CO2 Treatment Research Articles

Effects of CO2 on the Mechanical Properties of Hanna Sandstone

Possible deterioration of a rock’s structure and mechanical properties due to chemical reactions between the host rock, formation water, and CO2 requires due attention. In this study, cylindrical sandstone specimens obtained from the Hanna Formation, Wyoming, were prepared under three treatment conditions: dry, submerged in water, and treated with water + CO2 for one week at a pressure of 5 MPa and room temperature. Specimens were subjected to three effective confining pressures of 5, 15, and 25 MPa. The mechanical test results show that water + CO2 treatment, on average, decreases the peak strength and elastic modulus of the specimens by 36% and 20%, respectively, compared to dry specimens. For all three effective confining pressures, the dry specimens exhibited higher compressive strengths, larger Young’s moduli, and more brittle behavior. CO2-treated specimens showed significantly lower calcite contents.

Treatment of liquid anaerobic digestate with natural zeolite and Arthrospira platensis cyanobacteria from laboratory to pilot-scale

Using liquid digestate as nutrients source for microalgae cultivation has gained interest this last decade but high ammonium content and strong turbidity can limit the growth performances. For this purpose, natural zeolite was investigated as a novel and innovative solution to mitigate liquid digestate toxicity before microalgae cultivation at both laboratory and pilot-scales. Natural zeolite (clinoptilolite) was used in adsorption columns at a ratio of 0.5 kgzeolite.L-1 to treat liquid digestate (0.45 L). After 24 h of treatment, the ammonium concentration was significantly reduced from 2273 to 115 mgN.L-1, resulting in a removal efficiency and adsorption capacity of 95% and 4.31 mg.gzeolite-1, respectively. Arthrospira platensis cells were able to proliferate in the treated digestate with relative low dilution factors (≤ 5x) whereas high dilution factors (≥ 20x) were necessary for the untreated digestate. The results obtained at laboratory-scale were successfully scaled-up to pilot-scale with similar treatment performances when detoxifying 15.5 L of anaerobic digestate. The resulting pretreated digestate was used as culture medium for Arthrospira platensis in flat panel photobioreactors without being diluted, reaching a final Arthrospira platensis concentration of 0.82 gDW.L-1 and biomass productivity of 33 mg.L-1.d-1. The findings of this study highlight the potential of natural zeolite in the development of microalgae-based processes for digestate and CO2 treatment.

Effects of ocean warming with stable and fluctuating ocean acidification on seawater transition in Chinook salmon smolts

Anadromous salmon populations are declining in the Pacific Northwest, with high mortality during the transition from fresh- to seawater as smolts, a stage particularly vulnerable to adverse environmental conditions. This study seeks to explore the impacts of warming and ocean acidification on the transition of life in freshwater to life at sea in Chinook salmon smolts. In a fully factorial experiment, we transitioned Chinook salmon from fresh- to seawater at current and future conditions of temperature (13 °C and 16 °C, respectively) and ocean acidification (400 and 1400 atm CO2), including a fluctuating CO2 treatment (between control and high CO2) that may be more representative of natural environmental conditions associated with upwelling and tidal cycling. We hypothesized that constant elevated CO2 levels would impair smoltification success immediately following seawater transfer, but that fluctuating conditions would be even more physiologically challenging. We predicted that elevated temperatures would exacerbate these effects. To test this, we measured plasma ion concentrations, gill Na+/K+-ATPase (NKA) isoform mRNA and protein expression, as well as condition indices in freshwater and following 1, 3, 6, and 18 days in seawater at the respective treatments. We confirmed the existence of gill freshwater and seawater isoforms of NKA (α1a and α1b, respectively) in Chinook salmon for the first time, and found an upregulation of both isoforms in the fluctuating CO2 treatment but a reduction of the number of NKA α1b cells 3-days post seawater transfer at 13 °C. At 16 °C, NKA α1b was upregulated in high CO2 levels, with an elevated hematocrit indicating fish were likely stressed. Taken together, plasma ions, gill NKA and condition indices revealed a complex response to interacting warming and acidification during the first few days in seawater, however there were no longer-term adverse physiological responses. Thus, Chinook salmon appear to be relatively resilient to near-future climate change.

Organic and Metal–Organic Polymer-Based Catalysts—Enfant Terrible Companions or Good Assistants?

This overview provides insights into organic and metal–organic polymer (OMOP) catalysts aimed at processes carried out in the liquid phase. Various types of polymers are discussed, including vinyl (various functional poly(styrene-co-divinylbenzene) and perfluorinated functionalized hydrocarbons, e.g., Nafion), condensation (polyesters, -amides, -anilines, -imides), and additional (polyurethanes, and polyureas, polybenzimidazoles, polyporphyrins), prepared from organometal monomers. Covalent organic frameworks (COFs), metal–organic frameworks (MOFs), and their composites represent a significant class of OMOP catalysts. Following this, the preparation, characterization, and application of dispersed metal catalysts are discussed. Key catalytic processes such as alkylation—used in large-scale applications like the production of alkyl-tert-butyl ether and bisphenol A—as well as reduction, oxidation, and other reactions, are highlighted. The versatile properties of COFs and MOFs, including well-defined nanometer-scale pores, large surface areas, and excellent chemisorption capabilities, make them highly promising for chemical, electrochemical, and photocatalytic applications. Particular emphasis is placed on their potential for CO2 treatment. However, a notable drawback of COF- and MOF-based catalysts is their relatively low stability in both alkaline and acidic environments, as well as their high cost. A special part is devoted to deactivation and the disposal of the used/deactivated catalysts, emphasizing the importance of separating heavy metals from catalysts. The conclusion provides guidance on selecting and developing OMOP-based catalysts.

Enlightenment of ancient Tabia for sustainable construction material manufacture by accelerated CO2 treatment

Inspired by the wisdom of Tabia, an ancient building material with superior mechanical properties, this paper utilized accelerated CO2 mineralization (CM) method to treat silty waste soil (SWS) with active lime after the pressing forming process for construction block manufacture. The influence of Ca(OH)2 content and curing duration were explored. Results indicate that the generated CaCO3 could fill pores and improve strength of the SWS blocks after CM treatment. At the optimal Ca(OH)2 content of 15 % and curing duration of 24 h, the CM-SWS blocks possessed the compressive strength of 12.8 MPa, CO2 emissions of 84.59 kgCO2/m3 and cost of 196.26 CNY/m3, comparable with or superior than the commercial blocks. The findings would deepen the mechanistic understandings of CM treatment in material reinforcement, and pave a proof-of-concept path to sustainably upgrade the SWS of poor engineering performance for building material production.

Selective Synthesis of 3D Aligned VO2 and V2O5 Carbon Nanotube Hybrid Materials by Chemical Vapor Deposition.

3D carbon nanotube hybrid materials containing VO2 and V2O5 evenly distributed onto vertically aligned carbon nanotubes (VACNTs) is reported. Adjustable loading of particles in controllable sizes onto the VACNTs was developed via a stepwise chemical vapour deposition (CVD) approach. Solid VO(acac)2 is chosen as vanadium source. CO2 acts as reactive gas for the pre-functionalisation of the VACNTs. The process temperature was identified as key parameter to control the deposited vanadium oxide phase. A temperature of 550°C results in monoclinic VO2, while 600 °C results in the deposition of V2O5 onto the VACNT support. The morphology and the amount of deposited material was found to be dependent on the reactor dimensions and the degree of functionalization of the carbon support. An increase of the D/G ratio of the VACNT from 0.75 to 1.08 caused by a CO2 treatment step within the process led to an increase of the particle coverage from a scarce coverage without prior CO2 treatment to a dense coverage of the VACNT support after 15 min of CO2 exposure time. Size and crystallinity of the as deposited particles can be further adjusted by a controlled heat treatment after VO(acac)2 precursor deposition.

Evaluation of Elevated CO2 on Nutritional Quality of Green Gram for the Management of Callosobruchus chinensis (L.) during Storage

An experiment was conducted to study the assessment of nutritional quality parameters of green gram treated with elevated levels of carbon dioxide to manage Callosobruchus infestation during 2020-21 at Seed Entomology Laboratory, Seed Research and Technology Centre, College of Agriculture, Rajendranagar, Hyderabad, India. Nutritional quality of Callosobruchus chinensis infested green gram seeds exposed to four different concentrations of CO2 viz., 20, 40, 60 and 80 per cent was studied. The results revealed that the 80 per cent CO2 concentration maintained high carbohydrate content (62.93 per cent) and crude fat (4.51 per cent) besides less protein (25.26 per cent) content after two months of storage. The 80per cent CO2 treatment was consistently found to be the best treatment when it was retested in bulk quantity (25 kg of seed) after two months of storage period. High carbohydrate, crude fat content and low protein content were observed in all the CO2 treatments (20, 40, 60 and 80 per cent) when compared to untreated control. These findings suggest that using elevated CO2 levels could be a viable alternative to synthetic pesticides chemical fumigants for preserving green gram during storage.

CO2 treatment of recycled concrete aggregates with high mortar contents: From finding optimal treatment condition, quality enhancement, to life cycle assessment

With increasing construction and demolition waste, the demand for recycled concrete aggregates (RCA) has risen, yet their inherent poor-quality limits usage. In response, CO2 treatment has been developed to enhance RCA quality while contributing to CO2 reduction efforts. This study investigates the effect of CO2 treatment on RCA with high mortar contents for sustainable construction applications. Treatment conditions were optimized by evaluating the CO2 consumption ratio and reaction kinetics under various temperatures (10–50°C), pressures (250–1000 kPa), relative humidity (30–70 %), and initial saturation (30–100 %). X-ray imaging confirms carbonation within the mortar, evidenced by increased greyvalues. Environmental assessment of leachate reveals a significant reduction in chromium concentration from 0.18 mg/L to 0.11 mg/L and a decrease in pH from 10.1 to 7.8 after CO2 treatment, suggesting the potential of CO2 conditioning to mitigate the environmental impacts. Mechanical tests, the aggregate crushing value (ACV) test, and the freeze-thaw (FT) resistance test, demonstrate the improved resistance and durability, with a decrease in ACV from 35.5 % to 33.2 % and FT mass loss from 25.1 % to 20.0 %. The life cycle assessment analysis shows that a simplified CO2 treatment achieved a significant reduction of 138.257 kg CO2 eq per ton of RCA compared to the conventional RCA process. These findings highlight the dual benefits of CO2 treatment: enhanced mechanical performance and reduced environmental impact, promoting the use of recycled aggregates in sustainable construction practices.

Evaluating CO2 concentration effects on growth kinetics and fatty acid composition in Euglena gracilis

ABSTRACT Industrial development has significantly increased CO2 emissions, from 280 ppm in the pre-industrial era to over 400 ppm today, contributing to the greenhouse effect and climate change. This study investigates the impact of varying CO2 concentrations on the growth, biomass accumulation, and biochemical composition of Euglena gracilis as microalgae-based carbon capture and utilization. E. gracilis was cultivated with CO2 concentrations of 0%, 5%, 10%, and 30%, using white LED lights at 3000 lux. Growth was monitored through cell counts and optical density, while biomass and primary metabolites were analysed using standard methods. Fatty acid content was assessed using GC-MS and GC-FID. The results showed optimal growth at 5% CO2, with biomass reaching 2.3 g l‒1 on the day of harvest. The highest lipid content was obtained in the 15% CO2 treatment with a total lipid of 0.35 g l‒1. As for the decrease in pH, it showed that each treatment experienced a reduction in pH from 3.5 to almost 2.0. Fatty acid content was dominated by polyunsaturated fatty acids (PUFAs), especially in the control group and 15% CO2 treatment, contributing up to 47.66%, and 46.36% to the group, respectively. The study highlights the importance of optimizing CO2 levels for microalgae cultivation to enhance biomass and lipid production. Elevated CO2 levels boost lipid synthesis but can stress cells if too high, suggesting a need for adaptive CO2 addition methods.

Gradual and abrupt increase in atmospheric CO2 concentrations trigger divergent responses of microbial necromass accumulation in paddy soils

Microbial necromass C (MNC) plays a critical role in promoting soil organic C (SOC) formation and stabilization, particularly in the context of climate change. Most investigations on the impact of elevated CO2 concentrations (eCO2) on MNC have been performed by exposing ecosystems to an abrupt increase in CO2. However, the atmospheric CO2 increase is a gradual process, and knowledge about the response of necromass to gradual increase in CO2 is lacking. We tested the hypothesis that microbial necromass would show different responses to abrupt and gradual CO2 increases. Furthermore, it is still unknown whether eCO2 will trigger similar responses between surface and subsurface soil layers. Here, we determined the MNC concentrations and their proportions in SOC in surface and subsurface soil layers via open-top chambers. CO2 treatments included ambient control, abrupt CO2 increase by 200 ppm above control, and gradual CO2 increase by 40 ppm each year until reaching 200 ppm over five years. Overall, compared with the ambient control, abrupt eCO2 induced a significantly stronger decrease in necromass (20.3 %) when averaged across three soil layers, while gradual eCO2 led to insignificant variations in necromass (6.7 %). The necromass proportion in SOC decreased with depth under both eCO2 treatments with a significant decline occurring in abrupt eCO2 treatment. The observed greater magnitude of eCO2 effects on fungal necromass relative to bacterial necromass in subsurface layers illustrates a distinct microbial community response to climate change. Taken together, abrupt and gradual eCO2 approaches differed in their impact on MNC, and its response to eCO2 may be somewhat overestimated by abrupt eCO2 approach. Furthermore, MNC in subsurface soil witnessed a more sensitivity or vulnerability to eCO2 than that of topsoil. We suggest vigilant attention will need to be paid to the feedback of necromass C in deep soil poised by future climate change.

Ocean acidification may alleviate the toxicity of zinc to the macroalga, Ulva lactuca

We investigated the toxic effects of different zinc (Zn) concentrations (natural seawater, 25 μg/L, and 100 μg/L) under two CO2 concentrations (410 ppmv, and 1000 ppmv) on Ulva lactuca. A significant decrease in the relative growth rate of U. lactuca was observed with an increase in Zn concentration under the low CO2 treatment condition, and we observed a notable decrease at 100 μg/L Zn under the high CO2 treatment condition. Moreover, the net photosynthetic rate increased when thalli were cultured under 25 and 100 μg/L Zn under the high CO2 treatment condition. The concentrations of chlorophyll a and b were significantly increased under 100 μg/L Zn and the high CO2 treatment conditions. Malondialdehyde content decreased under high CO2 treatment conditions, compared with the low CO2 treatment conditions, regardless of the Zn concentration. These findings suggest that ocean acidification may alleviate the toxic effects of Zn pollution on U. lactuca.

Species interactions amplify functional group responses to elevated CO2 and N enrichment in a 24-year grassland experiment.

Plant functional groups (FGs) differ in their response to global changes, although species within those groups also vary in such responses. Both species and FG responses to global change are likely influenced by species interactions such as inter-specific competition and facilitation, which are prevalent in species mixtures but not monocultures. As most studies focus on responses of plants growing in either monocultures or mixtures, but rarely both, it remains unclear how interspecific interactions in diverse ecological communities, especially among species in different FGs, modify FG responses to global changes. To address these issues, we leveraged data from a 16-species, 24-year perennial grassland experiment to examine plant FG biomass responses to atmospheric CO2, and N inputs at different planted diversity. FGs differed in their responses to N and CO2 treatments in monocultures. Such differences were amplified in mixtures, where N enrichment strongly increased C3 grass success at ambient CO2 and C4 grass success at elevated CO2. Legumes declined with N enrichment in mixtures at both CO2 levels and increased with elevated CO2 in the initial years of the experiment. Our results suggest that previous studies that considered responses to global changes in monocultures may underestimate biomass changes in diverse communities where interspecific interactions can amplify responses. Such effects of interspecific interactions on responses of FGs to global change may impact community composition over time and consequently influence ecosystem functions.

The influence mechanism of water-liquid CO2 treatment on the hydrophobicity of vitrinite and inertinite

Liquid CO2 has similar properties to non-polar hydrocarbon oils and can be used to achieve hydrophobic aggregation separation of coal macerals. To reveal the influence of the water-liquid CO2 treatment on the interfacial properties of vitrinite and inertinite, the effects of the water-liquid CO2 system on the interfacial properties of vitrinite and inertinite were investigated by SEM, BET, FTIR, and XPS. The results showed that the content of oxygen-containing functional groups on the coal macerals were reduced more significant than the hydrocarbons due to the physical adsorption and chemical extraction of liquid CO2, which led to an increase in the hydrophobicity of vitrinite and inertinite. The higher porosity and specific surface area of inertinite causing the decrease in the content of oxygen-containing functional groups in inertinite was greater than that in vitrinite. This study provides theoretical support for the separation of coal macerals using liquid CO2 hydrophobic agglomerates.

Permeability of porous membrane polymers modified by supercritical carbon dioxide

An approach to predict the gas permeability of membrane polymers after supercritical CO2 treatment is proposed. The approach is based on the connection of the temperatures of secondary relaxation transitions with the effective sizes of mobile free volume elements in the polymers. The correlation between permeability of nitrogen and effective sizes of mobile holes for a set of polymers is established. The effect of supercritical CO2 on the nitrogen permeability of polycarbonate, polysulfone, polyvinylbutyral is analyzed by FTIR spectroscopy of low-molecular weight conformationally-inhomogeneous compounds introduced in the polymers. Membranes were exposed at 40 MPa and 333 K for 4 h through static treatment and dynamic treatment separately. For polyvinylbutyral, the nitrogen permeability did not change after supercritical CO2 modification while for polysulphone, the effective volume of mobile holes increased, but the nitrogen permeability decreased. For polycarbonate after supercritical CO2, the effective volume of mobile holes and the nitrogen permeability increased.

The performance of CO2 reduction by dielectric barrier discharge plasma coupled Cu-Ni binary silicon-based composites

As a major greenhouse gas, the rational conversion and utilization of CO2 can help reduce carbon emissions and mitigate the greenhouse effect. In this study, mesoporous SiO2 as a carrier, with CuO and NiO employed to construct a binary metal composite silica-based catalyst, coupled with dielectric barrier discharge (DBD) plasma, for the conversion of CO2. Physicochemical analysis confirmed the successful introduction of CuO into the mesoporous SiO2. NiO and CuO bimetals were dispersed on SiO2 surfaces with large specific surface areas, ensuring an optimal distribution of metal oxide. Gas chromatography was utilized to investigate the performance of DBD-coupled x%CuO-3 %NiO/Si for CO2 conversion. The results indicated that the CuO-NiO binary composite silica catalysts significantly improved CO2 conversion, CO yield, and energy efficiency compared to the monometallic 3 %NiO/Si materials. Further microstructural analysis of the 9 %CuO-3 %NiO/Si catalyst revealed near-elliptic particles with dimensions of 200 by 500 nm and a large number of irregular fine particles attached to the surface. When the CuO loading reached an optimal level and the input power was set at 30 W, the energy efficiency of the 9 %CuO-3 %NiO/Si catalyst increased by 119.6 %. The CuO-NiO binary composite Si-based catalyst developed in this study boasts simple operation and environmental friendliness, making it highly significant for CO2 treatment.

The regulation of postharvest strawberry quality mediated by abscisic acid under elevated CO2 stress

Elevated CO2 was a potential strategy for strawberry preservation. However, the regulatory mechanism remained unclear. In current study, transcriptome analysis showed that elevated CO2 played important roles in regulating strawberry fruit quality at the transcriptional level, and plant hormones metabolism at least partially involved in the regulatory process. Further, ABA was demonstrated to play important roles in the response to elevated CO2. Elevated CO2 inhibited the accumulation of ABA, which was 61% lower than that in control. Elevated CO2 repressed ABA synthesis by inhibiting NCED activity and the expression of FaNCED1/2, leading to the reduction of ABA accumulation as a result. Meanwhile, elevated CO2 also decreased ABA sensitivity by down-regulating FaSnRK2.4/2.6 and FaABI5 expression. The dual down-regulation of ABA signaling accounted for the regulation of fruit quality under elevated CO2 treatment. These results provide new insights into the mechanism of strawberry fruit response to elevated CO2.

Hepatic Transcriptomic Responsiveness of Polar Cod, Boreogadus saida, to Ocean Acidification and Warming

Background: This study was part of a larger comprehensive project (BIOACID) addressing the physiological resilience of Polar cod, Boreogadus saida, to ocean acidification and global warming and aimed to unravel underlying molecular mechanisms of the observed physiological responses. Methods: Fish were acclimated long-term to three CO2 concentrations comprising control conditions (390 ppm) and two projected climate scenarios (780 ppm and 1170 ppm). Each CO2 treatment was combined with four temperatures: 0, 3, 6, and 8 °C. Here, we focused on the hepatic transcriptomic profiles from these previously physiologically characterized fish. Results: Generally, we did not detect signs of a classical stress response. Consistent with functional observations, warming induced much stronger molecular responses compared to elevated PCO2, but an interaction between both factors existed to some extent. Gene ontology analysis revealed a strong response in lipid, amino acid, and protein metabolism. With increasing temperature, we observed a shift away from lipid metabolism, while carbohydrate metabolic pathways remained stable. Conclusions: Although we found Polar cod to be quite resilient to ocean acidification, temperature will remain a critical parameter for this valuable Arctic keystone species, and the question remains as to whether the observed acclimation strategies can be implemented in its natural habitat, especially when food supply is limited.

Study the structure, stability and CO2 adsorption of the ScVB5 cluster

A combination of genetic algorithm and density functional theory (GA-DFT) was used to calculate the minimum structures of ScVB5 clusters. The thirteen isomers of ScVB5 cluster were investigated at the level of PBE/def2-TZVPP, TPSSh/def2-TZVPP, and TPSSh/def2-QZVP levels. The relative energies, the structural geometry, ionization energy, affinity energy of neutral isomers were reported. The ScVB5 cluster can be formed by adding atom into smaller clusters. The proposed structure of ScVB5 cluster for CO2 treatment is a pentagonal bipyramid in the Cs symmetry with vanadium atom at one of the vertices and scandium atom in the base of bipyramid. The favor position for adsorp CO2 by the ScVB5 cluster were at around of Sc and V atoms. The dual transition metal-doped boron clusters can interact with CO2 molecules stronger than pure boron clusters.

Gas-phase and liquid-phase purification of plastic waste derived carbon nanotubes: Effect of purification agent and operational parameters

The preparation of carbon nanotubes (CNTs) by catalytic pyrolysis of waste plastics is one of the most promising technologies to realize the harmless and high-value recycling of waste plastics. However, there are limited studies on the purification of waste-derived carbons, which is of significance for downstream applications. In this paper, the effects of different gas-phase purification conditions (temperature, gas type), liquid-phase purification (hydrochloric and nitric acid reflux), and combined gas-liquid purification on the properties of CNTs prepared from waste plastics were investigated. The as-obtained and purified CNTs were characterized using SEM, TEM, TPO, XRD, XPS, Raman spectroscopy, and FTIR spectroscopy. Results showed that operational temperatures have distinct impacts on the properties of CNTs during gas-phase purification. An appropriate temperature range for gas-phase purification was determined, with temperatures around 450 °C for air, 650 °C for CO2, and 700 °C for steam respectively, so that the amorphous carbon could be removed and the graphitization of CNTs was retained. Approximately 93 wt% of the metal catalyst particles could be removed with acid treatment for 4 h. In addition, carboxyl and hydroxyl functional groups were introduced to CNTs after acidic treatment. Furthermore, it was found that the approach combining CO2 treatment and nitric acid washing yielded CNTs with relatively higher quantities and lower defect levels. Results showed the properties of CNTs varied from the purification methods, which could meet different needs based on the downstream specific application requirements.

Performance Evaluation of Three Peanut Cultivars Grown under Elevated CO2 Concentrations

This study explored the performance and physiological responses of three commercially used peanut cultivars in Australian farming systems under ambient and elevated CO2 conditions, aiming to identify the most suitable genotype for dual-purpose (grain and graze) cropping experiments. The experiment utilized an open-top chamber (OTC) facility to regulate CO2 concentrations. The elevated CO2 (EC) treatment targeted approximately 650 ± 50 µmol mol−1, while both ambient CO2 (AC) and control plots operated at a concentration of approximately 400 µmol mol−1. Notably, control plots without chambers served as a reference for current CO2 and environmental conditions. In contrast, despite having the same ambient CO2 concentration, AC plots were enclosed in chambers, allowing for plant growth comparisons with EC plots with the same environmental conditions aside from CO2 levels. The analyses revealed significant effects of CO2 enrichment on peanut plants. In particular, the EC treatment led to enhanced photosynthetic rates (20% in Kairi, 31% in Holt, and 19% in Alloway), alongside reduced stomatal conductance (−55% in Kairi, −32% in Holt, and −40% in Alloway), transpiration, and increased water use efficiency compared to AC conditions. Elevated CO2 levels positively influenced pod yields in Kairi (+41%) and Alloway (+36%). However, CO2 enrichment did not significantly alter the protein content, total phenolic content, cupric-reducing antioxidant capacity, and ferric-reducing antioxidant power of peanut plant material. Furthermore, no significant differences were observed in the phytochemical composition among the three cultivars under ambient or elevated CO2 conditions. On the other hand, analysis of the fibre structure conducted on peanut stover harvested at plant maturity suggested potential declines in feedstock quality. Based on the findings of this research, further investigations and testing, including simulated grazing trials, will be carried out to identify a single breed line suitable for dual-purpose management under future elevated CO2 conditions.