Awareness as a catalyst for sustainable behaviors: A theoretical exploration of planned behavior and value-belief-norms in the circular economy.

This study explores the interplay of intrinsic and extrinsic factors influencing sustainable behaviours within the Circular Economy (CE) through the lenses of the Theory of Planned Behaviour (TPB) and the Value-Belief-Norm (VBN) theory. This objective was achieved by conducting a large scale survey in Brazil and using Composite-Based Structural Equation Modeling (cSEM) technique in conjunction with R software to analyze data and assess our research hypotheses. Our findings underscore the paramount importance of intrinsic factors-such as personal values, beliefs, and positive evaluations of sustainability outcomes-over external pressures like environmental laws and organizational policies in fostering sustainable actions. While increased awareness of the CE significantly enhances attitudes towards and the likelihood of engaging in sustainable behaviours, the study reveals that external pressures and perceived barriers, such as time, cost, and skill limitations, do not significantly deter those with a high level of awareness and positive sustainability evaluation from acting sustainably. Academically, the study enriches environmental psychology by extending TPB and VBN theories, advocating for a refinement of TPB to better account for contexts where personal values are stronger drivers than external pressures or immediate practical constraints.

Upcycling waste polyethylene terephthalate (PET) bottles into high-performance activated carbon for electrochemical desalination.

Upcycling waste polyethylene terephthalate (PET) bottles has attracted intensive research interests. This simultaneously alleviates plastic pollution and achieves a waste-to-resource strategy. Waste PET water bottles were used to fabricate value-added activated carbon (AC) electrodes for capacitive deionization (CDI). The KOH activation temperature (greater than 700 °C) prominently affected the physi-chemical properties and desalination performance of PET-derived activated carbons (PET-AC). Profiting from a large Brunauer-Emmet-Teller specific surface area (1448 m2 g-1) with a good mesoporous structure (the ratio of the mesopore volume to the total pore volume was 41.3%), PET-AC-1000 (activated at 1000 °C) possessed a huge specific capacitance of 108 F g-1 for capacitive ion storage. Moreover, when utilized as the electrode material in single-pass CDI, PET-AC-1000 exhibited a maximum electrosorption capacity of 10.82 ± 0.11 mg g-1 and a low level of energy consumption (0.07 kWh mol-1), associated with good electrochemical charging-discharging cyclic stability. The results provide a promising facile approach to tackle the challenge of plastic pollution and promote the advancement of electrode materials for economic affordable and energy-efficient electrochemical desalination process, which meets the United Nations (UN) sustainable development goals (SDGs).

Furfural as a low-volume, high-value asset from agricultural residues: A review on production, agricultural applications and environmental sustainability.

This comprehensive review explores furfural production from agricultural residues, focusing on its significance as a low-volume, high-value asset crucial for environmental sustainability. It covers diverse production technologies, recent advancements, and applications in agriculture, evaluating furfural's potential to enhance crop resilience and yield. Showing its role in a circular economy, the review discusses how furfural can replace conventional petrochemical processes, thereby reducing environmental impact. Case studies, such as successful implementations with cotton biomass byproducts, illustrate furfural's practical applications and environmental benefits. The study underscores the need for ongoing research, supportive policies, and furfural's growing role in sustainable agriculture and industry. It is focused on furfural's essential contribution to promoting environmental stewardship and sustainable practices. By examining furfural's role as a value-added product from agricultural residues, this review provides insights into its economic viability and potential challenges.

Pharmaceutical waste from a Danish hospital.

The healthcare sector is a major contributor of greenhouse gas emissions, and reduction and proper sorting of healthcare waste is essential to achieve sustainable healthcare. This study aimed to characterize the quantity and composition of pharmaceutical waste from a major Danish hospital. Pharmaceutical waste was collected from Odense University Hospital, including departments located in both Odense and Svendborg. The average daily production of pharmaceutical waste was 1150 g/day in Odense and 5967 g/day in Svendborg, with the operating rooms in Svendborg contributing 3143 g/day. The amount and composition of pharmaceutical waste varied greatly between departments, but some common patterns were identified. Propofol accounted for about one third of the pharmaceutical waste obtained from operating rooms. Antibiotics for systemic use constituted a significant proportion of the pharmaceutical waste from several departments and were the therapeutic group from which most different drugs were identified. Paracetamol accounted for 33.5% of the discarded tablets/capsules in Odense and 12.6% in Svendborg. Medications dispensed by automated dose dispensing accounted for a significant proportion of the discarded tablets/capsules in departments using this service. This study highlights some key areas for reduction and management of pharmaceutical waste and contributes to the currently limited evidence within this area.

Potential of metal recovery from printed circuit boards in Brazil.

In this study, the generation of domestic waste electrical and electronic equipment (WEEE) and waste printed circuit board (WPCB) were estimated, from 2015 to 2030. Based on the number of EEE put on the Brazilian market, the possession rate in the Brazilian households and obsolescence amounts of five EEE types were estimated using time series. The results show that, between 2015 and 2030, the quantity of WEEE generated per year will increase from 131.87 kt to 195.22 kt. In this period, WPCB generation will stay around 10% of WEEE generation. Additionally, this study shows that the urban mining potential of the materials recoverable from WPCB can be an important revenue source, with environmental benefits deriving from energy savings and a reduction in CO2 emissions. The results of this study provide a quantitative basis that may help decision makers develop strategic policies for WEEE management, considering material circularity.

Reclamation of boron from solid and liquid streams for fertilizer application.

Boron (B) is a crucial element for efficient plant growth and development; therefore, B-based fertilisers have been employed in agricultural applications. The need for B-based fertilisers for agricultural uses is continuously increasing as a result of the world's growing population. It is expected that the global market for B-based fertiliser will grow by around $6.3 billion by 2032; hence, demand for B sources will also increase. In addition to being used in fertiliser, B is also employed in the production of neodymium iron B (NdFeB) permanent magnets. The demand for NdFeB magnets is also continuously increasing. Hence, it is of the utmost importance to reclaim B from secondary resources due to the rising demand for B in a wide variety of applications. This review study addresses the recovery of B from various waste streams. The main focus is on the recovery of B from spent NdFeB magnets, borax sludge, and liquid streams such as brine water, seawater, sewage, industrial wastewater, and agricultural effluents. Different technologies for B recovery are discussed, such as sorption, solvent extraction, membrane processes, precipitation, and hydrometallurgical methods. Solvent extraction has been found to be a very effective approach for reclaiming B from spent NdFeB magnet waste and from liquid streams with high B concentration (>1-2 g/L). Further, the application of B-based fertiliser in agriculture application is reviewed. Challenges associated with B recovery from waste streams and future perspectives are also highlighted in this review.

Enhancing supply chain relationships in the circular economy: Strategies for a green centralized supply chain with deteriorating products.

This article introduces a green centralized supply chain in a two-stage stochastic programming model using deteriorating products. The model reduces the cost of purchasing, transporting, storing, product recovery and shortages. This cuts down on greenhouse emission related to transportation, product recovery, and recycling programs. On the basis of this, we explore the utilization of the circular economy to the damages that could occur from used products. Furthermore, revenue sharing and quantity discount contracts are examined in the business models between the members of the supply chain and the external manufacturer. Demand is assumed to be uncertain, and scenarios are created to account this. The model specifies the optimal order quantities, transportation modes and contract terms that minimize costs and environmental impacts. Numerical examples analyze the trade-offs between economic and environmental objectives under different supply chain parameters. The results provide insights for circular supply chains that reconcile economic incentives with environmental responsibility for deteriorating product.

Sustainable repurpose of end-of-life fiber reinforced polymer composites: A new circular pedestrian bridge concept.

In response to global challenges in resource supply, many industries are adopting the principles of the Circular Economy (CE) to improve their resource acquisition strategies. This paper introduces an innovative approach to address the environmental impact of waste Glass Fiber Reinforced-Polymer (GFRP) pipes and panels by repurposing them to manufacture structural components for new bicycle and pedestrian bridges. The study covers the entire process, including conceptualization, analysis, design, and testing of a deck system, with a focus on the manufacturing process for a 7-m-long prototype bridge. The study shows promising results in the concept of a sandwich structure utilizing discarded GFRP pipes and panels, which has the flexibility to account for variabilities in dimensions of incoming products while still meeting mechanical requirements. The LCA analysis shows that the transportation of materials is the governing contributing factor. It was concluded that further development of this concept should be accompanied by a business model that considers the importance of the contributions from the whole value chain.

Efficient dark-fermentation biohydrogen production by Shigella flexneri SPD1 from biowaste-derived sugars through green solvents approach.

This study evaluated the dark-fermentative hydrogen (H2) production potential of isolated and identified Shigella flexneri SPD1 from various pure (glucose, fructose, sucrose, lactose, and galactose) and biowastes (coconut coir, cotton fiber, groundnut shells, rice-, and wheat-straws)-derived sugars. Among sugars, S. flexneri SPD1 exhibited high H2 production of up to 3.20 mol/mole of hexose using glucose (5.0 g/L). The pre-treatment of various biowastes using green solvents (choline chloride and lactic acid mixture) and enzymatic hydrolysis resulted in the generation of up to 36.0 g/L of sugars. The maximum H2 production is achieved up to 2.92 mol/mol of hexose using cotton-hydrolysate. Further, the upscaling of bioprocess up to 5 L of capacity resulted in a maximum yield of up to 3.06 mol/mol of hexose. These findings suggested that S. flexneri SPD1, a novel H2-producer, can be employed to develop a circular economy-based approach to produce clean energy.

The hidden concept and the beauty of multiple "R" in the framework of waste strategies development reflecting to circular economy principles.

There are numerous unresolved research questions, along with ongoing debates regarding how to achieve circular economy and at what level. The forthcoming circular economy standard (ISO 59000 framework) as a result from the ISO/TC 323, from the International Organization for Standardization (ISO) aims to offer global implementation pathways using a unified technical language. The most challenging aspect of circularity, whether viewed scientifically, technically, and/or legislatively, is how to enhance prosperity while reducing reliance on primary materials and energy to achieve climate neutrality by 2050, thereby aiding the EU in achieving a successful and equitable transition towards a sustainable future. Strategies in the framework of waste management and circular economy are essential and needed to reduce the impact of several processes on the environment through product, processes, and corporate policies using green applicable sustainable resources and environmental management systems. In addition, "measuring something that is not there" is very complex and not fully comprehensible, not clear and not tangible from organizations, researchers, policy makers and citizens. The willingness and ability of individuals or organizations to take actions towards a low-carbon society involves grappling with various perspectives, such as social norms and economic viability. Circular economy is considered a tool in combating climate change and implementing climate mitigation (as well as adaptation) measures. Moreover, to date, there has been no common scientific or technical language for the application of the circular economy concept. This paper highlights the multitude of "Rs" beyond the well-known (3Rs) Reduce-Reuse-Recycle pattern, which can be applied in various contexts to assist SMEs and organizations (and even more citizens) in successfully adopting circular economy principles, while also shedding light on how these "Rs" can be utilized to measure intangible aspects (something that is not there). The results indicates that more than 55Rs exist which directly involved in the circular economy framework considering also waste management strategies. The findings of this study reveal the existence of over 82 "Rs" beyond the well-known principles of "reduce, reuse, recycle," each playing a distinct role in the development of strategies aimed at addressing waste management issues and advancing circularity towards a low-carbon society. Furthermore, the results could be useful for any policy makers, consultants, engineers, practitioners, urban planners, academics etc., in order to develop, apply, monitor and improve any strategy such as waste prevention, reuse, reduce, energy recovery etc., in the framework of circular economy principles, solid waste management and beyond.

Phosphorus recovery from ultrafiltered membrane wastewater by biochar adsorption columns: The effect of loading rates.

The present study used bench scale columns filled with biochar for phosphorous (P) recovery from real ultrafiltered wastewater. No studies are available about the potentiality of biochar using ultrafiltered real wastewater. Therefore, this study aimed to assess phosphate (PO4 3-) recovery by biochar-packed columns employing real treated wastewater from an ultrafiltration process. Three flow rates were tested, specifically 0.7, 1.7 and 2.3 L h-1, to gain insights into the optimal working conditions. Results revealed that the maximum amount of PO4 3- recovery (namely, 3.43 mg g-1 biochar) can be achieved after 7 h by employing the highest tested flow rate. Furthermore, the phosphorus exchange capacity (PEC) was inversely correlated with the feeding flow rate (FFR), with PEC values equal to 35, 25 and 9 % for FFR of 0.67, 1.7 and 2.3 L h-1, respectively. The pseudo-first order model best approximated the adsorption kinetics, thus suggesting that the adsorption of phosphate by biochar depends on its concentrations (i.e. physiosorption mechanism).

Integrated sustainability assessment of wood building products: The case of larch and chestnut cascading systems in Northern Italy.

Wood is increasingly being appreciated in construction due to its valuable environmental attributes. This paper explores the environmental and market performance of two wood supply chains in Northern Italy. Larch and chestnut wood are extracted and processed to obtain beams, planks, MDF panels and energy. LCA is performed to evaluate the environmental impacts of 1m3 of extracted wood through a cradle-to-gate approach. Then, a biogenic carbon analysis is carried out using the EN 16449:2014 standard including a comparison of different end-of-life treatments. Also, OSB is proposed as an alternative path for wood chips and contrasted to the current energy scenario. Moreover, solid wood beams and planks are compared with engineered wood products (EWPs). Lastly, a market analysis is conducted to assess the market trends of the different wood products studied. The LCA shows similar results for both wood species across most impact categories, with slightly higher values for the chestnut system. Most impacts are related to the production of MDF boards and the energy valorization of wood chips. Biogenic carbon analysis shows a negative balance of emissions with -314 and -205 kg of CO2 eq for larch and chestnut, respectively. It also suggests that OSB manufacturing can be a valuable alternative to the energy use of wood chips and that the end-of-life treatment with better results is recycling. The comparison of beams and planks with engineered wood products supports that solid wood poses a better environmental alternative in similar applications. Market analysis shows stagnation in the apparent consumption of wood products in the European market and a slight growth in the Italian one between 2018 and 2022. Overall, the systems studied suggest that the potential environmental benefits of using wood in construction are not being matched by current market trends.

Synergies between the circular economy and carbon emission reduction.

Climate change and sustainable development drive transformation in economic development models. Carbon emission reduction and the circular economy propel climate change and sustainable development, yet it's unclear if they synergize or counteract each other. This study examines the question from theoretical and practical perspectives. Using a theory-practice framework, bibliometric and big data analyses were conducted on the Web of Science and Chinese case data, totaling 2.29GB, to explore synergies between carbon emission reduction and the circular economy. The study finds predominantly synergistic interactions between the circular economy and carbon emission reduction, with minimal offsetting effects. That is, the circular economy markedly enhances carbon emissions reduction. At the theoretical level, the two fields are gradually evolving towards in-depth research, while at the practical level, collaboration is coalescing around four areas: hot fields, potential fields, auxiliary fields and common goals. A noteworthy contribution of this study is the development of a framework that synergizes theory and practice, providing a structured approach for future research in this domain. By quantifying the synergistic and offsetting relationship between the circular economy and carbon emissions reduction through systematic big data analysis, this research offers insights essential for achieving the UN's Sustainable Development Goals. We also stress the need for diverse case studies and multi-dimensional analyses in ongoing research.

Circular economy in construction - findings from a literature review.

The paper aims to enable a comprehensive definition for a Circular Economy (CE) that will support its effective introduction in the building and construction sectors. According to the European Commission (EC), the building sector in 2020 accounted for 40 % of the primary energy demand in the European Union (EU) and 37 % of its greenhouse gas emissions. Thus, the sector can play a crucial role in decarbonisation and hence in achieving a zero-emissions future in response to climate change. A CE aims to harmonise economic growth with environmental protection and is based on the concept of closing the loop with minimal practical waste as in a natural ecosystem. The adoption of CE concepts is therefore seen as a feasible response to climate change through the deployment of more sustainable construction processes that significantly reduce the need for natural resources by maximising recycling and reuse. However, and despite the recognition of the potential of a CE in relation to sustainability issues, the adoption of a CE model within building and construction sectors is challenging because of the wide range of aspects and priorities which are reflected in the diversity of definition resulting in a narrow and limited adoption. There are currently many definitions of CEs as related to building and construction in the literature, creating confusion and preventing effective implementation. The study presented here intends, using a comprehensive literature review as its basis, to define the key domains of a CE on which to align a concise and accurate definition that will enable effective application in the building and construction sectors. The research also aims to identify current research gaps and barriers to contribute to the future of CE research in the building sector and thus drive the implementation of CE projects to mitigate the effects of climate change and support the achievement of the UN Sustainable Development Goals (SDGs) by laying the foundations for a novel and forward-looking approach to circularity based on properly established, defined and understood principles of CEs.

Biohythane production via anaerobic digestion process: fundamentals, scale-up challenges, and techno-economic and environmental aspects.

Biohythane, a balanced mixture comprising bioH2 (biohydrogen) and bioCH4 (biomethane) produced through anaerobic digestion, is gaining recognition as a promising energy source for the future. This article provides a comprehensive overview of biohythane production, covering production mechanisms, microbial diversity, and process parameters. It also explores different feedstock options, bioreactor designs, and scalability challenges, along with techno-economic and environmental assessments. Additionally, the article discusses the integration of biohythane into waste management systems and examines future prospects for enhancing production efficiency and applicability. This review serves as a valuable resource for researchers, engineers, and policymakers interested in advancing biohythane production as a sustainable and renewable energy solution.

Understanding driving forces of food waste separation intention to enhance regional and local solid waste planning: application of PLS-SEM and multi-group analysis.

This study extended the theory of planned behaviour (TPB) and applied it to analyse influencing factors of food waste separation intention (FSI) among households in central Vietnam. Partial least squares structural equation modelling (PLS-SEM) was employed to analyse the data. The heterogeneity of factors contributing to FSI in cities of three levels was examined using multi-group analysis (MGA). The results indicate that attitudes, subjective norms (SN), perceived behavioural control (PBC), awareness of benefit (AB), information publicity (IP), facility availability (FA), and trust significantly affected FSI of households. MGA results indicated the heterogeneity of impacts of PBC and attitude on FSI of households among three municipal levels. The results will serve as basic data for waste officers, solid-waste management project leaders, non-governmental organisations (NGOs), and other related stakeholders to lay the foundation of food waste management planning in terms of regional scale and local scale. This study will also aid the creation of a circular economy by providing a scientific base for enhancing food waste separation at source in central Vietnam.

Implementation of Circular Economy in a Developing Economy's Mining Industry Using Institutional Theory: The Case of Namibia.

Despite the global focus on sustainability, transitioning from linear to circular production systems is slow in the mining sector of most developing economies like Namibia. However, mining plays a crucial role in supporting the livelihoods of local communities. Furthermore, existing literature indicates that the potential for regenerative production systems using the remanufacture and recycle approach remains low and limited within the mining and developing economies. Institutional theory can help reveal the reasons for the slow take-up of the regenerative circular economy models in mining. This study uses a unique dataset of 40 semi-structured interviews with key players in the mining sector of Namibia to understand the current phase of circular economy adoption and the role played by institutional pressures in the process of institutional isomorphism, when companies would display a similar level of practices within a shared institutional environment. The findings reveal: (1) 72.5% of participants believe that Namibian mines are adoption-decision phase-a beginning stage of circular economy adoption; (2) companies are reliant on heavy government participation through policy/legislation and tax incentives is recommended; (3) the ranked order-coercive, normative, and mimetic pressures-describes their significance among key actors, for the successful adoption; and (4) proactive implementation and a mindset shift towards circularity is needed to meet emerging expectations on social and environmental concerns in mining.

Towards carbon neutrality and circular economy: an innovative combination of enhanced biogas production and nutrient recovery from sludge dewatering liquor at a municipal wastewater treatment plant in Germany.

An innovative circular economy (CE) system was implemented at the wastewater treatment plant (WWTP) in Brunswick. The performance of the CE system was evaluated for 4 years: the thermal pressure hydrolysis enhanced the methane production by 18% and increased the digestate dewaterability by 14%. Refractory COD formed in thermal hydrolysis and increased the COD concentration in the WWTP effluent by 4 mg L-1 while still complying with the legal threshold. Struvite production reached high phosphorus recovery rates of >80% with a Mg:P molar ratio ≥0.8. Nitrogen was successfully recovered as ammonium sulfate with high recovery rates of 85-97%. The chemical analyses of secondary fertilizers showed a low pollutant content, posing low risks to soil and groundwater ecosystems. The total carbon footprint of the WWTP decreased due to enhanced biogas production, the recovery of renewable fertilizers and a further reduction of nitrous oxide emissions. Using green energy will be crucial to reach carbon neutrality for the entire WWTP.

A critical review and analysis of plastic waste management practices in Rwanda.

Plastic products are now essential commodities, yet their widespread disposal leads to environmental and human health effects, particularly in developing nations. Therefore, developing nations require comprehensive studies to assess the current state of plastic and plastic waste production to enhance plastic waste management practices. This review analyzes the import and export of plastic and the production of plastic waste in Rwanda, aiming to improve waste management practices. This review used open-access papers, reports, and websites dealing with plastic waste management. In this review, 58 articles from the Web of Science and 86 from other search engines were consulted to write this review. The findings revealed that the daily estimated plastic waste produced per person ranges between 0.012 and 0.056 kg. The estimated amount of plastic waste generated per person per year in Rwanda could be between 4.38 and 20.44 kg. Plastic waste accounts for between 1 and 8% of the total municipal solid waste produced per person per day in the country, which ranges from 219 to 255.5 kg. The average annual amount of imported plastics could reach 568.2881 tons, whereas the average quantity of exported plastics could reach 103.7414 tons. This shows that plastic management practices have not yet adopted technically advanced or improved practices, which should concern efforts to protect our environment. This study suggests approaches that can vastly improve plastic waste management and potentially open massive opportunities for the people of Rwanda.