Carbon Dioxide Generation Research Articles

Designing advanced 0D-2D hierarchical structure for Epoxy resin to accomplish exceeding thermal management and safety

Epoxy resin (EP) is widely used in the package of modern electronic products for thermal management, but the extremely flammability and toxicity release have restricted its further application. In this article, zinc hydroxystannate (ZHS) nanocubes were in-situ fabricated on the surface of titanium carbide (Ti3C2Tx) MXene nanosheets (ZHS@M) for improving the thermal management capacity of EP. Due to the phonon thermal conductance from ZHS and electron-hole thermal conductance of Ti3C2Tx, the thermal conductivity was improved by 328% compared with the neat EP, which was benefit to dissipate heat for reducing the possibility of thermal disaster chain happening. Furthermore, owing to the 0D-2D hierarchical structure of ZHS@M, the fire safety and smoke suppression of these EP composites were highly strengthened. The peak heat release rate (pHRR) and total heat release (THR) decreased by 54.91% and 58.74%, respectively. Moreover, hazardous gases of EP during the combustion were also efficiently reduced, and the generation of carbon oxide (CO) and carbon dioxide (CO2) were decreased by 44.44% and 39.46% when the additive of ZHS@M was only 2 wt%. As a result, ternary catalytic effect and labyrinth structure improved the safety of EP in the thermal runaway incidents. Besides, EP-2.0 ZHS@M exhibited excellent tensile robustness (64.71 MPa) and modulus (2.39 GPa), which regarded as a reliable supporting material for electronics in thermal management field. Hence, this hierarchical EP-ZHS@M composites provided the help of cleaning the thermal accumulation and increasing fire safety while facing thermal runaway, which was significant to destroy the formation of thermal disaster chain and further applications of the modern electrons and devices.

Assessment of carbon dioxide emissions during production, construction and use stages of asphalt pavements

The carbon dioxide emissions generated during the life of flexible asphalt pavements are an important indicator of the sustainability of these infrastructures. The study aims at tentatively quantifying the CO2 released during production, construction and use stages of a road pavement, the analysis is performed adopting a Life Cycle Assessment approach. Each stage is structured based on data retrieved from an extensive literature review. Special focus is given to the use stage, which is usually only partially addressed. The study is achieved employing the “HERMES CO2” spreadsheet tool developed for the purpose and it is publicly available to maximize openness and the interaction with the user. As an illustrative application, the study then quantifies the generation of carbon dioxide for the three major categories of Norwegian highways referring to 1 km as functional unit with lifespan of 50 years. The analysis documents that the overall CO2 amount is approximately equal to 1 million metric tons, which is significantly related to the albedo and rolling resistance of the use stage. Overall, the research establishes a common methodology and analysis frame which is relevant to early planning of road pavements and can be refined further for specific case-studies.

Insights into the Mechanism of Methanol Steam Reforming Tandem Reaction over CeO2 Supported Single-Site Catalysts.

We demonstrated how the special synergy between a noble metal single site and neighboring oxygen vacancies provides an "ensemble reaction pool" for high hydrogen generation efficiency and carbon dioxide (CO2) selectivity of a tandem reaction: methanol steam reforming. Specifically, the hydrogen generation rate over single site Ru1/CeO2 catalyst is up to 9360 mol H2 per mol Ru per hour (579 mLH2gRu-1s-1) with 99.5% CO2 selectivity. Reaction mechanism study showed that the integration of metal single site and O vacancies facilitated the tandem reaction, which consisted of methanol dehydrogenation, water dissociation, and the subsequent water gas shift (WGS) reaction. In addition, the strength of CO adsorption and the reaction activation energy difference between methanol dehydrogenation and WGS reaction play an important role in determining the activity and CO2 selectivity. Our study paves the way for the further rational design of single site catalysts at the atomic scale. Furthermore, the development of such highly efficient and selective hydrogen evolution systems promises to deliver highly desirable economic and ecological benefits.

Reduction Characteristic of CaSO4-CuO Combined Oxygen Carrier Under CO Atmosphere

CaSO4 oxygen carrier is considered to be a potential oxygen carrier (OC) for Chemical Looping Combustion because of its high oxygen capacity and low price. But its reactivity is lower than the main metal oxide oxygen carriers, and it deactivates due to sulfur loss as well as sintering at high reaction temperatures above 920 ℃. To improve the performance of CaSO4-based oxygen carrier, small amounts of CuO particles were mixed mechanistically with CaSO4 particles to use as combined oxygen carrier in this work. The reduction reactions of CaSO4 oxygen carrier, CuO oxygen carrier and CaSO4-CuO combined oxygen carrier under CO atmosphere were investigated. The effects of reaction factors including reaction temperature, the oxygen-carrying ratio of CuO to CaSO4 and mass of oxygen carrier, on the reductions have been investigated in this study. XRD, SEM-EDS, BET and gas analyses were performed to investigate the variations of solid phase, element compositions in solid residual and sulfur release with reaction time. The results show that the addition of CuO increases the reactivity of the CaSO4-based oxygen carrier while also suppressing the release of the gas sulfur. For the individual reduction of CaSO4 by CO, with the increase of CaSO4 mass (500 - 1200 mg), CO2 yield also increases until 1000 mg stops and SO2 released rises remarkably; An increase in the reaction temperature aggravated the SO2 emission. The carbon dioxide generation efficiency also increases with an increase in temperature, but decreases when the temperature exceeds 950 ℃ due to sintering of the oxygen carrier particles; With respect to the reaction of CuO with CO, CO2 yield does not change significantly with increasing temperature, due to the sintering of the CuO oxygen carrier in a high temperature reaction environment;For the combined oxygen carrier: a.As the reduction reaction temperature increases, the reduction reaction performance of the combined oxygen carrier is enhanced within the reaction temperature range of 750~900℃. b. CaO the use of CuO additives not only improves the CO conversion rate, but also inhibits the release of gas sulfide. As the oxygen carrying fraction of CuO increases, SO2 released is reduced and the SO2 release time is delayed. What� more, the solid products after reduction reaction mainly contain CaS, CaO, CuO, Cu2O and CaSO4, and no copper sulfide is detected. c. When the oxygen-carrying ratio of CuO to CaSO4 is increasing from 15% to 20%, CO2 yield increases greatly.

Thermodynamic assessment of the novel concept of the energy storage system using compressed carbon dioxide, methanation and hydrogen generator

The main aim of this paper is to characterize the concept of a novel energy storage system, based on compressed CO2 storage installation, that uses an infrastructure of depleted coal mines to provide required volume of tanks, and, additionally, hydrogen generators, and a methanation installation to generate synthetic natural gas that can be used within the system or taken out of it, e.g., to a gas grid. A detailed mathematical model of the proposed solution was built using own codes and Aspen Plus software. Thermodynamic evaluation, aiming at determining parameters, composition and streams in all the most important nodes of the system for the nominal point and when changing a defined decision variable δ (in the range from 0.1 to 0.9) was made. The evaluation was made based on the storage efficiency, volume of the tanks and flows of energy within the system. The storage efficiency in the nominal point reached 45.08%, but was changing in the range from 35.06% (for δ = 0.1) to 63.93% (for δ = 0.9). For the nominal value of δ, equal to 0.5, volume of the low-pressure tank (LPT) was equal to 132,869 m3, while of the high pressure tank (HPT) to 1219 m3. When changing δ these volumes were changing from 101,900 m3 to 190,878 m3 (for LPT), and from 935 to 1751 m3 (for HPT), respectively. Detailed results are presented in the paper and indicate high storage potential of the proposed solution in regions with underground mine infrastructure.

Removal of psychoactive pharmaceuticals from wastewaters using microbial electrolysis cells producing hydrogen

Abstract In this study, hydrogen production was analyzed along with methane and carbon dioxide generation using paroxetine, venlafaxine, and o-desmethylvenlafaxine (ODV) as substrates in single-chamber microbial electrolysis cells (MECs). Combinations of all three drugs were examined at concentrations of 750 ng/mL and 170 ng/mL. At the beginning of MEC operations using a 750 ng/mL mixture of drugs, there was no hydrogen or methane, but carbon dioxide was detected. When the concentration of the drug mixture was reduced to 170 ng/mL, MECs produced hydrogen and methane gas. Removal of the drugs during MEC operations was also analyzed using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Paroxetine, venlafaxine and ODV drugs were removed up to 99% by MECs. In conclusion, MECs could offer an alternative treatment method for wastewaters containing psychoactive pharmaceuticals with the added benefit of fuel hydrogen generation.

A method for measuring the molecular ratio of inhalation to exhalation and effect of inspired oxygen levels on oxygen consumption

Using a new method for measuring the molecular ratio (R) of inhalation to exhalation, we investigated the effect of high fraction of inspired oxygen (FIO2) on oxygen consumption (VO2), carbon dioxide generation (VCO2), and respiratory quotient (RQ) in mechanically ventilated rats. Twelve rats were equally assigned into two groups by anesthetics: intravenous midazolam/fentanyl vs. inhaled isoflurane. R, VO2, VCO2, and RQ were measured at FIO2 0.3 or 1.0. R error was ± 0.003. R was 1.0099 ± 0.0023 with isoflurane and 1.0074 ± 0.0018 with midazolam/fentanyl. R was 1.0081 ± 0.0017 at an FIO2 of 0.3 and 1.0092 ± 0.0029 at an FIO2 of 1.0. There were no differences in VCO2 among the groups. VO2 increased at FIO2 1.0, which was more notable when midazolam/fentanyl was used (isoflurane-FIO2 0.3: 15.4 ± 1.1; isoflurane-FIO2 1.0: 17.2 ± 1.8; midazolam/fentanyl-FIO2 0.3: 15.4 ± 1.1; midazolam/fentanyl-FIO2 1.0: 21.0 ± 2.2 mL/kg/min at STP). The RQ was lower at FIO2 1.0 than FIO2 0.3 (isoflurane-FIO2 0.3: 0.80 ± 0.07; isoflurane-FIO2 1.0: 0.71 ± 0.05; midazolam/fentanyl-FIO2 0.3: 0.79 ± 0.03; midazolam/fentanyl-FIO2 1.0: 0.59 ± 0.04). R was not affected by either anesthetics or FIO2. Inspired 100% O2 increased VO2 and decreased RQ, which might be more remarkable when midazolam/fentanyl was used.

Reuse of the digestate obtained from the biomethanization of olive mill solid waste (OMSW) as soil amendment or fertilizer for the cultivation of forage grass (Lolium rigidum var. Wimmera)

The principal by-product from the two-phase olive oil production process is olive mill solid waste (OMSW). It is a highly-pollutant by-product, not only because of its characteristics, but also because of the considerable volume of OMSW which is generated, amounting to 2 to 4 million tons per year in Spain. The anaerobic digestion of this by-product is a well-studied process, and results in the generation of biogas, methane and carbon dioxide mainly of high calorific values (20–25 MJ m−3), and an effluent or digestate. The digestate of this by-product has never been characterized. This study presents an informative view on how the composition of OMSW digestate shows promising implications as a soil amendment or fertilizer due to the quality of the biomass from Lolium rigidum, a useful grass specie for the production of forage. Three OMSW digestate alternative applications or treatments were investigated: the digestate and the solid fraction of the digestate for a nutrient-poor soil amendment and the liquid fraction of the digestate as fertilizer. The results confirm that all the OMSW digestate treatments studied presented suitable characteristics for agricultural use, and showed an optimal Carbon/Nitrogen ratio with adequate values for heavy metals which are below the limits established by the Spanish and European legislation in the absence of pathogens. However, fertirrigation was the treatment that provided Lolium rigidum with the best characteristics, improving its shoot biomass, photosynthetic rate and nutritional content.

Optimal Synergy between Photovoltaic Panels and Hydrogen Fuel Cells for Green Power Supply of a Green Building—A Case Study

Alternative energy resources have a significant function in the performance and decarbonization of power engendering schemes in the building application domain. Additionally, “green buildings” play a special role in reducing energy consumption and minimizing CO2 emissions in the building sector. This research article analyzes the performance of alternative primary energy sources (sun and hydrogen) integrated into a hybrid photovoltaic panel/fuel cell system, and their optimal synergy to provide green energy for a green building. The study addresses the future hydrogen-based economy, which involves the supply of hydrogen as the fuel needed to provide fuel cell energy through a power distribution infrastructure. The objective of this research is to use fuel cells in this field and to investigate their use as a green building energy supply through a hybrid electricity generation system, which also uses photovoltaic panels to convert solar energy. The fuel cell hydrogen is supplied through a distribution network in which hydrogen production is outsourced and independent of the power generation system. The case study creates virtual operating conditions for this type of hybrid energy system and simulates its operation over a one-year period. The goal is to demonstrate the role and utility of fuel cells in virtual conditions by analyzing energy and economic performance indicators, as well as carbon dioxide emissions. The case study analyzes the optimal synergy between photovoltaic panels and fuel cells for the power supply of a green building. In the simulation, an optimally configured hybrid system supplies 100% of the energy to the green building while generating carbon dioxide emissions equal to 11.72% of the average value calculated for a conventional energy system providing similar energy to a standard residential building. Photovoltaic panels account for 32% of the required annual electricity production, and the fuel cells generate 68% of the total annual energy output of the system.

Enhanced Thermal Insulation and Flame-Retardant Properties of Polyvinyl Alcohol-Based Aerogels Composited with Ammonium Polyphosphate and Chitosan

Polyvinyl alcohol- (PVA-) based aerogels have attracted widespread attention owing to their low cost, eco-friendliness, and low density. However, the applications of PVA-based aerogels are limited by their flammability. In this study, a flame retardant, ammonium polyphosphate (APP), and a biopolymer, chitosan (CS), were added to polyvinyl alcohol (PVA), and the polymer was further crosslinked using boric acid (H3BO3). In the PVA aerogels, the negatively charged APP and positively charged CS formed a polyelectrolyte complex (PEC) through ionic interaction. Cone calorimetry and vertical burning tests (UL-94) indicated that the PVA composite aerogels have excellent flame retardancy; they could decrease the heat release rate, total heat release rate, and carbon dioxide (CO2) generation. Both PVA/H3BO3 and APP-CS in the composite aerogel could be burned to carbon, and the foamed char layer could act together to impart the PVA composite aerogels with good flame retardancy. Further, the decrease in the temperature at the backside of the aerogels with increasing APP-CS content, as determined by the flame-spraying experiment, indicated that the PVA-based aerogels with APP-CS can also serve as thermal insulation materials. This work provides an effective and promising method for the preparation of PVA-based aerogels with good flame retardancy and thermal insulation property for construction materials.

Application of Advanced Oxidation Process Using Ozonation Assisted with Hydrogen Peroxide for Organic Compounds Removal from Bayer Liquor

ABSTRACT One of the alumina industry’s main problems is the organic matter in the Bayer liquor during the Bayer Process released in the bauxite digestion process and accumulating in the process. It reduces as process efficiency and results in impurities in the final product. Several studies have shown that removing organic matter by ozonation can be attractive for industrial applications since ozone can be generated in situ and achieve faster results. For this reason, the goal of the present work was to study the removal of organic matter from the Bayer liquor. The effect of ozone dosage and O3/H2O2 combination was evaluated at 40 °C and 80 °C. Results indicated that the organic matter mineralization achieved 19% at 80 °C, using 6.5 g/L of O3 and 0.05 mol/L of H2O2, where 95.4% generated carbon dioxide. At the same conditions, 45.6% of oxalate was degraded. The UV/vis analyses demonstrated the decrease in organic chain size and the color of the samples before and after the oxidation process. An advanced oxidation process (O3 and O3/H2O2 combination) effectively removed a range of organic impurities from the Bayer liquor impacting the quality of the final product.

Thermal maturation, mineral catalysis, and gas generation kinetics of carbonate source rock

Source-rock evaluation must start by first characterizing thermal maturity. The concept of thermal maturation or thermal decomposition is a well-defined quantitative modelling of kinetic parameters to explain the generation and expulsion of liquid and gaseous hydrocarbons from sedimentary source rocks. However, unlike coal and shale source rocks, carbonate source rocks are emerging source rocks and no analyses of thermal maturation kinetics have been reported in the literature. Apparently, this study is one of the most recent and first laboratory study of thermal maturation kinetics of carbonate source rock. In this paper, we simulated this process by conducting controlled laboratory experiments under high temperature from 40 °C to 450 °C using advanced integrated analytical techniques. The dataset is modeled by the solid state kinetics of first order reactions. In addition, the poor knowledge of how catalytic minerals stimulate thermal maturation is investigated; a unique and significant contribution that sets this work apart from previous thermal maturation studies. The result from kinetic modelling showed that the distribution of activation energy in the range of 99–325 kJ/mol is bimodal, reflecting possible peak shift in the thermal decomposition process, reaction mechanism and maturation prediction. The model further suggests that the maturation process of carbonate-rich source rock is very likely to be different from that of clay-rich source rock. Elemental and mineralogical analyses of investigated sample revealed the presences of catalytic elements such as iron, gypsum, pyrite and kaolinite. The analysis of the generated gases constrained to only three gases showed that the volume content of carbon dioxide, methane and water are 2%, 46% and 52% respectively. The generation of carbon dioxide is constant whereas methane increases and water decreases respectively with thermal maturation. Although, the investigated sample has a high calcite content of 91.9%, the methane content of 46% gives a strong indication of high natural gas generative potential as contrasted with the 2% of carbon dioxide generated. The findings of this study can help to better understand the coupled mechanism controlling thermal maturation of carbonate source rock and also provide useful reference dataset for basin modelling of carbonate source rocks for field studies.

A Review of the Hardened Properties of Eco-Friendly Concrete Containing Ground Granulated Blast-furnace Slag

Cement manufacture depletes natural resources, requires significant energy usage, and emits large quantities of greenhouse gases. Roughly one tonne of carbon dioxide is released by ordinary Portland cement, which is roughly 7% of global carbon dioxide generation. In concrete production GGBS can be a partial alternative of cement. GGBS is produced by finely grinding of molten slag generated by the process of extraction of iron from ore. In this study the concrete properties incorporating GGBS is reviewed. The hardened properties of concrete incorporating GGBS are discussed. The cement replacement of about 35-40% by GGBS in concrete demonstrates various advantages like less heat of hydration, increase in ductility, increase in strength, reduction in carbon emission and better aesthetics. GGBS improves the durability properties of concrete, such as higher resistance to sulphate attack, increased resistance to alkali-silica reaction, reduced chloride ion penetration which enhances corrosion resistance. Denser microstructure and lower porosity due to the addition of GGBS, which in turn enhances the durability of concrete. With the use of GGBS in concrete, cement content can be reduced, which turns into an eco-friendly solution.

Directly sputtered nickel electrodes for alkaline water electrolysis

Hydrogen is regarded as a highly clean and renewable future energy resource. Water electrolysis (WE) is the most promising technology to produce hydrogen at large scale without carbon dioxide generation. In this study, we prepared Ni electrodes for alkaline water electrolysis purpose using various methods, including direct sputtering (DC and RF operational modes) and the Raney Ni process, and investigated their morphologies and electrochemical activities in the hydrogen evolution reaction (HER). The DC-sputtered Ni electrode showed well-controlled surface morphology with around 40-fold roughness enhancement, compared to the Ni substrate. Half-cell HER test showed that DC-sputtered Ni electrode provides the best electrochemical performance, including the lowest overpotential of 100 mV at a current density of 50 mA/cm2, and provides the lowest Tafel slope, representing the fastest charge transfer reaction and kinetics of HER. More importantly, for practical application purposes, single-cell test was also conducted to confirm the on/off durability and long-term stability, which showed highly stable electrochemical activity under harsh operational conditions. We expect that our approach will launch a new trajectory for realizing CO2-free, cost-effective, and scalable hydrogen production for industrial application purpose, even in combination with renewable power sources, including solar, wind, and hydro energy.

Insights into Formate Oxidation by a Series of Cobalt Piano-Stool Complexes Supported by Bis(phosphino)amine Ligands.

A series of (cyclopentadienyl)cobalt(III) half-sandwich complexes (1-4) supported by bidentate bis(phosphino)amine ligands was synthesized and characterized by NMR spectroscopy, X-ray crystallography, and cyclic voltammetry. The CoIII-hydride complex 4-H bearing the bis(cyclohexylphosphine) ligand derivative was successfully isolated via protonation of the neutral reduced CoI complex 5 with a weak acid. Experimental and computational methods were used to determine the thermodynamic hydride accepting ability of these CoIII centers and to evaluate their reactivity toward the oxidation of formate. We find that the hydride accepting ability of 1-4 ranges from 71 to 74 kcal/mol in acetonitrile, which should favor a highly exergonic reaction with formate through direct hydride transfer. Formate oxidation was demonstrated at elevated temperatures in the presence of stoichiometric quantities of 4, generating carbon dioxide and the CoIII-hydride complex 4-H in 72% yield.

Current Developments of Carbon Capture Storage and/or Utilization–Looking for Net-Zero Emissions Defined in the Paris Agreement

An essential line of worldwide research towards a sustainable energy future is the materials and processes for carbon dioxide capture and storage. Energy from fossil fuels combustion always generates carbon dioxide, leading to a considerable environmental concern with the values of CO2 produced in the world. The increase in emissions leads to a significant challenge in reducing the quantity of this gas in the atmosphere. Many research areas are involved solving this problem, such as process engineering, materials science, chemistry, waste management, and politics and public engagement. To decrease this problem, green and efficient solutions have been extensively studied, such as Carbon Capture Utilization and Storage (CCUS) processes. In 2015, the Paris Agreement was established, wherein the global temperature increase limit of 1.5 °C above pre-industrial levels was defined as maximum. To achieve this goal, a global balance between anthropogenic emissions and capture of greenhouse gases in the second half of the 21st century is imperative, i.e., net-zero emissions. Several projects and strategies have been implemented in the existing systems and facilities for greenhouse gas reduction, and new processes have been studied. This review starts with the current data of CO2 emissions to understand the need for drastic reduction. After that, the study reviews the recent progress of CCUS facilities and the implementation of climate-positive solutions, such as Bioenergy with Carbon Capture and Storage and Direct Air Capture. Future changes in industrial processes are also discussed.

A Technical Feasibility Study and Environmental Impacts of Green Cement Production from Recycled Fly Ash in Pakistan

This Research includes that how to switch from prior techniques towards the green cement. Green cement is environment friendly and less producing the carbon dioxide in the environment. First of all it seems that the possibility of best replaceable recycled material which is fly ash. There are set of materials which can replace the cement in making concrete like the rice husk, sugar cane, furnace slag etc. but we have worked on fly ash as recycled material which has the same constituents required for making cement and fly as required less amount of energy as fly ash already burned that’s why generation of carbon dioxide is less. In this thesis we have calculated the percentage amount of fly ash to limestone used for green cement production. In present study it can be replaced 80 to 100 percent of cement by fly ash but for this purpose we have to use sodium based activator. In this research work it have been found the best place for green cement plant in Sindh (Pakistan) in plant location and discussed all factors that affect the plant location.

Central heating by seasonal sensible heat storage of solar thermal energy

Production of required thermal energy to heat residential buildings is a considerable issue in energy studies. Kabul city is a city in which the coal-fired central heating systems for providing the mentioned energy is in expansion process. And, coal as feeding source of these systems with generation of carbon dioxide (CO2) is the main cause of greenhouse gases (GHGs) emissions in winter. Fortunately, Kabul city has maximum solar radiation in summer warm season which can be used for fulfilling of this demand in winter cold season. The method which can perform this task is the central heating by seasonal sensible heat storage of solar thermal energy. But, the economic and environmental feasibility and viability of this method is a discussable issue. In this study, the central heating by seasonal sensible heat storage of solar thermal energy and its economic and environmental feasibility and viability is studied. It is tried that this system is compared in a logical method with current coal-fired systems. The economic feasibility study is accomplished by comparison of initial or capital cost and annual operation and maintenance cost with the usage of existing data and thermodynamic analytic methods. The environmental viability study is accomplished by comparison of annual emissions of CO2 with the usage of online emissions calculator. Unfortunately, it is found that seasonal sensible heat storage of solar thermal energy is not an economically feasible method for central heating due to its high initial cost and cannot be used in an economically beneficial manner for central heating. But fortunately, it is an environmentally viable method and environmentally friendly way due to its no and/or zero CO2 emissions. To sum up, it is suggested that, this method should be used for district heating which can make this system economically feasible.

Carboxylate anion generation in aqueous solution from carbonate radiolysis, a potential route for abiotic organic acid synthesis on Earth and beyond

Low molecular weight carboxylate anions such as formate (HCOO−), acetate (CH3COO−) and oxalate (C2O42−) have been shown to play an important role in supporting deep subsurface microbial ecosystems. Their origin whether biological or abiotic is currently highly debated, but surprisingly radiolytic production has rarely been considered, as it is the case for H2. Here, we address this question through dedicated irradiation experiments. Aqueous solutions containing carbonate, formate, acetate or oxalate have been irradiated using both the 60.7 MeV α-beam of the ARRONAX cyclotron (Nantes, France) and 661.7 keV γ-Ray in order to reveal the mechanism and chemical yield of radiation-induced dissolved carbonate degradation.The yields (G-values) of carboxylate anions production/degradation in low-concentration carbonate solution (0.01 to 1 mmolL−1) are measured. Carbonate degradation occurs through three consecutive steps (Carbonate →I Formate →II Acetate →III Oxalate) involving formate radical (CO2−•), dihydrogen (H2), and carbon dioxide (CO2) generation. Dissolved carbonate radiolysis provides a consistent pathway for both enhancing two-fold the radiolytic H2 production compared to pure water and generating carboxylic species, chiefly oxalate, readily available for microbes. Radiation-induced carbonate degradation may produce substantial amount (millimolar concentration) of carboxylate anions in ancient groundwaters from deep crystalline bedrocks. Subsurface lithoautotrophic microbial ecosystems may not only be supported by radiolytic H2 but also by carboxylate species from carbonate radiolysis. Carbonate radiolysis can be also an endogenous source of carboxylate species on Mars and other planetary bodies.

New generation of carbon dioxide traps could make carbon capture practical

New generation of carbon dioxide traps could make carbon capture practical