Circular Economy最新文献

This study proposes an approach to combat construction waste in the architecture, construction, and engineering (ACE) industry by developing a disassemblable brick partition wall. Brick reuse is severely restricted by the presence of mortar; innovative approaches need to be explored. An existing strategy, utilizing mortarless interlocking, relies on non-standardized bricks. It is worth noting that these methods are not specifically created for disassembly, despite the fact that they theoretically could be. A relatively innovative technique for tightening and stabilizing brick units emerged in recent years, involving the utilization of metal components. Despite its potential, there are limited case studies of this approach. By drawing on two typical examples of pros and cons, MIFA 1862 and the UMAR Unit, we propose a new strategy and examine it from multiple perspectives. The findings of the analysis demonstrate how adaptable and versatile the proposed system is, allowing it to be modified into a variety of sizes and forms. Additionally, the system has proven to have considerable advantages in terms of construction speed, and energy efficiency throughout the structure's service time and in future use phases.

The ever-increasing rise in the generation of solid waste has become a global environmental issue. Many cities around the world have adopted zero-waste strategies, policies, and plans to achieve zero-waste goals. China puts great importance to solid waste management and has implemented a zero-waste city pilot program in 11 cities and 5 special areas. During the 14th Five-Year Plan period, China will promote the construction of “zero-waste city” in 113 cities and 8 special areas. This study introduces the exploration and practice of a zero-waste city in China, including the concept of a zero-waste city, the top-level design for constructing such cities, and the effectiveness of pilot programs. The top-level design of zero-waste city construction in China was explained, including the overall thinking, stage goal, main path, overall structural framework, and promotion method. This study also elaborates on the progress and achievements of zero-waste city construction, summarizing the reform measures in terms of legal processes, policy tools for goal-oriented guidance, and high-level promotion and overall planning. The construction of a zero-waste city is a powerful tool for deepening comprehensive solid waste management reform and is an important initiative for ecological civilization construction.

The practical application of plastics is as indispensable as it is problematic regarding disposal. Plastics present significant opportunities in the context of circular usage and recycling. A circular economy dictates the utilization of every side stream to minimize waste. Current waste management techniques are insufficient in reducing plastic waste entering landfills, wastewater treatment systems, and the environment. Under these circumstances, plastic biodegradation has emerged as a viable and environmentally responsible approach to plastic pollution. Methods are needed for the natural degradation of plastics using microbes that can utilize plastics as their sole carbon source. Studies to enhance the catalytic activity of plastic-degrading enzymes through protein engineering approaches are a relatively new field of research. Enzymatic degradation for product creation represents a purely biological plastic recycling method in a sustainable economy. This review builds insights derived from previous studies and provides a brief overview of plastic degradation using enzymes, improvements in plastic-degrading enzyme efficiency, and stabilization via various protein engineering strategies. In addition, recent advances in plastic waste valorization technology based on systems metabolic engineering and future directions are discussed.

This research explores the role of extended producer responsibility (EPR) as an enabler of circular value chain in the Chinese context. The driven forces and key stakeholders were identified to extend producer responsibility in developing the national-circular-economy strategies. An evaluation system was established to link the eco-design strategy of the producer with the downstream-recycling performance of products. The eco-design information was retrieved from the self-disclosure information in the sustainable development report of producers. The downstream-waste-flow information comes from multiple platforms of reuse and recycling companies. The aim of reforming the EPR system is to establish an open forum for competition and cooperation among different stakeholders to achieve a continuously-improving target of circularity and life cycle environmental performance of the products. With the evaluation results, the producers are encouraged to fully explore all opportunities in the circular value chain instead of focusing only on the final disposal or disassembly of waste. The conclusion suggests that EPR policies should break the restrictions on eco-design and innovation in business models by creating and capturing values of circularity along with the world's collective climate change mitigation efforts.

Plastic recycling is a critical aspect of achieving a circular economy, aiming to reduce fossil fuel dependency, greenhouse gas emissions, and biodiversity impacts from uncontrolled disposal routes. The study outlines the evolving landscape of plastic recycling in the European Union (EU), addresses challenges, and emphasizes the need for innovative approaches to achieve circular economy goals. This paper delves into the innovative approaches and strategies employed by the PHOENIX project, a multidisciplinary project funded by the Cariplo Foundation, which focuses on plasmix – a complex mixture of plastics often excluded from recycling due to its heterogeneous composition. The authors utilize a systemic design approach, integrating survey results, interviews, literature reviews, and case studies to provide a comprehensive understanding of plasmix and propose novel solutions. Key findings include the application of design from recycling, systemic design strategies, and the utilization of plasmix in new product developments. It presents survey insights and stakeholder perspectives, and introduces systemic strategies applied in the project. The study concludes with valuable considerations for future research and underscores the significance of such initiatives in reshaping the plastic recycling paradigm.

The recycling of waste printed circuit boards (WPCBs) generates nonmetallic fractions (NMFs); due to the complex components of NMFs and the limited nature of economic benefits of treating NMFs, treatment of NMFs is challenging. In this study, two types of NMFs—dry-NMFs (D-NMFs) and wet-NMFs (W-NMFs)—derived from the dry and wet separation processes of WPCBs, respectively, were investigated. These NMFs were used as fillers to reinforce the polyethylene (PE) matrix, and their effects on the composite properties were examined. Thermal property studies revealed that incorporating both types of NMFs improved the thermal stability of the prepared composite samples. When neat PE was filled with 15 wt% of D-NMFs and W-NMFs, the final decomposition temperature (T_f) increased from 475 to 482 and 487 °C, respectively. Mechanical property studies revealed that the addition of NMFs to the composite sample, particularly that of W-NMFs, enhanced the stiffness of the prepared samples, although at the expense of some reduction in their toughness values. The tensile strength, tensile modulus, flexural strength, and flexural modulus values increased from 9.41, 121.80, 5.89, and 99.15 MPa for neat PE to 11.15, 521.82, 17.94, and 597.29 MPa, respectively, for composites containing 25 wt% of W-NMFs. Furthermore, the introduction of shellfish wastes in the NMF/PE blend, especially that of clam shell, further enhanced the overall properties of the composite. After adding 8 wt% of clam shell with 15 wt% W-NMFs, the T_f increased from 487 to 498 °C. The tensile strength, tensile modulus, flexural strength, and flexural modulus values increased from 11.37, 355.13, 16.06, and 443.31 MPa for neat PE to 12.26, 466.73, 18.71, and 568.46 MPa, respectively, for the composite prepared with clam shell. Thus, this study contributes to the WPCB recycling literature and promotes circular economy development.