Carbon Water Research Articles

Ionic Liquid-Based Green Solvents for Extraction and Purification of Natural Plant Products

Introduction: This research paper explores the environmental sustainability of ionic liquid-based green solvents in the extraction and purification of natural plant products, with a focus on their entire life cycle. The objectives of the study were to assess the environmental impact of ionic liquid synthesis, energy consumption, water usage, emissions, recycling rates, policy effects, and stakeholder perceptions. Methods: Methodologically, we conducted a comprehensive Life Cycle Assessment (LCA) that involved primary data collection through field surveys and interviews with key stakeholders in the ionic liquid production and usage industry across various regions in India. The data were analyzed using specialized LCA software tools to quantify environmental impacts. Key findings include the identification of synthesis as a major contributor to environmental impact, emphasizing the need for greener synthesis methods. Results: The study revealed the significant carbon footprint, energy consumption, and water usage during production, highlighting opportunities for improvement. Emissions data underscored the importance of emission control measures, particularly for greenhouse gases and volatile organic compounds. Recycling and reuse were identified as environmentally friendly disposal methods. Policy compliance varied among stakeholders, indicating room for stricter regulations. Stakeholder perceptions varied, with researchers having the most positive outlook. Implications of the findings extend to sustainable chemistry practices, emphasizing interdisciplinary collaboration and the importance of considering the entire life cycle of chemical processes. Conclusion: This research contributes to a deeper understanding of green solvents and provides a foundation for promoting sustainable practices in industrial processes in India and globally.

Does the way workplace canteens are managed influence users’ plate waste?

Abstract Background Plate waste (PW) is part of the food waste and is defined as the amount of edible food served not eaten. There are few estimates of PW in the food services, mainly in school canteens, where PW appears to differ depending on the provider. Our aim was to analyse the role of different canteen management in determining PW in three hospital canteens in Italy. Methods On 5 working days between August and September 2022, healthcare workers’ trays were photographed before and after meal consumption. We compared two canteens managed by an external catering service (EC) with one internally managed (IC). The two canteens with similar sample size had different management. A modified visual Comstock scale was used to assess the PW. The Carbon Footprint (CF), Water Footprint (WF), energy and nutrient content were estimated using the SU-EATABLE LIFE database and the Italian Food Composition Database for Epidemiological Studies (www.bda-ieo.it). Significance was set at p < 0.05. Results 1227 trays were analysed (1026 in EC; 201 in IC), most of which contained no waste. The percentage of trays with leftovers was higher in EC (34%) than in IC (21%), as was the mean amount of PW (104g EC vs 60g IC) (p < 0.001). The PW contained significantly more energy (125 kcal vs 73 kcal) and protein (6.0g vs 2.4g) and had higher CF (204 CO2eq EC vs 76 CO2eq IC) and WF (178 LH20 EC vs 75 LH20 IC) in CE than in IC. The significance was confirmed independently to the sample size of the canteens, and when the analysis was repeated and only the first access of each user was considered. Conclusions Results suggest that an internally managed canteen produces less leftovers than a canteen operated by an external provider. This could be because an internally managed canteen is more adaptable to users in terms of food offerings and portion sizes, despite a smaller number of food options. However, further studies are needed to confirm our findings and to identify the causes of PW in food service. Key messages • Internally managed canteens seem to reduce plate waste, probably due to certain flexibility according to users’ plate waste. • Non-served food of the canteen should be estimated to confirm our data.

Satellite remote sensing reveals the footprint of biodiversity on multiple ecosystem functions across the NEON eddy covariance network

Abstract Biodiversity relates to ecosystem functioning by modulating biogeochemical cycles of carbon, water, energy, and nutrients within and between multiple biotic and abiotic components of the ecosystems. However, large-scale, systematic measurements of plant biodiversity are still lacking, and the effects of biodiversity on measured biogeochemical processes are understudied. Here, we combined alpha (α) and beta (β) taxonomic measurements, spectral diversity from satellite observations, structural properties of the vegetation, and climatic drivers to assess the effect of biodiversity on ecosystem functional properties. Ecosystem functional properties were computed from eddy-covariance fluxes at 44 sites of the National Ecological Observatory Network. Based on the spectral variation hypothesis, we used the near-infrared reflectance of vegetation (NIRv) derived from Sentinel-2 satellite imagery to compute Rao’s quadratic entropy (Rao Q), a distance metric related to spatial heterogeneity. Using an automatic model averaging technique, we found that biodiversity proxies hold substantial explanatory power when predicting several ecosystem functions related to carbon and water exchange. In particular, NIRv-based Rao Q (RaoQNIRv) reflected positive biodiversity effects on productivity, as expected from the literature. In contrast, traditional taxonomic α-diversity indices were generally not selected as relevant predictors of the ecosystem functional properties. Yet, β-diversity strongly contributed to the prediction of carbon use efficiency, surface conductance, and water use efficiency. We also found that the RaoQNIRv is less affected by issues of saturation and bare soil contribution compared to RaoQNDVI. We show that spectral heterogeneity based on remotely sensed NIRv holds the potential for globally characterizing the biodiversity-ecosystem functioning relationship (BEF). While systematic measurements of taxonomic diversity co-located at biogeochemical measurement stations could reduce the uncertainty surrounding the BEF relationship at whole-ecosystem scale, remotely- sensed metrics characterizing important functional and structural diversity aspects of the landscape will be crucial for continuous spatiotemporal monitoring of biodiversity with relevant implications for ecosystem services to humankind.

Riverine CH4 and CO2 emissions respond to associated agricultural land use and seasonality

ABSTRACT Recently, agricultural land use has significantly impacted carbon emissions and water quality in adjacent rivers. This study examined the influence of land-use types and seasonality on carbon emissions from agriculture-impacted rivers in Shanghai. Our results showed that the crop farming land-use-associated river (AR) had CH4 and CO2 fluxes 2.68 and 3.47 times higher, respectively, than those in the aquaculture land-use-AR and 2.86 and 2.81 times higher than in the livestock and poultry breeding land-use-AR. Statistical analyses revealed that total nitrogen, ammonia nitrogen, and humification index were significantly correlated with crop farming land-use-AR carbon emissions. Conversely, no clear correlation was found between chemical factors and carbon fluxes in the aquaculture land-use-AR and livestock and poultry breeding land-use-AR due to the complexity of pollution sources. Seasonality significantly influenced CH4 and CO2 fluxes from agriculture-impacted rivers, with carbon fluxes in summer being 3.5 and 2.5 times higher than in winter, respectively. Crop farming land-use-AR carbon fluxes exhibited the highest variability under seasonal influences. This study emphasizes the need for policies to mitigate agricultural land use impacts on river carbon emissions.

Drought-Induced Alterations in Carbon and Water Dynamics of Chinese Fir Plantations at the Trunk Wood Stage.

Over the past three decades, China has implemented extensive reforestation programs, primarily utilizing Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) in southern China, to mitigate greenhouse gas emissions and counter extreme climate events. However, the effects of drought on the carbon sequestration capacity of these forests, particularly during the trunk wood stage, remain unclear. This study, conducted in Huitong, Hunan, China, from 2008 to 2013, employed the eddy covariance method to measure carbon dioxide (CO2) and water fluxes in Chinese fir forests, covering a severe drought year in 2011. The purpose was to elucidate the dynamics of carbon and water fluxes during a drought year and across multi-normal year averages. The results showed that changes in soil water content (-8.00%), precipitation (-18.45%), and relative humidity (-5.10%), decreases in air temperature (-0.09 °C) and soil temperature (-0.79 °C), and increases in vapor pressure deficit (19.18%) and net radiation (8.39%) were found in the drought year compared to the normal years. These changes in environmental factors led to considerable decreases in net ecosystem exchange (-40.00%), ecosystem respiration (-13.09%), and gross ecosystem productivity (-18.52%), evapotranspiration (-12.50%), and water use efficiency (-5.83%) in the studied forests in the drought year. In this study, the occurrence of seasonal drought due to uneven precipitation distribution led to a decrease in gross ecosystem productivity (GEP) and evapotranspiration (ET). However, the impact of drought on GEP was greater than its effect on ET, resulting in a reduced water use efficiency (WUE). This study emphasized the crucial role of water availability in determining forest productivity and suggested the need for adjusting vegetation management strategies under severe drought conditions. Our results contributed to improving management practices for Chinese fir plantations in response to changing climate conditions.

Achieving collaborative pollutant and carbon emissions reduction through digital governance: Evidence from Chinese enterprises

Under China's dual carbon goals, it is imperative for enterprises to effectively reduce carbon emissions while achieving pollutant reduction. This article explores the potential role of government-implemented digital governance in facilitating these objectives. Utilizing a quasi-natural experiment on digital governance, we established an analytical framework to thoroughly examine how digital governance can help Chinese enterprises realize synergistic effects in pollution control and carbon reduction. Our study reveals that digital governance significantly reduces enterprises' emissions of carbon dioxide and pollutants, with emission intensities of the carbon dioxide, air pollutant and water pollutant being decreased by approximately 6.9%, 7.3%, and 7.0%, respectively. These reductions are primarily driven by improvements in energy efficiency, the promotion of green innovation, digital transformation, and enhanced role of media. However, it is important to note that digital governance also negatively impacts overall corporate productivity and widens the digital divide between large and small-to-medium enterprises. The research results have practical significance for promoting the achievement of emission reduction goals and sustainable development for enterprises.

Spatio-temporal heterogeneity and driving mechanism of ecosystem water use efficiency in the Loess Plateau, China

Study regionThe Loess Plateau, China Study focusThe trade-off between carbon uptake and water loss, characterized by ecosystem water use efficiency (WUE), deeply influences ecosystem sustainability. In this study, WUE was estimated based on GPP from the Moderate Resolution Imaging Spectroradiometer (MODIS) product and ET simulated by the Priestley Taylor Jet Propulsion Laboratory (PT-JPL) model. The emerging hot spot analysis (EHSA) was used to comprehensively examine the spatio-temporal heterogeneity of WUE. Additionally, the Geodetector model was employed to identify the main drivers of WUE and quantify the interactive effects of drivers on WUE, focusing on different vegetation types. New hydrological insights for the regionResults indicated obvious spatial heterogeneity of WUE under different vegetation and hydro-climatic conditions. Significant increases in WUE occurred in sub-humid cropland and grassland areas that have experienced large-scale ecological restoration and agricultural intensification. By contrast, slight decreases in WUE were observed in semi-arid grassland areas, some of which were accompanied by intensifying cold spots. It was noteworthy that WUE in some hot spots with excessive vegetation coverage also showed a slight downward trend. Further, the WUE pattern in cropland/forests/grassland was dominated by the interaction of vegetation coverage (characterized by the Normalized Difference Vegetation Index, NDVI) and precipitation/air temperature/vapor pressure deficit, with NDVI playing a leading role and hydro-climatic drivers playing a supporting role.

A Viability Study of Thermal Pre-Treatment for Recycling of Pharmaceutical Blisters

Pharmaceutical packaging is one of the most used packaging types which contains aluminum and plastics. Due to increasing amounts of waste and rising environmental concerns, recycling approaches are being investigated. Since blisters usually contain a balanced amount of plastics and metals, most of the approaches focus on recycling only one material. Therefore, more sustainable recycling approaches which recover both plastic and aluminum fractions are needed. This study investigates the thermal behavior and degradation mechanisms of plastic-rich and aluminum-rich pharmaceutical blisters using various analytical techniques. Structural characterization revealed that plastic-rich blisters have a thicker profile with plastic and aluminum layers, while aluminum-rich blisters consist of plastic layers between aluminum sheets. Thermal degradation analysis showed two main stages for both types: plastic-rich blisters (polyvinyl chloride) exhibited significant weight loss and long-chain hydrocarbon formation between 210 and 285 °C, and aluminum-rich blisters (polyamide/nylon) degraded from 240 to 270 °C. Differential Scanning Calorimetry and Fourier Transform Infrared Spectroscopy analyses confirmed the endothermic behavior of such a transformation. The gas emissions analysis indicated an increased formation of gasses from the thermal treatment of plastic-rich blisters, with the presence of oxygen leading to the formation of carbon dioxide, water, and carbon monoxide. Thermal treatment with 5%O2 in the carrier gas benefited plastic-rich blister treatment, reducing organic waste by up to 80% and minimizing burning risk, leveraging pyrolytic carbon for protection. This method is unsuitable for aluminum-rich blisters, requiring reduced oxygen or temperature to prevent pyrolytic carbon combustion and aluminum oxidation.

Effects of environmentally friendly soil remediation materials on soil quality and maize production

In the precent, the reclaimed raw soil of newly renovated abandoned homestead was considered as the research object, and study the effects of different environmentally friendly soil remediation material combinations on the quality of reclaimed raw soil and maize crop production. A total of 6 improved material treatments were set up, including decomposed chicken manure(YJ), fly ash(FMH), ferrous sulfate curing agent(SHJ), ferrous sulfate curing agent+organic fertilizer (SYJ), fly ash+decomposed chicken manure(FYJ), and control treatment(CK). The research results showed that, the organic carbon content and water storage of new reclaimed raw soil exhibited a significant increasing trend after the application of different environmentally friendly modified materials(P < 0.05). Among them, the organic carbon and water storage of reclaimed soil under FYJ improved, which increased by 132.3 and 14.4 %, respectively compared with CK. During the growth period of summer maize, the plant height and yield exhibited a trend of FYJ> SYJ> YJ> FMH> SHJ> CK. The yield of maize under SYJ and FYJ treatments increased by 38.8 and 53.4 %, respectively, compared with CK. The appropriate combination of environmentally friendly soil remediation materials is helpful to improve the quality of new reclaimed raw soil, promote soil carbon sequestration, increase the comprehensive utilization rate of waste resources, increase the production performance of crops, and help rural revitalization and beautiful rural construction. Bangladesh J. Bot. 53(3): 673-679, 2024 (September) Special

The Sustainable Management of Ecohotels for the Support of Ecotourism—A Case Study

Ecotourism represents a modern form of tourism that accepts the principles of sustainable development and the adequacy of the conditions of tourist destinations. The environmental awareness of all parties participating in tourism, objects, and subjects of tourism determines the development of ecotourism. Ecohotels, or “green hotels”, as an integral part of ecotourism, represent tourist accommodation facilities that have the “The Flower” certificate, their business activities minimize the impact on environmental quality. The management of ecohotels therefore implements programs and measures determining sustainable competitiveness at the local, regional, and supra-regional levels in the business in interaction with reducing the carbon footprint, water consumption, energy consumption, and waste production. They also support the use of recyclable materials and bio-products and the introduction of environmental management respecting the principles of green management in all areas of the tourism business. The competitiveness of ecohotels is in interaction with the willingness of tourists to use their pro-environmental services. The presented study is focused on the willingness of tourists to use the services of ecohotels, with an emphasis on identifying an effective strategy for supporting the development of ecotourism in the Slovak Republic. The study concentrates on the willingness of tourists to use ecohotels as part of their tourist activities based on a questionnaire survey. The study identifies the factors of strengths and weaknesses as well as the opportunities and threats of the use of ecohotels by tourists in supporting the development of ecotourism. Through the exact quantification of the weights of individual factors in terms of Saaty’s matrix and a SWOT analysis, an effective strategy for the use of ecohotels in supporting the development of ecotourism is defined. In recent years, the stimulation and use of tourists’ interest in environmental quality, with an emphasis on reducing negative impacts on the environment, has resonated; thus, a model of effective marketing strategy is presented.

Wetland Landscape Dynamics and Multi-Functional Assessment of Wuhan City, China

Under the dual pressures of rapid urbanization and intensifying global climate change, China has proposed governance policies aimed at promoting ecological urban construction. Wetland landscapes play a key role in sustaining human and social well-being. As a significant city in the middle reaches of the Yangtze River, Wuhan’s wetland resources play an irreplaceable role in maintaining the regional ecological balance and promoting sustainable economic and social development. However, urbanization poses a severe challenge to the ecological service functions of wetlands. Consequently, in this study, we analyzed the spatial–temporal evolution patterns of the sub-functional systems of carbon sequestration, biodiversity conservation, water yield, and water purification in five wetland types in Wuhan City from 2000 to 2020 by using the CASA model and InVEST model. Then, a wetland multi-functional assessment framework was constructed to quantify the comprehensive multi-function score. It is imperative to unravel the underlying mechanisms driving the changes in wetland functions and to explore the equilibrium point between wetland conservation and urban sustainable development. Our results show that the wetland area of Wuhan City decreased from 5077.33 km2 in 2000 to 4696.60 km2 in 2020, and the wetland multi-functions exhibited significant spatial heterogeneity from 2000 to 2020. Wetland carbon sequestration increased from 0.94 Tg in 2000 to 1.11 Tg in 2020. The wetland habitat quality declined from 0.13 in 2000 to 0.11 in 2020. The water production of the wetlands increased from 5.43 × 109 t in 2000 to 22.59 × 109 t in 2020. The wetland N loss decreased from 55,850.58 t in 2000 to 49,209.93 t in 2020. The highest multi-function score was in paddy fields, which increased from 0.41 ± 0.12 to 0.51 ± 0.12, followed by tidal flats, which increased from 0.39 ± 0.14 to 0.50 ± 0.16, and the lowest was rivers, which also increased from 0.33 ± 0.12 to 0.41 ± 0.14. The multi-function score was closely related to the wetland type and urban development direction over the past two decades, and it was negatively correlated with production and living density, providing new ideas for wetland ecological protection and construction in Wuhan City.

Density Functional Theory Study on Na+ and K+ Catalysis in the Transformation of Glucose to Fructose and HMF in Hydrothermal Environments

Hydrothermal carbonization (HTC) is an efficient method for converting biomass into biochar. Hydrochar contains catalytic components such as alkali and alkaline earth metals (AAEMs); however, the mechanisms by which highly active metals such as potassium (K) and sodium (Na) catalyze the conversion of small carbon–water compounds into hydrochar in hydrothermal environments remain unclear. In this study, glucose was used as a small molecule model, and Na+ and K+ were used as catalysts to investigate the catalytic reaction mechanism during the hydrothermal process using density functional theory (DFT). In the presence of different ions at various binding sites, glucose isomerizes into fructose, which subsequently undergoes three consecutive dehydration reactions to form 5-hydroxymethylfurfural (HMF). The results indicate that the catalytic effectiveness of Na+ and K+ in the isomerization of glucose to fructose is optimal when interacting with specific oxygen sites on glucose. For Na+, the interaction with the O1 and O2 oxygens provides the lowest reaction barrier of 37.16 kcal/mol. For K+, the most effective interactions are with the O3 and O4 oxygens and the O5 and O6 oxygens, resulting in reduced reaction barriers of 54.35 and 31.50 kcal/mol, respectively. Dehydration of fructose to HMF catalyzed by Na+ ions, the catalytic effectiveness at different positions is ranked as O5O6 > O1O5, whereas for K+, the ranking is O1O5 > O5O6. This study explores the catalytic effects of Na+ and K+ at different binding sites on the hydrothermal reactions of glucose at the atomic level, offering theoretical support for designing catalysts for the HTC of sludge.

In Situ and Ex Situ Bioremediation of Different Persistent Soil Pollutants as Agroecology Tool

Contamination or pollution of our environment has become a real global concern, especially in parallel with the increasing evolution of urbanization and industrialization, which in turn have released a plethora of different pollutants that end up being deposited in soils. It is crucial to investigate solutions that can minimize the extent of damage, and that are cost-effective, feasible and environmentally friendly, to treat a wide variety of contaminants in soils, as well as to detoxify various compounds. Bioremediation is a safe technique that has demonstrated satisfactory results and is easy to apply and maintain. This technique explores the degradation pathways of various biological agents (microorganisms, plants, algae, etc.) to neutralize contaminants. It is based on biodegradation through a complete mineralization of organic pollutants into inorganic innocuous compounds, such as carbon dioxide and water. This review aims to determine the feasibility of bioremediation as a cleanup technology for soils contaminated with pesticides, agrochemicals, chlorinated compounds, heavy metals, organic halogens, greenhouse gases, petroleum hydrocarbons, and many others, either in situ or ex situ. Different bioremediation approaches are described and compared, showing their advantages and drawbacks from a critical point of view. Moreover, both the economic and technical barriers of bioremediation are addressed, along with the outlook for the role of microorganisms in the process, the aim to identify future directions, and the application feasibility of this process.

The responses of ecosystem services in coastal cities to urbanization in 30 years: A case study of Qingdao City, China

Coastal urban areas play a pivotal role in regional economic growth, yet they are also sensitive regions where the natural environment interacts with human activities. Rapid urbanization has led to ecological issues, such as the degradation of key ecosystem services (ESs) in coastal cities. Understanding the impact of urbanization on the supply and demand of ESs in coastal cities is crucial for ensuring the healthy and sustainable development of the socio-economy in these areas. This study takes the coastal city of Qingdao as a case study, with a focus on the supply and demand relationships of seven key ESs—carbon sequestration, food production, habitat quality, recreational capacity, soil retention, water yield and marine aquaculture—as well as their responses to population growth, economic development, and spatial expansion, which are three distinct aspects of urbanization. The findings indicate that: (I) From 1992 to 2022, the evolution of different ESs exhibited variability, all displaying notable spatial imbalances. (II) During this period, the urbanization process in Qingdao had a pronounced negative effect on the supply and demand of ESs. Spatial urbanization had the most significant impact on carbon sequestration, food production, habitat quality, water yield, and marine aquaculture, while population urbanization most notably affected recreational capacity. (III) The sensitivity of different types of ESs to population, economic, and spatial urbanization varies. Carbon sequestration, food production, recreational capacity, soil retention, water yield, and marine aquaculture were most sensitive to economic urbanization, whereas habitat quality was most sensitive to spatial urbanization. This research provides a basis for decision-making in the sustainable development and comprehensive management of coastal cities and their ecosystems.

Evaluation and Trade-Offs/Synergies of Ecosystem Services in an Ecologically Fragile Region: A Case Study of Western Jilin Province

Ecosystem services (ES) are the foundation for the survival and development of human society. It is of great significance to clarify the trade-off and synergy between different types of ES in promoting regional sustainable development. This paper selects the western Jilin Province as a case, focusing on exploring the trade-offs and synergies of ES in ecologically fragile areas, enriching the geographical types of research on the relationships between ecosystem services. Utilizing the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model, this study focused on quantifying four pivotal services—carbon storage, water yield, soil conservation, and habitat quality index—over a two-decade span encompassing the years 2000, 2010, and 2020, and analyzed the trade-offs/synergies between the four ecosystem service functions. The results show that from 2000 to 2020, among the four ecosystem services, water yield and soil conservation increased by 13.57 × 109 m3 and 220.61 × 106 t, respectively, while carbon storage and habitat quality decreased by 5.09 × 106 milligrams and 0.01 units, respectively. At the regional scale, there were only synergistic relationships between carbon storage and soil conservation, and carbon storage and habitat quality. This study provides scientific references to promote sustainable development in the western Jilin Province and offers new insights into the trade-off and synergy of ecosystem services in ecologically fragile areas.

Environmental impact of intravenous versus oral administration materials for acetaminophen and ketoprofen in a French university hospital: an eco-audit study using a life cycle analysis.

The combination of acetaminophen with a nonsteroidal anti-inflammatory drug is the cornerstone of perioperative multimodal analgesia. These drugs can be administered intravenously or orally as premedication, consistent with the concept of pre-emptive and preventive analgesia. We aimed to assess the environmental impact of their intravenous and oral administration in a French university hospital. We carried out a life cycle assessment to determine the amount of greenhouse gas emissions and depletion of water resources resulting from the oral vs intravenous administration of 1g acetaminophen and 50mg ketoprofen. We assessed two schemes of intravenous administration, depending on the use of the same or a different infusion set for each drug. At our centre, the intravenous administration of both drugs was associated with the emission of 444-556g CO2 equivalent (CO2e), and with 9.8-12.2 L of water waste. The oral administration of both drugs generated 8.36g of CO2e emissions and consumed 1.16 L of water. At a national level, the switch from intravenous to oral premedication of the drugs could avoid the emission of 2,900-3,700 tons of CO2e and the waste of 58,000-74,000 m3 of water each year. This eco-audit indicates that oral administration of acetaminophen and ketoprofen results in significantly lower carbon emissions and water consumption than intravenous administration. These findings highlight the importance of using the oral route for most patients, limiting intravenous administration for those with specific needs because of higher environmental impact and cost.

A closed-loop recycling of wastewater derived from aqueous carbonation of basic oxygen furnace slag in cement paste production

Aqueous carbonation (AC) treatment is a promising method for enhancing the cementitious activity of Ca- and Mg-rich solid wastes, such as basic oxygen furnace slag (BOFS), while also reducing carbon emissions. However, the carbonated filtrate (CF) solution generated during the AC process poses significant environmental challenges and limits its large-scale application. This paper, therefore, explores the feasibility of recycling CF in cement paste production as a strategy for managing AC wastewater. The study examines the impact of CF on the physico-mechanical properties, hydration behavior and microstructure of cement pastes (pure and blended with either 10% as-received or carbonated BOFS), compared to those prepared with tap water (TW) and carbonated water (CW). The results indicate that carbonated solutions (CF and CW) promote the hydration of aluminate phase in cement, with a more pronounced effect observed for CW. The solid suspensions in CF, particularly nesquehonite, restrict the growth space for calcium silicate hydrates (C-S-H) in the paste matrix, resulting in the formation of foil-like Type II C-S-H and lowering compressive strength. However, the additional nucleation sites provided by calcite crystals in carbonated BOFS (C-BOFS) accelerate cement hydration in CF-based pastes and mitigate strength loss by promoting the formation of more fibrillary C-S-H. Furthermore, the addition of a superplasticizer reduces interparticle forces in the C-BOFS-CF paste, further enhancing strength development and achieving a 28-day strength comparable to that of the control sample (OPC-TW paste).

Spatial–Temporal Variations in Water Use Efficiency and Its Influencing Factors in the Li River Basin, China

As a vital indicator for measuring the coupled carbon–water cycle of an ecosystem, water use efficiency (WUE) can also reflect the adaptive capacity of plants in different ecosystems. Located in Southwest China, the Li River Basin has a representative karst landform, and the uneven rainfall in the region leads to severe water shortage. In this study, we analyzed the spatial–temporal transformation characteristics of the WUE of the basin and its relationship with different influencing factors from 2001 to 2020 based on a correlation analysis and trend analysis. The main conclusions are as follows: (1) The average value of WUE in the Li River Basin was 1.8251 gC· mm−1·m−2, and it kept decreasing at a rate of 0.0072 gC· mm−1·m−2·a−1 in the past 20 years. With respect to the spatial distribution of the multi-year average of WUE, it exhibits a gradual increasing trend from west to east. (2) Between gross primary productivity (GPP) and evapotranspiration (ET), it was found that ET was the primary influencing factor of WUE. Precipitation was positively correlated with WUE in the Li River Basin, accounting for 67.22% of the total area of the basin. The air temperature was negatively correlated with WUE, and the area was negatively correlated with WUE, accounting for 92.67% of the basin area. (3) The normalized difference vegetation index (NDVI) and leaf area index (LAI) were negatively correlated with WUE, and the proportions of negatively correlated areas to the total area of the basin were similar; both were between 60 and 70%. The growth of vegetation inhibited the increase in WUE in the basin to a certain extent. Regarding Vapor Pressure Deficit (VPD), the proportions of positive and negative correlation areas with WUE were similar, accounting for 49.58% and 50.42%, respectively. (4) The occurrence of drought events and the enhancement in its degree led to a continuous increase in WUE in the basin; for different land cover types, the correlation of the standardized precipitation evapotranspiration index (SPEI) was in the following order from strongest to weakest: grassland > cropland > forest > shrubland.

Elimination of microplastic from soil by pyrolysis and potential hazard analysis: Effects of pyrolysis temperature and holding time

AbstractEfficient and harmless treatment of microplastics in soil is the current focus of microplastic pollution management. In this study, the pyrolysis effect of soil microplastics at different temperatures and holding times was analyzed. The results showed that temperature and holding time significantly affected the morphology and compositional structure of soil. Pure microplastics and product adhesion after pyrolysis at low temperature (400°C) were not easy to remove. Interestingly, compared with pure polyethylene (PE), direct pyrolysis of microplastics in soil could obtain better results, and the content of organic matter and polycyclic aromatic hydrocarbons (PAH) could be significantly reduced. However, the pyrolysis performance was very unsatisfactory even if the action time was prolonged at 400°C. Prolonged high‐temperature treatment accelerated the fragmentation of the alkane main chain of PE, thus generating more PAH, and the temperature was not high enough (400°C) for further effective degradation of PAH into carbon dioxide and water. Therefore, higher temperature and longer holding time need to be selected to ensure the pyrolysis performance. This study revealed the role and mechanism of pyrolysis in soil microplastic mixed systems, aiming to provide a basis for the treatment of microplastics in terrestrial ecosystems.

A synthesis of research on the sequestration of carbon in forests and the conservation of water

Forests help solve environmental issues by sequestering carbon and conserving water. Forest management's ultimate goal is to optimize dual functions to reduce greenhouse gas emissions and maintain the water cycle. Increased forest production and ecosystem water balance have costs and benefits. This study reviews forest carbon sequestration and hydrological principles for future research. The interaction between forest carbon sequestration and water conservation revealed information gaps and research needs. Previous research has helped comprehend forest carbon fixing and hydrological regulation. Many equipment and methods can quantify and monitor forest carbon and hydrological issues at multiple geographical and temporal levels. Afforestation programs that improve carbon sequestration and water maintenance ecosystem services lack knowledge. Top-down scheduling of afforestation in locations with uncertain water supplies must address how much and where to plant assumed existing land, ecological implications, and local progress and income. Planting decisions dominate local management. Cooperative research is needed to build and manage planted forests for carbon sequestration, water management, and other societal purposes. This study's integrated paradigm for forest management considers carbon sequestration and water conservation can assist future research.