Search Results (15)

The global shift toward renewable energy and circular economy models requires industrial systems that minimize waste and recover value across entire life cycles. This review synthesizes recent advances in by-product recovery technologies supporting renewable energy and circular industrial processes. Thermal, biological, chemical/electrochemical, and biotechnological routes are analyzed across battery and e-waste recycling, bioenergy, wastewater, and agri-food sectors, with emphasis on integration through Life Cycle Assessment (LCA), techno-economic analysis (TEA), and multi-criteria decision analysis (MCDA) coupled to process simulation, digital twins, and artificial intelligence tools. Policy and economic frameworks, including the European Green Deal and the Critical Raw Materials Act, are examined in relation to technology readiness and environmental performance. Hybrid recovery systems, such as pyro-hydro-bio configurations, enable higher resource efficiency and reduced environmental impact compared with stand-alone routes. Across all technologies, major hotspots include electricity demand, reagent use, gas handling, and concentrate management, while process integration, heat recovery, and realistic substitution credits significantly improve life cycle outcomes. Harmonized LCA-TEA-MCDA frameworks and digitalized optimization emerge as essential tools for scaling sustainable, resource-efficient, and low-impact industrial ecosystems consistent with circular economy and renewable energy objectives. Full article

Algal biofuels have been investigated as an alternative to fossil fuels and first-generation biofuels for transportation in the United States since the 1970s. Yet after five decades of development, scalability and implementation remain limited—largely due to persistent barriers such as low biomass productivity, modest lipid yields, and energy-intensive processing methods. These technical challenges significantly constrain the feasibility of large-scale commercialization despite substantial research and investment. To evaluate progress toward commercial viability, this study harmonized energy inputs and outputs across 508 observations on the production of algal biofuel energy return on energy investment (EROEI) in the United States. While bioethanol achieves an EROEI of (2.8) and oil (8.7), the analysis produced a mean EROEI of 1.01—essentially the break-even point—irrespective of system boundaries. Life-cycle analysis results showed that hydrothermal liquefaction in algal diesel production yielded a slightly higher mean EROEI (0.67) than transesterification (0.51), yet both showed net energy losses. Co-products were found to increase EROEI values, particularly when recycled into production processes. Collectively, these findings indicate that research and development to date has not produced a technology with net energy gains sufficient for commercial viability. For this reason, algal biofuels show little potential to alleviate the ongoing decline in the EROEI of petroleum and are not a promising renewable energy option for reducing greenhouse gas emissions from the transportation sector. They also show little promise for alleviating the land use, food vs. fuel and other controversies that have plagued first and second-generation biofuels. Full article

The ventilation system is one of the most important elements of a building for the appropriate insurance of indoor climate parameters. Nowadays, textile ventilation systems are increasingly being used as a solution for low-energy buildings. Greater air movement and distribution in ventilation systems often leads to one of the most noticeable issues for people—increased noise in the indoor environment. One of the solutions is to use noise reducing diffusers. The aim of this research was to design and test a diffuser that fulfills noise regulations, would be light (weight less than 3 kg), be able to flexibly change geometry and have a design that harmonizes with the interior design, could be easily installed into a suspended ceiling, have a simple connection to the ventilation duct and be able to be effortlessly removed for maintenance, and be sustainable (usage of recycled materials). Three types of diffusers were created according to set characteristics and tested. The test results showed that the aim of the research was achieved—the emitted noise levels are below the regulation’s required level of less than 45 dBA. Also, it is light—the weight is 1.7 kg and 2.8 kg, respectively, for square and rectangular diffusers; has a flexible construction and design; is made from recycled materials. Full article

This study evaluates the environmental impacts of shipbuilding materials through life cycle assessment (LCA) and assesses potential exposure under the EU Carbon Border Adjustment Mechanism (CBAM). Three representative vessel types, a pure car and truck carrier (PCTC), a bulk carrier, and a container ship, were analyzed across scenarios reflecting different steelmaking routes, recycling rates, and regional energy mixes. Results show that structural steel (AH36, EH36, DH36, A/B grades) overwhelmingly dominates embedded emissions, while aluminium and copper contribute secondarily but with high sensitivity to recycling and energy pathways. Coatings, polymers, and yard processes add smaller but non-negligible effects. Scenario-based CBAM cost estimates for 2026–2030 indicate rising liabilities, with container vessels facing the highest exposure, followed by bulk carriers and PCTCs. The findings highlight the strategic importance of steel sourcing, recycling strategies, and verifiable supply chain data for reducing embedded emissions and mitigating financial risks. While operational emissions still dominate the life cycle, the relative importance of construction-phase emissions will grow as shipping decarbonizes. Current EU-level discussions on extending CBAM to maritime services, together with recognition of domestic carbon pricing as a potential pathway to reduce liabilities, underscore regulatory uncertainty and emphasize the need for harmonized methods, transparent datasets, and digital integration to support decarbonization. Full article

Light-emitting diodes (LEDs) have gained widespread adoption as solid-state lighting sources due to their compact size, long operational lifetime, high brightness, and mechanical robustness. This paper presents the development and implementation of an isolated AC-DC LED electronic lighting driver circuit that integrates a modified flyback converter with a lossless snubber circuit, along with inherent power factor correction (PFC). The proposed design operates the transformer’s magnetizing inductor in the discontinuous conduction mode (DCM), thereby naturally achieving PFC without the need for complex control circuitry. Furthermore, the circuit is capable of recycling the energy stored in the transformer’s leakage inductance, improving overall efficiency. The input current harmonics are shown to comply with the IEC 61000-3-2 Class C standard. A 72 W (36 V/2 A) prototype has been constructed and tested under a 110 V AC input. Experimental results confirm the effectiveness of the proposed design, achieving a power factor of 0.9816, a total harmonic distortion (THD) of 12.094%, an output voltage ripple factor of 9.7%, and an output current ripple factor of 11.22%. These results validate the performance and practical viability of the proposed LED driver architecture. Full article

The rapid growth of low-power Internet of Things (IoT) applications has created an urgent demand for compact, battery-free power solutions. However, most existing RF energy harvesters rely on active rectifiers, multi-phase topologies, or complex tuning networks, which increase circuit complexity and static power overhead while struggling to maintain high efficiency under microwatt-level inputs. To address this challenge, this work proposes a harmonic-recycling, passive, RF-energy-harvesting system with integrated power management (HR-P-RFEH). The system adopts a planar microstrip architecture compatible with MEMS fabrication, integrating a dual-stage voltage multiplier rectifier (VMR) and a stub-based harmonic suppression–recycling network. The design was verified through combined electromagnetic/circuit co-simulations, PCB prototyping, and experimental measurements. Operating at 915 MHz under a 0 dBm input and a 2 k$\Omega$ load, the HR-P-RFEH achieves a stable 1.4 V DC output and a peak rectification efficiency of 70.7%. Compared with a conventional single-stage rectifier, it improves the output voltage by 22.5% and the efficiency by 16.4%. The rectified power is further regulated by a BQ25570-based unit to provide a stable 3.3 V supply buffered by a 47 mF supercapacitor, ensuring continuous operation under intermittent RF input. In comparison with the state of the art, the proposed fully passive, harmonic-recycling design achieves competitive efficiency without active bias or adaptive tuning while remaining MEMS- and LTCC-ready. These results highlight HR-P-RFEH as a scalable and fabrication-friendly building block for next-generation energy-autonomous IoT and MEMS systems. Full article

With the growing wave of end-of-life new energy vehicles, the recycling of lithium iron phosphate (LFP) batteries has become increasingly imperative. In contrast to conventional pyrometallurgical and hydrometallurgical approaches, recent efforts have shifted toward innovative recycling strategies and emerging applications for spent LFP materials. During battery operation, the irreversible oxidation of Fe²⁺ to Fe³⁺ often leads to lithium loss and performance degradation. To address this, various approaches—such as electrochemical delamination and ultrasonic separation—have been developed to efficiently detach cathode materials from current collectors, followed by thermal or wet-chemical regeneration to restore their electrochemical activity. Beyond conventional regeneration, the upcycling of spent LFP into value-added functional materials offers a sustainable pathway for resource reutilization. Notably, phosphorus extracted from LFP can be converted into slow-release fertilizers, broadening the scope of secondary applications. As the volume of spent LFP batteries continues to rise, there is an urgent need to establish an integrated recycling framework that harmonizes environmental impact, technical efficiency, and economic viability. Henceforth, this review summarizes recent advances in LFP recycling and upcycling, discusses critical challenges, and provides strategic insights for the sustainable and high-value reuse of spent LFP cathodes. Full article

Rapid growth of electric vehicles has increased demand for lithium-ion batteries (LIBs), raising concerns regarding their end-of-life management. This study comprehensively evaluates the closed-loop recycling of cathode materials from spent LIBs by integrating life cycle assessment (LCA), technoeconomic analysis, and technological comparison. Typical approaches—including pyrometallurgy, hydrometallurgy, and other processes such as organic acid leaching and in situ reduction roasting—are systematically reviewed. While pyrometallurgy offers scalability, it is hindered by high energy consumption and excessive greenhouse gas emissions. Hydrometallurgy achieves higher metal recovery rates with better environmental performance but requires complex chemical and wastewater management. Emerging methods and regeneration techniques such as co-precipitation and sol–gel synthesis demonstrate potential for high-purity material recovery and circular manufacturing. LCA results confirm that recycling significantly reduces GHG emissions, especially for high-nickel cathode chemistry. However, the environmental benefits are affected by upstream factors such as collection, disassembly, and logistics. Technoeconomic simulations show that profitability is strongly influenced by battery composition, regional cost structures, and collection rates. The study highlights the necessity of harmonized LCA boundaries, process optimization, and supportive policy frameworks to scale environmentally and economically sustainable LIB recycling, ensuring long-term supply security for critical battery materials. Full article

The outlook for biobased plastics in packaging applications is increasingly promising, driven by a combination of environmental advantages, technological innovation, and shifting market dynamics. Derived from renewable biological resources, these materials offer compelling benefits over conventional fossil-based plastics. They can substantially reduce greenhouse gas emissions, are often recyclable or biodegradable, and, in some cases, require less energy to produce. These characteristics position biobased plastics as a key solution to urgent environmental challenges, particularly those related to climate change and resource scarcity. Biobased plastics also demonstrate remarkable versatility. Their applications range from high-performance barrier layers in multilayer packaging to thermoformed containers, textile fibers, and lightweight plastic bags. Notably, all major fossil-based packaging applications can be substituted with biobased alternatives. This adaptability enhances their commercial viability across diverse sectors, including food and beverage, pharmaceutical, cosmetics, agriculture, textiles, and consumer goods. Several factors are accelerating growth in this sector. These include the increasing urgency of climate action, the innovation potential of biobased materials, and expanding government support through funding and regulatory initiatives. At the same time, consumer demand is shifting toward sustainable products, and companies are aligning their strategies with environmental, social, and governance (ESG) goals—further boosting market momentum. However, significant challenges remain. High production costs, limited economies of scale, and the capital-intensive nature of scaling biobased processes present economic hurdles. The absence of harmonized policies and standards across regions, along with underdeveloped end-of-life infrastructure, impedes effective waste management and recycling. Additionally, consumer confusion around the disposal of biobased plastics—particularly those labeled as biodegradable or compostable—can lead to contamination in recycling streams. Overcoming these barriers will require a coordinated, multifaceted approach. Key actions include investing in infrastructure, advancing technological innovation, supporting research and development, and establishing clear, consistent regulatory frameworks. Public procurement policies, eco-labeling schemes, and incentives for low-carbon products can also play a pivotal role in accelerating adoption. With the right support mechanisms in place, biobased plastics have the potential to become a cornerstone of a sustainable, circular economy. Full article

An important task for the European Union is to transpose agreements and international standards in regulation and directives that are binding on member states. The resultant European action plans and directives identify priority areas in the building and energy sectors where circular economy principles can be applied. Italy records a general circular materials rate of 20.8%, surpassing the mean European value. But low recycling rates are still registered in the construction sector. This paper aims to assess the position of Italy with respect to the European regulatory framework on circularity in the energy transition of buildings. Firstly, the government’s initiatives and technical standards are introduced and commented upon. Secondly, the study illustrates the current Italian platforms, networks, and public and private initiatives highlighting opportunities and obstacles that the energy sector has to overcome in the area of circularity. It emerges that Italian policies still use voluntary tools that are not sufficiently in line with an effective circular economy model. Moreover, data collection plays a crucial role in accelerating the implementation of future actions. Italy should consider the foundation of a National Observatory for the Circular Economy to elaborate European directives, harmonize regional policies, and promote the implementation of effective practices. Full article

Objective: The rapid growth of electric vehicle (EV) adoption has led to an unprecedented increase in lithium-ion battery (LIB) demand and end-of-life waste, underscoring the urgent need for effective recycling strategies. This review evaluates current progress in EV battery recycling and explores future prospects. Design: Review based on PRISMA 2020. Data sources: Scientific publications indexed in major databases such as Scopus, Web of Science, and ScienceDirect were searched for relevant studies published between 2020 and 15 April 2025. Inclusion criteria: Studies were included if they were published in English between 2020 and 15 April 2025, and focused on the recycling of electric vehicle batteries. Eligible studies specifically addressed (i) recycling methods, technologies, and material recovery processes for EV batteries; (ii) the impact of recycled battery systems on power generation processes and grid stability; and (iii) assessments of materials used in battery manufacturing, including efficiency and recyclability. Review articles and meta-analyses were excluded to ensure the inclusion of only original research data. Data extraction: Data were independently screened and extracted by two researchers and analyzed for recovery rates, environmental impact, and system-level energy contributions. One researcher independently screened all articles and extracted relevant data. A second researcher validated the accuracy of extracted data. The data were then organized and analyzed based on reported quantitative and qualitative indicators related to recycling methods, material recovery rates, environmental impact, and system-level energy benefits. Results: A total of 23 studies were included. Significant progress has been made in hydrometallurgical and direct recycling processes, with recovery rates of critical metals (Li, Co, Ni) improving. Second-life battery applications also show promise for grid stabilization and renewable energy storage. Furthermore, recycled batteries show potential in stabilizing power grids through second-life applications in BESS. Conclusion: EV battery recycling is a vital strategy for addressing raw material scarcity, minimizing environmental harm, and supporting energy resilience. However, challenges persist in policy harmonization, technology scaling, and economic viability. Future progress will depend on integrated efforts across sectors and regions to build a circular battery economy. Full article

The increasing adoption of electric vehicles (EVs) has led to a surge in end-of-life (EOL) lithium-ion batteries (LIBs), necessitating efficient recycling strategies to mitigate environmental risks and recover critical materials. This study compares the EV battery recycling frameworks in China and the United States, focusing on policy effectiveness, technological advancements, and material recovery efficiencies. China’s extended producer responsibility (EPR) policies and 14th Five-Year Plan mandate strict recycling targets, achieving a 40% battery recycling rate with 90% material recovery efficiency. Hydrometallurgical methods dominate, reducing energy consumption by 50% compared to virgin material extraction. The US, leveraging incentive-based mechanisms and private sector innovations, has a 35% recycling rate but a higher 95% resource recovery efficiency, mainly due to direct recycling and AI-based sorting technologies. Despite these advancements, challenges remain, including high recycling costs, inconsistent global regulations, and supply chain inefficiencies. To enhance sustainability, this study recommends harmonized international policies, investment in next-generation recycling technologies, and second-life battery applications. Emerging innovations, such as AI-driven sorting and direct cathode regeneration, could increase recovery efficiency by 20–30%, further reducing lifecycle costs. By integrating synergistic policies and advanced recycling infrastructures, China and the US can set a global precedent for sustainable EV battery management, driving the transition toward a circular economy. Future research should explore life cycle cost analysis and battery reuse strategies to optimize long-term sustainability. Full article

Recently, a new type of lighting source, deep ultraviolet light-emitting diode (LED), has appeared in the markets of space purification and surface sterilization. In this paper, a new type of electronic lighting driver for supplying a deep-ultraviolet LED sterilization lamp is proposed and developed. The main circuit combines a buck converter and a flyback converter into a single-stage single-switch buck-flyback AC-DC power converter with power factor correction. In addition, the proposed electronic lighting driver leverages a wide bandgap SiC Schottky diode as the output diode to lower the power diode losses and recycles the energy stored in the leakage inductance of the transformer in order to improve the circuit efficiency. The magnetizing inductor inside the presented AC-DC power converter is designed to operate in discontinuous conduction mode (DCM), which naturally enables power factor correction (PFC). A single-stage prototype driver with a power rating of 3.6 W (90 V/40 mA) was developed and implemented for providing a deep ultraviolet LED disinfection and sterilization lamp. Experimental results show that the measured power factor (PF) is greater than 0.9 and the measured total harmonic distortion (THD) of the input current is less than 18% at an input utility voltage of 110 V. Furthermore, the measured output voltage ripple factor is less than 1% and the output current ripple factor is less than 4%. In addition, the proposed single-stage electronic lighting driver for supplying a deep ultraviolet LED disinfection and sterilization lamp achieves high circuit efficiency (greater than 90%), low circuit component count, and low circuit cost. Full article

With the help of circular strategies, products can be used longer (i.e., reuse, repair, and refurbish). Products that are difficult to use will be recycled efficiently. The present paper provides actionable guidelines for reducing environmental impact at all stages of a product’s life cycle, including the manufacture and assembly of the materials that make up the product, environmental impacts during use, and environmental impacts at final disposal, as well as specific actions and evaluation mechanisms. The circular economy is a concept that encompasses specific actions and their evaluations. To clarify the contribution of this circular economy to carbon neutrality, the present paper highlights how it is important to recognize the role of carbon as both an energy carrier and a material. CO₂ is a waste product from burning and powering carbon. CO₂ must be disposed of like any other waste product, but carbon itself is also an energy carrier. Thus, when promoting the carbon cycle, it is important to harmonize carbon’s function as a material with its role as an energy carrier. The further introduction of renewable energy and societal shift towards circular economy would contribute to carbon neutrality and more resource efficient use in a mutually complementary manner. Full article

Microalgae have attracted significant attention worldwide as one of the most promising feedstock fossil fuel alternatives. However, there are a few challenges for algal fuels to compete with fossil fuels that need to be addressed. Therefore, this study reviews the R&D status of microalgae-based polyculture and biocrude oil production, along with wastewater treatment. Mixotrophic algae are free to some extent from light restrictions using organic matter and have the ability to grow well even in deep water-depth cultivation. It is proposed that integrating the mixotrophic microalgae polyculture and wastewater treatment process is the most promising and harmonizing means to simultaneously increase capacities of microalgae biomass production and wastewater treatment with a low land footprint and high robustness to perturbations. A large amount of mixotrophic algae biomass is harvested, concentrated, and dewatered by combining highly efficient sedimentation through flocculation and energy efficient filtration, which reduce the carbon footprint for algae fuel production and coincide with the subsequent hydrothermal liquefaction (HTL) conversion. HTL products are obtained with a relatively low carbon footprint and separated into biocrude oil, solid, aqueous, and gas fractions. Algae biomass feedstock-based HTL conversion has a high biocrude oil yield and quality available for existing oil refineries; it also has a bioavailability of the recycled nitrogen and phosphorus from the aqueous phase of algae community HTL. The HTL biocrude oil represents higher sustainability than conventional liquid fuels and other biofuels for the combination of greenhouse gas (GHG) and energy return on investment (EROI). Deep water-depth polyculture of mixotrophic microalgae using sewage has a high potential to produce sustainable biocrude oil within the land area of existing sewage treatment plants in Japan to fulfill imported crude oil. Full article