Circular Economy

Waste Manag. 2025 Apr 4;201:114778. doi: 10.1016/j.wasman.2025.114778. Online ahead of print.

ABSTRACT

The valorization of industrial byproducts is a crucial step towards sustainable production. Sotol bagasse, a lignocellulosic residue from Sotol spirit production, is a promising feedstock for biorefineries. This study aimed to optimize microwave-assisted pre-treatment of sotol bagasse biomass for fermentative lactic acid production using a microbial consortium from cow manure. Microwave irradiation was employed to hydrolyze the complex structure of the Sotol bagasse, releasing fermentable sugars. Notably, these pre-treatments were more selective than traditional acid hydrolysis, minimizing the formation of inhibitory compounds like hydroxymethylfurfural. Instead, microwave pre-treatments promoted levulinic acid formation through autohydrolysis driven by steam explosions, a valuable chemical platform for various industrial applications. The optimal microwave pre-treatment conditions that led to almost pure glucose attaining a 3 % w/w efficiency in converting lignocellulose to glucose resulted in a maximum lactic acid production of 9.6 g/L. This study demonstrates the potential of Sotol bagasse as a sustainable feedstock for lactic acid production, contributing to a more circular economy.

PMID:40187168 | DOI:10.1016/j.wasman.2025.114778

Environ Res. 2025 Apr 3:121536. doi: 10.1016/j.envres.2025.121536. Online ahead of print.

ABSTRACT

Incineration is an effective method for handling the increasing volume of municipal solid waste, but the resulting fly ash presents a significant problem that needs to be addressed. Municipal solid waste incineration fly ash (MSWI FA) contains toxic and hazardous substances, including heavy metals, dioxins, and chlorides, and is classified as hazardous waste. This paper analyzes the current situation of MSWI FA and summarizes the main treatment methods, including solidification/stabilization, thermal treatment, and chemical separation/resource recovery. The review critically evaluates research on the chemical separation/resource recovery of MSWI FA, covering chlorides removal and resource utilization, heavy metals recovery through hydrometallurgy, thermal separation, and electrochemical methods, as well as calcium extraction and CaCO₃ production by CO₂ mineralization. It highlights innovative chemical separation/resource recovery technologies and future prospects to promote the development of MSWI FA valorization technologies and achieve sustainable management of MSWI FA.

PMID:40187390 | DOI:10.1016/j.envres.2025.121536

Environ Sci Pollut Res Int. 2025 Apr 5. doi: 10.1007/s11356-025-36351-1. Online ahead of print.

ABSTRACT

This paper presents a comprehensive database on the morphological, mineralogical, chemical, and contaminant release characteristics of construction and demolition waste (CDW). Scanning Electron Microscopy (SEM) was employed to analyse the particle morphology, revealing their angular and porous nature. X-ray Diffraction (XRD) was used to identify key minerals, such as quartz, calcite, and gypsum, providing vital information on the mineralogical composition of CDW. X-ray Fluorescence (XRF) analysis allowed the characterisation of the elemental composition, highlighting predominant oxides, like SiO₂, Al₂O₃, and CaO, with a notable presence of Na₂O in glass waste. Critical oxides, such as Fe₂O₃ (8.78%) and MgO (14.19%), were also identified. Recycled aggregates exhibited higher porosity and water absorption compared to natural aggregates, with fines constituting less than 27%, which presents an opportunity for their reuse, particularly in the production of geopolymers. Organic matter content was low, reaching up to 4.6%. The main contaminants identified include arsenic, cadmium, lead, chromium, and sulphates, with sulphate concentrations reaching up to 6,000 mg/kg, while arsenic, chromium, and lead reach up to 28 mg/kg, 310 mg/kg, and 6,580 mg/kg, respectively. These findings support the adoption of circular economy principles and regulatory frameworks that promote recycling and the use of innovative materials, thereby reducing the environmental footprint of construction projects.

PMID:40188192 | DOI:10.1007/s11356-025-36351-1

J Environ Manage. 2025 Apr 3;381:125119. doi: 10.1016/j.jenvman.2025.125119. Online ahead of print.

ABSTRACT

Water scarcity is a growing concern due to population growth, climate change, pollution, and inadequate water management. Innovative approaches are necessary to secure a reliable water supply to address this challenge. Seawater desalination has emerged as a promising option to supplement freshwater resources, but its by-product (i.e., salt-concentrated brine) poses a significant environmental threat. Current disposal methods include direct disposal, evaporation ponds, and, in specific cases, land application in irrigation for low-salinity brines, but these practices have negative environmental consequences. As a result, alternative strategies for brine management directed to materials circularity by process integration are being developed. Integration of membrane technologies, such as Nanofiltration, has shown promising efficiency for improving pre-concentration, while Electrodialysis with bipolar membranes (EDBM) can transform brines into chemicals. Additionally, Ion Exchange processes could be used as a polishing stage to ensure the safe operation of EDBM by reducing the levels of divalent cations responsible for membrane scaling. This study proposes integrating three technologies and assesses their feasibility by conducting a techno-economic analysis using previously developed simulation tools. Results suggest that the proposed technologies integration can be a promising alternative of Minimum Liquid Discharge system to treat desalination brines, while producing high-purity chemicals. Finally, the economic results demonstrated a minimum total Levelized Cost of NaOH of 344 €/tonNaOH. This indicates that the system proposed in this study is cost-effective and competitive with current market supplies.

PMID:40185015 | DOI:10.1016/j.jenvman.2025.125119

Waste Manag. 2025 Apr 3;200:114773. doi: 10.1016/j.wasman.2025.114773. Online ahead of print.

ABSTRACT

Two biochars were prepared from pyrolysis of sugarcane bagasse (SC) at 550 and 750 °C for 3 h and named as BC550 and BC750, respectively. One hydrochar was prepared from Hydrothermal Carbonization (HTC) of SC solution at 200 °C for 2 h (HC200). Chars (BC550, BC750 and HC200) were mixed with thiourea (10 % in weight) and heated at 350 °C for 1 h leading to BC550-TU, BC750-TU, and HC200-TU, respectively. Pristine and thiourea-activated biochars were characterized by FTIR, N₂ isotherms, XRD, XRF and ultimate analysis. Thiourea activation increased the H/C of biochar, indicating that the presence of N and S and their reaction with carbon structures of biochar hinders the formation of aromatic carbon. Thiourea activation increased the surface area of biochar prepared at 550 °C, while decreasing the surface area of biochar prepared at 750 °C or hydrochar. Finally, both pristine and activated biochars were used as catalysts in the oxidation of sulfide minerals for metal recovery. The addition of thiourea-activated biochars significantly enhanced the extraction of Cu and Zn from mining waste, from 47.4 % of Cu and 88.1 % of Zn to values of 99.4-100 %, while reducing As extraction. However, in leaching processes involving minerals with higher Cu and Zn content, the extraction percentages did not reach such high values (<50 % for Cu and < 90 % for Zn). It can be concluded that the use of thiourea-activated biochars enable the development of low cost and sustainable processes for the recovery of metals from wastes.

PMID:40184862 | DOI:10.1016/j.wasman.2025.114773

Food Chem. 2025 Mar 27;481:144028. doi: 10.1016/j.foodchem.2025.144028. Online ahead of print.

ABSTRACT

Barrier films are essential for food packaging, but conventional solutions hinder the circular economy. This study introduces hemicellulose-based antioxidant crosslinked composite films as a sustainable alternative. We develop pH-responsive films (K-B/PVA/OA) using polyvinyl alcohol (PVA), silanized hemicellulose (KHC), blueberry anthocyanin (BA) as a pH indicator, and oxalic acid (OA) as a crosslinker. The films exhibit excellent oxygen and water vapor barrier properties and can be easily fabricated via solution casting with food-safe dispersions. The oxygen permeability (OP) decreases from 13.22 ± 0.65 × 10^-14 to 3.24 ± 0.98 × 10^-14 cm³·μm/(m²·d·Pa), and the water vapor permeability coefficient (Pv) drops from 15.43 ± 0.85 × 10^-13 to 7.27 ± 0.46 × 10^-13 g·cm/(cm²·s·Pa). Tensile strength and modulus increase from 32.63 MPa and 765.80 MPa to 41.24 MPa and 1281.39 MPa. Esterification between PVA and hemicellulose raises surface energy, increasing the contact angle from 39.4° to 78.34°. Strawberries packaged in these films maintain their structure and exhibit a visible color change after 7 days, offering sustainable, real-time monitoring packaging.

PMID:40184924 | DOI:10.1016/j.foodchem.2025.144028

Front Nutr. 2025 Mar 13;12:1553942. doi: 10.3389/fnut.2025.1553942. eCollection 2025.

ABSTRACT

This study aims to explore the transformative role of Artificial Intelligence (AI) in food manufacturing by optimizing production, reducing waste, and enhancing sustainability. This review follows a literature review approach, synthesizing findings from peer-reviewed studies published between 2019 and 2024. A structured methodology was employed, including database searches and inclusion/exclusion criteria to assess AI applications in food manufacturing. By leveraging predictive analytics, real-time monitoring, and computer vision, AI streamlines workflows, minimizes environmental footprints, and ensures product consistency. The study examines AI-driven solutions for waste reduction through data-driven modeling and circular economy practices, aligning the industry with global sustainability goals. Additionally, it identifies key barriers to AI adoption-including infrastructure limitations, ethical concerns, and economic constraints-and proposes strategies for overcoming them. The findings highlight the necessity of cross-sector collaboration among industry stakeholders, policymakers, and technology developers to fully harness AI's potential in building a resilient and sustainable food manufacturing ecosystem.

PMID:40181942 | PMC:PMC11966451 | DOI:10.3389/fnut.2025.1553942

Integr Environ Assess Manag. 2025 Apr 4:vjaf047. doi: 10.1093/inteam/vjaf047. Online ahead of print.

ABSTRACT

Global solid waste mismanagement has reached unprecedented levels, leading to significant environmental and social challenges, including pollution, resource depletion, and labor exploitation. The circular economy's principle of reuse offers a potential solution, but more research is needed to facilitate this transition. The informal sector plays a key role in waste reuse, yet its integration with formal regulatory framework and waste management systems remains challenging. A study in Lebanon, using semi-structured interviews with stakeholders, explored the informal sector's role in waste reuse. The findings reveal that while the reuse and repair market has grown due to the economic crisis, it remains underdeveloped. Informal workers create challenges by hindering the efficiency of formal waste management systems and undermining the economic sustainability of recycling projects. Their unregulated activities can lead to operational disruptions, reduced material value, and increased public health and environmental costs. The informal sector operates with little oversight, and the system's deficiencies-legal, technical, and economic-exacerbate these issues, including the absence of an effective cost-recovery mechanism. Formalizing or integrating the informal sector is a complex process that involves not only waste management issues but also political and regional challenges. The research suggests that regulating the waste management sector is the best approach to address these challenges, helping transition informal workers into a formalized system. This would improve overall waste management, making informal operations less financially viable over time.

PMID:40184213 | DOI:10.1093/inteam/vjaf047

J Biotechnol. 2025 Apr 1;404:1-8. doi: 10.1016/j.jbiotec.2025.03.020. Online ahead of print.

ABSTRACT

Sugarcane vinasse management is one of the biggest challenges of distilleries around the world. Vinasse can be used for crop fertigation, but it requires a prior conditioning treatment. This study investigates the short-term effect of the fertigation with raw vinasse (V₀) and vinasse biologically treated with the filamentous fungus Aspergillus sp. V2 (V_t) on the growth of Triticum aestivum L. (wheat), soil nutrient replenishment and soil enzyme activities. Effects of commercial chemical fertilizer (NPK) and water tap (W_t) on the parameters studied were also analyzed. The fertigation with V_t had positive effects on wheat, increasing all the plant growth parameters compared with V₀, NPK and W_t. Fertigation with V_t also induced positive changes in soil with respect to the other solutions tested, favoring the replenishment of organic matter and nutrients such as potassium (K), phosphorous (P), and magnesium (Mg). Moreover, soil enzymes (particularly dehydrogenase enzyme) responded differentially to changes in the fertigation conditions tested, providing reliable information on system quality. These results demonstrate that a fungal-based pretreatment improves the vinasse properties for agricultural uses, contributing to the advance towards a bio-based circular economy.

PMID:40180291 | DOI:10.1016/j.jbiotec.2025.03.020

Sci Total Environ. 2025 Apr 2;975:179267. doi: 10.1016/j.scitotenv.2025.179267. Online ahead of print.

ABSTRACT

The disposal of end-of-life tires (ELTs) is an important issue in the context of solid waste management. In the last decades, the main recycling route consists of the ELTs transformation in crumb rubber, which is widely used worldwide in playgrounds and sports fields as infill material. Crumb rubber represents the largest source of intentional microplastics in the environment. This microplastic material contains high metal concentration including toxic and heavy metals. Few studies deal with the metal(loid) characterization of real crumb rubber samples taken in situ from sports and leisure facilities. Research is especially scarce for playgrounds, despite interest due to the population using these facilities (children). This study aims at addressing the metal(loid) distribution in a large number of real samples from different urban places, most from Galicia (NW Spain) but also from other countries. 32 elements including metals (Ag, Al, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, In, K, Li, Mg, Mn, Mo, Na, Nb, Ni, Pb, Se, Sr, Ti, Tl, U, V, Zn) and 4 metalloids (As, B, Sb, Si) were determined. For comparison purposes, some alternative materials (cork, sand, and thermoplastic elastomers) were collected. The results showed high Zn levels (1-2 %) in crumb rubber, exceeding the safety limits set in the European directives for related matrices. Heavy and toxic elements (Pb, Cr, As, Cd, Sb) were found in all samples, reaching concentrations up to 100 mg kg^-1. Co presented concentrations of 200 mg kg^-1, well above the safety limits (10 mg kg^-1 for toys). ANOVA showed statistical differences between playgrounds and football fields for some elements. The alternative materials proved safer regarding metal(loid) content. This study is the largest one about metal(loid) characterization in crumb rubber surfaces attending the number of samples, origin, and elements analyzed.

PMID:40179745 | DOI:10.1016/j.scitotenv.2025.179267