Rate Of CO2 Release Research Articles

Co Hybrids modified piperazine pyrophosphate towards efficient flame retardancy, smoke suppression, and high mechanical properties of styrenic thermoplastic elastomer

The highly flammable nature of thermoplastic elastomers (TPE) results in poor fire safety performance. The large addition of flame retardants leads to a significant decrease in mechanical properties. To solve above challenges, we design a multilayer core-shell flame retardant, piperazine pyrophosphate@ tannic acid@ Co amorphous hybrids (PAPP@TA@Co-2-MIM) and add it to TPE to enhance the fire safety and mechanical performance simultaneously. It was found that the addition of 32 wt% PAPP@TA@Co-2-MIM achieved a UL-94 V-0 rating of TPE composites, with a limiting oxygen index of 27 %. Compared to pure TPE, the peak heat release rate, total heat release, total smoke production, and peak CO release rate of TPE/PAPP@TA@Co-2-MIM were reduced by 79.8 %, 37.1 %, 42.9 %, and 82.5 %, respectively, effectively suppressing the release of heat, smoke, and toxic gases. Besides, the flame-retardant mechanism was also explained. In terms of mechanical performance, benefiting by the bridging effect of the core-shell structure, the tensile strength of TPE/PAPP@TA@Co-2-MIM increased by 52.7 %, compared to TPE/PAPP. This study designed a TPE composite material that showed good thermal stability, high fire safety performance and enhanced mechanical properties.

Fabricated ZnIn2S4/Cu2S S-scheme heterojunction with snowflake structure for boosting photocatalytic CO2 reduction in gas–solid reactor

Designing S-scheme heterojunctions has become a powerful strategy to enhance photocatalytic activity and improve the localization of catalyst surface charge. Therefore, more and more research has been devoted to S-scheme heterojunctions. In this work, we employed a simple two-step hydrothermal method to fabricate S-scheme ZnIn2S4/Cu2S (ZIS/Cu2S) heterojunctions. The results show that the composites exhibit good performance in the photoreduction of CO2 to CO and CH4. Especially, at 40 %-ZIS/Cu2S, the release rates of CO and CH4 were 13.35 μmol g−1 and 34.81 μmol g−1 under the condition of a 4 h reaction, and the selectivity of CH4 reached 80 %. In addition, the in situ FTIR test revealed that the catalyst promoted the formation of the key intermediates COOH* and CH3O* under the effect of light interaction, which was favorable to the photoreduction of CO2. This indicates that the electron transfer path of S-type not only promotes the separation of carriers for conversion but also has a strong redox ability to selectively convert CO2 to CH4, which provides some thoughts for the design of S-scheme heterojunction photocatalysts. This provides some thoughts for the design of S-scheme heterojunction photocatalysts.

Magnetic, self-heating and superhydrophobic sponge decorated with BN and CoFe2O4 for high-efficient cleanup of crude oil spills using facile co-precipitation strategy

Accidents involving petrochemical spills have repeatedly threatened the security of the eco-environment. The leaked crude oil exhibits poor fluidity, low adsorption efficiency, and urgent issues such as potential fire risks that require immediate attention. Herein, a multifunctional superhydrophobic sponge Si@CFO@BN@PU was prepared by a simple co-precipitation strategy based on BN and CoFe2O4. The results demonstrate that Si@CFO@BN@PU exhibits excellent superhydrophobic properties, with a water contact angle of 162° and a slide angle of less than 10°, and oil adsorption capacity ranging from 32.3 to 68.4 g/g. Furthermore, the modified sponge also possesses certain magnetic properties, allowing Si@CFO@BN@PU to be moved on the water surface via an external magnetic field and effectively adsorb floating oil. Meanwhile, the modified sponge exhibits excellent photothermal properties. The whole sponge can be heated up to 80 °C in just 60 s under simulated sunlight conditions, effectively reducing the adsorption time of viscous oil by 90 %. Moreover, the cone calorimeter test results demonstrate excellent fire safety of Si@CFO@BN@PU even after adsorption of petroleum. The peak heat release rate (pHRR), total heat release (TSR), maximum CO release rate, and maximum CO2 release rate have decreased by 37.8 %, 23.3 %, 45.4 %, and 34.1 %, respectively. Therefore, Si@CFO@BN@PU is an effective, safe and sustainable new adsorbent material with a wide range of applications in treating petrochemical spills.

Construction of MXene-based flame retardant with multiple carbonization towards for reducing fire hazard and smoke release of epoxy resin

MXene is a promising flame retardant for composites. Currently, how to construct modified MXene nanomaterials with high flame-retardant efficiency is a challenge. In this work, a functionalized MXene-based flame retardant (MXene-AP-Cu) was synthesized by grafting phytic acid copper complex onto the surface of MXene, and was utilized to prepare high performance epoxy resin (EP) composites. Only 2 wt% MXene-AP-Cu increased limited oxygen index (LOI) of EP to 29.7% from 21%, with an enhancement of 41.4%. In addition, EP/2% MXene-AP-Cu presented excellent suppression effect on the release of heat, smoke and CO, as reflected by a 40%, 18%, 25.3% and 33.3% decreases in peak of heat release rate (PHRR), total heat release (THR), total smoke product (TSP) and peak of CO release rate, respectively, compared to EP. The multiple carbonization of MXene-AP-Cu, including lamellar barrier effect, catalytic carbonization of MXene and copper irons, dehydration and carbonization of phytic acid, contributed to better flame retardancy. Besides, the impact strength of EP/MXene-AP-Cu was increased to a certain extent, compared to EP.

Construction of three-coordinated (N3C) nitrogen vacancies in g-C3N4 for efficient photocatalytic CO2 reduction

Defect engineering has been widely applied in the field of photocatalysis, and defects can be used to modify the surface structure and photoelectric properties of catalysts so as to achieve the purpose of regulating the activity and stability of catalysts. However, design of a highly efficient photocatalyst with abundant defects remains a challenging task in current research. Therefore, in this study, graphitic carbon nitride (g-C3N4) with abundant three-coordinated nitrogen (N3C) vacancies and pore structures was obtained using a facile hydrothermal method with the assistance of glycerol. Under visible light (λ > 420 nm) irradiation, the 50CN (volume ratio of glycerol/water is 50/10) catalyst exhibits a superior CO release rate (4.18 μmol g−1 h−1), which is 12.06 times higher than the reference GCN (0.32 μmol g−1 h−1), and the corresponding apparent quantum yields (AQY) of 50CN is 0.24 %, which is significantly higher than that of GCN (0.045 %). Successful introduction of N3C vacancies is conducive to broaden light response range of the catalyst, enhancing the separation and migration efficiency of photogenerated charges, and providing more adsorption active sites to promote the adsorption and activation of CO2 molecules, thus effectively boosting photocatalytic CO2 reduction activity. In addition, the N3C vacancies can effectively lower the CO2 activation energy barrier and reduce the energy consumption required for the reaction. This work offers valuable new insights into defect engineering in g-C3N4 for the development of high-performance photocatalysts for CO2 reduction.

Development of multiple alkali metals doped La-Ni based perovskites for CO2 gasification of biochar to produce CO rich syngas

Under the background of carbon neutrality, there is an urgent need for the production of high-valued syngas from renewable carbon resources. This work focused on the evaluation of multiple alkali metals doping on the catalytic activity of La-Ni based perovskite catalysts in CO2 gasification of biochar. The structure and property evolution of samples were analyzed by XRD, SEM, TEM, XPS, Raman spectra, CO2-TPD, etc. The experiment results found that Li+ exhibited a stronger catalytic gasification promotion effect than K+ and Na+, owing to the high mobility of the smallest radius ions in the lattice. Among the samples, La0.4K0.2Na0.2Li0.2NiO3 possessed the best catalytic performance with the maximum release rates of CO of 116.76 mL min−1·g−1 and 3.25 times in reactivity indexes in contrast to the LaNiO3. Correspondingly, it also showed significant resistance to ash in the cycle gasification experiments. Deep substitution with multiple alkali metals at A-site produced more active oxygen species ([O]) on the oxygen vacancies (Ov) and increased the proportion of Ni3+ of the La0.4K0.2Na0.2Li0.2NiO3, resulting in excellent catalytic CO2 gasification capacity. Furthermore, the adsorption and activation capacity of CO2 were also enhanced by the surface basic active sites generated by alkali metals substitution. Based on the experiments and characterization results, the redox recycling between Ni2+−Ov and Ni3+−[O] were proposed as the main reaction mechanisms for CO2 gasification of biochar. This study provides a valuable exploration for the complex substitution of perovskite catalysts and high-efficiency CO2 gasification of biochar.

High anti-ablative epoxy resin-based flame retardant and thermal insulation coating based on spontaneous Ceramization and vitrification

In order to improve the burn-through resistance and environmental friendliness of epoxy resin-based flame-retardant coatings, high-performance coatings were developed by modifying them with silicone resin and B4C. By incorporating B4C and silicone resin, the coating's thermal stability was significantly enhanced. By participating in a series of chemical reactions when the coating was exposed to fire, they promoted spontaneous ceramicized and vitrified modification, increased the mass of char residue, improved the surface compactness, optimized the foam structure, and improved the specific surface area of char residue. Compared to blank sample E10S0 and others, E85S15B3 coating co-modified with silicone resin and B4C showed the best performance. The backside temperature of E85S15B3 was only 164.34 °C after a 2 h combustion test. The peak heat release rate (PHRR), total heat release rate (THR), total smoke production (TSP), peak smoke production rate (PSPR), peak CO release rate (PCOPR), and peak CO2 release rate (PCO2PR) of E85S15B3 were all significantly improved, with a decrease of 20.38 %, 40.06 %, 37.67 %, 49.21 %, 64.71 %, 0.03 % compared with that of E10S0 sample. The LOI value was 34.6 %, which was 48.24 % better than that of E10S0. Moreover, the compressive, tensile, and bending strengths of E85S15B3 were measured at 85.6 MPa, 25.6 MPa, and 45.3 MPa, respectively, marking a 22.1 % increase, 11.23 % increase, and 23.19 % increase over those of E10S0. The mechanism of flame-retardant includes cooling insulation, non-flammable gas-phase dilution flame retardancy, condensed phase physical insulation, reinforced-phase flame retardancy, and free radicals capturing to block combustion.

Effects of Land-Use Type and Salinity on Soil Carbon Mineralization in Coastal Areas of Northern Jiangsu Province

Sea level rise due to glacier melting caused by climate warming is a major global challenge, but the mechanism of the effect of salinity on soil carbon (C) mineralization in different land types is not clear. The pathways by which salinity indirectly affects soil carbon mineralization rates need to be investigated. Whether or not the response mode is consistent among different land-use types, as well as the intrinsic links and interactions between soil microbial resource limitation, environmental stress, microbial extracellular enzyme activity, and soil carbon mineralization, remain to be demonstrated. In this paper, three typical land-use types (wetland, forest, and agroforestry) were selected, and different salinity levels (0‰, 3‰, 6‰, and 32‰) were designed to conduct a 125-day laboratory incubation experiment to determine the soil CO2 release rate, soil physicochemical properties, and soil enzyme activities, and to correlate C mineralization with biotic and abiotic factors. A correlation analysis of soil physical and chemical properties, extracellular enzyme activities, and carbon mineralization rates was conducted to investigate their intrinsic linkages, and a multiple linear regression of C mineralization at different sites was performed to explore the variability of mineralization among different site types. Structural equation models were established in the pre- and post-incubation stages to study the pathways of soil C mineralization at different incubation times, and the mechanism of mineralization was further verified by enzyme stoichiometry. The results showed that, at the end of 125 days of incubation, the 32‰ salinity addition reduced the cumulative mineralization of forest and agroforestry types by 28.41% and 34.35%, respectively, compared to the 0‰ salinity addition. Soil C mineralization in the three different land-use types was highly correlated with the active C fractions of readily oxidizable C (ROC), dissolved organic C, and microbial biomass C (MBC) in the soil, with the standardized coefficients of multivariate linear regression reaching 0.67 for MBC in the wetland and −0.843 for ROC in the forest. Under long-term salinity additions, increased salinity would reduce the microbial respiratory quotient value by inhibiting β-glucosidase activity, thus indirectly affecting the rate of CO2 release. With added salinity, the mineralization of non-saline soil was more susceptible to the inhibitory effect of salinity, whereas the mineralization of salinized soil was more controlled by soil C pools.

Spatial and temporal patterns of fuelwood consumption and its associated CO2 emissions in Muzaffarabad division, a western Himalayan region

BackgroundIn the Himalayan region, fuelwood serves as a critical energy source for rural communities. Being vital for meeting energy needs, fuelwood combustion is a source of carbon dioxide (CO2) emission and, consequently, global warming, as well as deforestation and public health damage. Therefore, quantifying fuelwood consumption patterns and its associated CO2 emissions is essential to understand the environmental impact and promote sustainable resource management.MethodsThis research conducts an evaluation of fuelwood burning patterns and the associated CO2 emissions in Azad Jammu and Kashmir (AJK), situated within the western Himalayan region. The study entails an extensive survey of 24 villages representing 240 households, equally distributed between the subtropical and temperate regions, each comprising 120 households. Data collection was executed through a combination of direct queries and the weight survey method, following standard protocols.ResultsIn the study area, the mean annual fuelwood comsumption per household amounts to 24.28 ± 3.1 Mg (or 3.195 ± 1 Mg capita−1). A variance was observed between subtropical and temperate zones, with the latter exhibiting higher consumption rates. The consequential CO2 emissions were assessed as 41.88 ± 4.5 Mg per household (5.51 ± 0.6 Mg capita−1). On a daily basis, households consumed an average of 66.52 ± 6.4 kg of fuelwood (8.75 ± 1.5 kg capita−1), resulting in a daily CO2 release rate of 114.745 ± 8.6 kg (15.095 ± 2 kg capita−1). The findings unveiled seasonal variations, indicating increased fuelwood consumption and emissions during the winter season. Statistical analysis shed light on the significance of altitude and family size in shaping the patterns of fuelwood use.ConclusionsThe results revealed the importance of prioritizing forest conservation and strategically implementing sustainable practices, including reforestation, afforestation, responsible harvesting, and actively promoting sustainable fuel sources. This research highlights the vital role of well-designed policies focused on preserving ecosystems and improving energy management. Policy intervention can ensure the sustainable stewardship of local and regional forest resources.

Vegetation Loss Following Vertical Drowning of Mississippi River Deltaic Wetlands Leads to Faster Microbial Decomposition and Decreases in Soil Carbon

AbstractWetland ecosystems hold nearly a third of the global soil carbon pool, but as wetlands rapidly disappear the fate of this stored soil carbon is unclear. The aim of this study was to quantify and then link potential rates of microbial decomposition after vertical drowning of vegetated tidal marshes in coastal Louisiana to known drivers of anaerobic decomposition altered by vegetation loss. Profiles of potential CH4 and CO2 production (surface to 60 cm deep) were measured during anaerobic incubations, organic matter chemistry was assessed with infrared spectroscopy, and soil porewater nutrients and redox potentials were measured in the field along a chronosequence of wetland loss. After vertical drowning, pond soils had lower redox potentials, higher pH values, lower soil carbon and nitrogen concentrations, lower lignin: polysaccharide ratios, more NH4+ and PO43−, and higher rates of potential CO2 release than vegetated marsh soils. Potential CH4 production was similar in vegetated marshes and open water ponds, with depth‐dependent decreases in CH4 production as soil carbon concentrations increased. In these anoxic soils, vegetation loss exerts a primary control on decomposition rates because flooding drives sustained increases in porewater nutrient availability (NH4+ and PO43, dissolved organic carbon) and decreases in redox potential (from −150 to −500 mV) that lead to higher potential CO2 fluxes within a few years. Without new carbon inputs following wetland loss, the sustained decomposition in open water ponds may lead to losses of stored soil carbon and could influence global carbon budgets.

Eco-friendly preparation of advanced epoxy composites and their pyrolysis and flame retardant mechanisms

Traditional additive flame retardants pose issues including high dosage, easy precipitation, and poor compatibility with the matrix. Designing efficient organic-inorganic synergistic flame retardants can enhance the flame retardancy and mechanical properties of epoxy (EP) composites while reducing their smoke toxicity. In our study, we initially employed Tetrakis(hydroxymethyl)phosphonium sulfate (THPS) for intercalation modification of montmorillonite (MMT). Subsequently, we achieved a green and efficient exfoliation of MMT by reacting urea with hydroxyl groups, resulting in the simultaneous preparation of efficient organic/inorganic synergistic flame retardants (THPSU-MMT). EP composites containing 5wt% THPSU-MMT can attain UL-94 V0 classification. Furthermore, the peak heat release rate (PHRR), total heat release (THR), and peak release rates of CO can be reduced by up to 78.42 %, 62.26 %, and 72.50 %, respectively. Simultaneously, we systematically investigated the synergistic flame retardant mechanism of the EP composite. The findings reveal that THPSU-MMT exhibits a dual flame retardant effect in both the gaseous and condensed phases. Moreover, the combination of MMT and THPSU substantially enhances the presence of phosphorus-containing pyrolysis products in the condensed phase. The fire performance index (FPI) of the flame retardant EP increased from 0.05 m2/s/W in pure EP to 0.36 m2/s/W, attributed to the enhanced catalytic carbonization and assisted gas-phase free radical capture. Additionally, the flame spread index (FGI) decreased from 11.55 kW/m/s in pure EP to 1.18 kW/m/s, signifying a substantial enhancement in fire safety. Furthermore, the THPSU-MMT synergistic flame retardants improved the tensile strength of EP composites. This study offers an environmentally friendly and efficient approach for the effective exfoliation of MMT, while also presenting novel concepts for the design of efficient organic-inorganic synergistic flame retardants.

Responses of labile organic carbon fractions and mineralized carbon to straw return combined with fertilizer application in the maize–Melilotus officinalis intercropping system

AbstractMollisol is crucial for solving food security issues, but long‐term excessive application of chemical fertilizers has led to severe Mollisol degradation in Northeast China, especially a rapid decline in soil organic carbon (SOC). In context of the use of crop‐herbage intercropping and straw return as alternatives for some chemical fertilizers, it is important to understand how crop‐herbage intercropping and straw return combined with chemical fertilizers influence labile organic carbon (LOC) fractions that improve SOC. To address this, this study explored how the combined application of maize (Zea mays L.)–Melilotus officinalis intercropping, straw return, and chemical fertilizers affect LOC fractions and mineralized carbon (MC) from the perspective of physical property‐mediated pathways. Thus, a field experiment with six treatments was established in the Songnen Plain of Northeast China: (1) maize monoculture without chemical fertilizers and straw return (CK), (2) maize monoculture with chemical fertilizers and no straw return (CF), (3) maize monoculture with chemical fertilizers and straw return (CFS), (4) maize–M. officinalis intercropping and straw return combined with full application of chemical fertilizers (CFSM), (5) maize–M. officinalis intercropping and straw return combined with half application of chemical fertilizers (1/2CFSM), and (6) maize–M. officinalis intercropping and straw return without chemical fertilizers (SM). The CF and CFS groups had no effect on bulk density and porosity but reduced specific gravity. The CFSM group increased water contents, porosity, LOC fractions, SOC, MC, and CO2 release rate and decreased bulk density and specific gravity. Compared with the CF group, the 1/2CFSM group enhanced water contents, microbial biomass carbon, and water‐soluble organic carbon (WSOC) to 6.36%, 17.91%, and 11.6%, respectively. We found that maize–M. officinalis intercropping, straw return, and reducing chemical fertilizers application improved LOC fractions to increase SOC by positively affecting bulk density, specific gravity, and water contents. Further analysis indicated that WSOC was a key determinant of SOC and maize yields. These findings provide a strategy to increase SOC and rehabilitate degraded soils through crop‐herbage intercropping and straw return combined with reducing chemical fertilizers application, which will contribute to a sustainable and environmentally friendly agriculture.

Construction of Au-modified CN-based donor-acceptor system coupled with dual photothermal effects for efficient photoreduction of carbon dioxide

Conversion of CO2 into high value-added fuels through the photothermal effect is an effective approach for utilizing solar energy. In this study, we prepared the CN-based photocatalyst Py-CTN-Au with both donor-acceptor (D-A) system and dual photothermal effects using a simple two-step method involving calcination and photo-deposition. Real-time monitoring with a thermal imaging camera revealed that Py-CTN-Au0.5 achieved a maximum stable temperature of 180 °C, which was approximately 1.2 times higher than that of Py-CTN (155 °C) and 1.9 times higher than that of g-CN (95 °C) under the same reaction conditions. Under the optimized reaction conditions, Py-CTN-Au0.5 exhibited a CO release rate of 30.59 umol g−1 after 4 h of reaction, which was 7.3 times higher than that of pure g-CN (4.18 umol g−1). The D-A system not only facilitated the separation and transformation of charge carriers but also induced a photothermal effect to accelerate the photoreduction of CO2. Additionally, the cocatalyst Au nanoparticles (Au NPs) further enhanced the charge carrier dynamics and photothermal effect by increasing the built-in electric field intensity and localized surface plasmon resonance (LSPR) effect, respectively. The dual photothermal effects resulting from the non-radiative photon conversion of the D-A structure and the Au NPs LSPR effect, along with the enhanced charge carrier dynamics, catalyzed the efficient photoreduction of CO2. DFT simulations were used to confirm the effect of D-A system and Au NPs. In-situ FTIR results demonstrated that the synergistic photothermal effect promoted the formation of the key intermediate species COOH*, which is beneficial for the photocatalytic reduction of CO2. This study provides valuable insights into the multiple photothermal synergistic effects in photocatalytic reactions.

Climate and vegetation collectively drive soil respiration in montane forest-grassland landscapes of the southern Western Ghats, India

Abstract CO2 release rates from soils via soil respiration play an important role in the carbon budget of terrestrial ecosystems. Though the roles of soil temperature and moisture on soil respiration are well recognised, less is known about how their effects vary across different land-cover types. This study looked at the interactive effects of land-cover change and microclimate on temporal patterns of soil respiration in a montane forest-grassland-plantation mosaic in a highly diverse but climatically sensitive ecosystem in the tropical Western Ghats of India. Across all vegetation types, soil respiration rates were highest during south-west monsoon (June–October), when root growth, litter decomposition and microbial activity are relatively high and were lowest during the summer. Among vegetation types, soil respiration rates were higher in grasslands compared to non-native pine plantations, whereas that of forest and invasive wattle (Acacia mearnsii) plantations were intermediate between grasslands and pine plantations. The decline in respiration rates following conversion from grasslands to pine plantations could be due to relatively lower microbial activity, soil temperatures and, subsequently, slower litter decomposition. In addition, the sensitivity of soil respiration to changes in temperature and moisture differed between different vegetation types. Across all vegetation types, respiration was largely insensitive to changes in soil temperature when moisture levels were low. However, when soil moisture levels were high, respiration increased with temperature in grassland and wattle patches, decreased in the case of pine plantations and remained largely unchanged in shola forests. Our results suggest that changes in aboveground vegetation type can significantly affect soil C cycling even in the absence of any underlying differences in soil type.

A Low‐Temperature Carbonization Strategy for Efficient Viscous Crude Oil Spill Disposal without Hydrophobic Coating: CoFe‐PBA‐Catalyzed Carbonization of Superhydrophobic Flame Retardant Melamine Sponge

AbstractDue to the difficulty of absorbing viscous crude oil, there is an urgent need for carbon sponges with excellent photothermal properties and oil‐water separation capabilities to reduce viscosity and facilitate oil absorption. However, the preparation of high‐temperature carbonization leads to poor mechanical properties, low absorption capacity, and stringent preparation conditions. To solve these challenges, a highly hydrophobic flame‐retardant melamine sponge (CPBA@CMS) is designed by assembling sponge at the interface of cobalt–iron Prussian blue (CoFe‐PBA) derived from metal–organic frameworks (MOFs) and conducting low‐temperature catalytic carbonization under nitrogen. The results demonstrate that CPBA@CMS exhibits excellent superhydrophobic properties (water contact angle = 169.7°) and oil absorption capacity (80.7–219.5 g g−1). Furthermore, CPBA@CMS displays remarkable photothermal effects and thermal conductivity, making it adaptable to various environmental conditions. It can rapidly rise to 141 °C under 1 kW m−2 solar irradiation, with the maximum oil absorption rate reaching 98% and the highest oil absorption capacity at 105.5 g g−1. Additionally, CPBA@CMS shows significant fire safety performance, reducing heat release rate by 84.2%, smoke factor by 97.5%, and CO release rate by 81.4%, respectively. It provides an efficient, safe, and sustainable practical solution for effectively addressing spills of crude oil.

Disposable bamboo fiber meal boxes characterized by efficient preparation, excellent performance, and the potential for beneficial degradation

Disposable plastic meal boxes account for a significant proportion of global plastic pollution, which has caused an increasingly urgent need for substitution with biodegradable plant fiber-molded meal boxes. Compared to other chemical-mechanical pulp pre-treatment methods, steam explosion is a more efficient and clean approach for the preparation of molded meal boxes. In this study, disposable bamboo fiber meal boxes made from steam-exploded pulp (SEP) were prepared using steam explosion. The results showed that the meal boxes prepared using this method had a compact interweaving structure, good tensile performance (with a tensile modulus 1.9 times higher than that of meal boxes prepared using chemical-mechanical pulp (CMP)), excellent water resistance (with a permeability 0.58 times lower than that of CMP), high compression strength, and excellent toughness. After being discarded, SEP was found to have no adverse effects on the soil pH or electrical conductivity (EC) during the degradation process. Furthermore, it could increase the levels of major nutrients for plant growth, such as N and P, improve the C/N ratio, enhance microbial activity, and improve soil fertility. Moreover, the CO2 release rate during the entire degradation process was found to be low. Thus, the bamboo fiber meal boxes developed in this study can alleviate the environmental pressure caused by the greenhouse effect, thereby achieving a green life cycle of highly efficient preparation, stable use, and beneficial degradation.

Construction of macromolecular structure in KunNing coal and analysis of Macro-Micro oxidation characteristics

To explore the macro–micro coal oxidation characteristics for the purpose of preventing coal spontaneous combustion and achieving efficient coal conversion and utilization, the enclosed coal oxidation characteristics of KunNing coal sample (KN) under 25–70 °C were investigated. KN coal molecular models were constructed based on analysis and testing results of X-ray Photoelectron Spectroscopy (XPS), Carbon-13 Nuclear Magnetic Resonance Spectroscopy (13C NMR), Fourier Transform Infrared Spectroscopy (FTIR) and other techniques. The pyrolysis processes of coal-oxygen reaction systems with different oxygen contents were simulated using ReaxFF force field. The results show that the oxygen consumption rate, CO release rate, CO2 release rate and oxidation heat release intensity of coal increase exponentially with rising temperature. The ratio of aromatic bridge carbon to peripheral carbon in KN coal molecular structure is 0.08, and the molecular formula is C149H76O15N2S2. In the later stage of the experimental and molecular dynamics simulation processes, the CO content decreased while the growth rate of CO2 increased. Different indicator gases exhibit varied responses to oxygen content. The C-atom labeling and traceback results for the four indicator gas molecules demonstrate that CO2 mainly comes from aldehyde, hydroxyl, carboxyl and methoxy groups in coal molecules, CO is primarily generated from esters, phenols, carbonyls, C2H2 is predominantly derived from ring-opening and cracking of cycloalkanes, and the source of C2H4 is related to cycloalkanes and alcohols.

Net effect of chemical erosion in a tropical basin on carbon cycle: Constraints from elemental and sulfur isotopic composition of the Mahanadi river water

Chemical erosion in river basins influence the climate by both consuming (via silicate erosion and carbon burial) and releasing (via H2SO4-mediated carbonate weathering and organic oxidation) atmospheric CO2. Net erosional effect of a basin on carbon cycle, therefore, requires precise rate assessment of all these pathways; combined data for the four processes for a given basin are sparse. In this contribution, we have quantified these process intensities for a large tropical basin (Mahanadi river) from the eastern part of India using new time-series (weekly) data for dissolved major ions and sulfur isotopes, and compiled data for rhenium concentrations and particulate carbon isotopes for the basin. The discharge-weighted silica concentrations (∼215 μM) of these samples is higher than that reported as global average for rivers (∼145 μM), indicating intense silicate erosion in the basin. The δ34S of the riverine sulfates vary between 8.8 ‰ and 17 ‰, with a discharge-weighted average of 12 ± 4 ‰ (global riverine value ∼4.4 ± 4.5‰). Temporal changes in concentrations for most of the elements (and δ34S) show relatively higher (enriched) values during lean-flow stages. Mass balance calculations involving Ca, Mg and Si values confirm that these seasonal changes are mainly due to increase (by 18 ± 9%) of groundwater supply to the stream during non-monsoon seasons. The silicate-derived cations (Catsilicate) for the Mahanadi show minimal changes during monsoon (36 ± 5%) and non-monsoon (33 ± 8%) seasons. These data correspond to a CO2 consumption rate of 2.4 ± 1.6 tC/km2/yr, which is about two times higher than that reported for global rivers. Comparison of δ34S values of riverine sulfate with its possible sources computes the relative supply of sulfates from atmospheric deposition (38%), gypsum (46%), and sulfides (16% (a lower limit)) to the river. The minimal contribution via sulfide oxidation confirms low CO2 release (0.1 ± 0.1 tC/km2/yr) in this basin through sulfuric-acid mediated carbonate weathering. Average rhenium for this river is 5 ± 3 pmol/kg. The source apportionment using S/Re and Na/Re ratios indicates that 85 ± 10% of the Re is derived through organic oxidation. The rhenium data are used to estimate the CO2 release rate (0.50 ± 0.57 tC/km2/yr) by oxidation of petrogenic carbon, which is higher than the estimated organic burial rate (0.27 ± 0.12) for the basin. The estimated four erosion rates confirm a net negative (∼ − 2.1 ± 1.7 tC/km2/yr) effect of chemical erosion in the Mahanadi basin on the CO2 budget. Low sulfide-oxidation in this supply-limited regime is possibly linked to limited exposure of fresher minerals, whereas high silicate erosion in the basin is consistent with its silicate-dominated lithology and tropical climate.

The Soil Respiration of Coal Mine Heaps’ Novel Ecosystems in Relation to Biomass and Biotic Parameters

The biodiversity, including the diversity of autotrophic organisms of mostly plant species, assembled in vegetation patches and its impact on the course of ecosystem processes is still a key subject of research in natural sciences around the world. Certain aspects of the relationship between biodiversity and CO2 release processes have been studied only in some natural and semi-natural ecosystems (semi-natural ecosystems such as meadow or grasslands). In contrast, very little is known about the biotic parameters related to natural processes and the functioning of novel ecosystems. This study was performed on post-black coal mining heaps. The studied sites were established on carboniferous mineral material. Among the considered biotic parameters, the vegetation plant species composition, soil organic matter, soil enzymatic activity, soil fauna presence, and the plant species biomass were studied. The aim of the research was to analyse the influence of the selected biotic factors on the CO2 release from the mineral material of black coal mining heaps’ novel ecosystems. The range of CO2 release at the analysed sites was 0.00158–1.21462 [g CO2/m2/h]. The activity of soil enzymes such as dehydrogenase, acid phosphatase, and basic phosphatase was positively correlated with the amount of CO2 released, however, there was no correlation between urease activity and CO2 emissions from the soil. In our study, a comparison of the soil organic matter developed under the vegetation types studied and CO2 release (rate) showed a dependence on vegetation type. The amount of biomass was not linearly correlated with CO2 release from the soil. The presence of soil fauna displayed a positive effect on CO2 release.

Surface engineering and functionalization of MoS2-based nanoarchitecture for constructing epoxy composites with excellent fire resistance and mechanical properties

To overcome the shortcomings of epoxy resins (EP) such as high flammability and emission of toxic gases, a MoS2-based nanoarchitecture (CeZrOx-MoS2@PDA) was designed and prepared through surface engineering and functionalization method. At 2 wt% incorporation, the nanoarchitectures were homogeneously dispersed in EP matrix, showing good conditions for the formation of strong labyrinth barrier effect. Concurrently, EP/CeZrOx-MoS2@PDA offered enhanced thermal stability with higher char residues and lower maximum weight loss rate (MLR) value. Furthermore, the peak heat release rate (PHRR), total heat release (THR) and smoke factor (SF) of EP/CeZrOx-MoS2@PDA were reduced by 35.5%, 29.1% and 54.5%, respectively, while the CO release rate and CO2 release rate were dropped significantly, which was associated with the strong labyrinth effect, good char-forming effect and beneficial free radical quenching effect of CeZrOx-MoS2@PDA nanoarchitecture. Moreover, the ternary nanoarchitecture also resulted in a 56.8% increase in the storage modulus of EP composites. Therefore, the CeZrOx-MoS2@PDA developed in this work contributed to the generation of high performance EP with excellent fire resistance and mechanical properties, providing a promising strategy for the design of superior EP composites.