Lower CO2 Emissions Research Articles

Performance Analysis and Rapid Optimization of Vehicle ORC Systems Based on Numerical Simulation and Machine Learning

The organic Rankine cycle (ORC) system is an important technology for recovering energy from the waste heat of internal combustion engines, which is of significant importance for the improvement of fuel utilization. This study analyses the performance of vehicle ORC systems and proposes a rapid optimization method for enhancing vehicle ORC performance. This study constructed a numerical simulation model of an internal combustion engine-ORC waste heat recovery system based on GT-Suite software v2016. The impact of key operating parameters on the performance of two organic Rankine cycles: the simple organic Rankine cycle (SORC) and the recuperative organic Rankine cycle (RORC) was investigated. In order to facilitate real-time prediction and optimization of system performance, a data-driven rapid prediction model of the performance of the waste heat recovery system was constructed based on an artificial neural network. Meanwhile, the NSGA-II multi-objective algorithm was used to investigate the competitive relationship between different performance objective functions. Furthermore, the optimal operating parameters of the system were determined by utilizing the TOPSIS method. The results demonstrate that the highest thermal efficiencies of the SORC and RORC are 6.21% and 8.61%, respectively, the highest power outputs per unit heat transfer area (POPAs) are 6.98 kW/m2 and 8.99 kW/m2, respectively, the lowest unit electricity production costs (EPC) are 7.22 × 10−2 USD/kWh and 3.15 × 10−2 USD/kWh, respectively, and the lowest CO2 emissions are 2.85 ton CO2,eq and 3.11 ton CO2,eq, respectively. The optimization results show that the RORC exhibits superior thermodynamic and economic performance in comparison to the SORC, yet inferior environmental performance.

Effect of Stand Age on Soil CO2 Emissions in Pedunculate Oak (Quercus robur L.) Forests

The emission of CO2 from soil represents one of the most significant fluxes between terrestrial ecosystems and the atmosphere. It is crucial to investigate the impact of stand age on soil CO2 emissions in order to evaluate the possibility of carbon sequestration through the establishment of new forests. In this study, soil CO2 emissions and microclimate variables (soil temperature and moisture) were investigated in the chronosequence of three differently aged stands (4-, 14-, and 70-year-old stands) in floodplain pedunculate oak (Quercus robur L.) forests in Serbia. This study highlights how the artificial regeneration of pedunculate oak forests (establishment of new stands) can affect CO2 emissions from soils. Seasonal fluctuations in soil CO2 emissions were observed in all of the monitored stands, along with variations in the influence of soil temperature and moisture. Multiple linear regression, incorporating soil temperature, soil moisture, and their interaction, offered the most comprehensive explanation for the variation observed in soil CO2 emissions. The seasons had statistically significant effects (p < 0.001) on CO2 emission from the soil in the examined stands during 2022. The youngest stand (4-year-old) had significantly higher soil CO2 emissions (p < 0.05) compared to the older stands over the entire study period (2021–2022). These results showed that the 70-year-old stand (natural high stand) had significantly lower soil CO2 emissions compared to the 4-year-old stand (artificially regenerated stand).

Carbon balance in Maize (Zea mays L.) with various combinations of organic and inorganic fertilizers

Fertilization in agricultural cultivation has an important role in the carbon cycle. This study aims to evaluate using organic fertilizers with inorganic fertilizers that can produce high carbon sequestration with low CO2 emission levels in maize (Zea mays L.) cultivation. There were seven combinations of NPK and organic fertilizers, namely ¼ NPK + 1 OF (C), ½ NPK + 1 OF (D), ¾ NPK + 1 OF (E), 1 NPK + 1 OF (F), ¾ NPK + ¼ OF (G), ¾ NPK + ½ OF (H), ¾ NPK + ¾ OF (I), and two controls, namely no fertilizer (A) and standard NPK (350 kg/ha, SP36 150 kg/ha, KCl 75 kg/ha) (B). Organic fertilizer was applied one week before planting, SP-36 and KCl fertilizer at planting, and urea fertilizer at 0, 14, and 28 HST. Maize was planted with a spacing of 20 x 70 cm. Parameters observed included CO2 emissions, soil pH, C-Organic, C-microbial, and plant growth parameters. The combined use of NPK and organic fertilizer significantly increased soil carbon stocks (33.25-64.04 Mg/ha) and carbon sequestration by plants (3.76-5.98 Mg/ha). Therefore, using organic and inorganic fertilizer can be considered more environmentally friendly and effective in managing carbon balance on farmland and has great potential to contribute to climate change mitigation through increased soil and plant carbon sequestration.

Treatment of brominated epoxy resin waste in subcritical dimethylformamide wastewater: Upcycling of brominated epoxy resin and dimethylformamide degradation

The debromination and upcycling of brominated epoxy resin (BER) waste is important for the e-waste treatment, while the degradation and removal of N, N-dimethylformamide (DMF) is the critical step for the DMF wastewater treatment. In this study, a co-treatment strategy was proposed for the BER waste and DMF wastewater by the subcritical water process. The co-treatment was carried out using subcritical DMF wastewater (SDW) as the reaction medium. The results showed a significantly synergistic effect between the BER conversion and DMF degradation in the SDW process. The optimal reaction conditions were as follows: reaction temperature of 300 °C, solid-to-liquid ratio of 1:15 g/mL, DMF wastewater of 30000 mg/L and reaction time of 60 min. Under the optimal reaction conditions, the debromination ratio of the BER was 98.57 %, the degradation ratio of the DMF reached 99.59 %, and phenolic substances with a purity of 86.61 % were recovered. The formation of HBr from the debromination of the BER was the most significant factor affecting the pH of the system, which had a noticeable impact on the degradation of the DMF. The main degradation products of the DMF were dimethylamine (DMA), methylamine (MA), NH3, NH4+, and CO2. The products degraded from the DMF could significantly promote the debromination and conversion of the BER. Life cycle assessment (LCA) analysis showed that the SDW process had low CO2 emissions. It is believed that the SDW process proposed in this study is an efficient technology for the synergistic treatment of the BER waste and DMF wastewater.

Enhancing the usability range of acetylene in CI engines through split injection of high-reactive fuel under RCCI operation: Optimized operability using an MCDM approach

Reactivity Controlled Compression Ignition (RCCI) has emerged as a promising solution to address the challenges of advanced combustion techniques in diesel engines, balancing combustion control and emission reduction. This study investigates the impact of split-injection high-reactivity fuel (HRF) dosing in RCCI to enhance charge homogeneity at lower injection timing advancements. It systematically explores progressive advancements in HRF injection timing, distinguishing between main and pilot injections. The main injection varied from 20° bTDC to 70° bTDC, while the pilot injection, relative to the main injection, spans 25°-40° CA ahead with a 5° progression. As an LRF, Port-injected Acetylene supplements the process with variable premixed ratios. Further, using a multi-criteria decision-making method (AHP), the study optimizes operating conditions, proposing a main injection at 20° bTDC, a pilot injection 40° CA ahead, and 70 % LRF participation. This optimized condition yields significant benefits such as 32.99 % higher brake thermal efficiency (BTE), 160 % longer premixed duration, 18.65 % lower maximum temperature, 89.41 % lower NO emissions, 91.83 % lower hydrocarbon (HC) emissions, 91.24 % lower CO emissions and 97.20 % lower smoke opacity compared to conventional diesel combustion (CDC) operation. The results highlight the advantages of multiple fuel injections in RCCI, improving blending characteristics at lower injection angles.

Accelerating development in wood‐plastic composites: Presenting key material properties and demonstrating statistical methods

AbstractIn a time when global initiatives to lower CO2 emissions are accelerating the shift towards bio‐based products, various efforts are being made to develop wood plastic composites (WPCs) and similar bio‐composites using a variety of raw materials. This paper first showcases benchmark material properties serving as standards and models the composition, for polypropylene‐based WPCs integrating wood flour and maleic anhydride‐modified polypropylene. Subsequently, by applying statistical modeling techniques, we demonstrate an adaptive experimental design that efficiently and rapidly adjusts formulations. Beginning with an empirical dataset (24 samples), we established high‐performing models that articulate the individual contributions of the constituents on ten vital properties of WPCs. Our adaptive experimental design, leveraging nonlinear partial least squares regression and the Bayesian optimization, successfully refined formulations to enhance bending and impact strengths. Notably, we proposed optimal conditions starting from just eight samples with minimal iterations. This study shows that statistical techniques can quickly optimize WPC formulations, making the overall development process faster. By addressing the multiple conflicting properties, these techniques can greatly reduce the time and effort needed for development.Highlights Applied several regression methods to analyze ten properties of PP‐based WPCs. Showcased distinct impacts of the formulations of WF and MAPP on WPCs. Implemented the adaptive experimental design for formulation optimization. Enhanced bending and impact strengths in the formulations of WPCs. Advanced sustainable material development with data‐driven approach.

Financial inclusion and environmental pollution in sub-Saharan Africa: moderating effects of economic growth and renewable energy

A thriving literature exists about the role of financial inclusion in socio-economic development. Nevertheless, the environmental effects of financial inclusion are largely unknown in the literature, especially in sub-Saharan African countries. Therefore, this study explores the association between financial inclusion and CO2 emissions utilizing data from 23 sub-Saharan Africa for the period 2004–2019. Based on different estimation methods such as dynamic ordinary least squares (DOLS), fully modified ordinary least squares (FMOLS), canonical correlation regression (CCR), and an instrumental variable generalized-method of moment (IV-GMM), the results show that financial inclusion is responsible for a substantial increase in CO2 emissions. In addition, financial inclusion moderates economic growth, resulting in higher CO2 emissions. Alternatively, financial inclusion moderates renewable energy use to lower CO2 emissions. The outcomes also verify the presence of the Environmental Kuznets Curve hypothesis (EKC). This study proposes uniting financial inclusion and environmental policies as a strategy for reducing CO2 emissions in sub-Saharan Africa.

Superheated fuel sprays: A comparative study of flash boiling ammonia fuel sprays with methanol, ethanol, and gasoline for multi-hole fuel injection

The rising energy demand creates a huge need to explore and implement sustainable alternative fuels e.g., ammonia, hydrogen, methanol, ethanol, etc. to mitigate emission challenges and significantly lower CO2 emissions. Ammonia has gained much attention as promising alternative fuels for internal combustion engines due to its carbon-neutral nature, which can reduce the carbon footprint in transportation. The advantages of ammonia as a fuel includes carbon-free nature, high volumetric energy density compared to hydrogen, and renewable resource-based production. However, there is lack of the deep understanding of the ammonia spray characteristics and fuel-air mixing process, in particular, the superheated spray, which potentially improve the vaporization and fuel-air mixing. This study focused on investigating the impact of superheating on ammonia, methanol, ethanol, and gasoline fuel sprays by heating the fuel injector tip from non-evaporating to flash boiling temperatures. The fundamental spray parameters were investigated in a constant volume spray chamber using a multihole solenoid driven injector for 150 bar constant injection pressure under 10 bar and 30 bar chamber pressure conditions. To observe flash boiling and the dual-phase flow, a Z-type Schlieren imaging technique, known for its sensitivity to density gradients, was used. The experimental results indicated that ammonia spray behavior significantly differed from other tested fuels for both under cold and superheated conditions. The effect of superheating on methanol, ethanol, and gasoline sprays was very similar, resulting in the shrinkage of spray width and the merging of adjacent plumes into a single thick cloud of spray for elevated tip temperatures. However, ammonia sprays exhibited considerable differences in evaporative conditions, developing a more significant dual phase flow than other fuels upon increment in tip temperature. Overall, the results showed that the spray tip penetration and area for all tested fuels reduced upon heating.

Techno-enviro-economic analysis of grid-connected solar powered floating PV water pumping system for farmland applications: A numerical design model

To meet the required load of a farm in the rural area in Mafraq, Jordan, the complete floating photovoltaic (FPV) water pumping sizing, modelling, and optimization of an on-grid PV system with comprehensive capacity, energy output cost, and emission estimations are outlined in this work. The novelty of this study lies in its comprehensive approach that integrates technical, environmental, and economic factors into a unified framework for designing a PV water pumping system, particularly in scenarios where grid supply is feasible or economically viable. A proposal has been made to install PV panels over the water lake to improve the overall system efficiency and to give an aesthetic appearance. The proposed system is composed of a 165 kW PV array and three 55 kW inverters, which cost 54696.92 JD as the initial cost, CO2 emission reduction of more than 5000 tons and produce electricity at 0.028 JD/kWh. The results indicated that the FPV option demonstrates an about 5 % increase in efficiency compared to the other two scenarios. Also, the FPV option has higher costs due to a 25 % increase in system cost but results in lower CO2 emissions compared to the other two options. Top of Form As shown from the results, the two sizing methods for solar water pumping systems, the equations-based method, and the PVsyst simulation tool give the same results. By following this methodology, one can assess the load, size the system, simulate its operation, and analyse the expected performance. Furthermore, the findings of this study could be valuable in designing a grid-connected FPV water pumping system.

Determination of Fracture Mechanic Parameters of Concretes Based on Cement Matrix Enhanced by Fly Ash and Nano-Silica.

This study presents test results and deep discussion regarding measurements of the fracture toughness of new concrete composites based on ternary blended cements (TCs). A composition of the most commonly used mineral additive (i.e., fly ash (FA)) in combination with nano-silica (NS) has been proposed as a partial replacement of the ordinary Portland cement (OPC) binder. The novelty of this article is related to the fact that ordinary concretes with FA + NS additives are most often used in construction practice, and there is a decided lack of fracture toughness test results concerning these materials. Therefore, in order to fill this gap in the literature, an extensive evaluation of the fracture mechanic parameters of TC was carried out. Four series of concretes were created, one of which was the reference concrete (REF), and the remaining three were TCs. The effect of a constant content of 5% NS and various FA contents, such as 0, 15%, and 25% wt., as a partial replacement of cement was studied. The parameters of the linear and nonlinear fracture mechanics were analyzed in this study (i.e., the critical stress intensity factor (KIcS), critical crack tip opening displacement (CTODc), and critical unit work of failure (JIc)). In addition, the main mechanical parameters (i.e., the compressive strength (fcm) and splitting tensile strength (fctm)) were evaluated. Based on the studies, it was found that the addition of 5% NS without FA increased the strength and fracture parameters of the concrete by approximately 20%. On the other hand, supplementing the composition of the binder with 5% NS in combination with the 15% FA additive caused an increase in all mechanical parameters by approximately another 20%. However, an increase in the FA content in the concrete mix of another 10% caused a smaller increase in all analyzed factors (i.e., by approximately 10%) compared with a composite with the addition of the NS modifier only. In addition, from an ecological point of view, by utilizing fine waste FA particles combined with extremely fine particles of NS to produce ordinary concretes, the demand for OPC can be reduced, thereby lowering CO2 emissions. Hence, the findings of this research hold practical importance for the future application of such materials in the development of green concretes.

Strong climate mitigation potential of rewetting oil palm plantations on tropical peatlands

For decades, tropical peatlands in Indonesia have been deforested and converted to other land uses, mainly oil palm plantations which now cover one-fourth of the degraded peatland area. Given that the capacity for peatland ecosystems to store carbon depends largely on hydrology, there is a growing interest in rewetting degraded peatlands to shift them back to a carbon sink. Recent estimates suggest that peatland rewetting may contribute up to 13 % of Indonesia's total mitigation potential from natural climate solutions. In this study, we measured CO2 and CH4 fluxes, soil temperature, and water table level (WTL) for drained oil palm plantations, rewetted oil palm plantations, and secondary forests located in the Mempawah and Kubu Raya Regencies of West Kalimantan, Indonesia. We found that peatland rewetting significantly reduced peat CO2 emissions, though CH4 uptake was not significantly different in rewetted peatland compared to drained peatland. Rewetting drained peatlands on oil palm plantations reduced heterotrophic respiration by 34 % and total respiration by 20 %. Our results suggest that rewetting drained oil palm plantations will not achieve low CO2 emissions as observed in secondary forests due to differences in vegetation or land management. However, extrapolating our results to the areas of degraded oil palm plantations in West Kalimantan suggests that successful peatland rewetting could still reduce emissions by 3.9 MtCO2 yr−1. This result confirms that rewetting oil palm plantations in tropical peatlands is an effective natural climate solution for achieving national emission reduction targets.

Experimental testing and geometric optimization of a domestic cooker burning 80%Natural-Gas+20%Hydrogen

In urban pipelines, blending hydrogen into natural gas has been considered as an effective way of hydrogen usage to reduce carbon emission on household appliances. However, few studies, especially experimental ones are dedicated to address the characteristics of a typical domestic cooker due to the transition from natural gas to 20%hydrogen-enriched natural gas. This study experimentally investigated the changes in terms of the gas flow rate, flame temperature, heat transfer and emission characteristics of a domestic cooker as a result of such transition.Using a self-developed gas blending system, the flow rates of the both the mixed fuel and its components are obtained. The data shows that after blending hydrogen, the mixed gas flow rate becomes higher. Compared to the original cooker burning natural gas, hydrogen blending results in a decreased natural gas flow rate, leading to lower carbon emission. In addition, the thermal input to the cooker is lowered and hydrogen blending leads both the inner and outer combustion zones of the flame to shorten while the flame temperature to increase.As an attempt to optimize the performance of the cooker, the effects of wok stand height on heat transfer efficiency and NO/NOx/CO emissions are examined. It is found that the cooker fueled by 20%hydrogen-enriched natural gas exhibits lower heat transfer efficiency, higher NO/NOx emissions and lower CO emission. According to the fact that the heat transfer efficiency increases at lower wok stand height, the wok stand height is lowered from its original 7 cm–6 cm and 5 cm. The finding indicates that when the wok stand height is moderately decreased to 6 cm, NO/NOx emissions decrease and CO emission is only marginally increased. This study proposes that when natural gas is replaced by 20%hydrogen-enriched natural gas on a swirl flame cooker, the wok stand height can be slightly lowered to exploit the advantages of blended hydrogen combustion.

Reuse of straw in the form of hydrochar: Balancing the carbon budget and rice production under different irrigation management

Hydrochar is proposed as a climate-friendly organic fertilizer, but its potential impact on greenhouse gas (GHG) emissions in paddy cultivation is not fully understood. This two-year study compared the impact of exogenous organic carbon (EOC) application (rice straw and hydrochar) on GHG emissions, the net ecosystem carbon budget (NECB), net global warming potential (net GWP), and GHG emission intensity (GHGI) in a rice pot experiment using either flooding irrigation (FI) or controlled irrigation (CI). Compared with FI, CI increased ecosystem respiration by 23 – 44 % and N2O emissions by 85 – 137 % but decreased CH4 emissions by 30 – 58 % (p < 0.05). Since CH4 contributed more to net GWP than N2O, CI reduced net GWP by 16 – 220 %. EOC amendment increased crop yield by 5 – 9 % (p < 0.05). Compared with CK, hydrochar application increased initial GHG emission, net GWP and GHGI in the first year, while in the second year, there was no significant difference in net GWP and GHGI between CI–hydrochar and CK. Compared with straw addition, hydrochar amendment reduced net GWP and GHGI by 20 – 66 % and 21 – 66 %; and exhibited a lower net CO2 emission when considering the energy input during the hydrochar production. These findings suggest that integrated CI-hydrochar practices would be a sustainable and eco-friendly way for organic waste management in rice production as it holds potential to enhance the NECB and SOC sequestration of rice production, while also offsetting the extra carbon emissions from organic inputs.

A Three-Step Weather Data Approach in Solar Energy Prediction Using Machine Learning

Solar energy plays a critical part in lowering CO2 emissions and other greenhouse gases when integrated into the grid. Higher solar energy penetration is hindered by its intermittency leading to reliability issues. To forecast solar energy production, this study suggests a three-step forecasting method that selects weather variables with a moderate to strong positive correlation to solar radiation using Pearson correlation coefficient analysis. Low-level data fusion is used to combine weather inputs from a reliable local weather station and an on-site weather station, significantly improving the forecasting model’s accuracy regardless of the machine learning method used. Weather data was obtained from the Kisanhub Weather Station located in Cranfield University, UK and the meteorological station in Bedford, UK. In addition, PV power supply data was obtained from four solar plants. Using the Regression Learner app in MATLAB, the proposed architecture is tested on a utility scale solar plant (1 MW), showing a 6% and 13% prediction accuracy improvement when compared to solely using data from the on-site and local weather station respectively. It is further validated using data from three residential rooftop solar systems (8 kW, 10.5 kW and 15 kW), achieving root-mean square values of 0.0984, 0.0885, and 0.1425 respectively. The data was pre-processed using both rescaling and list-wise deletion methods. Training and testing data from the 1 MW solar plant was divided into 75% and 25% respectively, while 100% of the residential rooftop solar plants was used for validation.

Sustainable concrete production: Mechanical and durability behaviour of slag-based geopolymer containing recycled geopolymer aggregate

Geopolymer binders, synthesized by activating aluminous and silicate-rich materials with alkalis, are attracting great interest as an environmentally friendly building material to replace cement due to their low CO2 emissions and the possibility of disposing of industrial wastes. Intensive research on geopolymer binders and the prospect of their future widespread use have raised questions about end-of-life strategies for geopolymer concrete (GPC). In this study, the durability and mechanical properties of new geopolymer concrete (GRAC) produced from aggregate derived from one-part slag-based GPC subjected to ambient curing were investigated. In addition to the properties of recycled geopolymer aggregates (RGAs) such as ASR reactivity, water absorption rate, organic matter content, specific gravity, the effects of RGA size and amount on mechanical strength, SEM analysis, surface topography and length variation of new GRAC produced by adding different proportions of fine and coarse RGAs (30 %, 60 % and 100 %) were investigated. Consequently, it was observed that GRAC exhibited a mechanical strength comparable to that of GPC produced with natural aggregate, while the void content, water absorption rate, surface pores and microcracks of GRAC increased with the increase in RGA content. In addition, the resistance of GRAC to environmental degradation (acid, sulfate, salt and water effect) decreased with the increase in porosity. The high water absorption rate, porous structure and weak interface region (ITZ) of RGAs make GRAC produced with these aggregates more sensitive to external aggressive chemicals.

Decarbonizing of power plants by ammonia co-firing: design, techno-economic, and life-cycle analyses

ABSTRACT This research investigates the decarbonization of India’s electricity grid using ammonia in power plants. It focuses on ammonia produced in Western Australia and transported to India, co-fired with high rank coal, and compared with power plants utilizing carbon capture and sequestration (CCS). The study assesses the overall costs and the life cycle greenhouse gas (LC GHG) emissions for both new plants and retrofits. For 20% gray, blue, and green ammonia, the levelized cost of electricity is 86, 89, 125 $/MWh, with corresponding LC GHG emissions of 1,234, 1,079, and 1,062 kg CO2e/MWh. Co-firing with green ammonia, though more expensive than blue ammonia, yields lower CO2 emissions. Conversely, reducing the same amount of direct CO2 emission via CCS costs $84/MWh and a LC GHG emission of 1,227 kg CO2e/MWh. While CCS is cheaper, it results in higher LC GHG. There is a trade-off between cost and emissions across the strategies. Under scenarios with low capacity factors or reduced ammonia production costs, coal-ammonia co-firing could become more economical and greener than the CCS. This study provides quantitative insights for policymakers and project developers. However, it is crucial for decision-makers to consider several factors: (1) the potential impact of social resistance to CCS; (2) the time required for large-scale commercialization of CCS technology, which is expected to be significantly longer than the implementation time for a coal-ammonia co-firing decarbonization strategy; (3) the potential of either CCS or ammonia-coal co-firing strategy to enhance India’s electricity mix, thus contributing to energy security.

Life Cycle Carbon Assessment of Mortars with Carbonated and Non-Carbonated Recycled Aggregates

Global warming is one of the most important issues that the world is currently facing. The cement industry accounts for around 7% of total global CO2 emissions. According to the 13th United Nations Sustainable Development Goals, cement plants must become carbon neutral by 2050. This neutrality may be achieved by a reduction in CO2 emissions complemented with carbon capture, utilization and storage (CCUS) technologies. In accordance with these sustainable goals, several approaches have been studied. This paper investigates life cycle carbon of mortars produced with carbonated recycled aggregates. In previous works, the carbon dioxide capture capacity of construction and demolition waste (CDW) was analysed, and mortars with CDW recycled aggregates submitted to high levels of CO2 were evaluated in terms of their mechanical performance. This paper focus on the life cycle carbon impact assessment (LCCA) of industrial mortar formulations in a cradle-to-gate boundary. This assessment is carried out through a global warming potential environment impact assessment, since it represents the amount of CO2 equivalent that is sent to the atmosphere and contributes to the “greenhouse effect”. This LCCA includes the impacts associated with the treatment and additional transportation routes of the recycled aggregates. With this work, it was found that mortars with carbonated recycled aggregates have a considerably lower global warming potential impact than mortars without recycled aggregates. The mortars with recycled aggregates presented lower CO2 emissions of up to 6.31% for 100% incorporation of non-carbonated recycled aggregates. These values were incremented with the carbonation of the recycled aggregates, achieving a reduction of CO2 emissions of up to 36.75% for 100% of incorporation.

Thiadiazol ligand-based laccase-like nanozymes with a high Cu+ ratio for efficient removal of tetracyclines through polymerization

A promising water treatment technology involves inducing the polymerization of organic pollutants to form corresponding polymers, enabling rapid, efficient, and low CO2 emission removal of these pollutants. However, there is currently limited research on utilizing polymerization treatment technology for removing tetracyclines from water. In this study, we synthesized a laccase-mimic nanozyme (Cu-ATZ) with a high Cu+ ratio using 2-amino-1,3,4-thiadiazole as a ligand inspired by natural laccase. The Cu-ATZ exhibited enhanced resistance to more severe application conditions and improved stability compared to natural laccase, thereby demonstrating a broader range of potential applications. The excellent catalytic properties of Cu-ATZ enabled the nanozyme to be used in the polymerization process to remove tetracyclines from water. In order to simulate actual antibiotic pollution of water bodies, tetracyclines were added to the water from sewage treatment plants. Following Cu-ATZ treatment of the water sample, the chemical oxygen demand (COD) content was found to have decreased by over 80 %. In conclusion, this study presented a novel approach for tetracycline elimination from water.

Thermo-economic analysis and comparison of novel desiccant air conditioning systems

Desiccant air conditioning (DAC) systems are considered an effective alternative to traditional vapor compression systems due to their ability to independently control temperature and humidity, coupled with their environmentally friendly design. Consequently, this paper deals with experimental and simulation study on DAC systems. The experiments were conducted on a reference system (RS) equipped with all necessary control and measurement devices. This reference system includes a traditional desiccant evaporative air-conditioning system with an additional heat exchanger placed after the desiccant wheel, functioning as an after-cooler. In addition, steady state and transient simulation models were developed using TRNSYS software to predict the performance of four different configurations of DAC systems and the reference system, under hot and humid climatic conditions.The experimental data verify the precision and relevance of the simulation results, with an average error of 2.57 % for the air temperatures. The steady state findings showed that Config-4 exhibited the best thermal performance compared to the other configurations. Also, Config-4 demonstrates a stable thermal cooling capacity despite fluctuations in outdoor air dry-bulb temperature. Transient results revealed that, Config-4 has levelized costs of CO2 emissions that are 64.2 % lower than RS, followed by Config-3, Config-2, and Config-1. Lower CO2 emissions result in a positive impact on mitigating climate change and improving air quality. Economic analysis revealed that the total levelized cost of cooling (LCOC) for Config-4 is 70.5 % lower than RS, demonstrating the most significant cost reduction. Configurations 3, 2, and 1 also showed lower LCOC compared to the reference system.

The nexus between economic growth, urbanization, technological advancement, and CO2 emissions: Where does the GCC stand?

Most countries, particularly developing and growing economies, have the primary goal of achieving greater economic growth in order to improve living standards. However, a boost in economic activity raises energy demand, which in turn raises carbon dioxide emissions and deteriorates the environment. This paper investigates the effect of economic growth, energy consumption, and research and development on CO2 emissions in Gulf Council Cooperation (GCC) countries. The study uses the Vector Error Correction Model to investigate the short- and long-run synergy between variables over the period 2000–2022. The results indicate that boosting economic activity requires more energy consumption and will increase CO2 emissions in the long run. Investing in research and development can enhance the quality of the environment, yet the effect of urbanization on CO2 emissions in GCC countries remains unclear. To reduce energy consumption, it is first necessary to expand renewable energy sources and encourage energy-saving techniques. Then, to lower CO2 emissions, the government must promote investments in green technologies, particularly in manufacturing. Third, the government should encourage sustainable urbanization by putting laws in place that encourage the growth of green cities and transportation networks.