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Zinc oxide quantum dots for textile dyes and real industrial wastewater treatment: Solar photocatalytic activity, photoluminescence properties and recycling process
摘要： Three samples of ZnO quantum dots (ZQDs) were synthesized by a modified sol–gel method at different temperatures for 3 h. The first sample (S1) was prepared at room temperature 27 °C, while second and third samples (S2) and (S3) were prepared by the calcination process at 500 and 900 °C, respectively. A study of XRD and TEM determines the purity, high crystallinity and the presence of elongated shape of the prepared catalysts. On using TEM, DRS and EBT analysis, the crystallite size values, bandgap energy, and active surface area were (7.1 nm, 3.49 eV, and 150.1 m2/g), (9.8 nm, 3.45 eV and 112.2 m2/g) and (13.5 nm, 3.39 eV and 78.94 m2/g) for S1, S2, and S3, respectively. The Photoluminescence properties showed that the fluorescence rate for S1 was doubled the observed one in the S2 sample. The photodegradation results of both methyl orange as an industrial raw material and real industrial wastewater of S1 sample showed the finest activity when compared with the rest samples. It was cleared from the collecting data that the photocatalytic performance decreases with the crystallite size increases The mineralization efficiency of the real industrial wastewater that exposed to sunlight for six months were evaluated according to the allowed COD limit for Egyptian Environmental Law, In addition the recycling process for reusable for ZnO prepared samples for 8 times investigated and evaluated.
关键词： Real industrial wastewater,Zinc oxide quantum dots,Solar photocatalytic activity,Recycling process,Sol-gel method
更新于2025-09-23 15:21:01
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Physical Separation and Beneficiation of End-of-Life Photovoltaic Panel Materials: Utilizing Temperature Swings and Particle Shape
摘要： One of the technical challenges with the recovery of valuable materials from end-of-life (EOL) photovoltaic (PV) modules for recycling is the liberation and separation of the materials. We present a potential method to liberate and separate shredded EOL PV panels for the recovery of Si wafer particles. The backing material is removed by submersion in liquid nitrogen, while the encapsulant is removed by pyrolysis. After pyrolysis, separation of the liberated particles (i.e., Si wafer and glass) is carried out by using particle size and shape with mechanical screening. Using this robust approach, a Si wafer grade of 86% and a recovery of 88% were achieved.
关键词： Recycling,Silicon,Particle shape,Photovoltaic panels,Silicon compounds,Temperature swings
更新于2025-09-23 15:21:01
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Challenges and opportunities for efficiency boost of next generation Cu(In,Ga)Se <sub/>2</sub> solar cells: prospect for a paradigm shift
摘要： Cu(In,Ga)Se2 photovoltaic technology has notably progressed over the past years. Power conversion efficiencies above 23% were reached in spite of the absorber polycrystalline nature. Although efficiencies are still far from the practical limits, the material quality is approaching that of III-V compounds that yield the most efficient solar cells. High carrier lifetime, low open circuit voltage deficit and external radiative efficiency in single-digit percentage range, suggest the next efficiency boost may arise from the implementation of alternative device architectures. In this perspective paper, we describe the current challenges and pathways to enhance the power conversion efficiency of Cu(In,Ga)Se2 solar cells. Specifically, we suggest the use of non-graded absorbers, integration of charge selective contacts and maximization of photon recycling. We examine these concepts by a semi-empirical device modelling approach, and show that these strategies can lead to efficiencies of 29% under the AM1.5 global spectrum. An analysis whether or not current state-of-the-art Cu(In,Ga)Se2 solar cells already benefit from photon recycling is also presented.
关键词： Cu(In,Ga)Se2,charge selective contacts,photon recycling,power conversion efficiency,solar cells
更新于2025-09-23 15:21:01
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Reliability and Ecological Aspects of Photovoltaic Modules || Toxic Materials Used in Thin Film Photovoltaics and Their Impacts on Environment
摘要： Photovoltaic industry has proved to be a growing and advantageous source of energy as it can be renewable, sustainable, reliable and clean. Significant improvements have been made in materials used and the production processes to reduce the costs, and to avoid possible issues induced by some hazardous materials. However, some health and environment challenges last, which must be overcome to make this technology a source of truly clean energy. This chapter provides an overview on the major environmental impacts of thin film technology associated with the use of toxic materials and the chemicals in the manufacturing processes. A summary of Environmental, Health and Safety issues associated with some thin film technologies like copper indium gallium diselenide (CIS/CIGS), cadmium telluride (CdTe) and amorphous silicon (a-Si) is done, in order to investigate potential infections induced by the environmental release of trace elements, usually coming from chemical vapor inhalation and eventually accidental spills during the manufacturing processes, on the health of humans and animals. Potential solutions will be provided to prevent some environmental issues.
关键词： waste minimization,recycling,environmental impacts,thin film technology,hazardous materials,toxic chemicals,manufacturing processes
更新于2025-09-23 15:19:57
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Assessment of LED lamps components and materials for a recycling perspective
摘要： LED lamps have already conquered the market of general lighting. This new product will generate a substantial flow of e-waste requiring studies for the correct management, especially concerning recycling alternatives. This study proposes a material characterization of all the tubular and bulb LED lamp components (carcass, LEDs, printed circuit board and LED module). After manual disassembling, polymers were characterized by infrared spectroscopy (FTIR), and the metals by X-ray fluorescence (XRF) and acid leaching followed by ICP-OES analysis. By the novelty of separating and characterizing the LED lamp’s components, a process which has not yet been studied, the results allow for a better interpretation of the different materials distribution within the lamps which is essential to improve the efficiency of a recycling route. To exemplify, the element gallium, which has a recycling appeal from the LEDs, is present in a larger quantity in the printed circuit boards. The study also provides an analysis of the materials recycling rates and economic values, and the comparison with the concentration of natural ores. Thus, it was possible to discuss about target components and materials and the recycling alternatives for each component. LED lamps contain interesting materials, with even higher concentrations than natural ores, such as gold, silver, copper, aluminum, tin and gallium. If recycled, tubular lamps and bulb lamps would have the economic recovery of USD 2405.99 and USD 2595.02 per ton, respectively. The gold was found to be the most valuable material, and the LEDs the most valuable component of the LED lamps.
关键词： Recycling,LED lamp,Gallium,WEEE,Gold,Material characterization
更新于2025-09-23 15:19:57
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High Performance Organic Solar Cells Fabricated Using Recycled Transparent Conductive Substrates
摘要： The power conversion e?ciency (PCE) of organic solar cells (OSCs) has been gradually increasing over the past years, but these emerging photovoltaic devices still su?er from relatively short lifetimes. To promote circular economy and reduce costly electronic materials wastes, we explore the possibility of recycling durable zinc oxide coated indium tin oxide (ITO/ZnO) from nonfullerene OSCs through sequential ultrasonication in a series of solvents followed by thermal annealing. With the adequate cleaning sequence, the recycled ITO/ZnO substrates produce PCEs of 8.65%, a value comparable to the PCEs obtained with freshly prepared substrates (8.73%). Our results also indicate that isopropanol gradually removes the zinc oxide layer and should thus be avoided when attempting multiple successive recycling of the same substrate. ITO/ZnO substrates recycled 10 times with and without isopropanol yield PCEs of 5.14% and 7.93%, respectively. By optimizing the recycling procedure, we introduce a simple strategy to considerably increase the lifecycle of transparent electrode substrates employed in organic electronic devices and decrease the amount of wastes from the electronic industry.
关键词： Recycling,Zinc oxide,PBDB-T,Organic electronics,Nonfullerene acceptors
更新于2025-09-23 15:19:57
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LCA Case Study to LED Outdoor Luminaries as a Circular Economy Solution to Local Scale
摘要： The replacement of luminaires with discharge lamps with high luminous e?cacy and long life-time LED based equipment is a reality worldwide promoted by policies that favor their gradual substitution. There is a great concern in this manufacturing industry to develop new luminaires with low environmental impact during the manufacturing and transportation processes and its end-of-life disposal (reducing greenhouse gas emissions, toxic or hazardous components, . . . ). Life cycle assessment (LCA) is a very extended tool used to provide information on the quality and quantity of environmental impacts in the life cycle phases of any product, system, or service. This article includes all phases of the LCA analysis of a selected streetlight LED luminaire manufactured by a SME where a land?ll deposit is the end-of-life scenario. In a second phase, alternatives are sought for the reuse of the most signi?cant elements that improve its local economy. The results are classi?ed and sorted according to the ISO 14040 standard.
关键词： LED lighting,streetlight waste,life cycle assessment,recycling,circular economy
更新于2025-09-23 15:19:57
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Review on direct metal laser deposition manufacturing technology for the Ti-6Al-4V alloy
摘要： Direct laser metal deposition (DLMD) is a breaking edge laser-based additive manufacturing (LAM) technique with the possibility of changing the perception of design and manufacturing as a whole. It is well suitable for building and repairing applications in the aerospace industry which usually requires high level of accuracy and customization of parts; this technique enables the fabrication of materials known to pose difficulties during processing such as titanium alloys. Ti-6Al-4V, which is the most employed titanium-based alloy is one of the materials that are most explored for additive manufacturing process. However, this process is currently at its pioneer stage and very little is known about the fundamental metallurgy and physio-chemical basis that govern the process. Currently, the major problems faced in additive manufacturing include evolution of residual stresses leading to deformed parts and formation of defects such as pores and cracks which are detrimental to the quality of deposits. The presence of these unwanted defects on additively manufactured parts depends on the complex mechanisms taking place in the melt pool during melting, cooling, and solidification which are dependent on processing variables. In addition, during fabrication, some feedstock powder does not melt and thus does not make up part of the final product. The present text entails classification of LAM technologies, operational principles of DLMD, feedstock quality requirements, material laser interaction mechanism, and metallurgy of Ti-6AL-4V alloy.
关键词： Ti-6Al-4V,Process variables,Powder recycling,LAM,DLMS
更新于2025-09-23 15:19:57
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Eco-Energetical Life Cycle Assessment of Materials and Components of Photovoltaic Power Plant
摘要： During the conversion of solar radiation into electricity, photovoltaic installations do not emit harmful compounds into the environment. However, the stage of production and post-use management of their elements requires large amounts of energy and materials. Therefore, this publication was intended to conduct an eco-energy life cycle analysis of photovoltaic power plant materials and components based on the LCA method. The subject of the study was a 1 MW photovoltaic power plant, located in Poland. Eco-indicator 99, CED and IPCC were used as calculation procedures. Among the analyzed elements of the power plant, the highest level of negative impact on the environment was characterized by the life cycle of photovoltaic panels stored at the landfill after exploitation (the highest demand for energy, materials and CO2 emissions). Among the materials of the power plant distinguished by the highest harmful effect on health and the quality of the environment stands out: silver, nickel, copper, PA6, lead and cadmium. The use of recycling processes would reduce the negative impact on the environment in the context of the entire life cycle, for most materials and elements. Based on the results obtained, guidelines were proposed for the pro-environmental post-use management of materials and elements of photovoltaic power plants.
关键词： recycling,photovoltaics panels,CED,LCA,IPCC,landfill,Eco-indicator 99
更新于2025-09-23 15:19:57
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Synthesis, characterization and thermoelectric performance of Mg2(Si,Sn,Ge) materials using Si-kerf waste from photovoltaic technology
摘要： The recycling acquisition of silicon waste from photovoltaic industry has gained an increasing attention nowadays, since more than 50% of high purity material ends up as kerf during the wafer cutting process. Currently, different Si-based applications are being exploited in terms of using such Si kerf, in order to lower cost and significantly increase environmental impact. Thermoelectric devices can efficiently contribute towards this recycling approach, via the preparation of highly efficient silicides for power generation. In this work, Bi doped Mg2(Si,Sn,Ge) materials were prepared using Si-kerf originated from photovoltaic (PV) cutting wastes. Different Bi concentrations were studied in terms of thermoelectric properties and performance and a high figure-of-merit of 1.1. was achieved at 800K. In addition, a thorough structural and mechanical property characterization, such as morphology, phase identification, hardness and indentation modulus has been conducted. These results, which were evaluated and compared to materials prepared with pure Si (>99.9%), are presented for the first time for Mg2(Si,Sn,Ge) materials.
关键词： magnesium silicides,thermoelectric figure of merit,mechanical/structural properties,multiphase,silicon,recycling
更新于2025-09-19 17:13:59