Recent advances in biochar-mediated mitigation of microplastics: A comprehensive review on removal mechanisms, toxicity alleviation strategies, and synergistic environmental impacts.

Depth-temperature coupling shapes denitrifier community assembly and metabolic adaptation in drinking water reservoir sediments.

Apply machine learning to predict greenhouse gas emissions in aerobic composting and achieve emission reduction by nanomembrane covering mode.

Nitrification inhibitors (NIs) are crucial for enhancing nitrogen use efficiency (NUE), minimizing nitrogen losses, and reducing environmental impacts in agriculture; however, their effectiveness under varying conditions remains unclear. A present meta-analysis assessed how NIs affect crop yields, nitrogen recovery efficiency (REN), soil ammonium (NH 4 + -N), nitrate (NO 3 - -N), ammonia (NH 3 ), and nitrous oxide (N 2 O) emissions, and the results revealed that NIs increase crop yield by an average of 4.7 % with Nitrapyrin, DCD, and DMPP showing specific yields increase of 6.11 %, 4.61 %, and 3.79 %, respectively. Yield increases are most significant with nitrogen rates below 250 kg ha -1 , while rates above this threshold lead to yield declines of 1.76 %. The application of NIs improved REN by 13.14 %, while soil NH 4 + -N levels increased by 42.04 % with the highest increase occurring at lower nitrogen application rates at < 150 kg ha -1 (83.49 %). NIs also reduced soil NO 3 - -N levels by 24.65 % with DCD showing the greatest reduction at -28.17 %, while DMPP had the smallest reduction at -20.04%. the study also revealed cumulative NH 3 volatilization increased by 12.06 %. Among them, DCD and DMPP caused minor increases of 8.52 % and 8.13 %, respectively, while nitrapyrin had little effect, resulting in a 23.42 %. NIs also significantly lowered cumulative N 2 O emissions by 47.39 % relative to the control. Overall, NIs help regulate soil nitrogen levels and mitigate greenhouse gases by slowing nitrification. Their effectiveness may vary based on factors like soil type and management practices, highlighting the need for further research to optimize their use in sustainable nitrogen management strategies. • •Meta-analysis synthesized recent field studies on nitrification inhibitor effects. • •Nitrification inhibitors significantly increased crop yield, nitrogen recovery efficiency (REN), and soil ammonium • •Application reduced N 2 O emissions and nitrate leaching under field conditions. • •NIs help regulate soil nitrogen levels and mitigate greenhouse gases by slowing nitrification

Healthcare contributes considerably to global greenhouse gas emissions, with operating theatres amongst the most energy-intensive hospital environments. While carbon footprints have been quantified for several surgical procedures, the environmental impact of hand surgery, characterised by high case volumes and short procedures, remains poorly studied. This study aims to quantify carbon emissions of hand surgery procedures. This single-centre observational pilot study quantified the carbon emissions associated with hand surgery procedures performed during two half-day theatre lists at a UK NHS hospital. Data was collected under the Greenhouse Gas Protocol Scopes and emissions calculated using UK Government greenhouse gas conversion factors. Data collected included theatre electricity and heating, anaesthetic use, staff and patient transport, waste incineration, supply-chain emissions, and instrument sterilisation. Five trauma hand surgery cases were analysed. Case-level emissions ranged from 8.32 to 22.56kg CO2. When combined at a list level, total emissions were substantial, reaching 311.36kg CO2 and 285.30kg CO2 per half-day list. Purchased electricity (Scope 2) was the largest contributor, followed by heating and anaesthetic gases (Scope 1). Scope 3 emissions were largely attributed to staff travel and single-use consumable supply-chain emissions, while waste disposal and reusable instrument sterilisation contributed comparatively little. Individual hand surgery procedures have a relatively low carbon footprint, but the cumulative emissions at list-level are large. Theatre energy use, heating and staff transport represent key targets for emission reduction. Interventions focusing on energy-efficient infrastructure, renewable energy, greener staff travel, and reduced reliance on single-use consumables may result in meaningful environmental benefits. Larger multicentre studies with improved energy metering are needed to refine estimates and guide sustainable surgical practice. Quantifying the carbon emissions associated with common hand surgery procedures may help hand surgery teams and healthcare organisations identify opportunities to reduce emissions.

To provide an initial estimate of the carbon footprint of PET/CT imaging at a UK imaging centre, indicating the major contributing factors to the emission of greenhouse gases. Data were collected for patient and staff travel, energy use, consumables and waste from the PET/CT department at the Paul Strickland Scanner Centre (PSSC). Additional travel data from two other UK departments were used as a guide to ensure reasonable representation of UK travel distances. Data were converted to carbon dioxide equivalent emissions (kg CO2e) and expressed in terms of emissions per patient scanned. The carbon footprint of PET/CT imaging at PSSC was measured as 19kg CO2e or 21kg CO2e per patient, depending on the scanner used. The most significant contributors to this were patient travel, and the energy taken by the scanner (this includes the energy taken when the scanner is not operating). Whilst 20kg CO2e is not large by healthcare standards, it is not negligible, representing around 4% to 10% of the emissions of a typical course of radiotherapy. The findings demonstrate the areas of focus to reduce the footprint, and act as a base for future work. This is an initial estimate and does not include the footprint of production and distribution of the radiotracer, nor the "embedded footprint" of the imaging facility and equipment.

• Real-LIFE test protocol for log wood stoves developed considering all phases. • Validation with two log wood stoves performed using the Real-LIFE test protocol. • Good repeatability of emissions while applying the new test protocol achieved. • Challenging to get comparable results from four laboratories using new protocol. • Study emphasizes the importance of measuring different combustion conditions. The use of log wood stoves is common in residential homes and are tested in a type test procedure following EN 16510-1:2022 at optimal combustion condition. Since this does not represent real-life operation, a novel test protocol was developed and validated using two different log wood stoves. The new test protocol includes the ignition phase (two batches) at natural draught, followed by three batches at nominal load, two batches at partial load and one final batch at overload. Typical emission parameters such as carbon monoxide (CO), nitrogen oxides (NO X ), organic gaseous carbon (OGC) emissions were recorded as well as TPM emissions in the hot undiluted flue gas. This study shows that it is challenging to get similar emission results for the same stove in different laboratories even when using the same fuel and well-defined test protocol, differences in results are due to measurement uncertainty, differences in appliance operations and not following exactly the defined Real-LIFE test protocol. Coefficients of variation for TPM, CO, OGC and NO X were 17.8 %, 20.1 %, 30.6 % and 8.7 %, respectively for stove A and 32.7 %, 13.9 %, 19.6 % and 10.0 %, respectively for stove B based on two to three repetitions per lab. The novel test protocol showed that combustion appliances may behave differently in different combustion phases, and this emphasizes the importance of measuring different combustion conditions in official testing to ensure that the appliances work properly in the field and that the measured emissions cover the whole operating range.

Modelling greenhouse gas and ammonia emissions from housing and manure storage in three laying hen production systems

Water-energy-carbon nexus and de-carbonation pathways in integrated urban water system for a megacity study.

Life cycle and net environmental impact assessment of a shared e-bike service: application to the case of Madrid

Nitrogen cycle in the riverine hyporheic zone: A systematic review from processes to environmental function.

As the biggest greenhouse gas (GHG) emitter globally, China has pledged to achieve carbon neutrality by 2060. However, the environmental sustainability of this goal has not been assessed comprehensively on a life cycle basis. Focusing on the electricity sector, which contributes >40% to China's GHG emissions, this study evaluates the role and the potential of renewables for achieving net-zero by estimating their life cycle impacts across 31 provinces in China. A future (2050) renewable electricity grid is designed considering daily demand and generation curves, as well as resource potential and future technological advancements. Most of the electricity is generated by solar and wind (70%), followed by hydro (9%), biomass with and without carbon capture and storage (6%), and energy storage (14%). This mix achieves a net-negative climate change impact of −12 kg CO 2 eq./MWh electricity generated (compared to the current 877 kg CO 2 eq./MWh). The net negative impact is found in 18 provinces (−2.1 to −166.1 kg CO 2 eq. per MWh) owing to the biomass energy with carbon capture and storage (BECCS). The rest of the provinces have a net-positive but still relatively low impact (0–42 kg CO 2 eq./MWh) because of the high share of renewables. The majority of the remaining 17 impacts are also significantly lower (5.5–96%) than the impacts of the current grid, except for metal depletion, water consumption and freshwater and marine ecotoxicity. The minimum requirements for achieving the net-zero target for the electricity sector are either the utilisation of 55% of the total estimated biomass energy potential of 22 EJ, or BECCS share of 46% in the total capacity of biomass plants, equivalent to 2.25% of electricity generation. These results help to identify the environmental trade-offs in meeting the decarbonisation targets and to guide a future deployment of net-zero electricity in China.

Numerical simulation-driven machine learning and particle swarm optimization of burner fuel distribution for cleaner combustion in a thermal power plant

Incorporation of postconsumer recycled (PCR) plastics in asphalt mixes is reported to improve the mechanical performance of asphalt mixes when used at a lower dosage. However, overstiffening of asphalt mixes due to the addition of higher amounts of plastic has been a serious concern. To this end, this study aims at increasing the percentage of plastic in asphalt mixes by incorporating a biorejuvenator. For this purpose, a control mix was designed using the balanced mix design (BMD) approach and then modified with two different types of PCR plastics, namely low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE). The asphalt mixes were then further modified by adding a biorejuvenator. The volumetric properties were determined, and the mechanical performances (rutting, cracking, and moisture-induced damage resistance) of the asphalt mixes were evaluated using the Hamburg Wheel Tracking (HWT) and Indirect Asphalt Tensile Cracking Test (IDEAL-CT). The optimum dosage of plastics was determined using the BMD criteria. The optimum dose of LDPE was found to be 1.5% with 2% waste cooking oil (WCO)-modified binder. In addition, environmental impact analyses were performed on the plastic-modified mixes. A significant reduction in greenhouse gas emission was observed from the use of plastic in asphalt mixes. A minimum of 7.5% reduction in greenhouse gas generation was found by using optimum LDPE and WCO-modified asphalt mixes.

In 2022, the amount of Waste Cooking Oil (WCO) in the Java–Bali region was estimated to reach 207 million kiloliters. This poses a significant environmental challenge due to the lack of proper utilization. With the increasing demand for cooking oil in Indonesia, the generation of WCO continues to rise. Low-quality WCO, often traded by street vendors, cannot be reused and must be discarded. Improper disposal into drainage systems leads to long-term problems such as water pollution, soil degradation, greenhouse gas emissions, and contamination of clean water sources. The development of Co/ZrO₂–SO₄ catalysts and optimized conversion processes plays a crucial role in reducing reliance on imported catalysts, particularly for the production of environmentally friendly fuels (green fuels) such as bio-jet fuel. Given the high fatty acid content in WCO, several pretreatment stages are required. This study aims to convert WCO into bio-jet fuel through hydrodeoxygenation and Pyrolytic Catalytic Cracking (PCC) accompanied by isomerization. The PCC process was carried out under atmospheric pressure and relatively mild temperatures. The Co/ZrO₂–SO₄ catalyst was employed to enhance conversion into bio-jet fuel products. In this work, cobalt-dispersed sulfated zirconia nanocatalysts (Co/SZ) were synthesized with varying cobalt loadings (1%, 3%, and 5%). Beyond hydrodeoxygenation and cracking, the catalyst was also applied in the isomerization process. The synthesized catalysts were characterized using FTIR, XRD, SEM, and NH₃-TPD. Meanwhile, the cracking process was conducted at different reactor temperatures (400, 450, 500, and 550 °C), with the resulting products analyzed by BET, XRF, TEM-SAED, and GC-MS.

Responses of greenhouse gases emissions from wetland soils to the interactive effects of nitrogen input and warming in Sanjiang Plain, China

Towards green steel from hydrogen-based direct reduction of low-grade iron ores: Techno-economic and greenhouse gas emissions assessment

• A nested optimization framework for marine hybrid propulsion systems is proposed. • The framework integrates optimal power management and component sizing. • Pareto-optimal solutions minimize system investment cost and GHG emissions. • Case study shows 27% less emissions or 6% investment cost reduction compared to requirement-based design. • The framework is tested for robustness to ship power request variations. The growing demand for decarbonization of the shipping sector calls for integrated design strategies that simultaneously address energy management and propulsion system sizing. This paper presents a nested optimization framework for designing ship hybrid propulsion systems that identifies the Pareto-optimal front balancing economic and Well-to-Wake environmental performance. The framework utilizes a multi-objective genetic algorithm (NSGA-II) in the outer layer to efficiently explore the design space for battery capacity and generator sizing. For each candidate design, an inner optimization layer determines the minimum achievable greenhouse gas emissions through optimal power resource management. This nested approach ensures that each point on the resulting Pareto frontier represents a design in which both sizing and operation are simultaneously optimized. The methodological accuracy is validated by benchmarking NSGA-II against an exhaustive grid search, while its effectiveness is demonstrated in a small ferry case study by comparing results with a standard requirement-based design (RBD) approach. The results demonstrate that the optimized framework can achieve up to a 27% reduction in emissions at the same investment cost, or a 6% reduction in investment cost at the same level of emissions, compared to the RBD baseline. A sensitivity analysis is conducted to assess the method’s robustness to realistic variations in power demand and to evaluate the impact of component cost fluctuations on the resulting Pareto frontier. The proposed optimization framework serves as a decision-support tool for ship designers, enabling them to make informed, consistent choices when designing marine hybrid propulsion systems. The proposed structure is generalizable to a wide range of vessel types and operational scenarios.

The transition to refrigerants with low-GWP in residential heat pumps is driven by global regulations to reduce greenhouse gas emissions. R454B stands out as a promising alternative to R410A, due to its moderate GWP (531) and similar thermodynamic properties, making it ideal for compact brine-to-water heat pumps designed for indoor installation. However, R454B is mildly flammable (A2L), so its charge should be minimized without compromising performance. This aspect is particularly relevant in modern heat pumps equipped with variable speed compressors, which are increasingly used to meet stringent energy efficiency requirements. Despite numerous studies on R454B drop-in tests, research on the combined effect of refrigerant charge and variable-speed operation remains scarce. This paper investigates a brine-to-water heat pump originally designed for R410A and tested with R454B as a drop-in replacement. Experiments were conducted under EN 14511 and EN 14825 rating conditions for low- and intermediate-temperature space heating applications. The effects of refrigerant charge and compressor speed on heating capacity, COP, discharge temperature, and seasonal performance were analyzed. Results reveal that improper charge significantly affects the unit performance and operating limits, identifying an optimal charge range for maximizing COP and SCOP. Compared to R410A, R454B achieves slightly higher COP and requires less charge, though at the expense of lower heating capacities and higher discharge temperatures. A SCOP evaluation showed better performance with R454B at equal design heating load. These findings provide practical guidelines for optimizing R454B charge in variable-speed heat pumps, supporting its adoption as a lower-GWP alternative in residential applications. • The R454B charge impact in a domestic heat pump designed for R410A is analyzed. • Heat pumps without a liquid receiver are highly sensitive to the refrigerant charge. • Improper charge affects efficiency and operating limits in variable-speed systems. • An optimum refrigerant charge that maximizes the system COP or capacity was found. • R454B needs less charge than R410A and can achieve a higher SCOP.

This study investigates the effect of purification (neutralization, washing, and drying) on improving the fuel properties, storage stability, engine performance, and exhaust gas emissions of enzymatic biodiesel derived from sludge palm oil. Neutralization was first optimized at laboratory scale, and under the optimal conditions, the acid value was successfully reduced from 6.15 ± 0.13 to 0.40 ± 0.09 mg KOH g −1 , meeting the EN 14214 standards (≤0.50 mg KOH g −1 ). Using these conditions, crude and partially-purified enzymatic biodiesels (CEB and PPEB) were produced at pilot scale and assessed for engine suitability. CEB failed to meet most of the EN 14214 specifications, whereas PPEB achieved 97.00 ± 0.48 wt% ester content and met most of the requirements. Over 6 weeks of storage at 40 °C, PPEB showed minimal changes in ester content and acid value due to its high oxidative stability (13.9 h), while CEB exhibited greater degradation. Engine tests (50 h) showed that power outputs for CEB, PPEB, and petrodiesel followed similar trends across the tested load range, with differences within ±13 %. All fuels showed similar fuel consumption rates, averaging 0.46 ± 0.04 L h −1 . Additionally, PPEB recorded 470 ± 28 ppm CO and 188 ± 29 ppm NO x , which were lower than those of CEB (871 ± 98 ppm CO and 290 ± 52 ppm NO x ). Conclusively, purification significantly improved biodiesel quality, stability, and emissions. Future work should focus on optimizing pilot-scale purification to achieve full EN 14214 compliance and explore strategies to reduce biodiesel viscosity and NO x emissions. • Neutralization of SPO-derived enzymatic biodiesel was optimized at laboratory scale. • The properties, engine performance, and emissions of CEB and PPEB were compared. • PPEB had 97 wt% FAME content and met most of the EN 14214 biodiesel specifications. • Similar power output trend and fuel efficiency for CEB, PPEB, and petrodiesel. • Purifying CEB to PPEB improved its quality and stability, and reduced emissions.