Resources, conservation & recycling advances最新文献

End-of-life vehicle (ELV) plastics pose technical challenges in conventional recycling due to their diverse polymer compositions. Consequently, landfilling remains the prevailing disposal method. This study explores an innovative approach by upcycling ELV plastics as a substitute for natural sand in concrete. The study investigates the physical, mechanical and economic performance of ELV plastic-containing concrete. Plastic aggregates were prepared from real-world ELV plastics, featuring particle sizes below 4.75 mm, with over 90 % falling within the range of 1.18–4.75 mm. The research involves replacing natural sand with ELV plastics at varying volumes (0 %, 15 %, 25 %, 35 %, and 40 %) and examines the effect of sand replacement on various concrete properties. The results suggest that as the replacement ratio increases, the workability, density, and strength of concrete decrease. However, the 28-day compressive strength of concrete at the maximum replacement rate of 40 % was found to be 39 MPa, which suffices for certain non-structural strength applications, such as traffic routes, shared-use paths, local streets and curbs. In addition, compared to previous studies using mixed commodity plastics, ELV plastics lead to significantly lower strength reductions at high replacement ratios. Scanning Electron Microscopy (SEM) analysis reveals a distinctive rough and fibrous aggregate morphology, which enhances physical binding and provides bridging effects within the concrete matrix, potentially mitigating strength loss. Moreover, the economic analysis highlights a significant potential to commercialize ELV plastics for concrete applications. This study demonstrates that ELV plastics can be effectively used at high replacement rates (up to 40 % by volume) in non-structural applications.

Hospitals generate large amounts of waste, part of which is recyclable. However, research shows that recycling opportunities in hospitals often get missed with human behaviour playing an important role. Following current behavioural science, better understanding the influences on hospital recycling behaviour can support the design of promising behaviour change interventions, which draw on identified facilitators and help overcome identified barriers, to maximise recycling potential. Therefore, this systematic review aimed to investigate the barriers and facilitators to hospital waste recycling.

Three databases were searched to identify studies in high-income countries, pertaining to barriers and facilitators to hospital waste recycling. Their findings were thematically analysed and narratively synthesised drawing on a combination of the Capability, Opportunity, Motivation – Behaviour (COM-B) model with a multi-level framework.

Twenty-four studies met pre-defined inclusion criteria. Reported influences on hospital waste recycling pertained to factors beyond the hospital environment (e.g. product design preventing recycling), the internal hospital environment (e.g. lack of access to recycling bins) and individuals working within hospitals (e.g. concerns about infection control). Most influences were located in the internal hospital environment. Many related to the physical opportunity of recycling behaviour, with the most dominant barriers being difficulties accessing appropriate recycling bins and lack of information or education on recycling.

This overview of barriers and facilitators to hospital waste recycling will aid researchers and practitioners in designing hospital waste recycling interventions addressing key identified influences. Combining the COM-B model with a multi-level framework allowed for identified influences to be organised in a nuanced manner.

Circular economy (CE) processes, such as reuse, remanufacturing, and recycling, play a significant role in reducing the environmental impacts of modern manufacturing industries. However, electric and electronic equipment (EEE) is still often designed to function for a short usable life after which it is discarded. Furthermore, the current relatively low price and high availability of virgin raw materials, compared to those of recycled materials, decrease the financial viability of recycling. This study conducts a systematic literature review on product design-related issues in the CE of EEE and induces a novel model of product design considerations for the CE of EEE. The aim is to identify design traits that are hindering the CE of EEE and what measures can be taken in the product development phase to create EEE compatible with CE. This study points out general issues in the disassemblability and recyclability of EEE, as well as a recurring theme of conflicting design needs between different CE processes. Furthermore, the minimum entropy product design priority model is introduced as the novel contribution of this study to highlight the dependency between technological maturity, expected product lifespan, and suitable CE processes.

This study expands the STIRPAT framework and utilizes mechanistic analysis and spatiotemporal heterogeneity analysis to examine the impact of market integration on carbon emission intensity and heterogeneity in East China. The findings reveal that market integrations play a significant role in reducing carbon emission intensity, and tax environment, urbanization, and consumption power prove to be important mechanism factors. The average treatment effect of industrial structure and energy structure also positively promotes emission reduction efforts. However, market integration coupling coordination degree, technology level, and the gap in high-quality development act as inhibiting factors on carbon emission intensity. Furthermore, the spatial and temporal heterogeneous evolution trend demonstrates distinct and evident agglomeration patterns among economic regions. To effectively leverage the unified large market mechanism to reduce carbon emission intensity, it is essential to consider the regional characteristics of different influencing factors and also focus on the role of important node cities in driving emission reduction efforts.

Polyhydroxyalkanoates (PHAs) are polymers synthesized by diverse bacteria for carbon and energy storage applications. PHAs are biodegradable and nontoxic. They also exhibit properties similar to those of petroleum-based polymers. Therefore, these materials are promising alternatives to conventional plastics. This review aims to provide a comprehensive overview of PHA research, from production to application. This review summarizes the thermal and mechanical properties of various PHA homopolymers and copolymers, and compares them with those of common petroleum-based polymers. This comparison indicates that elongation at break is a major weakness of many PHAs. Different organic wastes used in PHA microbial production by mixed culture fermentation are summarized in this review. Important parameters of feedstock fermentation, culture selection, and PHA accumulation were compared. The pH and organic loading rate significantly affected the overall PHA yield, and various feedstocks led to different PHA compositions. Physical (blending and fiber reinforcement) and biological (cofeeding) modifications to improve the mechanical properties of PHA are elaborated in this review. Tensile properties are the major improvements among the mechanical properties after modification. Current applications of PHA and its derivatives are also presented in this work. They are primarily applied in the medicine, agriculture, and packaging industries. The widespread application of PHA faces challenges such as high production costs and limited mechanical properties. This study intends to stimulate further research into cost-effective methods for PHA production and to explore additional modification techniques.

Government is often seen as the arbiter for environmental protection. Alternatively, firms can volunteer to proactively take collective action toward sustainability, called industry self-regulation. But, what happens when neither of the two alternatives can deliver the expected outcomes? This inductive study addresses such a situation in managing hazardous consumer waste in the province of Ontario, Canada, where waste management and later circular economy have been on the agenda since the 1980s. However, both self- and government regulation failed to spur the advancements required to close material loops effectively and efficiently. Finally, after three decades, actors developed a new path to transition to circular economy. This longitudinal process study focuses on this process to explore the changes in business-policy interactions that realized this transition. I analyze extensive qualitative data, including 55 interviews with top-level decision-makers in all stakeholder groups (businesses, policy-makers, NGOs, consultants, etc.). Based on the unearthed patterns, I propose a hybrid model for regulation. In this model, both business and government coordinate throughout the process to set the rules and enforce them. By allowing organically shaped competition, this model can spur proactivity and innovation, which are crucial for the transition to circular economy but are hard to incentivize in conventional policy-making. The model can be used in any situation where an urgent issue needs immediate proactive responses by business.

In environmental conservation, mangrove forests play a crucial role. Retransplanting mangrove propagules, however, faces challenges, and success rates are notably low. Achieving an optimal protector for propagules, balancing strength without impeding growth, is challenging. Mangrove propagules require a temporary protector with an optimal balance, neither too weak nor too strong, to shield them from current waves which is difficult. We propose using pervious concrete pots with high-volume fly ash activated with low NaOH concentrations. The investigation focuses on the influence of the mixing procedure on workability, compressive strength, and mineral composition. The novel discovery in this study is the specific sequence of stirring the ingredients using an alkali activator, which adds an interesting dimension to the research. It is recommended to adopt Sequence 2 in pervious concrete production, where NaOH dissolved FA in the mixture forming albite as N-A-S-H gel product. It surely enhanced both workability and the strength confirming uniform application processes. The two recommended variants, PFS-60 and PFBS-50, effectively utilize coal ash, meeting the target compressive strength range of 3–5 MPa and providing support for mangrove pots over a 3–4 year period. Notably, both compositions maintained consistent mechanical properties during exposure to tidal conditions for 240 days.They exhibit high permeability (694 liter/m²/minute), facilitating efficient water passage without sediment entrainment.

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.

LinkedIn is a social media networking platform that provides users with publicly available data related to user and company profiles, job advertisements, groups, events, services, etc. The main feedback on the organizational trends around the Circular Economy (CE) has been mostly based on corporate reports and survey analytics while there are huge data volumes available online. This article aims to deliver valuable insights regarding global CE business activities. Those insights arise from data extracted οut of 7533 companies’ profiles on LinkedIn, containing the term CE in any profile section. Some significant findings include the companies’ geographical distribution (headquarters), the different industry sectors, each company's number of employees, followers, and foundation year. The last shows a significant increase in new CE companies over the last decade. Additionally, our work focuses on companies’ specialties and descriptions, which provide each organization's business activities and specialization. Finally, we investigated the presence of already studied and new Re- strategies, complemented by their most important interactions which undeniably indicate the dominance of the reuse-reduce-recycle triptych.

Agent-based modeling is a promising approach in industrial symbiosis (IS) simulation due to its bottom-up approach. However, the role of implementing feasible technologies in agent-based modeling of IS has been underexplored. In this paper, an agent-based model was developed to optimize the economic benefits of IS stakeholders in a case study region. Feasible technologies were integrated into the proposed model to generate additional economic profit and enhance circularity. The model was implemented on a case study involving a chicken farm, cow farm, dairy, edible oil plant, and a Combined Heat and Power (CHP) plant. Technologies including anaerobic digestion, organic Rankine cycle, heat pump, and membrane separation were employed to produce biogas, recover waste heat, and purify wastewater. While the fossil-based energy consumed by industries reduced, all the waste streams could be recovered. The techno-economic specifications of these technologies had a significant impact on the symbiotic relationships.