Using high-volume construction and demolition (C&D) waste for concrete production is an environmentally sustainable approach. However, the use of C&D waste often adversely affects concrete performance. This study proposed a novel biomimetic strengthening method for recycled aggregates (RAs) treated with dopamine (DA) hydrochloride and investigated its effects on the mechanical properties and durability of recycled aggregate concrete (RAC) to produce high-quality precast concrete. The results show that using an appropriate amount of DA hydrochloride solution to enhance RA significantly improved the interface compactness of RAC due to the strong adhesion ability of polydopamine (PDA), which promotes cement hydration around RA. Furthermore, PDA increases the hydration degree of cement by promoting the dissolution of aluminate phase (C3A and C4AF) in cement clinker and the formation of AFt. When the biomimetic strengthening time of RA was 18 h, the new matrix around the RA had the highest hydration degree, and its interfacial transition zone width was 16.67% smaller than that of the untreated sample. Compared to RAC containing untreated RA, RAC containing RA by biomimetic enhancement for 18 h showed an increase in 28-d compressive strength by 1.59–18.02% and a decrease of 5.22–71.90% in sorptivity coefficient.
The deployment of new artificial intelligence (AI) methods is pivotal in driving innovative automation systems within the construction sector, with growing relevance for improving material sustainability assessment and decision-making. Among different methods, transfer learning (TL) has recently emerged as a key enabler of deep learning success in construction engineering, especially in computer vision applications using convolutional neural networks (CNNs). Recognizing the central role of concrete materials in construction and their significant life-cycle environmental impacts, this review examines the transformative potential of combining TL and CNN to automate assessment and optimization in different areas of concrete technology. It begins by introducing the concept of TL, highlighting prominent off-the-shelf image datasets and CNN models employed in concrete research. The review then showcases the potential of TL-enabled CNN computer vision systems across different stages of the concrete life-cycle, including material selection, construction, quality control, and maintenance, supporting data-driven and resource-efficient practices. Lastly, the review proposes future research directions to foster the integration of these AI-based automation systems into the concrete industry, contributing to more cost-effective and sustainable life-cycle performance of concrete infrastructure.
The assessment of the environmental impact of additively manufactured parts is difficult due to the hard-to-compare system boundaries. This study proposes a novel property-dependent option for the comparison of additively to conventionally produced parts based on the life cycle assessment (LCA) of two different designs of structural components for energy-absorption applications. While the optimized additive manufacturing (AM) lattice structure led to significant reduction of global warming potential (GWP), cumulative energy demand (CED), and material footprint (MF) (−45%, −51% and −56%, respectively), additively manufacturing the standard design led to an increase of those environmental indicators (+33.9%, +33.1% and +34.6%, respectively) as compared to the conventionally manufactured standard design. It is demonstrated that the environmental impact of metallic components is only reduced by AM if the freedom of design offered by these techniques is utilized to realize weight reduction and, more importantly, that this design must be based on critical part properties. Especially, argon consumption during atomization was found to drastically increase the environmental impact. Consequently, the material yield during powder atomization and AM, combined with minimized gas consumption, can pave the way towards more sustainable AM.
Non-conventional slag (NCS), including copper, lead, lithium, nickel, phosphorus, and zinc slags are under-utilised industrial by-products with potential in sustainable construction. This review evaluates their use as partial replacements for cement and aggregates, focusing on performance and mechanisms. NCS behaviour varies with composition and activation, with some enhancing strength and durability. Most importantly, NCS supports waste valorisation, reduced material consumption, and more sustainable concrete development.
Green hydrogen via renewable-powered electrolysis is vital for decarbonization, yet OER anode scalability remains a key limitation. A comparison of ALK, PEM, AEM, and SOEC technologies reveals challenges in dynamic integration. Lab-to-industrial translation suffers from mass/heat transfer and stability constraints. Understanding fluctuating operation–induced degradation is critical. Future advances demand co-design of materials, interfaces, and systems to bridge performance gaps and enable sustainable, large-scale deployment.
Abstract Machine learning (ML) can support the development of lower-carbon concrete through improved cement production, mix design, supplementary cementitious materials and alternative binders, and recycled aggregate concrete. This review synthesizes these applications and shows that ML can strengthen process control and multi-objective optimization. Current limitations arise mainly from data heterogeneity, limited generalizability, and weak interpretability. Closer integration with physical understanding is needed for reliable low-carbon decision-making.
Abstract Alkaline industrial by-products have significant potential for permanent CO 2 sequestration, but their reaction kinetics and controlling factors are often overlooked. This study examined the direct aqueous carbonation of basic oxygen furnace (BOF) slag in a slurry setup with continuous mechanical mixing and CO 2 -enriched air bubbling in ultrapure water and natural seawater, at 25% pCO 2 under ambient temperature and 1 atm for 24 h. CO 2 sequestration into carbonate minerals was higher in the ultrapure water (105 ± 5 kg CO 2 t −1 slag; 90% CO 2 capture efficiency) than in seawater (78 ± 4 kg CO 2 t −1 slag; 70% CO 2 capture efficiency). Carbonation proceeded in two distinct stages: an initial rapid carbonation phase (4–12 h), dominated by reactive Ca-(hydr)oxides, silicates and aluminates (e.g. wollastonite), followed by slower reactions involving less-reactive phases as the system gradually approached equilibrium with the pCO 2 in the gas phase. Ionic inhibitors (e.g. Mg 2+ ) affected the overall carbonation rate throughout the process. These findings highlight the importance of considering multi-stage kinetics and the influence of the aqueous matrix on reaction-inhibiting factors when evaluating the achievable extent of CO 2 sequestration potential and the time required to reach it.
Bacterial consortia, with broad metabolism and environmental resilience, show promise for bioaugmentation treatment of plastic wastes. Consortia design principles and plastic degradation enhancements in laboratory and simulated-system studies were reviewed. Practical barriers include narrow polymer scope, long treatment duration, limited scalability, ecological risks, and scarce techno-economic assessments. Bioaugmentation can be realized through the development of bacterial formulations, the integration of pretreatment–bioaugmentation workflows, and the implementation of long-term field trials.
Abstract Adoption of electric vehicles and battery stationary storage is increasing lithium demand. The EU is import-dependent and has formulated supply-security targets for self-sufficiency (10% by 2030) and recycled content (6% by 2031 and 12% by 2036). This study critically assesses these targets by developing scenarios for lithium supply, demand, and recycling, and shows that recycled batteries make only a modest contribution to self-sufficiency, falling short of policymakers’ targets. The finding is sensitive to assumed battery lifetimes. The EU lithium projects designated as strategic are more than sufficient to meet the 2030 self-sufficiency target. By 2036, self-sufficiency ranges between 31% and 78%, assuming all projects commence as announced. In addition, future supply from European companies’ investments in other continents is estimated to exceed domestic output. The findings indicate that resource efficiency and substitution are key to achieving high levels of self-sufficiency, while recycling has a limited role in the short term.
Both the native lignin contained in biomass and the technical lignin that is a by-product of pulp and paper manufacture represent potential resources, and so efficient, low-cost valorization of lignin has attracted worldwide attention. The present work developed a means of extracting methanol from lignin in high yields under mild conditions and without an external power supply. This technology is based on the generation of numerous redox reaction sites by physically mixing powdered anode and cathode materials with an electrolyte, after which lignin and humidified air are supplied. Active oxygen species produced via water oxidation are proposed to attack the methoxy groups of the lignin to generate methanol. Optimization of the system provided a methanol yield of 73.4% at 75 °C and atmospheric pressure, exceeding the yields obtainable when operating in fuel-cell and electrolysis modes. This method can potentially be applied to the native lignin present in biomass, thus minimizing the environmental impact of methanol production.
Abstract Adhering to PRISMA-ScR guidelines, this systematic review evaluates sustainable alternatives to petroleum-based micro/nanospheres. We classify biodegradable materials into natural, synthetic, and composite systems, analyzing their fabrication alongside diverse applications in cosmetics, biomaterials, environmental remediation, catalysis, and thermal energy storage. By addressing technical trade-offs, standardized testing, and critical research gaps, this work provides a strategic roadmap for engineering high-performance, eco-friendly microspheres to mitigate the global microplastic crisis and promote a circular bioeconomy.
Abstract The current study presents a green approach for developing sustainable and biodegradable chitosan (CH) films enhanced with Magnesium Oxide nanoparticles (MgO NPs), utilizing lemon juice (LJ) and lemon peel extract (LPE). This work aims to engineer active films with improved mechanical, barrier, and water-soluble properties for food packaging applications. The films were characterized by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and mechanical testing. FTIR confirmed the successful incorporation of MgO NPs into the CH matrix via M–O vibrational peaks, while SEM revealed MgO NPs acting as structural fillers. The films showed improved mechanical properties with the tensile strength increasing from 0.6 MPa to 1.02 MPa upon incorporation of 1.5% MgO NPs. Water solubility increased from 26.8% (pure CH) to 31.6% (1.5% MgO-CH), indicating enhanced biodegradability. MgO NPs also filled polymeric matrix voids, improving barrier properties. Additional analyses included color, water vapor permeability (WVP), moisture content (MC), and swelling degree (SD). This integrated green-chemistry approach demonstrates the valorization of citrus waste into functional active packaging. The MgO NP-reinforced CH films serve as a sustainable alternative to conventional plastics, directly contributing to UN SDG 12 (Responsible Consumption) and SDG 2 (Zero Hunger) by reducing plastic pollution and food spoilage.
Petroleum coke, a low-value byproduct of oil refining, is widely used as an industrial fuel with significant carbon and sulfur emissions. Converting petroleum coke into battery-grade graphite reduces its environmental footprint while meeting the rising demand for sustainable energy materials. Conventional graphitization, however, requires extreme temperatures (>3000 °C) and long processing times, limiting industrial adoption. We demonstrate a catalytic graphitization process that transforms the coke into graphite at <1600 °C within hours, using iron (Fe) as a recoverable and reusable catalyst. Structural analyses confirm a high degree of graphitization, and electrochemical testing shows lithium-ion battery anode performance comparable to commercial graphite. By operating at reduced temperature and shortening reaction time, our method theoretically lowers energy by more than 9-fold as compared to the conventional process. By reducing energy demand and enabling resource recovery, this method offers a scalable, energy-efficient route to valorize petroleum coke. Our results highlight catalytic graphitization as a practical pathway to reduce emissions from oil refining byproducts while supporting sustainable energy storage technologies.
An attempt was made to demonstrate the efficient and selective extraction of the tetravalent plutonium from aqueous nitric acid medium using a novel anion functionalized task-specific ionic liquid: tri-n-octyl methyl ammonium n-dodecyl sulfate [ $${({\rm{C}}}_{8}{)}_{3}{{\rm{C}}}_{1}{{\rm{N}}}^{+}{{\rm{DS}}}^{-}]$$ . The maximum separation factor for Pu(IV) over U(VI) was found to be more than 103; whereas that for Pu(IV) over Am(III) was more than 105. At 4 M HNO3, the majority of Pu existed as $${\rm{Pu}}({\rm{N}}{{\rm{O}}}_{3}{)}_{2}^{2+}$$ (~80%) and $${\rm{Pu}}{({\rm{N}}{{\rm{O}}}_{3})}^{3+}\,( \sim 11 \% )$$ , leading to the formation of ML2 and ML3 species viz. ( $${\rm{Pu}}({\rm{N}}{{\rm{O}}}_{3}{)}_{2}^{2+}\,({\rm{D}}{{\rm{S}}}^{-}{)}_{2}$$ and $${\rm{Pu}}({\rm{N}}{{\rm{O}}}_{3}{)}_{2}^{2+}\,({\rm{D}}{{\rm{S}}}^{-}{)}_{3}$$ ). On the other hand, in 8 M HNO3, plutonium existed as cationic, neutral, and anionic species with the relative composition: Pu(NO3)22+ ~16%, Pu(NO3)62-(~42%), and Pu(NO3)4 ~ 40%. Hence, the extraction of Pu(IV) proceeded via the $$({({\rm{C}}}_{8}{)}_{3}{{\rm{C}}}_{1}{{\rm{N}}}^{+}{)}_{2}{\rm{Pu}}({\rm{N}}{{\rm{O}}}_{3}{)}_{6}^{2-}$$ , $${\rm{Pu}}({\rm{N}}{{{\rm{O}}}_{3})}_{4}.\,{({\rm{C}}}_{8}{)}_{3}{{\rm{C}}}_{1}{{\rm{N}}}^{+}{{\rm{DS}}}^{-}$$ and $${\rm{Pu}}({\rm{N}}{{\rm{O}}}_{3}{)}_{2}^{2+}\,({\rm{D}}{{\rm{S}}}^{-}{)}_{2}$$ , species getting transferred into the ionic liquid phase. In the case of uranium, such speciation analyses were performed as well, which revealed the predominance of the ML2 species: $$({\rm{U}}{{\rm{O}}}_{2}^{2+})\,({\rm{D}}{{\rm{S}}}^{-}{)}_{2}$$ and $${\rm{U}}{{\rm{O}}}_{2}({\rm{N}}{{\rm{O}}}_{3}{)}_{2}.\,2{({\rm{C}}}_{8}{)}_{3}{{\rm{C}}}_{1}{{\rm{N}}}^{+}{{\rm{DS}}}^{-}$$ during its extraction from 4 M HNO3 and 8 M HNO3, respectively. The sluggishness in the extraction of Pu(IV) and U(VI) was attributed to the viscosity-induced slow diffusion of the actinides and the actinide-ionic liquid complexes. The extraction processes were exothermic. The extent of exothermicity was found to be greater for Pu(IV) as compared to that for U(VI), and it was more for the extraction from 8 M HNO3. The solvent systems exhibited good radiation stability. However, a gradual deterioration in the extraction performance with increasing gamma ray exposure was evidenced. Multiple contacts with a solution of 10 mM of oxalic acid were found to be effective for quantitative back extraction of Pu(IV) from the loaded ionic liquid phase.
Abstract The increasing global demand for sustainable waste valorization and organic soil amendments has driven interest in Black Soldier Fly Larvae (BSFL) mediated bioconversion. This study investigated co-composting of fecal sludge cake (FSC) with cattle manure (CM) or fruit/vegetable waste (FVW). Seven treatments were tested: T1 (100% FSC, control); T2 (75% FSC + 25% CM); T3 (65% FSC + 35% CM); T4 (55% FSC + 45% CM); T5 (75% FSC + 25% FVW); T6 (65% FSC + 35% FVW); and T7 (55% FSC + 45% FVW). BSFL composting significantly altered substrate properties: frass pH increased from 7.08–7.63 to 7.49–7.96, moisture content declined by 24–32%, and organic carbon decreased 14–46%. Nitrogen increased most in FVW-amended treatments (14–22%), phosphorus was highest in the FSC control (20–21 g/kg), and potassium peaked in T7 (16–20 g/kg). Among all treatments, T7, with the highest FVW proportion, achieved the most balanced nutrient enrichment and the most effective organic matter stabilization. Essential elements exhibited substrate-dependent trends: magnesium and silicon increased, while calcium, sulfur, and micronutrients (zinc, molybdenum, copper, iron, manganese, and chlorine) decreased by 16–44%. These results demonstrate that BSFL co-composting efficiently converts high-organic wastes into nutrient-dense soil amendments, with feedstock composition critically influencing agronomic quality. The process offers a viable circular bio-economy strategy for integrated organic waste management and fertilizer production.
Abstract Methane pyrolysis (MP) is a promising method to produce hydrogen with no reaction-based carbon dioxide emissions. It has been speculated that the solid carbon co-produced from MP may be sequestered in cementitious systems to lower the environmental impact of both the hydrogen and cement industries. In this paper, for the first time, we report on the feasibility of incorporating solid carbon co-product, in the form of carbon nanotube pulp (CNTP), from a commercial-scale MP plant in cementitious composites. Mechanical strength tests alongside rheological tests are conducted on composites in which Portland cement has been replaced by various amounts of this CNTP from 0 to 1% by weight. The addition of this material mildly increases the early-age compressive strength of the CNTP-cement composites. The fresh properties of CNTP-cement composites are significantly impacted with a large increase in yield stress, resulting in 74.2% increase for a paste replacing cement with 1% (wt.) CNTP relative to a plain cement paste. The results indicate that cementitious composites may be used to sequester MP-coproduced carbon, although the complex form and poor dispersion of the material at high replacements limits large-scale implementation as-is.
Abstract Mechanocatalysis refers to catalytic chemical transformations driven by mechanical energy. It has emerged as a promising framework for sustainable chemistry and circular materials processing. By directly coupling mechanical stress with catalytic function, mechanocatalysis enables solvent-free transformations and unlocks reactivity that is difficult to access under conventional thermal or photochemical conditions. Beyond its green chemistry attributes, mechanocatalysis represents a conceptual shift in catalysis, in which force, structure, and reactivity are intrinsically coupled. Recent advances demonstrate its potential in biomass valorization and polymer depolymerization. However, significant challenges remain in understanding force-induced activation mechanisms, designing mechanically robust catalysts, and engineering scalable reactors. This perspective critically evaluates these advances and argues that integrating mechanical variables as controllable reaction parameters could redefine sustainable chemical manufacturing.
1,3-Propanediol (PD) is a C3 diol with wide applications in biopolymers and personal care products. Microbial production of PD from crude glycerol (CG) has gained attention as a sustainable alternative to petrochemical routes, where yield and process cost are critical factors. In this study, the PD production potential of an adaptively evolved Levilactobacillus brevis PD20.100 was evaluated using fish protein hydrolysate (FPH), an industrial by-product of the fisheries sector, as a nitrogen source. Batch, fed-batch, and immobilized fermentation modes were investigated and compared with a conventional nutrient-rich modified MRS (mMRS) medium. Fermentation performance was assessed based on cell growth, substrate utilization, and formation of PD, lactic acid (LA), and acetic acid (AA). Batch fermentation with suspended cells in mMRS resulted in the highest PD titer of 39.75 g/L, while FPH-supported fermentation achieved a comparable PD concentration of 31.16 g/L. Although fed-batch and immobilized systems offered operational stability and reusability, they exhibited lower productivity. Overall, the results demonstrate that FPH can serve as a cost-effective and sustainable nitrogen source for microbial PD production, supporting the valorization of fish-processing by-products.
The construction industry is rapidly changing to meet growing demand and reduce its environmental impact. These objectives can be met, in part, through improved selection of construction materials. However, the material properties including embodied carbon (EC) of emerging construction materials are less well documented in material property databases compared to conventional ones, providing barriers to their utilisation and correct perception of their decarbonisation potentials. This study provides material property data for emerging structural materials through a comprehensive literature review, visualises the results on material property charts, and analyses these data comparing to conventional materials. Only 18% (37 out of 204) of the emerging structural materials reviewed had EC values; less (11%) had embodied energy values. Analysis of the data demonstrates that using alternative and emerging materials for structural beams and columns can substantially reduce EC. For example, in the beam case study presented and using cradle-to-gate EC data (excluding stored carbon in wood), engineered wood products (glulam, cross-laminated timber) and reused steel achieve 3-5% of the EC of primary steel. Therefore, we highlight the benefits of collecting material property and environmental impact data for emerging materials and their potential for greater adoption to achieve lower carbon construction.
The valorization of carbon dioxide (CO2) into fuels and chemicals represents both a scientific challenge and an opportunity for sustainable energy transition. This review bridges heterogeneous and homogeneous approaches, highlighting how molecular precision and materials robustness can converge to address the intrinsic stability of CO2 and the complexity of its multi-electron transformations. Advances in single-atom catalysts, MXenes, and carbon nitrides demonstrate how structural control at the atomic scale can enhance activity and selectivity, while homogeneous complexes continue to provide mechanistic insights and tunable active sites. In parallel, machine learning (ML) is emerging as a transformative tool to accelerate catalyst discovery, identify descriptors, and guide rational design; however, its effectiveness depends critically on realistic datasets and experimental validation. We argue that future progress will rely on integrative strategies: combining computation, experiment, and automation within materials acceleration platforms. By adopting this integrative vision, CO2 can evolve from an environmental burden to a versatile feedstock for next-generation sustainable fuels and chemicals.
