Search Results (11,987)

This study investigates the application of pipe freeze crystallization (PFC) as a sustainable, zero-waste technology for treating high-salinity industrial wastewater, enabling the simultaneous recovery of salts and clean water. PFC addresses the limitations of traditional brine treatment methods such as evaporation ponds and distillation, which are energy-intensive, produce concentrated brine requiring disposal, and emit significant CO₂. A pilot demonstration plant in Olifantsfontein, South Africa, served as the basis for this research. The plant operates at an energy consumption rate of 330 kJ/kg, significantly lower than distillation’s 2200 kJ/kg. It efficiently recovers high-purity Na₂SO₄ and clean ice, which can be reused as water, with plans underway to incorporate NaCl recovery. Comparative analyses highlight PFC’s energy efficiency and reduced CO₂ emissions, achieving an 82% reduction in greenhouse gas emissions compared to evaporation-based methods. This study evaluates the operational parameters and scalability of PFC for broader industrial applications. X-ray Diffraction analysis confirmed that the Na₂SO₄ recovered from the pilot plant achieved a purity level of 84.9%, demonstrating the process’s capability to produce valuable, market-ready by-products. These findings reinforce PFC’s potential as a cost-effective and environmentally sustainable alternative to conventional methods. PFC offers a transformative solution for managing saline effluents, aligning with zero-waste objectives and contributing to reduced environmental impact. This technology provides industries with an economically viable solution for resource recovery while supporting compliance with stringent environmental regulations. Full article

Combustion is the most advanced and proven method on the market for using agricultural by-product residues and waste from the agri-food industry. Currently, a wide range of combustion technologies is used to produce heat and electricity in low-power heating devices (> 50 kW) using various types of biofuels from biomass (woody biomass, herbaceous biomass, waste and residues from the agri-food industry). Combustion of biomass fuels, especially those of wood origin, causes lower carbon dioxide (CO₂) and sulfur oxides (SO_x) emissions into the atmosphere compared to coal combustion. The growing interest in solid biofuels has contributed to intensive activities on improving the combustion process and energy devices enabling effective and economic conversion of chemical energy contained in biomass into other usable forms such as heat, electricity. Having good quality fuel, it is necessary to ensure an appropriate, clean combustion technique, which allows to achieve the highest thermal efficiency of the heating device and at the same time the lowest emission of pollutants. The article presents issues related to the theory, characteristics of the combustion process and problems related to the formation of harmful chemical compounds nitrogen oxides (NO_x), SO_x, carbon monoxide (CO), particulate matter (PM) emitted to the atmosphere during the combustion process in low-power heating devices. The analysis indicates the possibility of minimizing undesirable phenomena during the combustion of these biofuels related to ash sintering, the formation of deposits, corrosion and improving the amount of condensable solid particles formed and therefore reducing the emission of gaseous products to the environment. Full article

This study addresses the challenges of and opportunities for achieving the ambitious greenhouse gas emissions reduction target of the fishery sector of the Republic of Korea, set at 96% by 2030. We also focus on the current status of land-based aquaculture and underground seawater resource development, quantitatively compare energy inputs for land-based fish cultivation, and evaluate the potential of underground seawater to reduce CO₂ emissions. Since 2010, 762 underground seawater boreholes have been developed, yielding a cumulative daily pumpage of 125,780 m³. Jeollanam-do was found to have the highest daily pumpage, with an annual energy requirement of 131,205,613 Mcal. Despite the fact that the energy demands for underground seawater are higher in some months, it provides a 22.6% reduction in total annual energy consumption compared to surface water. The use of underground seawater for heating or cooling resulted in a 24.1% reduction in the required input energy. However, energy requirements increase due to the relatively high surface water temperature in some regions and seasons. This study also highlights the utilization of underground seawater in heating or cooling surface water via indirect applications using geothermal heat pumps. This innovative research broadens the methods of greenhouse gas mitigation, particularly in the agriculture, livestock, and fisheries industries. Full article

Since manure sources are widely dispersed and the disposal of manure in landfills or its direct application onto soil is often restricted by laws in many countries, selecting suitable sites for manure management facilities is an important step for sustainable livestock farming. The main purpose of this study is to explore suitable locations for situating large-scale biogas plants from livestock manure in Bangladesh using spatial modeling. This study analyzed land suitability based on several geographical, topographical, environmental, and socio-economic criteria, which were also optimized by reflecting optimum transportation distances from manure sources to the chosen sites using GIS (Geographic Information System) network analysis. Then, the environmental benefits of selected biogas plants were estimated through mathematical equations. It was found that 475, 15, and 68 large-scale biogas plants were spatially possible from large-animal, small-animal, and poultry manure, respectively, to produce a total electricity of 7682.72 GWh (gigawatt) in 2023. By implementing the proposed scenarios, renewable energy production will be increased in Bangladesh by at least 8.69%, and GHG (greenhouse gas) emissions will be reduced by approximately 6636.09 gigagram CO₂eq by disposing of 90.14 million tons of manure each year. Hence, the potential selection of biogas plant locations and benefit analysis of different scenarios will guide the establishment of a local decision for the utilization of regional bioenergy from livestock manure in Bangladesh. Full article

High uniformity of positron emission tomography (PET) images in the field of nuclear medicine is necessary to obtain excellent and stable data from the system. In this study, we aimed to apply and optimize a PET/magnetic resonance (MR) imaging system by approaching the gray-level co-occurrence matrix (GLCM), which is known to be efficient in the uniformity correction of images. CAIPIRINHA Dixon-VIBE was used as an MR image acquisition pulse sequence for the fast and accurate attenuation correction of PET images, and the phantom was constructed by injecting NaCl and NaCl + NiSO₄ solutions. The lambda value of the GLCM algorithm for uniformity correction of the acquired PET images was optimized in terms of energy and contrast. By applying the GLCM algorithm optimized in terms of energy and contrast to the PET images of phantoms using NaCl and NaCl + NiSO₄ solutions, average percent image uniformity (PIU) values of 26.01 and 83.76 were derived, respectively. Compared to the original PET image, an improved PIU value of more than 30% was derived from the PET image to which the proposed optimized GLCM algorithm was applied. In conclusion, we demonstrated that an algorithm optimized in terms of the GLCM energy and contrast can improve the uniformity of PET images. Full article

Thailand has committed to achieving carbon neutrality by 2050, targeting the power generation sector, which contributes 35% of the country’s CO₂ emissions, as a critical area for intervention. This study explores the transition toward carbon neutrality in power generation, focusing on fossil-fuel-based plants, particularly lignite and natural gas, which remain central to Thailand’s electricity production. A key strategy adopted by the Electricity Generating Authority of Thailand (EGAT) is “Sink Co-creation”, which includes the deployment of Carbon Capture and Storage (CCS) technologies in existing and future lignite power plants, leveraging favorable storage conditions. Additionally, natural gas power plants exhibit significant CCS potential through source–sink matching mechanisms. This study finds that the total greenhouse gas (GHG) emission reductions from fossil-fuel-based power plants could reach 17.07 MtCO₂. Of this total, lignite power plants are projected to achieve a reduction of 3.79 MtCO₂ by 2036, while natural gas power plants are expected to contribute an additional 13.28 MtCO₂ in reductions by 2050. However, the realization of these reductions faces significant challenges, including the high costs associated with CCS implementation and limited investor interest, underscoring the critical need for sustained government support and policy incentives to facilitate progress toward carbon neutrality. Full article

Due to the limited availability of medical facilities and the urgency and irreplaceability of medical-seeking behaviors, the transportation processes used to access these resources inherently result in high carbon emissions. Unfortunately, pediatric medical facilities are among the least substitutable destinations, making it challenging to reduce travel-related CO₂ emissions by traditional means such as decreasing travel frequency or optimizing transportation means. This study proposes enhancing the spatial allocation of pediatric medical facilities to effectively reduce travel-related CO₂ emissions. This study selects 27 hospitals with pediatric departments in Tianjin as the research subject. It introduces a model for measuring travel-related CO₂ emissions for pediatric medical-seeking, STIRPAT, and ridge regression models as well as conducts simulations under various scenarios to test the hypotheses. Therefore, methods for enhancing the spatial allocation of pediatric medical facilities are proposed. The results show that (1) travel-related CO₂ emissions for pediatric medical-seeking are the highest in the city center, outpatient-related CO₂ emissions surpass inpatient ones, and children’s hospital-related CO₂ emissions are higher than those related to comprehensive hospitals, from which potential carbon reduction points can be explored; (2) children’s hospitals with multibranch and composite functional allocations can significantly reduce CO₂ emissions; (3) comprehensive hospitals can further alleviate CO₂ emissions from children’s hospitals by enhancing the medical level, transportation infrastructure, population distribution, and other spatial environmental factors; (4) from the perspective of low-carbon travel and equity, a spatial allocation strategy should be adopted for children’s hospitals that includes multiple branches and composite functions, while comprehensive hospitals should focus on service capacity, parity, supply–demand ratio, and the population density of children. Full article

Since private cars and vans accounted for more than 25% of global oil consumption and about 10% of energy-related CO₂ emissions in 2022, increasing the share of electric vehicle (EV) ownership is considered an important solution for reducing CO₂ emissions. At the same time, reducing emissions entails certain economic losses for those countries whose exports are largely covered by the oil trade. The explosive growth of the EV segment over the past 15 years has given rise to overly optimistic forecasts for global EV penetration by 2050. One of the major obstacles to such a development scenario is the limited availability of resources, especially critical materials. This paper proposes a mathematical model to predict the global EV fleet based on the limited availability of critical materials such as lithium, one of the key elements for battery production. The proposed model has three distinctive features. First, it shows that the classical logistic function, due to the specificity of its structure, cannot correctly describe market saturation in the case of using resources with limited serves. Second, even the use of a special multiplier that describes the market saturation process taking into account the depletion (finiteness) of the used resource does not obtain satisfactory economic results because of the “high speed” depletion of this resource. Third, the analytical solution of the final model indicates the point in time at which changes in saturation rate occur. The latter situation allows us to determine the tracking of market saturation, which is more similar to the process that is actually occurring. We believe that this model can also be validated to estimate the production of wind turbines that use rare earth elements such as neodymium and dysprosium (for the production of powerful and permanent magnets for wind turbines). These results also suggest the need for oil-exporting countries to technologically diversify their economies to minimize losses in the transition to a low-carbon economy. Full article

DC micro-grids are emerging as a promising solution for efficiently integrating renewable energy into power systems. These systems offer increased flexibility and enhanced energy management, making them ideal for applications such as heat pump (HP) systems. However, the integration of intermittent renewable energy sources with optimal energy management in these micro-grids poses significant challenges. This paper proposes a novel control strategy designed specifically to improve the performance of DC micro-grids. The strategy enhances energy management by leveraging an environmental mission profile that includes real-time measurements for energy generation and heat pump performance evaluation. This micro-grid application for heat pumps integrates photovoltaic (PV) systems, wind generators (WGs), DC-DC converters, and battery energy storage (BS) systems. The proposed control strategy employs an intelligent maximum power point tracking (MPPT) approach that uses optimization algorithms to finely adjust interactions among the subsystems, including renewable energy sources, storage batteries, and the load (heat pump). The main objective of this strategy is to maximize energy production, improve system stability, and reduce operating costs. To achieve this, it considers factors such as heating and cooling demand, power fluctuations from renewable sources, and the MPPT requirements of the PV system. Simulations over one year, based on real meteorological data (average irradiance of 500 W/m², average annual wind speed of 5 m/s, temperatures between 2 and 27 °C), and carried out with Matlab/Simulink R2022a, have shown that the proposed model predictive control (MPC) strategy significantly improves the performance of DC micro-grids, particularly for heat pump applications. This strategy ensures a stable DC bus voltage (±1% around 500 V) and maintains the state of charge (SoC) of batteries between 40% and 78%, extending their service life by 20%. Compared with conventional methods, it improves energy efficiency by 15%, reduces operating costs by 30%, and cuts CO₂; emissions by 25%. By incorporating this control strategy, DC micro-grids offer a sustainable and reliable solution for heat pump applications, contributing to the transition towards a cleaner and more resilient energy system. This approach also opens new possibilities for renewable energy integration into power grids, providing intelligent and efficient energy management at the local level. Full article

The electrocatalytic reduction of carbon dioxide (CO₂RR) into high-value-added products is considered to be a promising way to mitigate carbon emissions. However, it remains a challenge to design an efficient catalyst with an excellent performance. In this work, we synthesized a metal azole framework (MAF) by changing 2-methylimidazole ligands into 5-mercapto-1-methyltetrazole (MMT) for use as organic linkers and mercaptan groups as anchoring sites for the Ag nanoparticles. The Ag NPs@ MAF-MMT material displayed a wide potential window from −0.6 to −1.2 V vs. RHE, with a maximum CO Faradaic efficiency (FE_CO) over 90.5%, and a current density of 18 mA cm⁻² at −1.1 V vs. RHE for 11 h in an H-cell. This work provides a new option to immobilize Ag nanoparticles in MAFs material for the exploration of carbon dioxide reduction catalysts. Full article

Poor housing quality contributes to poor Indoor Air Quality (IAQ) and overheating with older adults, children, pregnant women, and those living in poverty most at risk. While retrofit strategies could help to reduce carbon emissions by improving building energy efficiency, they could simultaneously lead to ‘unintended’ outcomes including overheating, damp, mould, and exposure to harmful indoor air pollutants by making buildings more airtight and trapping heat and air pollutants inside. Occupants’ lifestyles, attitudes, and awareness have also been identified as some of the key challenges when it comes to improving energy performance, winter/summer thermal comfort, and IAQ in buildings. This paper provides insight into the effects of energy efficient retrofit strategies and occupant behaviour on energy performance, IAQ, thermal comfort, and health, with a focus on older people living in social housing. A mixed method is employed involving: (1) physical measurements, to record actual energy consumption and indoor environmental conditions (i.e., temp., RH%, CO₂); (2) questionnaire surveys, to assess occupants’ behaviours and health; (3) dynamic thermal modelling, to evaluate the effects of retrofit strategies; and (4) thermal imaging, to assess the building fabric performance and identify possible defects. The results revealed that although retrofit strategies reduced energy consumption by up to 60%, some resulted in significant risk of overheating. Occupants’ behaviours combined with debatable building management practices also contributed to risks of overheating and poor IAQ that could negatively affect health and wellbeing of building occupants in the long-term. Full article

A negative carbon emission scenario via pyrolysis of three different food waste blends was investigated. A tube reactor was utilized for pyrolysis runs at temperatures of 650 °C, 725 °C, and 900 °C, while the carbon inventory was prepared. The blend of rice and french fries resulted in the highest char yield, being 212 g/kg at 650 °C pyrolysis temperature. In this case, each kg of food waste can correspond to 536 g of captured or removed CO₂ from the air. The blend of roast pork and breaded chicken showed significantly less carbon removal potential of 348 g_CO2/kg_sample measured at 650 °C pyrolysis temperature, compared to rice and French fries. A higher pyrolysis temperature resulted in lower char yields, but, on the other side, it resulted in a higher carbon content of char. Additionally, higher pyrolysis temperature resulted in lower carbon capture potential within the temperature range utilized in this study. The heating value of dry pyrolysis gas was between 12.0–16.6 MJ/Nm³ and 10.3–12.3 MJ/Nm³ during the heat-up and constant temperature period, respectively. Based on the results, negative CO₂ emission can be reached via pyrolysis of food waste with the benefit of capturing carbon in solid form, and therefore, this method can be considered a promising and alternative method to treat food waste. Full article

As global CO₂ emissions continue to rise, addressing their environmental impact is critical in combating climate change. Photocatalytic CO₂ reduction, which mimics natural photosynthesis by converting CO₂ into valuable fuels and chemicals using solar energy, represents a promising approach for both reducing emissions and storing energy sustainably. However, the development of efficient photocatalysts, particularly those capable of absorbing visible light, remains a challenge. Graphitic carbon nitride (g-C₃N₄) has gained attention for its visible light absorption and chemical stability, though its performance is hindered by rapid electron–hole recombination. Similarly, bismuth tungstate (Bi₂WO₆) is a visible-light-active photocatalyst with promising properties, but also suffers from limited efficiency due to charge recombination. To overcome these limitations, this study focuses on the design and synthesis of a g-C₃N₄/Bi₂WO₆ composite photocatalyst, leveraging the complementary properties of both materials. The composite benefits from enhanced charge separation through the formation of a heterojunction, reducing recombination rates and improving overall photocatalytic performance. The optimized g-C₃N₄/Bi₂WO₆ composite exhibited significant improvements in the production rates of both CH4 and CO, achieving 18.90 and 17.78 μmol/g/h, respectively, which are 2.6 times and 1.6 times higher than those of pure B_i2WO₆. The study explores how optimizing the g-C₃N₄/Bi₂WO₆ interface, increasing surface area, and adjusting material ratios can further enhance the efficiency of CO₂ reduction. Our findings demonstrate the potential of this composite for solar-driven CO₂ conversion, offering new insights into photocatalyst design and paving the way for future advancements in CO₂ mitigation technologies. Full article

Power plants are one of the main sources emitting the CO₂ that is responsible for climate change consequences. Post-combustion carbon capture (PCC), particularly using an aqueous solution, is highly recommended to be used as a mitigation solution to reduce the emissions of CO₂ from power plants. Although PCC is a promising solution, the process still needs further development to reduce the energy demand for solvent regeneration. This paper reviews the challenges related to the post-combustion processes and finds the correlations between selected variables addressed by several researchers. Moreover, this study provides valuable insights into the factors influencing the reduction in energy demand and efficiency penalties. The research findings highlight the importance of considering two key drivers during the design of the PCC process. These are the absorber temperature and the type and amount of the selected solvent. Indeed, statistical analyses show that there is a correlation between the identified drivers’ values and the energy demand of solvent regeneration. Full article

The shallow-sea hydrothermal vent at Guishan Islet, located off the coast of Taiwan, serves as a remarkable natural site for studying microbial ecology in extreme environments. In April 2019, we investigated the composition of prokaryotic picoplankton communities, their gene expression profiles, and the dissolved inorganic carbon uptake efficiency. Our results revealed that the chemolithotrophs Thiomicrorhabdus spp. contributed to the majority of primary production in the waters affected by the hydrothermal vent plume. The metatranscriptomic analysis aligned with the primary productivity measurements, indicating the significant gene upregulations associated with carboxysome-mediated carbon fixation in Thiomicrorhabdus. Synechococcus and Prochlorococcus served as the prokaryotic photoautotrophs for primary productivity in the waters with lower influence from hydrothermal vent emissions. Thiomicrorhabdus and picocyanobacteria jointly provided organic carbon for sustaining the shallow-sea hydrothermal vent ecosystem. In addition to the carbon fixation, the upregulation of genes involved in the SOX (sulfur-oxidizing) pathway, and the dissimilatory sulfate reduction indicated that energy generation and detoxification co-occurred in Thiomicrorhabdus. This study improved our understanding of the impacts of shallow-sea hydrothermal vents on the operation of marine ecosystems and biogeochemical cycles. Full article