Resources Conservation and Recycling最新文献

Electronic plastics (e-plastics) are indispensable in modern society, but their low recycling rate and environmental persistence have raised significant concerns. Prevailing plastic recycling strategies are inadequate to fully capture the economic benefits inherent to e-plastics, providing limited incentives for recycling. Therefore, there is an urgent need to develop innovative approaches aimed at maximizing the capture of value from e-plastics. Herein, acrylonitrile butadiene styrene (ABS) from discarded keyboards was unconventionally “re-tooled” to produce highly porous bioadaptive 3D sponge-like constructs for advanced in vitro applications. The ABSponge was surface functionalized via layer-by-layer (LBL) electrostatic deposition method to generate 3D human breast, colorectal and bone cancer spheroids as a drug screening tool or adapted for co-culturing of cancer spheroids and cancer-associated-fibroblasts to emulate the complex tumor niche. Collectively, our findings reveal the promising potential of using discarded keyboards as a "waste-to-resource" feedstock for advanced in-vitro biotechnological applications, achieving waste reduction and maximizing value-capture.

Plastic is ubiquitous in everyday social practices, and few consumer activities do not involve its direct or indirect use. Single-use plastic (SUP) based on fossil fuels is particularly problematic, as it seems virtually unavoidable, especially in everyday products, from plastic wrapping cucumbers to shampoo bottles. Although reducing SUP is crucial, there is little evidence of achieving this in everyday social practices. This paper examines the practicality of reducing SUP and consumer frustration. We studied the social practices of 20 adults using diary records and workshops over the course of two weeks. Our findings suggest that everyday practices shape SUP use, and reducing it disrupts daily life, even for eco-conscious consumers. Packaging-free shops are a popular approach to reducing SUP. However, consumers are hindered from using this alternative by limited availability, convenience and product variety. Future research should explore the seamless integration of alternatives to reduce SUP into everyday social practices.

Recycling spent lithium-ion batteries (LIBs) could alleviate supply risks for critical metals and be less harmful to the environment compared to new production of metals from mining. Developing a cost-effective LIB bioleaching process could be a promising alternative to traditional energy-intensive recycling technologies. This study aimed to optimize bioleaching conditions for maximum economic competitiveness through design of experiments using iterative response surface methodology (RSM), assisted by thermodynamic modeling. The optimal condition was identified as 2.5% pulp density in 75 mM gluconic acid biolixiviant at 55°C for 30 h which could recover 57%–84% of nickel, 71%–86% of cobalt, and 100% of lithium and manganese, yielding a 17%–26% net profit margin. The recommended pulp density and acid concentrations, together with the observed metal solubilization, were supported by thermodynamic modeling predictions. Our study demonstrated that combining RSM with thermodynamic simulations could be a powerful tool for optimizing bioleaching conditions.

End-of-life tyres (ELTs) are difficult to recycle due to their complex composition. Although there are several possible pathways to manage ELTs, in Germany roughly 50 % of the ELTs are still incinerated. One emerging technology that promises recycling of ELTs is the thermochemical processing through pyrolysis. This technology enables to recover carbon black and pyrolysis oil that can be reused for new tyres. Therefore, this study presents a comprehensive life cycle assessment to compare the environmental impacts from pyrolysis of ELTs against current dominant alternative end-of-life treatment pathways. The investigated alternative end-of-life pathways are (i) incineration in a cement plant, (ii) incineration in a dedicated incineration plant, and (iii) production of infills for artificial turfs. The results show that the recycling of ELTs for material recovery has lower environmental impacts in the categories global warming, particulate matter and resource use compared to end-of-life pathways that target energy recovery.

Waste materials and industrial by-products are increasingly used in the production of cement clinker and cement, serving as secondary fuels, secondary raw materials, and supplementary cementitious materials. As these waste-derived materials are partially or fully incorporated into the product, they are technically recycled. Consequently, a certain proportion of the cement consists of recycled materials. This paper presents a method to calculate this recycled content in cement not only based on mass streams, but also based on valuable chemical components and compares the results for both calculation methods in the course of a case study of two Austrian cement plants. It is demonstrated that one metric ton of cement consists of 365 kg and 387 kg of secondary materials, respectively. This results in an average recycled content of 37.6 %. In addition, the contribution of primary and secondary materials to the heavy metal content of cement is assessed.

Bio-based plastics are attracting increasing attention due to their perceived sustainability and circularity. While enabling circularity by using renewable feedstocks, they still contribute to plastic pollution. Furthermore, their rapidly growing market will cause bio-based plastics to constitute significant fractions of plastic waste, necessitating efficient recovery at end-of-life. Technical overviews of potential recovery pathways for bio-based plastics exist, although these have not yet been translated into product design recommendations. In this article, we assess the impact of material composition and product design on the feasibility of eight recovery pathways for bio-based plastics. The ability to recover a plastic not only depends on the plastic composition, but also on the way a product is designed. The alterations made to tailor plastics to be applied in products, and the product architecture, can enable or prohibit some recovery pathways. The outcomes highlight the importance of establishing a wider range of recovery pathways for plastics, and the crucial role of product design in enabling a circular economy for bio-based plastics. We also present a first guidance for product design to enhance the recovery of bio-based plastics.

This study characterizes the copper cycle, quantifying flows, stocks, and losses from 1960 to 2020, and explores global copper supply and demand under six scenarios until 2050. Results show substantial growth in copper production, consumption, and trade over six decades, with around 761 Tg of copper extracted, resulting in 483 Tg in-use stocks. Monte Carlo simulations indicate an 11.4 % uncertainty. These stocks, redistributed globally, form independent secondary resources for each country, with Chile, Peru and Australia holding dominant underground reserves, and China and the United States primarily having above-ground stocks. Targeted policies are needed to close the copper cycle due to current loss rates. Copper shortages are anticipated around 2040, further exacerbated by the development of low-carbon technologies and extended copper product lifespans, but mitigated by alternative technologies and increased recycling rates.

China is the largest zirconium manufacturing country in the wassssssorld. The security of its zirconium industry affects the stability of the global zirconium supply chain. However, China has very limited zirconium reserves and highly relies on importing such resource, leading to great concerns on how to maintain the sustainable operation of its zirconium industry. This study aims to measure the security of China's zirconium industry by establishing one assessment framework, which covers resource, politics, economy, and technology perspectives. As such, both catastrophe progression (CP) method and path analysis method are adopted to evaluate the security of China's zirconium industry and uncover the driving mechanism of China's zirconium industry for the period of 2005–2021. The results demonstrate that the security level of China's zirconium industry is in an “early warning” state, which is seriously influenced by political turbulence and technological development. Several policy recommendations are then proposed to improve the overall sustainability of China's zirconium industry.

The circular economy is a major topic in import-dependant nations like Japan, China or the European Union, where supply security, strengthening domestic value chains and greening economic growth are key concerns. In contrast, extractive economies, mostly in the Global South, provide resources to the world market and thus exhibit inherently linear resource use while struggling for sustainable development. Circularity in resource importing regions could undermine extraction-based development modes, but such effects have rarely been studied yet.

Herein, we analyse economy-wide circularity for all flows of materials, energy, waste and emissions in South Africa, for the year 2017. We advance an established methodology regarding interlinked metals mining, constraints to sustainable biomass cycling, and informal disposal, waste picking and informal and formal reuse. Data were developed from national and international sources, and reviewed and co-produced with national experts in an online workshop series.

Cornerstones of South Africa's biophysical economy in 2017 are a domestic extraction of 875 Mt, low imports of 32 Mt dominated by oil, 170 Mt of exports dominated by coal and metal ores, resulting in 496 Mt of total waste and emissions. Processed material is 917 Mt or 16 t/cap (EU27: 16 t/cap). Materials use for stock-building is very low at 130 Mt (2.3 t/cap). Socioeconomic input cycling is only 2 % [1.4–2.8 %] and ecologically sustainable biomass cycling is only 4 % [3.9–6.1 %], totalling 6 % input circularity. Given the low circularity, we conclude on leverage points for a transformation towards increased circularity to yield socio-economic benefits in a highly unequal society.

The long–time gap between planting and harvesting in forestry obscures necessary timber prices to balance with silviculture costs and often causes disproportionate market timber prices. This discrepancy can lead to stagnant timber production in forestry countries and promote global unsustainable land use and timber production. This study presents an approach to estimate fair timber prices that ensure the economic sustainability of timber-producing forest stands. Supply curves are derived numerically under perfect competition and a proven stable forest state; thereby, the curves suggest the fair timber prices for continuously supplying a given mass. An application in Nagano Prefecture, Japan, suggested that the current timber prices are lower than those required to stably supply the current mass. The supply curves also suggested necessary timber price increments and carbon prices to ensure the current supply without subsidy. Furthermore, the need for selecting timber-producing forest stands to stabilize forest management was indicated.