Material Substitution Research Articles

Impact of On-Road U.S. Vehicle Electrification and Lightweighting on Critical Materials Demand.

The electrification of the transport sector is crucial for reducing greenhouse gas emissions and the reliance on fossil fuels. Battery electric vehicles (BEVs) depend on critical materials (CMs) for their batteries and electronic components, yet their widespread adoption may face constraints due to the limited availability of CMs. This study assesses the implications of vehicle electrification and lightweighting (material substitution) on the U.S. CM demand for light-duty vehicles (LDVs) and medium- and heavy-duty vehicles (MHDVs). Market sales scenarios of 100% internal combustion engine vehicles (ICEVs), 100% BEVs, and a 50%/50% mix are considered. The findings reveal that LDVs dominate the total CM demand despite MHDVs requiring more CMs per vehicle. Cobalt, graphite, lithium, neodymium, and nickel are critical for the 100% BEV adoption scenario, whereas palladium and rhodium are critical for ICEVs. LDV lightweighting increases total CM quantity per vehicle due to steel replacement with aluminum but reduces the vehicle's mass, operational energy consumption, and reliance on high-concern battery-related CMs. Transitioning from nickel manganese cobalt (NMC622) to lithium iron phosphate (LFP) battery chemistry reduces CM use but increases demand for strategic materials such as copper and phosphorus. This study uniquely evaluates U.S. CM demand for LDVs and MHDVs across conventional and electric powertrains and investigates light-weighting and battery chemistry impacts.

Temperature-induced mobility in octacalcium phosphate impacts crystal symmetry: water dynamics studied by NMR crystallography.

Octacalcium phosphate (OCP, Ca8(PO4)4(HPO4)2·5H2O) is a notable calcium phosphate due to its biocompatibility, making it a widely studied material for bone substitution. It is known to be a precursor of bone mineral, but its role in biomineralisation remains unclear. While the structure of OCP has been the subject of thorough investigations (including using Rietveld refinements of X-ray diffraction data, and NMR crystallography studies), important questions regarding the symmetry and H-bonding network in the material remain. In this study, it is shown that OCP undergoes a lowering of symmetry below 200 K, evidenced by 1H, 17O, 31P and 43Ca solid-state NMR experiments. Using ab initio molecular-dynamics (MD) simulations and gauge including projected augmented wave (GIPAW) DFT calculations of NMR parameters, the presence of rapid motions of the water molecules in the crystal cell at room temperature is proved. This information leads to an improved description of the OCP structure at both low and ambient temperatures, and helps explain long-standing issues of symmetry. Remaining challenges related to the understanding of the structure of OCP are then discussed.

Multi-indicators environmental impact analysis of takeaway lunch boxes based on life cycle assessment

Conventional plastic take-out food containers exert a substantial environmental impact, necessitating the identification of viable alternatives. A quantitative study assessed the environmental traits of five takeaway lunch boxes made from distinct materials (PP, PE-coated paper, pulp molding, aluminum foil, PLA). A life cycle assessment from 'cradle to grave' was conducted on the evaluation object. Combined with a carbon footprint scenario analysis, this study quantitatively compared and analyzed the environmental impacts of traditional plastic takeaway lunch boxes and their substitutes, spanning from raw material preparation to post-use disposal(including both landfill and recycling). Sensitivity analysis of the study data revealed that the production process significantly influences the environmental footprint of each assessed item. Among the five types of lunch boxes, the PE-coated paper lunch box had the lowest environmental impact, while the pulp-molded lunch box showed the least carbon emissions. Conversely, the PLA lunch box emitted higher carbon emissions than the conventional PP lunch box. Scenario analysis , using a 1250 ml lunch box as the functional unit , indicated that substituting the PP box with PE-coated paper or pulp-molded boxes could reduce the annual carbon footprint of Chinese take-out boxes by 43.20% and 54.35%, respectively. A material substitution ratio of 20:3:1:1 for PE-coated paper, pulp molding, PP, and PLA resulted in a 39.16% reduction in the lunch box's annual carbon footprint. Full recycling of lunch boxes could cut carbon emissions from PE-coated paper boxes by 54%. Implementing a synergistic material replacement scheme and complete recycling could further reduce the carbon footprint by 68.15%.

Optimizing Sustainability in High-Speed Rail Rolling Stock through CFRP Material Substitution

This research investigates the environmental and operational advantages of replacing traditional materials in high-speed rail (HSR) rolling stock components with advanced composite materials. By substituting key parts—such as the roof, door, car body, brake control unit, braking rheostat, and bogie transom—with glass-filled epoxy, polyester, and nylon, the study achieves a significant reduction in rolling stock weight by 24.61%. This weight reduction contributes to lower energy consumption and reduced CO2 emissions. Additionally, the recyclability and recoverability rates of these composite materials show marked improvements, reaching 73.9% and 78.9%, respectively, compared to 61.4% and 73.1% in the conventional model. The findings demonstrate that integrating composite materials can enhance the sustainability and efficiency of HSR systems by minimizing landfill waste and operational emissions. This study provides a foundational approach to using lightweight, recyclable materials in rail transportation, with promising implications for future sustainable developments in the industry.

Sustainable Solar Module Through the Substitution of Materials by Renewable Encapsulation, Recycled Backsheet, and Lead‐Free Interconnection

ABSTRACTSustainability and resource‐efficiency are the major topics for the 21st century. Most of the PV modules are manufactured of glass, polymers, metals, and silicon‐based solar cells. All these materials have the potential to be substituted by sustainable products. The substitution of materials for PV modules is challenging because of issues in significant unknown risks for short‐ and long‐term reliability of the PV module. Investigations for material and process routes of a 100% renewable solar module are necessary. This study investigates the suitability and reliability of different materials. For example, the reliability of an electrically conductive adhesive (ECA) to a leaded‐solder reference is under investigation as well as various polymers (recycled, bio‐based, or biodegradable). In the first step, the interconnections are tested with a standard module encapsulation bill of materials (known good reference). In the second step, the module encapsulation and backsheet materials are substituted by their sustainable counterparts. The goal is to identify the most promising material combinations for further integration of lead‐free interconnected solar cells. Reliability is assessed using accelerated ageing tests in accordance with IEC 61215/IEC 61730 with standard test duration and extended test duration for each material and interconnection batches. The condition of the samples is assessed by regular visual inspection, power measurements, and electroluminescence images. The study aims to demonstrate and assess the suitability and reliability of the selected material combinations to enable the steps toward a renewable material solar module.

Enhancing performance and reducing carbon emissions in sprayed concrete using green silica-lignin admixture and recycled aggregates

AbstractThe substitution of low-carbon and carbon-negative materials is an important pathway and a fundamental means of reducing carbon emissions in the construction sector. This work utilized the pulping wastewater (black liquor (BL)) produced from rice straw alkaline-oxygen cooking to synthesize a green concrete silica-lignin (SL) admixture through acid regulation. This novel admixture was employed to replace conventional high-carbon alkali powder, and its integration with recycled aggregates significantly enhanced the performance of sprayed concrete. The results show that the addition of the silica-lignin admixture increased the slump and compressive strength of sprayed concrete by 46.3% and 28.5%, respectively, while reducing the rebound ratio by 67.3%. Moreover, the use of recycled aggregates effectively reduces the global warming potential (GWP) of sprayed concrete production. When the substitution rate of recycled aggregates reaches 50%, carbon emissions are reduced by 44.7%, to only 183 kgCO2eq/m3. The sprayed concrete with added silica-lignin admixture not only exhibited increased compressive strength but also contributed to a reduction in CO2 emissions, decreased the amount of concrete used in building structures, and achieved the goal of carbon reduction. This work provides valuable insights for advancing sustainable practices in the construction industry.

Bone Substitute Material in the Surgical Therapy of Peri-Implantitis-3-Year Outcomes of a Randomized Controlled Trial.

To evaluate the potential mid-term benefit of the use of a bone substitute material in the reconstructive surgical treatment of peri-implantitis. A total of 120 subjects (127 implants) affected by peri-implantitis were followed over 3 years in a multicenter randomized clinical trial. Participants had been randomized to either control (access flap surgery) or test group (access flap surgery and bone substitute material). Clinical, radiographic, and patient-reported outcomes were assessed. The primary outcome was a composite measure including probing pocket depth ≤ 5 mm, absence of bleeding and suppuration on probing, soft tissue recession ≤ 1 mm, and implant neither reoperated nor lost. In an additional outcome (disease resolution), we allowed for one bleeding site and did not consider recession. While 14 implants (11%) were lost and a second surgical intervention had been performed at 3 implants (2.4%), pronounced improvements of clinical parameters were noted at remaining implants in both treatment groups at the 3-year follow-up. This was illustrated by a 3.2-3.5 mm reduction in probing pocket depth and a marginal bone level gain of 1.1-1.3 mm. The primary composite outcome, however, was only achieved at 14% of implants. The second composite outcome defining disease resolution was accomplished at 39% of implants. Patient-reported outcomes were generally favorable. At 3 years, the use of a bone substitute material in the surgical therapy of peri-implantitis did not result in a clear benefit over access flap surgery alone. ClinicalTrials.gov identifier: NCT0307706.

Life cycle assessment of coir fiber-reinforced composites for automotive applications

Past decades have seen an increasing prevalence of natural fiber-reinforced composites (NFRCs) due to growing conscientiousness around sustainability and a push towards vehicle lightweighting. The environmentally friendly and sustainable claims of NFRCs need to be validated due to their large variability and variety, particularly where material substitutions are concerned, such as in substituting glass fiber with natural fiber. The objective of this work is to determine the cumulative energy demand (CED) and greenhouse gas emissions (GHG) associated with an automotive part (of volume 0.001 m3) made from 40 wt% coir fiber-reinforced polypropylene (PP) and compared with a similar part made from 40 wt% glass fiber reinforced PP. SimaPro v. 9.0.0.49 was used for the analysis, whereas inventory data were collected from databases, such as Ecoinvent 3, Transportation Energy Databook, Greet model 2022, and published papers. The results showed that CED and GHG associated with the coir fiber-reinforced composite part were lower than the glass fiber-reinforced composite part for both cradle-to-gate (∼34-40%) and cradle-to-grave (excluding end-of-life) (∼24%) analysis.

Eco-friendly concrete bricks with tetris-t model

Abstract The development of construction has resulted in a higher demand for construction materials, especially concrete bricks. However, cement as one of the main components in concrete bricks has several problems. The process of cement making requires SiO2 and CaCO3 from natural sources, which can cause environmental damage. More environmentally friendly materials are needed to substitute the use of cement especially in concrete bricks. One of the materials rich in SiO2 is sugarcane Fiber ash, and materials rich in CaCO3 include eggshell powder. So, both materials are possible to be used as cement substitution materials. Innovation in form is also needed to reduce the use of cement in implementation as well as to speed up implementation time. The purpose of this research is to produce eco-friendly concrete bricks with a new design (Tetris-T model). The method used in this study is an experimental method based on SNI 03-0349-1989. The comparison of the brick mixture used is 1 pc: 6 sands with 4 variations of comparison between sugarcane Fiber ash: eggshell powder, namely variation A (0%:0%), variation B (5%: 10%), variation C (7.5%:7.5%), and variation D (10%:5%). The results of the study show that test specimen C has a compressive strength of 117.227 kg/cm2 and a water absorption of 4.87%. Based on the test results, it can be seen that variation C meets the standard requirements for SNI 03-0349-1989 quality III. The test of the effectiveness of installation on a wall measuring 1 × 1 meter shows that Tetris T innovation bricks take 38.85% less time to install compared to conventional bricks. Based on this research, reducing cement used about 15% can help the implementation of green projects to support sustainable development.

Optimization of the Mechanical Recycling of Phenolic Resins for Household Appliances.

In light of the significant impact of climate change, it is imperative to identify effective solutions to reduce the environmental burdens of industrial production and to promote recycling strategies also for thermosetting polymers. In this work, the mechanical recycling of phenolic resins, obtained from industrial production scrap of plastic knobs for household appliances, was optimized. The feasibility of a partial substitution of virgin materials with recycled ones was investigated both at a laboratory and industrial scale. Finally, the environmental benefits arising from the use of recycled material were quantified through a life cycle assessment (LCA). The results of laboratory characterization demonstrated that the thermal properties of the phenolic resins were not influenced by the presence of recycled material, and the mechanical performances were not significantly impaired up to a recycled content of 30 wt%. The industrial production trials demonstrated the feasibility of replacing up to 15 wt% of virgin material without any influence on the aesthetical features of the produced components. Finally, LCA of industrially produced knobs highlighted a limited benefit of virgin material substitution in the case of novolac chromium-plated samples, while an overall environmental impact reduction of around 7-10% was detected in the case of resol-based materials.

Combined effect of jute fiber and corn cob ash on sustainability assessment and mechanical properties of roller compacted concrete using RSM modelling

The increasing demand for cement has substantially affected the environment, and its manufacturing requires substantial energy usage. However, most countries in the world recently encountered a significant energy problem. So, researchers are exploring the use of agricultural and industrial waste resources with cementitious characteristics to minimize cement manufacturing, cut energy consumption, and contribute to environmental protection. Therefore, this research is performed on roller compacted concrete (RCC) reinforced with 5%, 10%, 15%, and 20% of corn cob ash (CCA) as substitution material with different percentage of cement and 0.25%, 0.50%, 0.75%, and 1% of jute fibre (JF) together for determining the mechanical properties and embodied carbon (EC) by applying response surface methodology (RSM) modelling. The cubical samples were prepared to achieve the targeted strength about 30 MPa at 28 days and then obtained mix proportions were employed for all combinations at various water-cement ratios to maintain roller-compacted concrete’s zero slump. Results showed that at 0.50% JF and 10% CCA, the flexural strength, splitting tensile strength and compressive strengths, and modulus of elasticity of RCC obtained were 5.3 MPa, 3.8 MPa, 32.88 MPa, and 33.11 GPa at 28 days, respectively. Besides, the embodied carbon of RCC is recoded reducing with combined addition of different levels of JF and CCA as compared to control mixture. In addition, the generation of response prediction algorithms was performed using analysis of variance (ANOVA) at a threshold of significance of 95%. The coefficient of determination (R2) readings for the statistical models ranged from 96 to 99%. It is observed that the use of 0.50% of JF along with 10% of CCA as cementitious constituent in RCC provides best outcomes. Therefore, this method is a superior choice for the construction industry.

From Fossil to Bio-Based AESO-TiO2 Microcomposite for Engineering Applications.

Environmental issues and the reduction of fossil fuel resources will lead to the partial or total substitution of petroleum-based materials with natural, raw, renewable ones. One expanding domain is the obtaining of engineering materials from vegetable oils for sustainable, eco-friendly polymers for different applications. Herein, the authors propose a simplified and green synthesis pathway for a thermally curable, acrylated and epoxidized soybean oil matrix formulation containing only epoxidized soybean oil, acrylic acid, a reactive diluent (5%) and just 0.15 mL of catalyst. The small amount of reactive diluent significantly reduced the initial system viscosity while eliminating the need for adding solvent, hardener, activator, etc. Both the thermally cured composite with a 2% TiO2 microparticle filler and its pristine matrix were comparably characterized in terms of structural, thermal, morphological, dielectric and wettability by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetry, scanning electron microscopy, broadband dielectric spectrometry and contact angle measurements. The 2% filler in the composite generated superior thermal stability via lower mass loss (48.89% vs. 57.14%) and higher degradation temperatures (395 °C vs. 387 °C), increased the glass transition temperature from -20 °C to -10 °C, rendered the microcomposite hydrophobic by increasing the contact angle from 88° to 96° and enhanced dielectric properties compared to the pristine matrix. All investigations recommend the microcomposite for protective coatings, capacitors, sensors and electronic circuits. This study brings new contributions to green chemistry and sustainable materials.

(Invited) Dependency of Calcination Temperature on Silanol and Bubble Concentration in High−Purity Synthetic Quartz Powder

Recently, high-purity synthetic quartz powder has emerged as a critical component in the semiconductor industry, extensively utilized to manufacture various quartz wares due to its high heat resistance (up to 1600 °C), high optical transmittance for ultraviolet and visible light wavelengths, and low thermal expanding coefficient (0.5 × 10−6/°C). In particular, quartz powder of 6N purity or higher is used in the semiconductor industry to produce blank masks for the ArF immersion process or crucibles for Si ingot growth. In this case, not only the impurities of the quartz powder but also the concentration of internal silanol groups are important factors. Silanol groups in quartz powder can induce the formation of bubbles and defects during the production of quartz glass, leading to a deterioration in both its optical transmittance and thermal expansion properties. When utilized in specific applications such as blank masks or crucibles, the presence of residual bubbles within the quartz can significantly impair the product's functionality. These bubbles strongly affect the overall quality, and in the case of blank masks, they contribute to light scattering, which can drastically reduce the precision and effectiveness of the mask in practical applications. However, It has not been reported what chemical properties of pure synthetic quartz powder produce bubbles.In this study, we investigated the dependency of calcination temperature on silanol and bubble concentration in high-purity synthetic quartz powder. The synthetic quartz powder, which was synthesized using the sol-gel process via ion exchange process [1], the bubble and OH contents were analyzed as a function of calcination temperatures of 900°C, 1000°C, 1100°C, and 1200°C. We observed a decreasing tendency in OH content from 196.38 ppm to 18.5 ppm as the calcination temperature increased, measured using FTIR analysis via the KBr pellet method. Furthermore, through thermogravimetric analysis [Fig 1(a)], we identified the removal temperature and mechanism of various types of silanols [Fig. 1(b)] within the quartz powder. To effectively remove each silanol group, we applied a 3-step temperature calcination process at 300°C, 700°C, and 1200°C, thereby reducing the OH content within the quartz powder to 0.0 ppm[Fig. 1(c)]. Finally, quartz glass substrates were fabricated via vacuum fusion using quartz powders calcined under these conditions, and after undergoing cutting and polishing processes, their characteristics were evaluated. The bubble density and OH concentration within the glass substrates, depending on the calcination process conditions, will be presented in detail, along with an elucidation of the reduction mechanism. Acknowledgement This work was supported by BrainKorea21 Four and Technology Innovation Program(00266205, HFC Substitute material development having low GWP for Semiconductor process) funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea) References [1] Choi, J.-H et al. Fumed Silica-Based Ultra-High-Purity Synthetic Quartz Powder via Sol-Gel Process for Advanced Semiconductor Process beyond Design Rule of 3 nm. Nanomaterials 13, 390 (2023) Figure 1

Deactivated Ca-based sorbent derived from calcium looping CO2 capture as a partial substitute for cement to obtain low-carbon cementitious building materials

Calcium looping CO2 capture is a highly promising technology for carbon capture, utilization, and storage. Nevertheless, the disposal of deactivated calcium-based sorbents following cyclic carbonation and calcination processes presents an unresolved challenge. Concurrently, the development of low-carbon cement products is also a critical priority. Given the calcium-rich composition and carbon-negative nature of the calcium-based sorbent, it is proposed that the deactivated sorbent could be utilized as a partial substitute for cement in the production of building materials. This paper explored the potential of using two types of deactivated calcium sorbent (DPC/DGC) to partial substitute cement for low-carbon cementitious materials production. The effects of partial substitution of cement materials on volume stability, compressive/flexural strength, hydration kinetics, and carbon emission of the composite cementitious materials were investigated. The results indicate that a 5 % and 10 % replacement of cement with DPC/DGC has modest impact on volumetric stability and compressive strength. The composite cement with 5 % DPC replacement achieves a 28-day compressive strength of 48.1 MPa, representing a 0.4 % increase compared to the 47.9 MPa observed in the reference sample. Specimens with 15 % DPC/DGC substitution exhibit inferior volume stability and mechanical performance than the control sample. The total hydration heat releases decrease with the increasing substitution ratio due to the dilution effect by the introduction of DPC/DGC. Additionally, substituting cement with Ca-based sorbents significantly reduced the carbon footprint of construction materials. The net carbon footprints for the building materials that containing 1 ton of binder (substitued with 10 wt% DPC and DGC) were 152.5 kg and 43.5 kg, corresponding to reductions of 79.6 % and 94.2 % compared to reference cement mortar. These carbon footprints are projected to further decrease to −108.5 kg and −375.5 kg when DPC and DGC were obtained after 100 CO2 capture cycles. A novel technological route combining the high-temperature calcium looping CO2 capture and CO2 mineralization curing was proposed, and the associated challenges of this method were also discussed.

Review on the Effect of Seed Rate and Improved Varieties on Grain Yield of Bread Wheat (Tritium Aestivum L.) in Ethiopia

Wheat is one of the strategic crops in Ethiopia, because of its role for food security, import Substitution and supply of raw material for agro-processing industry. Wheat Produced by 4.6 million smallholder farmers on 1.8 million hectares of land with an estimated annual production of 5.0 million tons at an average productivity of 2.9 t/ha which has been consistently increasing for the last 25 years, but much lower than the world average 3.3 t/ha. The lowest yield is attributed to many factors, such as the wheat variety, seed rate, seed source, unavailability of quality seed, use of poor quality seeds and inappropriate seed size are some of the factors. Seed rate are the most important management factor affected the agronomic characteristics of wheat. Seeding rate can impact on wheat tillering, grain yield and protein quality. Hence, achieving higher agronomic performance and better end-use quality requires optimizing and periodically reviewing management practices such as seeding rates. However, in varieties that produce fewer tillers, higher seeding rates compensated for reduced tiller. In a dense wheat population, grain yield decreased due to competition between plants that induced self-regulation. So optimum seed rate is recommended depending on the growth habit of the varieties and soil fertility level for increasing wheat production and productivity.

The Ones and Zeros of Carbon Capture

Leading services companies and specialty software firms alike have launched various tools and digital suites to assist carbon capture and storage (CCS) project operators with everything from ideal siting of facilities and pipelines to the efficient operations and around-the-clock monitoring of those facilities. CCS holds the promise of big business if industry can efficiently and economically operate at scale the slate of planned facilities. Oil and gas companies have been making investments in the space with aims to become leaders in a segment—ironic since the petroleum business is also one of the emitters of CO2 into the atmosphere. Last month, supermajor ExxonMobil executed the largest offshore CO2 storage lease in the US with the Texas General Land Office. The 271,000-plus-acre site complements the onshore CO2 storage portfolio ExxonMobil is developing and further solidifies the US Gulf Coast as a CCS leader, according to the operator. In an October 2024 report, the US Department of Energy (DOE) issued a draft strategy for carbon management technologies through 2030, stating that carbon capture and direct air capture are “essential” to achieving net-zero greenhouse gas emissions by 2050. The report says CCS projects will grow dramatically over the next decade and beyond, adding that 18 CCS facilities are operating now in the US. DOE’s near-term CCS strategy through 2030 incorporates focusing research, development, demonstration, and deployment funding on priority use cases; building out CO2 transportation and storage infrastructure where it likely will be needed most in the future; supporting the implementation of effective and evidence-driven policies and regulations related to carbon management at other federal agencies; engaging communities and workers to ensure projects deliver benefits and mitigate potential risks to public health and the environment; and supporting climate diplomacy efforts to accelerate the adoption of carbon management at scale globally in a way that aligns with the Paris Agreement. “DOE is funding a variety of technologies to assist in decarbonization in the industrial and power sectors,” the report explained. “These approaches include carbon management as well as electrification, fuel switching, materials substitution, efficiency, and other emissions-reductions measures. In parallel, DOE is working to envision and develop transformative emissions reductions approaches that will create new options in the long term.” The US government has been an active participant in making funding available for the advancement of CCS technologies. In 2024 alone, almost $3.5 billion was made available between two separate programs—CCS large-scale pilot projects ($937 million) and CCS demonstration projects ($2.5 billion)—as part of the Bipartisan Infrastructure Law. In June 2023, ceremonial shovels were plunged into the dirt in Ector County, Texas, to mark the start of construction for the largest direct air capture facility in the world, designed to capture 500,000 metric tons of CO2 from the atmosphere every year. Occidental subsidiary OnePointFive’s $1-billion Stratos project is located on a 65-acre site made up of a network of air contactors, pellet reactors, a centrifuge, and a calciner—all known components that operate in other industries.

Sustainable production of Pleurotus sajor-caju mushrooms and biocomposites using brewer’s spent and agro-industrial residues

Brazil is one of the world’s largest beer producers and also a major food producer. These activities generate a large amount of residues which, if disposed of inappropriately, can have adverse effects on the environment. The objective of this research was to evaluate the potential of using these residues for both mushroom cultivation (traditional use) and the production of mycelium-based composites (innovative use). Mushroom production (Pleurotus sajor-caju) was conducted using only brewer’s spent grains (fresh and dried) and also mixed with banana leaves (1:1) or peach palm leaves (1:1), which are residues widely available in the northern region of Santa Catarina, Brazil. The productivity of mushrooms cultivated using fresh and dried brewer’s spent grains did not exhibit a statistically significant difference, indicating that this residue can be utilized shortly after its generation in the industrial process, thereby reducing costs associated with production. Combining brewer’s spent grains with banana or peach palm leaves resulted in enhanced mushroom production (0.41 and 0.38 g day−1, respectively) compared to using the leaves as a sole substrate. The mushrooms produced contain sugars and a minimal sodium content, and are considered a source of phosphorus. In addition, no toxic elements (Hg and Pb) were present. The mycelium-based composites produced using the residual substrate (after the mushroom harvest) exhibited better mechanical properties (compressive strength = 0.04 MPa, density = 242 kg m−3, and low humidity sorption) than those produced using fresh substrate. The results demonstrate the synergistic effect of combining the two approaches under investigation. The use of brewer´s spent enhance the mushroom productivity and the residual substrate enhance the mechanical properties of mycelium-based composites. The compressive strength, density, and air humidity sorption properties are essential for determining the potential applications of mycelium-based composites. The use of brewer’s spent grains mixed with banana leaves demonstrated significant promise for mushroom production and subsequent application in the development of mycelium-based composites. These sequential approaches contribute to waste valorization and the rational utilization of natural resources, as the mycelium-based composites are considered for substitution of synthetic materials, thereby promoting sustainability for future generations.

Tradeoffs and synergy between material cycles and greenhouse gas emissions: Opportunities in a rapidly growing housing stock.

Management of building materials' stocks and flows is a major opportunity for circularity and de-carbonization. We examine the relationship between material consumption and associated greenhouse gas (GHG) emissions under different scenarios in Israel, a developed country with an already high population density that expects tremendous growth in its housing stock by 2050. We created scenarios of varying housing unit sizes and additional material efficiency practices: fabrication yield, lifetime extension, material substitution, recycling, and their combination, resulting in 18 scenarios. In each scenario, the material flows and stocks needed to supply the housing demand and the resulting life-cycle GHG emissions are quantified. No single material efficiency practice achieves a reduction in all indicators, suggesting a potential conflict between circular economy and decarbonization policies: The material substitution scenario allows for the biggest reduction in material consumption (12%-40% concrete reduction and 15%-51% steel reduction in 2050 compared with the baseline), while the recycling scenario achieves the biggest reduction in GHG emissions (22%-43% reduction in 2050 compared with the baseline). In the long-term, the life-extension scenario reduces most demolition waste. These findings can help policymakers and stakeholders consider the impacts of raw materials consumption and implement this knowledge in light of their priorities in policy packages. The results suggest a narrow window of opportunity within the next decade to influence material consumption and emissions to 2050. The findings could also shed light on the sustainability trajectories of other countries with similarly rapidly developing building stock, which have received little attention in this field.

Look before you leap: Are increased recycling efforts accelerating microplastic pollution?

To fight plastic pollution and reach net-zero ambitions, policy and industry set goals to increase the recycling of plastics and the recycled content in products. While this ideally reduces demand for virgin material, it also increases pressure on recyclers to find suitable endmarkets for the recyclate. This may lead to two effects: a multiplication of recycled content in applications already made of plastic and a substitution of non-plastic materials with cheap, low-quality recyclate. Both areas of application may be sources of microplastic (MP) pollution. Combined with the inherent degradation of recyclate during its lifecycle, but also during recycling, we expect the increase in recycled content will subsequently lead to an increase in MP pollution. We propose a framework to investigate the risk of MP generation through plastic applications throughout their subsequent lifecycle of production, use phase, and end of life. We apply the framework to two prominent examples of recyclate endmarkets, that is, textiles and wood-plastic, and point out where the degradation effects can cause higher release. To conclude, we outline a research agenda to support policymakers in their decision making on specifying targets for recycling and recycled content.

Synergistic environmental benefits from copper slag recycling in China: Pollutant mitigation and carbon reduction

In response to the dual challenges of climate change and environmental degradation, China is prioritizing efforts to manage both pollution and carbon emissions. Given China's leadership in global copper smelting, recycling substantial amounts of copper slag is considered a key strategy for environmental improvement. This study applies life cycle assessment (LCA) to evaluate the environmental benefits of three copper slag recycling strategies. Building on the LCA results, we introduced a synergistic reduction index system that assesses the combined effects of pollution mitigation and carbon reduction. Findings indicate that utilizing recycled copper slag in building materials not only significantly reduces local industry emissions but also demonstrates substantial synergistic effects. This strategy optimally reduces both air pollution and carbon emissions, largely due to the substitution of high-pollution materials with recycled copper slag. Based on these insights, we propose targeted recycling strategies tailored to regional needs and capacities, thereby offering practical suggestions for the sustainable management of copper slag.