Carbon Content Research Articles

Soils after forestry management activities in spruce plantations

The carbon accumulation in forest ecosystems helps to mitigate climate changes, therefore the interest in finding strategies for adapted forest management is a major goal of our time. The artificial plantations of Norway spruce (Picea abies Karst) are part of the Bulgarian project to restore the regulatory functions of forest ecosystems. Due to their low resistance, intensive processes of deposition and degradation take place in them, which emphasizes the need to understand the condition of soils and the amount of accumulated carbon in them. This paper reports results from a study on the thinning in even-aged Norway spruce plantations (Picea abies Karst) and its effect on some soil properties. The study includes two thinned plots and an untinned control: 1) Control – an unmanaged spruce plantation, without any activities in it through the last 20 years; 2) Thinned – managed with regular felling over the years, the last of which was carried out 10 years ago with 25% intensity; and 3) Ice storm – plantation damaged from an ice storm in 2007 (when it was 33 years old), felling followed by removal of all affected trees – over 95%, and afforestation with spruce saplings. The soil was examined by layers from 10 cm to 30 cm depth. The main soil characteristics connected with the carbon stocks in soil are analyzed - bulk density, skel-eton, and carbon content. The results of the experiment show that the performed forestry activities were conducted with abidance of the requirements for habitat protection and the ecosystem’s functionality in the studied sites. No significant changes in coarse fraction content and bulk density of soils were found. There is no statistical difference between the plots in the studied depths, but there is a trend of decrease in the organic carbon content in the managed sites. The differences in the soil carbon stocks are significant for the first two soil layers between the control and the managed trough thinning plot. 

Biomass Carbon and Nitrogen Content of Hardwoods in Novi Pazar (Serbia)

To investigate and compare hardwood species based on their carbon (C) and nitrogen (N) storage capacity, a study of the C and N content of the bark and wood of nine common hardwood broadleaves in Novi Pazar, southwestern Serbia, was conducted. Compared with sycamore maple, Norway maple, common ash, common hornbeam, black locust, European beech, Turkey oak, and sessile oak, field maple has the highest C/N ratio in wood (37.05 ± 3.23), representing the best hardwood species for biomass production.

Evaluation of mechanical properties and potential environmental applications of biomimetic mineralized composites

With the growing emphasis on environmental protection, there has been extensive research on new green cementitious materials suitable for different conditions. This study focuses on the influence of key environmental factors on proposed biomimetic mineralized composites (BMC) using polyacrylic acid (PAA) as a modifier, based on the biomimetic chemistry induced carbonate precipitation (BCICP) method. The environmental factors examined include the cementing matrices type, the magnesium ions concentration, and the cementing solution pH. The samples treated under various conditions were evaluated for their unconfined compressive strength (UCS) and calcium carbonate content, and their microstructure was characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results demonstrate that the BMC treatment could achieve high-strength cementation for both Toyoura sand and Fujian quartz sand, with a more pronounced enhancement observed for Toyoura sand. Magnesium ions reduce the cementation effect, and they cannot fully replace calcium ions in participating in the cementation process. Moreover, the cementing solution pH significantly influences the cementation effect, with the best acid-base condition for PAA to modify BMC sand samples found at a pH of 11.5. Overall, the BMC exhibits high performance under various environmental conditions. These findings could provide valuable insights into the influence of environmental factors and the potential applications of BMC in diverse environments.

Mineral and fluid transformation of hydraulically fractured shale: case study of Caney Shale in Southern Oklahoma

This study explores the geochemical reactions that can cause permeability loss in hydraulically fractured reservoirs. The experiments involved the reaction of powdered-rock samples with produced brines in batch reactor system at temperature of 95 °C and atmospheric pressure for 7-days and 30-days respectively. Results show changes in mineralogy and chemistry of rock and fluid samples respectively, therefore confirming chemical reactions between the two during the experiments. The mineralogical changes of the rock included decreases of pyrite and feldspar content, whilst carbonate and illite content showed an initial stability and increase respectively before decreasing. Results from analyses of post-reaction fluids generally corroborate the results obtained from mineralogical analyses. Integrating the results obtained from both rocks and fluids reveal a complex trend of reactions between rock and fluid samples which is summarized as follows. Dissolution of pyrite by oxygenated fluid causes transient and localized acidity which triggers the dissolution of feldspar, carbonates, and other minerals susceptible to dissolution under acidic conditions. The dissolution of minerals releases high concentrations of ions, some of which subsequently precipitate secondary minerals. On the field scale, the formation of secondary minerals in the pores and flow paths of hydrocarbons can cause significant reduction in the permeability of the reservoir, which will culminate in rapid productivity decline. This study provides an understanding of the geochemical rock–fluid reactions that impact long term permeability of shale reservoirs.

The potential linkage between sediment oxygen demand and microbes and its contribution to the dissolved oxygen depletion in the Gan River

The role of sediment oxygen demand (SOD) in causing dissolved oxygen (DO) depletion is widely acknowledged, with previous studies mainly focusing on chemical and biological SOD separately. However, the relationship between the putative functions of sediment microbes and SOD, and their impact on DO depletion in overlying water, remains unclear. In this study, DO depletion was observed in the downstream of the Gan River during the summer. Sediments were sampled from three downstream sites (YZ, Down1, and Down2) and one upstream site (CK) as a control. Aquatic physicochemical parameters and SOD levels were measured, and microbial functions were inferred from taxonomic genes through analyses of the 16S rRNA gene. The results showed that DO depletion sites exhibited a higher SOD rate compared to CK. The microbial community structure was influenced by the spatial variation of Proteobacteria, Chloroflexi, and Bacteroidota, with total organic carbon (TOC) content acting as a significant environmental driver. A negative correlation was observed between microbial diversity and DO concentration (p < 0.05). Aerobic microbes were more abundant in DO depletion sites, particularly Proteobacteria. Microbes involved in various biogeochemical cycles, such as carbon (methane oxidation, methanotrophs, and methylotrophs), nitrogen (nitrification and denitrification), sulfur (sulfide and sulfur compound oxidation), and manganese cycles (manganese oxidation), exhibited higher abundance in DO depletion sites, except for the iron cycle (iron oxidation). These processes were negatively correlated with DO concentration and positively with SOD (p < 0.05). Overall, the results highlight that aerobic bacteria’s metabolic processes consume oxygen, increasing the SOD rate and contributing to DO depletion in the overlying water. Additionally, the study underscores the importance of targeting the removal of in situ microbial molecular mechanisms associated with toxic H2S and CH4 to support reoxygenation efforts in rehabilitating DO depletion sites in the Gan River, aiding in identifying factors controlling DO consumption and offering practical value for the river’s restoration and management.

Hydrocarbon Generation Potential and Organic Matter Enrichment Mechanism of the Cambrian Marine Shale in the Tadong Low Uplift, Tarim Basin

AbstractCambrian shales in China and elsewhere contain abundant oil and gas resources. However, due to its deep burial and limited outcrop, there has been relatively little research conducted on it. The Cambrian shale of the Tadong low uplift in the Tarim Basin of western China, specifically the Xidashan–Xishanbulake Formation (Fm.) and overlying Moheershan Fm. provide a case study through the use of organic petrology, mineralogy, organic and elemental geochemistry, with the aim of analyzing and exploring the hydrocarbon generation potential (PG) and organic matter (OM) enrichment mechanisms within these shale formations. The results indicate that: (1) the Cambrian shale of the Tadong low uplift exhibits relatively dispersed OM that consists of vitrinite‐like macerals and solid bitumen. These formations have a higher content of quartz and are primarily composed of silica‐based lithology; (2) shale samples from the Xidashan–Xishanbulake and Moheershan formations demonstrate high total organic carbon (TOC) and low S2 content. The OM is predominantly type I and type II kerogens, indicating a high level of maturation in the wet gas period. These shales have undergone extensive hydrocarbon generation, showing characteristics of relatively poor PG; (3) the sedimentary environments of the Xidashan–Xishanbulake and Moheershan formations in the Tadong low uplift are similar. They were deposited in warm and humid climatic conditions, in oxygen‐deficient environments, with stable terrigenous inputs, high paleoproductivity, high paleosalinity, weak water‐holding capacity, and no significant hydrothermal activity; and (4) the relationship between TOC and the paleoproductivity parameter (P/Ti) is most significant in the Lower Cambrian Xidashan–Xishanbulake Fm., whereas correlation with other indicators is not evident. This suggests a productivity‐driven OM enrichment model, where input of land‐derived material was relatively small during the Middle Cambrian, and the ancient water exhibited lower salinity. A comprehensive pattern was formed under the combined control of paleoproductivity and preservation conditions. This study provides valuable guidance for oil and gas exploration in the Tarim Basin.

Physical and Chemical Properties of Soil of Different Villages of District Solan, Himachal Pradesh, India

The research was conducted to assess the physical and chemical properties of soils from twenty-one villages of Solan district, Himachal Pradesh within its geographical coordinates ranging from the latitude 30°44’53” to 31°22’01” N and longitude 76°36’10” to 77°15’14” E, during 2023-2024, India. The villages represent diverse landforms, including contour farming, plains, and slopes. Soil samples were collected from two depths, 0-15 and 15-30 cm, and analysed them using standard laboratory protocols. The predominant soil texture was sandy loam, bulk density ranges from 1.22 to 1.39 Mg m-3, particle density from 2.42 to 2.67 Mg m-3, and percent pore space varied between 40.50% and 46.68%, while the percent water holding capacity ranges from 37.65% to 45.53%. Soil pH ranged from 6.61 to 7.47. Electrical conductivity was measured between 0.18 and 0.34 dS m-1, indicating non-saline conditions. Organic carbon content was medium 0.30% to high 0.61%. The available nitrogen content ranged from 232.68 to 279.64 Kg ha-1, available phosphorus from 37.23 to 64.54 Kg ha-1, and available potassium from 262.14 to 365.34 Kg ha-1. These findings provide valuable insights into the soil health of the region, with implications for agricultural practices and land management.

The Role of Plant-Mycorrhizal-Fungal Interactions in Soil Health and Carbon Sequestration in Agroecosystems

Abstract: Understanding the intricate interactions between plants, mycorrhizal fungi, and soil health is crucial for sustainable agriculture and climate change mitigation. This review synthesizes current research to elucidate the multifaceted role of plantmycorrhizal-fungal interactions in soil health and carbon sequestration in agroecosystems. A meta-analysis of 75 studies spanning diverse ecosystems and plant species reveals a significant positive correlation between mycorrhizal colonization and soil organic carbon content, with an average increase of 25% compared to non-mycorrhizal systems. Furthermore, mycorrhizal symbiosis enhances soil structure and aggregation, promoting water retention and nutrient cycling, which are essential for maintaining soil fertility and resilience to environmental stressors. The contributions of different mycorrhizal types (arbuscular, ectomycorrhizal, and ericoid) to soil carbon dynamics are also examined, highlighting their unique roles in carbon allocation and stabilization. Additionally, the review discusses the potential implications of plant-mycorrhizal-fungal interactions for mitigating greenhouse gas emissions through enhanced carbon sequestration in agricultural soils. Insights into the mechanisms underlying these interactions, including mycorrhizal-mediated changes in root exudates, microbial communities, and soil enzymatic activities, are discussed. Overall, this review underscores the importance of integrating mycorrhizal symbiosis into agroecosystem management practices to enhance soil health, carbon sequestration, and climate resilience.

The Role of Plant-Mycorrhizal-Fungal Interactions in Soil Health and Carbon Sequestration in Agroecosystems

Abstract: Understanding the intricate interactions between plants, mycorrhizal fungi, and soil health is crucial for sustainable agriculture and climate change mitigation. This review synthesizes current research to elucidate the multifaceted role of plantmycorrhizal-fungal interactions in soil health and carbon sequestration in agroecosystems. A meta-analysis of 75 studies spanning diverse ecosystems and plant species reveals a significant positive correlation between mycorrhizal colonization and soil organic carbon content, with an average increase of 25% compared to non-mycorrhizal systems. Furthermore, mycorrhizal symbiosis enhances soil structure and aggregation, promoting water retention and nutrient cycling, which are essential for maintaining soil fertility and resilience to environmental stressors. The contributions of different mycorrhizal types (arbuscular, ectomycorrhizal, and ericoid) to soil carbon dynamics are also examined, highlighting their unique roles in carbon allocation and stabilization. Additionally, the review discusses the potential implications of plant-mycorrhizal-fungal interactions for mitigating greenhouse gas emissions through enhanced carbon sequestration in agricultural soils. Insights into the mechanisms underlying these interactions, including mycorrhizal-mediated changes in root exudates, microbial communities, and soil enzymatic activities, are discussed. Overall, this review underscores the importance of integrating mycorrhizal symbiosis into agroecosystem management practices to enhance soil health, carbon sequestration, and climate resilience.

Soil Solution Properties of Tropical Soils and Brachiaria Growth as Affected by Humic Acid Concentration

The soil solution is the compartment where plants uptake nutrients and this phase is in equilibrium with the soil solid phase. Changes in nutrient content and availability in the soil solution can vary among soil types in response to humic acid concentrations, thereby affecting Brachiaria growth. However, there are no studies demonstrating these effects of humic acid application on different soil types and how they affect Brachiaria growth. Thus, the aim of this study was to evaluate the effects of humic acid concentrations (0, 5, 10, 25, and 60 mg kg−1 carbon-humic acid) on Brachiaria brizantha growth and soil solution properties of contrasting tropical soils. Plants were grown for 35 days in greenhouse conditions in pots containing Sandy Entisol, Clayey (Red Oxisol), and Medium Texture (Red-Yellow Oxisol). Soil solution was assessed for pH, electrical conductivity (EC), carbon, and nutrient content. Shoot and root dry matter, as well as macro and micronutrients accumulation in the shoot, were determined. In a soil type-dependent effect, pH, EC, and concentrations of nutrients in solutions changed in response to carbon-humic acid concentration. In the less-buffered soils, Sandy Entisol and Red-Yellow Oxisol, the addition of 30–40 mg kg−1 carbon-humic acid increased root proliferation by 76–89%, while Brachiaria biomass produced in all soils increased by approximately 30%. Levels of carbon in solution were high (>580 mg L−1) and varied depending on the investigated soil type. Though solution carbon contents did not appear to be a driving factor controlling the positive effects of humic acid concentrations on Brachiaria dry matter, there was a direct relationship between other properties and nutrient content in the soil solution, and Brachiaria dry matter production.

Correlative Effects on Nanoplastic Aggregation in Model Extracellular Biofilm Substances Investigated with Fluorescence Correlation Spectroscopy

Recent studies show that biofilm substances in contact with nanoplastics play an important role in the aggregation and sedimentation of nanoplastics. Consequences of these processes are changes in biofilm formation and stability and changes in the transport and fate of pollutants in the environment. Having a deeper understanding of the nanoplastics–biofilm interaction would help to evaluate the risks posed by uncontrolled nanoplastic pollution. These interactions are impacted by environmental changes due to climate change, such as, e.g., the acidification of surface waters. We apply fluorescence correlation spectroscopy (FCS) to investigate the pH-dependent aggregation tendency of non-functionalized polystyrene (PS) nanoparticles (NPs) due to intermolecular forces with model extracellular biofilm substances. Our biofilm model consists of bovine serum albumin (BSA), which serves as a representative for globular proteins, and the polysaccharide alginate, which is a main component in many biofilms, in solutions containing Na+ with an ionic strength being realistic for fresh-water conditions. Biomolecule concentrations ranging from 0.5 g/L up to at maximum 21 g/L are considered. We use non-functionalized PS NPs as representative for mostly negatively charged nanoplastics. BSA promotes NP aggregation through adsorption onto the NPs and BSA-mediated bridging. In BSA–alginate mixtures, the alginate hampers this interaction, most likely due to alginate–BSA complex formation. In most BSA–alginate mixtures as in alginate alone, NP aggregation is predominantly driven by weaker, pH-independent depletion forces. The stabilizing effect of alginate is only weakened at high BSA contents, when the electrostatic BSA–BSA attraction is not sufficiently screened by the alginate. This study clearly shows that it is crucial to consider correlative effects between multiple biofilm components to better understand the NP aggregation in the presence of complex biofilm substances. Single-component biofilm model systems based on comparing the total organic carbon (TOC) content of the extracellular biofilm substances, as usually considered, would have led to a misjudgment of the stability towards aggregation.

Physical modeling of two-phase liquid–gas processes occurring in the refining ladle for Fe–Si alloy refining process

The article presents the results of research carried out using a water model of a refining ladle for the Fe–Si ferroalloys treatment. These studies were aimed at improving the efficiency of refining and homogenization of liquid Fe–Si ferroalloy in the refining ladle by using a new method of blowing gas through a system of nozzles installed at the bottom of the ladle. The obtained results allowed to determine the proper location of the plug at the bottom of the refining ladle and the possibility of using combined blowing. The tests were carried out for a refining ladle with a capacity of 3 m3 using a physical model on a linear scale of 1:3. The gas flow rate used in the model corresponded proportionally to the value previously used in industrial practice and amounted to 26.8 l/min. Experiments were performed for both combined blowing applications and through a purging plug at the bottom of the ladle. In the case of combined blowing, the volume of the gas stream was divided into two blowing sources (lance and purging plug). As a result of laboratory tests, one of the variants was selected and tested in industrial conditions. These studies confirmed the improvement in the efficiency of refining treatment of the FeSi alloy in terms of reducing the carbon and aluminum content in the alloy.x

Comparison of cooling tower blowdown and enhanced make up water treatment to minimize cooling water footprint

When water supply restrictions increasingly escalate to water supply risks, developing strategies to minimize the water footprint of wet cooling systems becomes crucial. This study compares two water engineering approaches to minimize the water footprint of a recirculating evaporative cooling tower (CT): (1) reusing cooling tower blowdown and (2) producing demineralized water to increase the cycles of concentration (CoC) of the CT.Our techno-economic analysis across various scenarios and CT settings reveals that reusing blowdown (option 1) is the most feasible approach for an industrial cooling system currently operating at CoCs of > 3, discharging blowdown with a conductivity of 2 mS/cm and a total organic carbon (TOC) concentration of approximately 20 mg/L. Compared to enhanced make up treatment, blowdown reuse allows higher water savings (13 %) and involves lower implementation and operation costs.Pilot scale trials validated the feasibility of both approaches. Blowdown and enhanced make up treatment included biologically activated carbon filtration, ultrafiltration and reverse osmosis, producing high-quality permeate, suitable for (re)use as CT make up or within other processes. The blowdown treatment reached a product quality of 80 μS/cm conductivity and 70 μg/L TOC, make up treatment 20 μS/cm in conductivity and 60 μg/L TOC, respectively.The study's findings underscore the viability of blowdown reuse as a cost-effective and efficient strategy to minimize the water footprint of cooling systems under increasing water scarcity conditions.

Production of biodiesel from palm kernel oil through base-catalyzed trans-esterification process

Growing concerns about environmental problems associated with fuels have engineered so much research into biofuels, such as biodiesel. However, continuous and large-scale production of biodiesel from edible oil could result in serious food security problems if cheap and viable alternatives are not made available. To solve this problem, oil was obtained from non-food/ underutilized seeds of palm kernel using Soxhlet apparatus. Physicochemical properties and fatty acids composition of these oils were determined using standard analytical and instrumental methods. Biodiesel was processed from these oils via sequential base (KOH) homogeneous catalysis. Fuel properties of biodiesel from the oil were determined using standard methods and the results obtained were compared with standards. Oil yields were found to be 37.6% for palm kernel seed respectively. Physicochemical properties of palm kernel oil respectively are: saponification value:(115.00)mg KOH/g, acid value(4.488)mgKOH/g, free fatty acid value (2.244)mg/KOH/viscosity:(29)mm2/s, moisture content: (0.46)%, peroxide value:(3.12)meqkg-1,refractive index:(1.455), specific gravity (0.899)g/cm. Fuel properties of biodiesel from palm kernel seed oil respectively are: Kinematic viscosity at 40oc: (nil) mm2/s, smoke point (100oc), flash point(90oc),fire point:(150oc),pour point(nil) and cloud point:(nil).The physicochemical properties of the biodiesel produced showed that the flash point, viscosity, density, ash content, percentage carbon content, specific gravity and the acid value fell within American Society for Testing and Materials (ASTM) specifications for biodiesel. Therefore, the biodiesel produced from the oil significantly met standard quality requirements.

Impact of moisture on the degradation and priming effects of poly(lactic acid) microplastic

AbstractThe degradation of biodegradable microplastics (MPs) can either stimulate or inhibit the decomposition of soil organic carbon (SOC), but the factors influencing these phenomena remain unclear. In this study, we used the 13C natural abundance to differentiate between carbon dioxide (CO2) arising from the mineralization of SOC and poly(lactic acid) (PLA) MP under varying soil water holding capacity (WHC) in alkaline and acidic soils. We also quantified the incorporation of soil‐ or PLA‐derived carbon (C) into phospholipid fatty acid (PLFA)‐distinguishable microbial groups. An increase in soil moisture did not significantly affect PLA MP degradation in alkaline soil, but significantly increased PLA degradability in acidic soil. In particular, the percentages of PLA‐derived C incorporated into PLFA‐distinguishable gram‐negative and gram‐positive bacteria were 14%–63% and 5%–33%, respectively, in all the treatments. The presence of PLA MP induced positive priming effects from 0 to 20 d in all the treatments but subsequently induced negative priming effects under some conditions. The total priming effects induced by PLA MP were significantly greater in alkaline soil with ≥70% WHC (37–43 mg C kg−1 soil) than in this soil with 50% WHC (8.6 mg C kg−1 soil). The total priming effect was 72–78 mg C kg−1 soil in acidic soil with ≤70% WHC, but a negative priming effect was observed in this soil with 90% WHC (−56 mg C kg−1 soil). In alkaline soil, the dissolved organic carbon content was positively correlated with the priming effect, but a negative relationship was observed between the priming effect and the amount of soil‐derived C incorporated into gram‐negative bacteria and fungi. In acidic soil, a positive correlation was found between the priming effect and the soil nitrate content. In summary, our findings indicate that 0.4%–2.8% of PLA MP was degraded in soils after 2 months, and that the intensity and direction of the priming effect induced by PLA MP are regulated by soil moisture and pH, but further exploration is needed to elucidate the microbial mechanisms underlying these effects.

Effect of biochar and iron ore tailing waste amendments on cadmium bioavailability in a soil and peanut seedling system.

Biochar and iron ore tailing waste have been widely separately applied for remediation of various contaminants, but the remediation effect of their combination on cadmium (Cd) pollution is unclear. In this study, the peanut biochar (BC), thermally activated iron ore tailing waste (TS), and the products of the co-pyrolysis of peanut shell and iron ore tailing waste (TSBC) were prepared for stabilizing Cd and reducing its bio-accessibility in soil and peanut seedling system. Present amendments enhanced soil pH, cation exchange capacity, electrical conductivity, and organic carbon content. The application of BC, TS, and TSBC led to decreases in acid-extractable Cd proportion of 2.2-8.81%, 2.43-7.20%, and 7.84-11.57%, respectively, and increases in the residual Cd proportion of 3.48-8.33%, 3.27-11.50%, and 9.02-13.45%, respectively. There were no significant differences in Cd accumulation in peanut roots due to three amendments treatments, especially at low Cd concentrations (i.e., Cd concentration of 0, 1, and 2mg·kg-1), and with a relatively small reduction (2.16-9.05%) in root Cd accumulation under the high Cd treatments of 5 and 10mg·kg-1. The Cd concentrations in seedling roots were significantly positively related to the acid-extractable Cd fraction, with a Pearson correlation coefficient of r = 0.999. The maximum toxicity mitigating effects were found in TSBC treatment, with increases in the ranges of 9.80-17.58% for fresh weight, 5.59-14.99% for dry weight, 5.16-10.17% for plant height, 5.96-10.34% for root length, 5.43-21.67% for chlorophyll a content, 17.17-71.28% for chlorophyll b content, and 13.11-39.60% for carotenoid content in peanut seedlings. Therefore, TSBC is a promising amendment for minimizing Cd contamination in peanut crops and utilizing industrial solid waste materials efficiently.

A bio‐based reactive P/N synergistic flame retardant for improving the fire safety and mechanical properties of epoxy resin

AbstractA high‐efficiency bio‐based P/N synergistic flame retardant (PVFD) is synthesized by combining furfurylamine and vanillin. The compound incorporates two different valence states of phosphorus as flame retardant structures, namely phenylphosphoryl dichloride (PPDC) and 9,10‐dihydro‐9‐oxa‐10‐ phosphophenyl‐10‐oxide (DOPO). PVFD and epoxy resin (EP) can cure into a cross‐linked network, thus not only improving the mechanical properties of EP but also achieving P/N synergistic flame retardant effects. Experimental results demonstrate that EP/PVFD‐5 obtained by adding 5 wt% of PVFD to EP passes the UL‐94 test and achieves V‐0 grade, whose limiting oxygen index (LOI) is up to 38.0%. EP/PVFD‐5 exhibits a decrease of 10.14% in peak heat release rate (PHRR), 16.90% in total heat release (THR), and 10.0% in total smoke release (TSP), while the residual carbon content increases by 8.5%. Additionally, the bending strength, bending modulus, tensile strength, and elongation at break of EP/PVFD‐5 increase by 3.9%, 4.9%, 45.1%, and 26.3%, respectively.Highlights The bio‐based raw materials we used are eco‐friendly and readily available. PVFD, an efficient P‐N synergistic compound, was synthesized. PVFD promotes the char formation of EP and dilutes the O2 concentration. PVFD does not cause the degradation of mechanical properties of EP.

Impact of mustard biodiesel and clove oil additives on particulate matter emission and carbon deposition in diesel engines

Recent studies suggest that the world is facing an energy crisis due to the depletion of fossil fuel reserves. To combat this issue, researchers have turned to biodiesel, a renewable bioenergy source made from vegetable oils, microalgae, and animal fats. A recent study analysed engine parts’ particulate matter emissions and carbon deposition during the long-term use of mustard biodiesel and clove oil as antioxidants in a compression ignition engine. Three samples of fuels: DF (diesel fuel), B30 (30% mustard biodiesel and 70% DF), and biodiesel blended fuel with 3000 PPM in a single-cylinder CI engine. The use of 30% biodiesel in diesel fuel (B30) for the endurance test was based on a good mix. The engine was run for 100 h to investigate the particulate matter emissions and carbon deposition. The particulate matter emission data was collected every 25 h, and for carbon deposition, the engine’s fuel injector was turned off after 100 h of engine running. The results showed a reduction in particulate matter emissions of about 9.97%, 13.367%, 7.24%, 14.64%, 5.3%, 12.32%, 1.88%, and 7.99% for PM1, PM2.5, PM7, and PM10 in biodiesel blended fuel and biodiesel blended fuel with clove oil, respectively. The deposition of clove oil added to biodiesel blended fuel in the fuel injector has been reduced compared with the other fuels. Carbon deposition of the fuel injector was analysed through SEM and EDX tests, and the results showed that the carbon content in biodiesel blended fuel was lower than in diesel fuel. The deposition of clove oil added to biodiesel blended fuel in the fuel injector has been reduced compared with biodiesel blended fuel.

Castor Bean Meal Fertilizer Improves Peanut Yield and Quality by Regulating the Soil Physicochemical Environment and Soil Enzyme Activities

Abstract Purpose Fertilization is important for improving crop yield and soil quality. Elucidation of the effects of castor bean meal (CBM) fertilizer on peanut yield and quality and soil fertility can lead to additional fertilization options for peanut and provide a theoretical reference for achieving a high-quality, high-yielding peanut. Methods During 2022–2023, a two-year long-term field experiment was conducted in Tongliao city, Inner Mongolia, China. No fertilizer (CK) was used as the control, and the effects of different treatments, i.e., CBM fertilizer (B1: 2520 kg ha-1, B2: 5040 kg ha-1, and B3: 10,080 kg ha-1), chemical fertilizer alone (F1: 175 kg ha-1, F2: 350 kg ha-1, and F3: 700 kg ha-1), and cow manure alone (N1: 3724 kg ha-1, N2: 7448 kg ha-1, and N3: 14,896 kg ha-1) on peanut yield and quality and soil fertility were investigated. Results The results showed that CBM fertilizer application improved soil ecology. Compared with other fertilization treatments, the soil pH of B3 treatment decreased by 8.5%, but significantly increased the contents of organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), alkali-hydrolyzed nitrogen (AN), basic phosphorus (AP) and rapidly available potassium (AK) in the soil, which increased by 86.4%, 64.6%, 70.5%, 11.3%, 75.8%, 150.1%, and 116.2%, respectively, compared with CK. Meanwhile, B1, B2, N1 and N2 treatments also led to the elevation of the above indexes. In addition, the activities of urease (URE), sucrase (SUC), phosphatase (PPL), catalase (CAT), amylase (AMY) and protease (PRO) in the B3 treatment were significantly greater than those in the other fertilization treatments, with increases of 256.4%, 248.4%, 68.2%, 96.8%, 267.3%, and 155.7%, respectively, compared with CK. The B3 treatment also significantly increased the rootlet length(PRL), number of branches(BN), plant height(PLH) and lateral branch length(LBL) of the peanut plants. Compared with the other treatments, the B3 treatment had a greater peanut yields, reaching 8059.5 kg ha-1 and 9935.7 kg ha-1 in 2022 and 2023, respectively. Compared with the other treatments, the B1 treatment significantly increased the contents of protein (Pro), fat (FAT), unsaturated fatty acid (UFA) and vitamin E (VE), which increased by 23.3%, 6.1%, 1.0%, 29.1%, respectively, compared with CK, but the total sugar (TS) content was reduced by 9.1%. Correlation analysis further confirmed that peanut yield and quality were significantly correlated with soil nutrients and enzyme activities. Conclusions This study showed that the application of CBM fertilizer has certain positive effects. For example, the B3 treatment has certain potential for increasing peanut yield, and the B1 treatment can be used for peanut quality improvement. Therefore, CBM fertilizer is recommended as a new type of organic fertilizer for improving the peanut quality and yield.

Evaluation of Seasonal Reservoir Water Treatment Processes in Southwest Florida: Protection of the Caloosahatchee River Estuary

In southwest Florida, the Caloosahatchee River flows from Lake Okeechobee into a biologically productive tidal estuarine system. A combination of excess water during the wet season, insufficient fresh water in the dry season, and poor quality of the river water are damaging the estuarine ecosystem. To better control the quality and quantity of the water entering the estuary, reservoirs are being constructed to store excess, poor quality water during the wet season and return it to the river for discharge into the estuary at an appropriate time. This stored water is enriched in nutrients and organic carbon. Because of the subtropical nature of the climate in southwest Florida and potential increases in temperature in the future, the return flow of water from the reservoirs must be treated before it can be returned to the river. Hence, an experimental water treatment system was developed and operated to compare biological treatment processes consisting of solely wetland plants versus adding some engineered processes, including slow sand filtration and a combination of slow sand filtration and ultraviolet (UV) treatment. These three treatment trains were operated and monitored through a seasonal cycle in 2021–2022. All three treatment methods significantly reduced the concentrations of nutrients and total organic carbon. While the enhanced engineered wetlands’ treatment trains did slightly outperform the wetland train, a comparison of the three process trains showed no statistically significant difference. It was concluded that upscaling of the slow sand filtration and UV process could improve the treatment efficiency, but this change would have to be evaluated within a framework of long-term economic benefits. It was also concluded that the Caloosahatchee River water quality is quite enriched in nutrients so that reservoir storage would increase the organic carbon concentrations, making it imperative that it be treated before being returned to the river. It was also discovered that the green alga Cladophora sp. grew rapidly in the biological treatment tubs and will present a significant challenge for the treatment of the reservoir discharge water using the currently proposed alum treatment.