Circular Economy

Environ Sci Pollut Res Int. 2026 Jan 14. doi: 10.1007/s11356-025-37363-7. Online ahead of print.

ABSTRACT

Soil salinization significantly hampers global food production, posing a serious threat to food security. Biochar and boiler ash, byproducts of the oil palm industry, have shown potential as soil amendments to enhance soil quality and support plant growth under saline soils. This study evaluated the effects of biochar and boiler ash on the growth performance of Amaranthus viridis cultivated in saline soil. Plants were subjected to four treatments: saline soil (SS) without amendments (control), SS with NPK fertilizer (N), SS with NPK and biochar (BCN), and SS with NPK and boiler ash (BAN). Among the salt-stressed plants, those grown with BAN exhibited the highest plant height, leaf count, leaf width, SPAD value, and fresh and dry biomass, followed by those in the BCN treatment. Biochar application reduced the EC of the saline soil, while both biochar and boiler ash increased soil pH. Control plants recorded the lowest levels of chlorophyll a, chlorophyll b, and carotenoids. On the other hand, pigment contents were significantly improved in salt-stressed plants treated with biochar and boiler ash. BAN-treated plants showed the highest chlorophyll b levels, while BCN-treated plants exhibited the highest carotenoid and chlorophyll a levels. Furthermore, biochar and boiler ash supplementation reduced oxidative stress markers (H₂O₂ and MDA) while enhancing antioxidant defenses, including proline, ascorbic acid, ascorbate peroxidase, catalase, and secondary metabolites such as anthocyanins, flavonoids, and phenolic compounds. These findings suggest that biochar and boiler ash, when combined with NPK fertilizer, serve as effective soil amendments for mitigating salt stress and enhancing plant growth and physiological resilience in saline environments.

PMID:41533037 | DOI:10.1007/s11356-025-37363-7

ChemSusChem. 2026 Jan;19(1):e202502648. doi: 10.1002/cssc.202502648.

ABSTRACT

Precious metals are indispensable for applications ranging from catalysis to electronics; however, their limited availability and the environmental burden of conventional recovery methods raise urgent sustainability concerns. Herein, we propose a single-atom catalysis strategy that enables the efficient and selective recovery of Pd, Pt, Rh, and Au from industrial spent catalysts, ternary automotive catalysts, and electronic waste. Atomically dispersed Co sites activate peroxymonosulfate to generate multiple reactive O species, resulting in the rapid oxidative leaching of precious metals under mild conditions without the use of strong acids, toxic cyanide, or external irradiation. Mechanistic analyses reveal that both radical and nonradical pathways mediated by single-atom catalysts drive the oxidative leaching of precious metals. The experimental catalyst maintains atomic dispersion and activity over multiple recycling cycles, and its integration into a semi-continuous flow apparatus demonstrates its scalability and economic feasibility. By coupling atomic-level catalytic design with practical recovery performance, this study offers a green and sustainable platform for precious metal recycling and contributes to advancing circular economy strategies for resource efficiency.

PMID:41533290 | DOI:10.1002/cssc.202502648

Environ Sci Pollut Res Int. 2026 Jan 13. doi: 10.1007/s11356-025-37381-5. Online ahead of print.

ABSTRACT

Cold-rolled magnetic sludge, typically regarded as industrial waste, contains substantial amounts of valuable components such as magnetic iron oxide and residual oil. Conventional disposal methods, including landfilling and incineration, impose significant environmental challenges. This study explores resource recovery from magnetic sludge using a magnetic field-assisted solvent extraction technique. Several organic solvents-ethyl acetate, acetone, and N-methyl-2-pyrrolidone-were assessed for oil extraction efficiency, followed by solvent regeneration through distillation to achieve a zero-waste process. The recovered iron oxide was comprehensively characterized using scanning electron microscopy (SEM), Raman spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), along with evaluations of its magnetic and semiconducting properties. Additionally, the extracted iron oxide demonstrated catalytic activity in an advanced electro-oxidation process for coke plant wastewater treatment, achieving up to 95% colour removal and reductions of 87% in cyanide and 93% in chemical oxygen demand (COD). The recovered oil was analyzed for moisture content, calorific value, and ferrography to determine its suitability as a reusable fuel. Overall, the findings highlight the potential of magnetic sludge as a source of value-added materials for steel plant operations, supporting sustainable waste management and circular economy initiatives.

PMID:41528623 | DOI:10.1007/s11356-025-37381-5

J Environ Manage. 2026 Jan 12;398:128594. doi: 10.1016/j.jenvman.2026.128594. Online ahead of print.

ABSTRACT

The accumulation of microplastics (MPs) in agricultural soils has become a growing environmental concern, particularly due to the use of plastic mulch films. Biodegradable mulch films (BMFs) have been proposed as a sustainable alternative, yet long-term field evidence remains scarce. In this study, we evaluated MPs occurrence and soil functionality in two commercial farms in northern Italy where BMFs have been applied for over a decade. Soil samples were collected from plots with and without mulch, MPs (25 μm-5 mm) were isolated and chemically characterized, and soil biochemical parameters were assessed. The results revealed a diverse composition of plastics mainly not related to agricultural practices, suggesting external inputs from diffuse sources such as atmospheric deposition or irrigation water. Overall, MPs concentration over the two fields ranged between 300 and 580 MP items kg_ds^-1 with control surrounding areas reaching >1000 MP items kg_ds^-1. Notably, among the fragments spectrally compatible with biodegradable materials, their origin could not be directly linked to the applied mulch films and are therefore presumed to originate from external sources. From a biochemical point of view, BMFs application enhanced, on average, microbial biomass carbon (+27 %) and enzymatic activity (+23 % for β-glu, +13 % for β-xyl, and +31 % for PME), although these effects were strongly site-specific, with soil type emerging as the main driver of variability. Overall, our findings indicate that long-term use of BMFs does not lead to clear MP accumulation within the assessed size range nor adversely affect soil functionality, supporting their potential as an environmentally compatible alternative to conventional polyethylene mulches. Further research is nevertheless required to better understand their long-term transformation and environmental fate under field conditions.

PMID:41529652 | DOI:10.1016/j.jenvman.2026.128594

ACS Appl Mater Interfaces. 2026 Jan 13. doi: 10.1021/acsami.5c21690. Online ahead of print.

ABSTRACT

Both phosphate and per- and polyfluoroalkyl substance (PFAS) contaminants pose significant threats to aquatic ecosystems, demanding urgent remediation strategies. Herein, this study proposed a sustainable approach that utilized droplet-microfluidics-assisted chemical cross-linking to graft waste PFAS onto monodisperse microspheres, converting it into a stable, high-performance, and eco-friendly phosphate adsorbent (PFAS-FMM). Importantly, the scalable droplet-microfluidic technology enabled precise control over microsphere dimensions (100-150 μm) and tailored core/shell architecture for effective cross-linker encapsulation. Meanwhile, unlike conventional cross-linking, the single-site grafting enabled by shell microcracks effectively avoided active-site masking and maximized amino group utilization by 4.29-fold, as evidenced by typical polyethylenimine (PEI)-based adsorbents. This structural advantage strengthened the electrostatic attraction and hydrogen bonding of the PFAS-FMM for phosphate adsorption. As a result, the optimized PFAS-FMM exhibited exceptional phosphate (50 mg P/L) adsorption capacity (Q_max of 252.5 mg/g PFAS) and satisfactory kinetics (equilibrium within 120 min). Meanwhile, it demonstrated tolerance to multiple competing anions and maintained an adsorption capacity of over 85% across five cycles. Crucially, microsphere encapsulation eliminated free PFAS leaching, avoiding risks of secondary environmental pollution and ecotoxicity. The application potential was also confirmed by the positive result of the overall sustainability footprint (OSF) (score of 87.5%). These findings provided inspiration for the synthesis of functional materials and presented a strategy for concurrent mitigation of dual aquatic pollutants via waste valorization.

PMID:41528011 | DOI:10.1021/acsami.5c21690

World J Microbiol Biotechnol. 2026 Jan 13;42(1):40. doi: 10.1007/s11274-025-04769-x.

ABSTRACT

The production of odd-chain fatty acids (OCFAs) is gaining increasing importance due to their diverse applications in food, chemical, and biofuel industries. These fatty acids, which are relatively rare in nature, can be produced from renewable carbon sources through microbial fermentation processes. This review covers the significance of OCFAs in the market and their occurrence, followed by a detailed exploration of their production in mixed and single strain cultures. Specifically, the anaerobic fermentation (AF) conditions and feedstocks used to produce short OCFAs (SOCFAs), such as propionic, valeric, and heptanoic acids are discussed. Additionally, the production of long OCFAs (LOCFAs) by single strains is focusing on yeast, bacteria, and microalgae. Novel approaches for LOCFAs generation from waste carbon sources are also reviewed. This work delves both into the manipulation of microbial communities covering bioaugmentation and process optimization for bioenrichment in open mixed cultures and genetic manipulation in single-strain systems. Finally, the potential for scalable and sustainable production of OCFAs through microbial processes is discussed, as well as the technological advances needed to optimize these pathways.

PMID:41528657 | DOI:10.1007/s11274-025-04769-x

Biotechnol Appl Biochem. 2026 Jan 12. doi: 10.1002/bab.70124. Online ahead of print.

ABSTRACT

The escalating global demand for biopharmaceuticals is placing increasing strain on conventional production systems, highlighting the need for innovative and sustainable alternatives. Industrial byproducts, produced extensively across pharmaceutical and allied sectors, remain an underexploited resource with significant potential to reduce production costs and strengthen circular economy integration. This review systematically explores the sources and classification of industrial wastes relevant to biopharmaceutical manufacturing, while addressing critical regulatory, safety, and quality considerations for their adoption. Emerging biotechnological strategies-such as microbial fermentation, enzymatic biotransformation, and synthetic biology-driven metabolic engineering-are evaluated for their ability to convert industrial residues into high-value therapeutic products. Representative case studies demonstrate the feasibility of these approaches, including the utilization of agro-industrial waste for therapeutic enzymes, marine-derived residues for bioactive compounds, and fermentation byproducts for vaccine components. Environmental and economic implications are assessed through life cycle analysis (LCA) and cost-benefit evaluations, underscoring the alignment of waste valorization with sustainable manufacturing principles. Despite these opportunities, technological limitations, stringent quality and standardization requirements, and complex policy and ethical challenges remain substantial barriers. Future perspectives highlight the role of green bioprocessing, artificial intelligence (AI), and automation in optimizing waste-to-medicine pathways, alongside the long-term vision of achieving zero-waste biopharmaceutical production. By positioning industrial byproducts as valuable feedstocks, this review underscores their transformative potential in driving sustainable, resilient, and responsible healthcare manufacturing.

PMID:41527212 | DOI:10.1002/bab.70124

Waste Manag Res. 2026 Jan 13:734242X251405987. doi: 10.1177/0734242X251405987. Online ahead of print.

ABSTRACT

There is currently no publicly available, scientifically sound data on solid waste generation in German hospitals, which is one reason why the implementation of circular economy initiatives on this subject has so far been largely unsuccessful. Therefore, this study aims to conduct a nationwide field study on waste generation in German hospitals. To this end, waste and structural data from 122 German hospital locations covering the 4 clusters of general hospitals, university hospitals, specialist hospitals and other hospitals in all 16 German states were collected in 2024 and statistically analysed. A total of 103,432 Mg of waste from these hospitals was documented, of which around 9% was hazardous and 1.4% infectious. The results show strong correlations between waste generation and staffing levels. Furthermore, differences between general and university hospitals were found for all eight key performance indicators examined. Based on the results, a differentiated extrapolation model for the mass of waste from German hospitals, which uses the number of beds as a reference value, is proposed.

PMID:41527971 | DOI:10.1177/0734242X251405987

J Environ Manage. 2026 Jan 11;398:128606. doi: 10.1016/j.jenvman.2026.128606. Online ahead of print.

ABSTRACT

With the globalization of low-carbon goals, investments in clean energy around the world have triggered an unprecedented demand for metals. Recovering critical and precious metals from secondary resources can effectively increase the recycling of metal resources due to advantages such as high economic value and low environmental risk. Compared to the mining industry, recovering metals from waste electrical and electronic equipment is an important part of the circular economy and resource regeneration. Traditional pyrometallurgical and hydrometallurgical technologies have problems with high energy consumption, heavy pollution, and difficulty in dealing with waste liquids. As a green technology with sustainable development potential, bioleaching has been widely applied in metal recovery in recent years. This review bridges the gap between fundamental microbial mechanisms and industrial applications by offering a systematic, waste-tailored analysis. It first delineates how the physical-chemical barriers inherent in specific e-waste streams dictate targeted pretreatment and microbial strategy selection. Subsequently, this study provides mechanistic insights into interfacial bioleaching processes, such as contact/non-contact, cyanide complexation, and organic acidolysis, which critically evaluate innovative engineering strategies like hybrid intensification, strain optimization, and additive reinforcement for performance enhancement. Crucially, this paper synthesizes these aspects into an integrated techno-economic and environmental assessment framework, addressing scale-up challenges and sustainability trade-offs. This holistic perspective not only clarifies the state-of-the-art but also charts a roadmap for developing efficient, scalable, and truly sustainable bioleaching processes within a circular economy context.

PMID:41525755 | DOI:10.1016/j.jenvman.2026.128606

Environ Sci Pollut Res Int. 2026 Jan 12. doi: 10.1007/s11356-025-37335-x. Online ahead of print.

ABSTRACT

The rapid increase in global textile waste poses significant environmental and resource challenges, necessitating effective recycling strategies. This article provides a global perspective on textile waste recycling (TWR), including policies in major countries and initiatives by international organizations. Through bibliometric analysis, four key research themes were identified: dye removal, physical recycling methods, chemical recycling methods, and sustainable development and the circular economy. Based on bibliometric analysis, the article reviews various TWR approaches and their applications, such as physical methods for fiber and composite production, chemical methods for material synthesis, and thermochemical conversion methods for carbon material and energy recovery. The study also analyzes the economic and environmental benefits of various recycling methods, highlights current challenges, and offers recommendations to guide future research in TWR. This work represents a significant advancement in the valorization of textile waste and provides valuable insights for designing effective strategies for sustainable textile waste management.

PMID:41526781 | DOI:10.1007/s11356-025-37335-x