The lifecycle assessment (LCA) framework is widely applied to comprehensively evaluate and improve the environmental performance of a circular economy (CE). The advances and application of LCA has ...been primarily restricted to evaluate the environmental performance of the CE at a micro-level, wherein the CE is implemented for a single product system.
However, the CE can be operationalized at two broader levels: the meso–level (for eco-industrial parks) and the macro-level (for a city, state, or nation). Six methodological challenges emerge when applying LCA to a meso‑ or macro-level CE and remain unaddressed in the existing literature. This includes: selecting a relevant system boundary and functional unit, addressing data paucity and uncertainty, accounting for stakeholder behavior, assessing the trade-offs from renewable energy (RE) use, accounting for manufacturing and technology evolution, and quantifying displacement and rebound. This article proposes potential solutions and research priorities to address the above challenges.
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Considerable efforts are undertaken to make the transition towards a more Circular Economy (CE). At the same time there is no generally accepted monitoring framework. Rather, what exists is a large ...variety of measurement approaches that aim to assess the progress. The different assessment methodologies cover different and varied aspects of the CE transition and are seemingly unrelated to each other. Therefore, the main contribution of this paper is the provision of a structured picture of the current stock of CE metrics, including the identification of methodology clusters and the related assessment perspectives. The method of Multiple Correspondence Analysis (MCA) was used to assess 63 CE metrics and 24 features relevant to CE, such as recycling efficiency, longevity and stock availability. The MCA was used to assess how the different CE features are associated to each other and how they are related with each of the 63 metrics. Also, it was determined which combinations of CE features are frequently assessed together. The analysis identified three main clusters of metrics, (1) a resource-efficiency cluster, (2) a materials stocks and flows cluster, (3) a product-centric cluster. The results of the analysis show poor integration of resource-efficiency and product-centric perspectives, while the product-centric and system-dynamic perspectives are least frequently assessed. Further, the analysis provides the most prevailing CE perspectives and it is shown that only a few CE metrics assess CE features that are related to the maintenance of value. The MCA provides a guidance for further metrics development, as it identifies areas with a lower metrics density. For a detailed analysis, a standardized visualisation framework for CE metrics is derived, which allows to compare individual metrics in a simple and illustrative way. The goal of the visualisation framework is to provide guidance for (i) the integration of the most complementary CE metrics and (ii) facilitate further metrics development.
•Structuring of 63 circular economy (CE) metrics along 24 identified CE elements.•Identification of three main clusters of CE metrics and their typical CE elements.•Visualisation framework for a detailed assessment and design of CE metrics.•Identification of most prevailing CE perspectives and their associations.•Guidance for case-specific and complementary selection of CE metrics.
In response to address the climate crisis, there has been a growing focus on substituting conventional refinery-derived products with those derived from biorefineries. The utilization of lipids as ...primary materials or intermediates for the synthesis of chemicals and fuels, which are integral to the existing chemical and petrochemical industries, is a key step in this transition. This review provides a comprehensive overview of the production of sustainable chemicals (acids and alcohols), biopolymers, and fuels (including gasoline, kerosene, biodiesel, and heavy fuel oil) from lipids derived from terrestrial and algal biomass. The production of chemicals from lipids involves diverse methods, including polymerization, epoxidation, and separation/purification. Additionally, the transformation of lipids into biofuels can be achieved through processes such as catalytic cracking, hydroprocessing, and transesterification. This review also suggests future research directions that further advance the lipid valorization processes, including enhancement of catalyst durability at harsh conditions, development of deoxygenation process with low H2 consumption, investigation of precise separation of target compounds, increase in lipid accumulation in algal biomass, and development of methods that utilize residues and byproducts generated during lipid extraction and conversion.
•Lipids are the renewable resources in producing chemicals and fuels.•Biorefinery methods for the production of sustainable chemicals/fuels are comprehensively reviewed.•Economic and environmental perspectives of using lipids as the feedstock for chemicals/fuels are highlighted.•Future research required for the practical use of lipid-based biorefinery is proposed.
Precious and scarce silver (Ag) is used as a front electrical contact in silicon solar panels. With massive amounts of solar panel waste coming to end-of-life, it is imperative to recover all the Ag ...from these modules. In this paper, we propose a novel method to easily reclaim Ag from end-of-life silicon solar cells using low concentration sulfuric acid (H2SO4) leaching followed by ultrasonication. Our process simplifies the Ag recycling procedure by directly recovering the Ag contacts from solar cells, eliminating the need for secondary precipitation/electrodeposition. First, scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) was used to study the leaching and ultrasonication process on rejected solar wafers. Next, a solar panel from landfill was heated in a furnace to burn off the polymer encapsulant. The silicon wafers were then collected from the burning process and leached in 2 M H2SO4 at two different shaking speeds for 48 h at room temperature. Finally, the end-of-life silicon wafer pieces were collected, sonicated in water, and then the sonication water was centrifuged to show a proof-of-concept to recover the Ag contacts. Inductively coupled plasma optical emission spectroscopy (ICPOES) is used to monitor dissolved elements in the leachate as a function of time and shaking speed. XPS is used to evaluate the composition of the silicon cell wafer surface before and after H2SO4 leaching. SEM is used to image the recovered Ag contacts morphology and EDX confirms the recovered particles contain high amounts of Ag. A proposed schematic illustrates the authors’ hypothesis for the peeling mechanism.
•A novel process for direct Ag recovery from silicon solar cells is presented.•Leaching in H2SO4 followed by ultrasonication dislodges Ag from the solar cell wafers.•Centrifuging allows for direct recovery of metallic Ag from the silicon solar cell wafers.•With direct recovery of Ag from cell wafers, secondary chemical processing is avoided.
Rethinking chemistry for a circular economy Kümmerer, Klaus; Clark, James H; Zuin, Vânia G
Science (American Association for the Advancement of Science),
01/2020, Letnik:
367, Številka:
6476
Journal Article
Recenzirano
Chemical complexity complicates product recycling and manufacturing sustainability
Earth is running out of resources needed for manufacturing materials such as chemicals, minerals, and petroleum. ...Thus, these components are available only at increasing economic and environmental costs. As an important contribution to a sustainable future, chemistry and its products must be adapted to a circular economy (CE)—a system aimed at eliminating waste, circulating and recycling products, and saving resources and the environment (
1
).
Even though the traction towards a circular economy (CE) is on the rise, and the benefits a CE has across ecological, economic, and social frontiers have been undeniable, still, CE-related ...developments and its adoption have not been appealing. This study conducts a systematic literature review of the CE-related literature in line with the ‘umbrella framework’ to find the current state of the diffusion and diversification of CE concepts both in the academic context as well as in application. Using a thematic and content analysis of the sampled literature, the study (i) develops a comprehensive and inclusive CE definition and (ii) examines the level of diffusion of CE in the economy. The study concludes that, even though CE-related developments are positive and promising, it is still in the validity phase of the umbrella framework and recommends focusing more on the application-based intervention of the CE.
The circular economy has been proposed to transform global textile supply chains which are currently challenged by a complex nexus of sustainability issues related to the dominant fast fashion trend. ...Research on circular economy in the textile sector often focuses on businesses or consumers as key enablers in circular transitions, yet it treats them as independent entities and thereby neglects the study of interactions that can provide insight at the systems level. The proclaimed “circular textile mission” in the Netherlands setting a national target for 100% circularity by 2050 is used as case study to address this research gap. We explore the circular textile transition processes found in the context of the Dutch mission and compare the development and interactions among various technical and non‐technological solutions produced by engaged actor constellations for assessing key factors driving and blocking the overall mission fulfilment. To these ends, we derive a theoretical framework based on innovation system theory and conceptualize the Dutch circular textile transition as a Mission‐oriented Innovation System (MIS). Analyzing the structure and functioning of the Dutch mission‐oriented innovation system, we show that (1) there is a good match between the formal Dutch circular textile mission and system actor perceptions; (2) system actors have formed structures around three dominant solution trajectories in the Dutch system: secondhand, mechanical recycling, and chemical recycling; (3) these trajectories expose distinct key virtuous and vicious cycles, which characterize (4) the entire system as formative. Overall, the secondhand trajectory shows most developed structures and most positive dynamics, chemical recycling carries most technological breakthrough potential, whereas mechanical recycling is a mature technology but lacks market demand and supply. We compare the three solution trajectories, discuss the disruptive nature of the Dutch circular textile transition, and suggest installing Extended Producer Responsibility (EPR) as a potential intervention for accelerating system transformation. The study concludes with reflections on the case learnings and considerations for further research on mission‐oriented innovation systems.
The study aims to understand the enablers and barriers of circular economy (CE) adoption along with the impact of CE actions on sustainable performance in the context of Australian small and medium ...enterprises (SMEs). Based on the analysis of primary data from 352 SMEs in Australia, the questionnaire survey-based study revealed a lack of clearly defined business processes to be the major impediment towards CE adoption. Analysis also showed environmental performance having a significant positive relationship with design, process, and recovery. Surprisingly, the research showed that the benefits associated with careful energy and resource management does not seem to be important to Australian SMEs. This is in direct contrast to the growing level of interest amongst Australian SMEs towards conservation of water resources and emission reductions. The findings of this research may drive SMEs to focus on CE adoption, as the results suggest that it is positively related to sustainable performance.
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•Antibiotics global consumption and their environmental contamination were shown.•The use biochar for antibiotic sorption yields economic and environmental benefits.•Biochar-based ...materials are effective in removing antibiotics from water solutions.•Trends in the preparation and application of engineered biochar were described.•Mechanisms involved in the binding and removal of antibiotics were discussed.
Antibiotic contamination and the spread of antimicrobial resistant bacteria are global environmental issues. Given the growing consumption of antibiotics, it is crucial to reduce their presence in the environment. Adsorption is one of the most efficient methods for removing contaminants from water and wastewater. For this process to be effective, it is of key importance to identify adsorption mechanisms that allow an efficient and selective adsorbent to be chosen. Carbon-based materials (including activated carbon, biochar and black carbon) are typically used for the adsorptive removal of antibiotics. To enhance the efficiency of adsorption of pharmaceuticals, engineered biochars (physically, chemically and biologically modified biochar) and their composites have attracted increasing interests. Biochar-based sorbents can be produced from various feedstocks, including waste products. The use of “green”, low cost or sustainable biochar for contaminant sorption yields economic and environmental benefits. Moreover, this is in line with global trends in creating a circular economy and sustainable development. This paper collates the most recent data on the consumption of antibiotics, their related environmental contamination, and their removal using biochar-based materials. Special attention is paid to the newly emerging approaches of biochar modification and biochar composites in relation to the antibiotic removal from water.
This introductory paper to the special issue “Circular economy and sustainability: The role of technology, producers, consumers and policy” serves three main goals. The first one is to analyze the ...theoretical context of circular economy from a triple-level approach (i.e. micro, meso and macro-level) and their relationship with sustainability as they are formulated in the current literature. The second goal puts emphasis on analyzing the main contributions of the published articles in the special issue to the triple-level approach and sustainability concept. The final goal focuses on analyzing the future prospects of the relationship of the circular economy and sustainability through the findings of the articles of this special issue.
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