact of the final products’ market conditions and processing rate (in the case of IRETA2), or machinery capacity (for ReComp) on the overall results. The results show that neither IRETA2 nor ReComp are financially viable based on the current output products’ market value and quantity produced. However, through a sensitivity analysis, it is demonstrated that IRETA2 could become financially viable if the processing rate or market conditions were to improve. Additionally, ReComp could become financially viable if there was an increase in machine capacity. Finally, this paper also explores possible implications of MFCA when applied to emerging recycling technologies on EU policy and strategy, particularly those related to the EU Green Deal, such as extended producer responsibility and supply chain acts. Full article

In this work, Rhodiasolv^® PolarClean was employed as a more sustainable solvent for the preparation of poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) flat sheet membranes via phase inversion technique by coupling vapour induced phase separation (VIPS) and non-solvent induced phase separation (NIPS) processes. Preliminary calculations based on Hansen solubility parameters well predicted the solubilization of the polymer in the selected solvent. The effect of exposure time on humidity and the influence of polyethylene glycol (PEG), polyvinyl pyrrolidone (PVP) and sulfonated polyether sulfone (S-PES) on membrane properties and performance, were evaluated. Three different coagulation bath compositions were also explored. The obtained membranes, prepared using a more sustainable approach, were compared with those produced with the traditional toxic solvent N-methyl-2-pyrrolidone (NMP) and characterised in terms of morphology, porosity, wettability, pore size, surface roughness and mechanical resistance. The potential influence of the new solvent on the crystallinity of PVDF-HFP-based membranes was also evaluated by infrared spectroscopy. The adjustment of the parameters investigated allowed tuning of the membrane pore size in the microfiltration (MF) and ultrafiltration (UF) range resulting in membranes with various morphologies. From the water permeability and rejection tests, performed with methylene blue dye, the prepared membranes showed their potentiality to be used in MF and UF applications. Full article