Search Results (744)

One-part geopolymer mortars provide an alternative to cementitious materials by using dry activators and industrial by-products. This study evaluated a multi-precursor matrix containing slag, fly ash, ceramic powder, red mud, and 5% MgO, reinforced with polyvinyl alcohol (PVA), basalt, or micro-steel fibers at 0.4% and 0.8% by volume. Specimens were cured at 20 ± 2 °C or at 80 °C for 24 h and assessed for flowability, mechanical properties, ultrasonic pulse velocity (UPV), Böhme abrasion, 24 h water absorption, and sorptivity. XRD, FTIR, and SEM/EDS were used only to compare by heat-cured mixtures. The results showed that at 28-day, heat curing increased compressive strength by 39.5–71.8%, flexural strength by 29.2–134.4%, and UPV by 20.5–36.4%, while reducing sorptivity by 12.2–35.7% relative to ambient curing. PVA reduced flowability likely because of its hydrophilic surface and high surface area. For 0.8PVA, the flow diameter was 23.6% below the reference, whereas the 28-day heat-cured flexural strength reached 7.5 MPa, with the lowest abrasion thickness loss of 0.63 mm. Micro-steel mixtures maintained compressive strength comparable to the reference, reaching 72–73 MPa at 28-day. Heat curing reduced water absorption in PVA and basalt mixtures, whereas the reference and micro-steel mixtures showed insignificant change. Microstructural analyses suggested the formation of a more compact and reacted aluminosilicate matrix under heat-cured conditions. A screening life-cycle assessment, limited to the non-fiber-reinforced reference matrix, showed that heat-curing increased global warming potential by 7.6%, while the two solid activators contributed approximately 45% of the ambient-cured reference GWP. The findings indicate that heat curing significantly enhances the performance of one-part geopolymers, while fiber selection provides additional mechanical and durability improvements. Full article

Biorefineries that convert the organic fraction of municipal solid waste (OFMSW) into advanced biofuels can integrate waste management with renewable energy production. However, their environmental performance remains insufficiently characterised owing to a scarcity of life cycle assessment (LCA) studies based on real operational data. This study presents a gate-to-gate LCA of a demonstration biorefinery processing source-separated food waste into bio-oils, bioethanol, and biogas. The ReCiPe 2016 Midpoint (H) method was applied across 18 impact categories, with system expansion crediting the displacement of rapeseed oil, maize-derived ethanol, and marginal biogas-derived electricity. The net global warming potential (GWP) was 68.5 kg CO₂ eq per tonne of wet OFMSW (69% reduction from gross), placing the biorefinery 83–93% below landfilling, 63% below incineration with CHP, and above standalone anaerobic digestion systems that lack the energy-intensive drying and enzymatic hydrolysis steps of the present configuration. Bio-oil and bioethanol achieved net-negative GWP per kilogram of product (−0.89 and −0.66 kg CO₂ eq, respectively), whilst eleven of eighteen categories achieved net savings under system expansion. Enzyme production dominated the bioethanol environmental profile (37–94% across categories), whilst drying dominated bio-oil (46–93%). Monte Carlo simulation confirmed that the sign of the net impact stayed unchanged across the entire 95% confidence interval (the interval did not span zero) for 17 of 18 categories. Full article

The transition toward a circular economy in the mining sector has increased the need for sustainable strategies capable of recovering value from tailings generated during mining activities and supporting the safe closure of tailings dams. The present study evaluates the environmental performance of reverse mining as a circular economy strategy by comparing two iron ore tailings valorization pathways: mineral reprocessing for iron recovery and reuse as aggregates in cementitious composites. A Life Cycle Assessment (LCA), conducted in accordance with ISO 14040 and ISO 14044 standards, was applied using OpenLCA software and primary operational data collected from a full-scale tailings dam decommissioning project in Minas Gerais, Brazil. Environmental impacts were assessed in ten impact categories using the ReCiPe Midpoint methodology, with emphasis on Global Warming Potential (GWP). Reverse-mined tailings presented a GWP of 1.91 kg CO₂ eq/t, substantially lower than conventionally mined iron ore (6.80 kg CO₂ eq/t) and comparable to natural sand (1.88 kg CO₂ eq/t). Mineral reprocessing reduced the GWP associated with iron ore production by approximately 50%, while the reuse of tailings as construction aggregates proved environmentally competitive under suitable transport conditions. These findings demonstrate that reverse mining can support sustainable tailings dam closure by reducing environmental impacts, recovering secondary resources, and advancing circular economy practices in the mining sector through a practical decision-support framework based on primary industrial data. Full article

Fuel cells (FCs) are critical for decarbonizing the transport industry, with Life Cycle Assessment (LCA) serving as the standard evaluation framework. However, existing literature exhibits severe methodological heterogeneities and divergent system boundaries that introduce deep epistemic uncertainties. This review conducts a systematic analysis to critically harmonize FC environmental performance across the road, aviation, and maritime sectors. Quantitative synthesis reveals global warming potential (GWP) as the dominant metric. For light-duty vehicles, GWP drops to around 30 gCO₂eq/km, matching battery-electric configurations exclusively under deeply decarbonized grids. Manufacturing FC stacks and advanced storage imposes a severe upfront carbon debt, particularly prominent in heavy-duty freight (60–130 tCO₂eq). In aviation, 80–90% in-flight GWP reductions trigger massive burden-shifting, transferring 60–70% of lifecycle damages to ground-based infrastructure. Maritime FCs shrink GWP to 0.06–0.60 kgCO₂eq/kWh, strictly contingent on upstream hydrogen production. Crucially, despite long-term GWP advantages, FC pathways face systematic penalties in acidification, eutrophication, and ecotoxicity, heavily driven by platinum-group catalysts and fluoropolymer membranes. By isolating software-driven biases and database discrepancies, this work delivers an actionable methodological roadmap, establishing a policy-aligned baseline for future FC transportation sustainability frameworks. Full article

In this article, Life Cycle Assessment (LCA) was applied to investigate the potential environmental impacts of bioethanol production pathways from six biomass feedstock options. The LCA cradle-to-gate modelling case studies involve (i) corn stover, (ii) wheat straw, (iii) rice straw, (iv) sugarcane bagasse, (v) woody biomass, and (vi) microalgae for the final production of 1 kg bioethanol as functional unit. Environmental impact results of GWP (Global Warming Potential), AP (Acidification Potential), and EP (Eutrophication Potential) were evaluated utilizing CML2001, a Life Cycle Impact Assessment (LCIA) methodology featuring midpoint evaluation and baseline environmental categories. Water Footprint (WF) indicators were also measured. Among the six feedstocks, the GWP results indicated the most favourable option to decarbonize bioethanol production is to utilize corn stover feedstock, enabling total-1.04 kg CO₂-eq/kg ethanol. Wood waste also displays favourable GWP impacts of −0.9 kg CO₂-eq/kg ethanol, along with negligible WF results. Both rice straw and microalgae exhibited the most unfavourable feedstock options, both resulting in GWP impacts of 12.71 kg CO₂-eq/kg ethanol and 11.32 kg CO₂-eq/kg ethanol respectively. Additionally, rice straw and microalgae require high volumes of WF during cultivation stages. Overall, the set of environmental impact results, based mostly on data derived from lab-scale or pilot scale reports, demonstrated substantial requirements for environmental reduction and management of some specific feedstocks to proceed for large scale set ups. Full article

The rapid expansion of electric vehicles is generating large volumes of spent lithium iron phosphate (LFP) batteries, yet the environmental performance of closed-loop regeneration under industrial conditions remains insufficiently quantified. Here we develop a life cycle assessment of a closed-loop recycling–regeneration pathway using factory-level inventory data from an integrated plant, benchmarking 1 kg of regenerated LFP cathode-active material (CAM) at the plant gate against virgin LFP CAM (ecoinvent v3.10; ReCiPe 2016 Midpoint). Relative to virgin production, the closed-loop route reduces global warming potential (GWP100) by 7.73% (from 6.59 to 6.08 kg CO₂-eq kg⁻¹ CAM), fossil fuel potential (FFP) by 3.80%, surplus ore potential (SOP) by 97.57%, and carcinogenic human toxicity (HTPc) by 36.72%—a clear but heterogeneous advantage, large for mineral resources and modest for climate. Iron phosphate and lithium carbonate recovery dominate the burdens, with H₂O₂ being the largest single GWP100 contributor (23.7%) and the most sensitive inventory parameter, while the SOP advantage is highly robust. Grid-decarbonization scenarios widen the GWP100 reduction to 22.4% under near-zero-carbon electricity. The carbon competitiveness of closed-loop LFP regeneration is therefore governed by the balance between avoided virgin-material burdens and reagent- and energy-intensive recovery operations. Full article

This study presents a gate-to-gate life cycle assessment (LCA) comparing the environmental impact of three torrefied municipal solid waste (MSW) energy sources (S1) solar photovoltaic (PV), (S2) grid electricity from India and (S3) biomass combustion. Experiments performed in a laboratory setting produced a yield of transitory MSW torrefaction of 28–32% at an input fuel energy of 2 kWh/kg at 200–300 °C for 30–60 min. The ReCiPe 2016 midpoints [Global Warming Potential (GWP); Human Toxicity Potential (HTP); Acidification Potential (AP); Particulate Matter Formation Potential (PMFP)] showed PV produced the least number of emissions (GWP = 0.0426 kg CO₂ equivalent; HTP = 0.00988 kg 1,4-DB equivalent), while grid power produced the greatest number of emissions (GWP = 2.2 kg CO₂ equivalent). Biomass produced intermediate results (GWP = 1.546 kg CO₂ equivalent). All sources had an average positive net energy ratio of approximately 2.78. The results indicate that integrating renewable energy sources significantly increases the environmental and social benefits of the torrefaction process. Additionally, the study provides a MS Excel-Based LCA framework to use when data are limited. Full article

As the construction industry seeks to reduce carbon emissions, timber has emerged as a key material due to its capacity for biogenic carbon storage and end-of-life (EoL) reuse. However, assessing the practical circularity potential of timber structures remains challenging. This is largely because recovered components suffer geometric and material losses at their connection points. This study evaluates the EoL reuse and recycling potential of a multi-storey timber building by combining Building Information Modelling (BIM) with Life Cycle Assessment (LCA). A digital model was used to quantify structural elements (beams, columns, and walls), explicitly accounting for material losses at connections to calculate the net recoverable timber. The recovered material (837.39 m³) was assigned to various cascading use scenarios based on material strength: structural reuse, non-structural reuse, engineered wood production, and energy recovery. To align with ISO 14044 principles, a functional equivalence factor (Q-factor) was applied to measure the environmental benefits of substituting new materials. Results indicate an overall material loss of 16.62% due to connections. Among the evaluated EoL pathways, structural reuse yielded the greatest net carbon benefit (−128.7 tCO₂e), significantly outperforming lower-value alternatives such as energy recovery (−29.3 tCO₂e). Additionally, a Design for Disassembly (DfD) sensitivity analysis showed that reducing connection losses by 50% could increase net global warming potential (GWP) savings by up to 19.7%. In conclusion, connection design is a critical factor in enabling timber circularity. Furthermore, combining BIM material tracking with LCA methods offers a practical approach to quantifying the long-term carbon benefits of timber reuse strategies. Full article

The global use of millions of small rodents annually in medical research creates a need for environmental enrichment that is both practical and sustainable. This study investigated the use of banana pseudostem, an agricultural residue, as a potential material for a laboratory-scale rodent enrichment prototype. A life cycle assessment (LCA) and life cycle costing (LCC) were conducted under a cradle-to-grave system boundary that included production, facility use, sterilization, freezer storage, transport, and infectious waste management. The prototype had a global warming potential (GWP) of 28.40 kg CO₂ eq per functional unit. The results showed that the production phase was the dominant contributor to the environmental impacts and costs. Heat pressing was identified as the main hotspot resulting from high electricity demand, while labor was the main cost contributor, as the manual production process at the laboratory scale was time-consuming. The scenario analysis revealed that modifying the press machine to press two pieces simultaneously reduced GWP by 37.54% and total life cycle cost by 29.11%. Full substitution of grid electricity with photovoltaic electricity for heat pressing reduced GWP by about 67.47%. Extending the replacement interval from 3 to 7 days showed the largest GWP reduction of 56.35%, although this option requires confirmation of animal welfare, hygiene, and structural durability. Although banana pseudostem is a renewable agricultural residue, the environmental impacts and costs of the prototype were mainly due to energy-intensive processing at the laboratory scale rather than the raw material. Further improvement in production efficiency and electricity sourcing is required to reduce impacts and increase the feasibility of the banana pseudostem enrichment prototype. Full article

Cities are confronted with heat, drought, and pluvial flooding, highlighting the need for renovation strategies that enhance climate resilience while minimizing greenhouse gas emissions. This research developed an integrated assessment framework to quantify the mitigation potential of urban and building surface components using five area-based key performance indicators (KPIs): Surface Heat Contribution (SHC), Flood Mitigation Factor (FMF), Water Storage Capacity (WSC), Evaporation Volume (EVA), and Global Warming Potential (GWP). The framework combines simplified life-cycle assessment with biophysical models for heat, water storage, and evaporation, designed as an accessible complement to 3D microclimate tools. Applied to an exemplary residential area in Daegu, South Korea, the method benchmarks existing surfaces and evaluates renovation scenarios targeting heat reduction, flood mitigation, and drought resilience. Results show that surface renovation measures improve mitigation potential. The performance varies across KPIs, involving trade-offs with embodied emissions. Optimal outcomes arise from balanced hybrid strategies integrating complementary measures. Selective greening combined with low heat capacity, high-conductivity materials (e.g., metal façades) effectively reduces heat stress but increases embodied GWP and structural demands. Permeable and greened surfaces improve WSC and EVA, supporting short-term flood mitigation, yet reveal limitations under prolonged rainfall. The proposed framework supports transparent and low-carbon climate-resilient renovation decision-making. Full article

Bioconversion of chicken manure by Hermetia illucens (black soldier fly, BSF) larvae offers a sustainable route for organic waste disposal and protein production, yet how carbon source bioavailability regulates this process remains unclear. We conducted 13-day trials on chicken manure across 27 combinations of three supplement-to-manure mixing ratios (SMMRs, 3:1, 1:1, and 1:3, dry weight basis) and nine carbon blends (sawdust, straw, and corn flour). Measured endpoints included larval yield, substrate temperature dynamics, GHG emissions, global warming potential (GWP), ammonia volatilization, carbon–nitrogen fixation, and frass characteristics. Carbon source identity showed a much stronger association with performance than did the manure-to-supplement mixing ratio. Dry-basis larval yield ranged from 3.5% to 13.2% (mean 7.4%), total GWP ranged from 5105.6 to 8737.2 mg kg⁻¹, and ammonia emissions from 419.6 to 1114.1 mg kg⁻¹. Optimal larval yield was combined with a 3:1 SMMR with corn-flour-rich blends, which boosted productivity and C-N retention. Labile carbon was associated with enhanced lipogenesis, amino acid accumulation, C-N sequestration, and reduced GHG emissions. In contrast, recalcitrant carbon (sawdust) restricted degradation, intensified microbial competition, and induced energy shortage and nutrient losses, impairing conversion efficiency. These findings are consistent with carbon bioavailability rather than C/N, being a key correlate of BSF performance through energy–microbe–substrate interactions. We further propose that substrate formulation targeting labile carbon enrichment can serve as a practical strategy to simultaneously improve larval production and mitigate environmental impacts, though the inferred mechanisms await direct microbiological validation. Full article

The environmental management of highly saline coal mine wastewater presents a critical challenge for European mining regions, particularly under the constraints of the EU Water Framework Directive. This study presents a cradle-to-grave life cycle assessment of a novel zero liquid discharge (ZLD) system developed under the EU-funded LIFE Brine-Mining project and deployed at the Ziemowit mine in Poland. The system was designed to treat coal mine brine (TDS ~80 g/L) and recover valuable resources, including high-purity water, sodium chloride, magnesium hydroxide, calcium carbonate, and calcium sulphate. The assessment was conducted in accordance with EN 15804 using the Environmental Footprint v3.1 methodology, ecoinvent v3.10, and a functional unit of 1 m³ of saline wastewater inflow, covering all life cycle stages from raw material extraction to end-of-life and resource recovery (Module D). The results indicate a fossil-based global warming potential of 73.86 kg CO₂ eq. per functional unit, with 66% attributed to operational electricity consumption (module B6, 44 kWh/m³) and 29% to auxiliary chemical consumption (module B1). Three key environmental hotspots were identified: module B1 dominates ozone depletion potential (67%), module B6 dominates acidification potential (66%), and raw material extraction (module A1) dominates abiotic depletion of minerals and metals (43%). Resource recovery credits (Module D) offset 11.80 kg CO₂ eq. of GWP-fossil, cause the ADP-minerals and metals indicator to become net negative, and reduce the water deprivation potential by approximately 50%. A sensitivity analysis confirmed that results are robust to ±10% variations in wastewater inflow, with GWP-total varying within a narrow −0.5% to +0.6% range once the volume-proportional nature of chemical and electricity consumption is correctly accounted for. These findings provide a quantitative sustainability baseline for the scale-up and replication of integrated ZLD technologies in the European mining sector, demonstrating that circular brine treatment can simultaneously address regulatory water quality targets, reduce primary resource consumption, and deliver measurable environmental credits aligned with EU circular economy and sustainable development objectives. Full article

The use of biochar derived from agricultural wood waste represents a promising long-term carbon storage strategy, contributing to mitigation of climate change effects while offering agronomic benefits. This residue is considered as an appropriate material since it does not compete directly with the food chain. Life Cycle Assessment (LCA) is a widely recognized methodology to evaluate the potential environmental impacts associated with all the stages of the life cycle of a product, process or service. In this study, the potential environmental impact of biochar production and its application on soil have been assessed employing a cradle-to-grave approach. The biochar was produced through the pyrogasification of residual lignocellulosic biomass in a pilot-scale plant. The LCA model has been generated employing the GaBi software (LCA for experts 10.7), in accordance with ISO LCA standards and ILCD Handbook, using the experimental results collected during the test carried out in the pilot plant. Two scenarios have been discussed: a basic scenario, involving the biochar production and application on the soil, and an improved scenario, in which by-products from biochar production are used to replace energy in thermal processes. The Global Warming Potential (GWP) of biochar production resulted in −5.52 kg CO₂ eq./kg of biochar including the sequestered carbon during plant growth and 1.81 kg CO₂ eq./kg of biochar stored in soil and the heat recovery resulted in approximately 20 MJ/kg of biochar of avoided consumption of fossil-based fuels. These findings provide additional support to evaluate biochar potential as an environmentally beneficial solution. Full article

The rapid expansion of hydrogen technologies has intensified the demand for platinum group metals (PGMs), particularly platinum (Pt) and iridium (Ir). Proton exchange membrane fuel cells (PEMFCs) and proton exchange membrane water electrolyzers (PEMWEs) rely on PGMs and fluoropolymer membranes such as Nafion, generating increasing volumes of end-of-life (EoL) membrane electrode assemblies (MEAs). Conventional recycling routes are often energy-intensive, hazardous and limited in polymer recovery. In this study, a closed-loop hydrometallurgical recycling route is assessed through a life cycle assessment (LCA), supported by primary experimental data from optimized recycling trials. Mechanical delamination enabled separation of catalyst layers while preserving membranes, followed by a chlorine-based hydrometallurgical process operating under mild conditions. Leaching efficiencies exceeded 99% for Pt and 80% for Ir, demonstrating the feasibility of metal recovery. Two LCA models were developed: (i) a gate-to-gate recycling model for EoL MEAs and (ii) a cradle-to-gate manufacturing model comparing virgin and recycled Pt. Results showed that substituting virgin Pt with recycled Pt reduced the global warming potential of MEA manufacturing by up to 70%. The analysis also identified electricity demand and Nafion membrane waste as key environmental hotspots. Overall, the study highlights the potential of closed-loop recycling to enhance circularity in hydrogen technologies. Full article

Developing low-carbon cement-based materials is a critical strategy for reducing the carbon footprint of the construction sector. This study optimized multi-component cement mortars incorporating natural zeolite (NZ), fly ash (FA), blast furnace slag (BFS), and calcium hydroxide (CH) using an L9 Taguchi orthogonal array and range analysis. Mechanical and physical properties, microstructural characteristics, statistical modeling and environmental impact were evaluated. The optimized mixture, OPT1 (10% NZ, 10% FA, 40% BFS, and 2% CH), achieved compressive strengths of 34.97 MPa and 62.67 MPa at 7 and 28 days, respectively, exceeding the control mortar by 8.4% at 28 days. The results indicated that supplementary cementitious materials (SCMs) reduced early-age strength due to the dilution effect; however, their pozzolanic and latent hydraulic reactions enhanced later-age strength development. OPT1 also demonstrated improved mechanical efficiency, reduced Global Warming Potential (GWP) by 35%, and achieved an eco-efficiency index (EEI) value of 124.6, which was 1.6 times that of the control mixture. These findings highlight the potential of the proposed system for high-performance and eco-efficient low-carbon cement mortars. Full article