Periodic Reporting for period 1 - GRACE (Rationale design of sustainable porous organosilicas for optimal CO2 uptake from biogas)
Reporting period: 2023-03-01 to 2025-08-31
Summary of the context and overall objectives of the project
The urgent need to mitigate climate change has placed reducing greenhouse gas emissions, particularly carbon dioxide (CO2), at the forefront of international policy agendas. As governments and industries strive to achieve the EU Green Deal’s target of climate neutrality by 2050, the development of efficient CO2 capture and utilization technologies has become an essential component of sustainable industrial transitions. Within this framework, biogas upgrading, where CO2 is separated from CH₄ to obtain high-purity biomethane, represents a critical technological and economic challenge. However, most current CO2 adsorbents are based on energy-intensive, non-renewable, or environmentally harmful materials, which hinder their large-scale and sustainable deployment.
The GRACE project directly addresses this challenge by pioneering the rational design of sustainable, structured porous organosilicas as next-generation CO2 adsorbents optimized for biogas upgrading under industrially relevant conditions by 1) rational design of sustainable and efficient periodic mesoporous organosilicas (PMO) adsorbents; 2) obtain structure-property relationships studying gas-sorbent interactions at the atomic/molecular scales by NMR and computer modeling techniques; 3) shape the PMO grains for biogas upgrading, able to work under industrially-relevant operating conditions. Alternatively, it also proposes the use of other sustainable-based adsorbents for enhanced CO2 and CH4 separation.
Project Developments:
1) Design of sustainable adsorbents: The project has developed a diverse portfolio of CO2 adsorbent materials, including PMO-based sorbents functionalized with amino and fluorine groups, as well as waste-derived polysaccharides, biochars, mesoporous carbons, and metal–organic frameworks. By leveraging the distinct adsorption properties of these material families, the project advances innovative solutions for efficient CO2 capture and separation. Furthermore, using microwave-assisted synthesis and other advanced preparation techniques, the project ensures highly efficient, reproducible, and scalable fabrication of these materials, directly addressing the need for robust and sustainable adsorbents suitable for biogas upgrading. Additionally, labeling techniques were introduced in the PMO
2) Unraveling the structure-property relationships in CO2-sorbents: Unraveling the structure-property relationships in CO2-sorbents: By combining multiple characterization techniques, chosen depending on the materials family, namely ssNMR, XPS, EA, operando TGA-IR, gas sorption isotherms, and microscopy which were combined by computational modeling for some of the materials families, the project found the CO2-sorption mechanism governing the CO2- adsorbent surface interactions.
3) Structuring adsorbent materials – proof of concept: To evaluate the sorbent behavior under conditions representative of real industrial applications, the project conducts breakthrough curve analyses using gas mixtures containing both CO2 and CH₄ at varying concentrations. These experiments assess the materials’ dynamic adsorption performance and selectivity under realistic process conditions. To facilitate large-scale implementation and overcome pressure drop issues commonly associated with powdered materials, the project has developed and optimized two shaping strategies: 3D-printed adsorbents and adsorbent incorporation into alginate beads. These approaches enhance the mechanical stability, processability, and overall applicability of the materials in industrial biogas upgrading systems.
Expected Impact
GRACE advances the development of sustainable, high-performance adsorbents for CO2 capture and biogas upgrading by combining green synthesis, advanced characterization, and industrial shaping strategies. The project enhances understanding of CO2 adsorption mechanisms, providing fundamental insight into gas–solid interactions through solid-state NMR, XPS, computational modeling, operando analyses, and gas adsorption measurements. These insights support the rational design of selective and durable sorbents bridging molecular science and industrial application. GRACE’s outcomes are expected to improve process efficiency and reduce CO2 emissions, contributing to the EU Green Deal and Circular Economy goals, while laying a foundation for continued innovation in sustainable carbon management and more climate-conscious industrial practices.
The GRACE project directly addresses this challenge by pioneering the rational design of sustainable, structured porous organosilicas as next-generation CO2 adsorbents optimized for biogas upgrading under industrially relevant conditions by 1) rational design of sustainable and efficient periodic mesoporous organosilicas (PMO) adsorbents; 2) obtain structure-property relationships studying gas-sorbent interactions at the atomic/molecular scales by NMR and computer modeling techniques; 3) shape the PMO grains for biogas upgrading, able to work under industrially-relevant operating conditions. Alternatively, it also proposes the use of other sustainable-based adsorbents for enhanced CO2 and CH4 separation.
Project Developments:
1) Design of sustainable adsorbents: The project has developed a diverse portfolio of CO2 adsorbent materials, including PMO-based sorbents functionalized with amino and fluorine groups, as well as waste-derived polysaccharides, biochars, mesoporous carbons, and metal–organic frameworks. By leveraging the distinct adsorption properties of these material families, the project advances innovative solutions for efficient CO2 capture and separation. Furthermore, using microwave-assisted synthesis and other advanced preparation techniques, the project ensures highly efficient, reproducible, and scalable fabrication of these materials, directly addressing the need for robust and sustainable adsorbents suitable for biogas upgrading. Additionally, labeling techniques were introduced in the PMO
2) Unraveling the structure-property relationships in CO2-sorbents: Unraveling the structure-property relationships in CO2-sorbents: By combining multiple characterization techniques, chosen depending on the materials family, namely ssNMR, XPS, EA, operando TGA-IR, gas sorption isotherms, and microscopy which were combined by computational modeling for some of the materials families, the project found the CO2-sorption mechanism governing the CO2- adsorbent surface interactions.
3) Structuring adsorbent materials – proof of concept: To evaluate the sorbent behavior under conditions representative of real industrial applications, the project conducts breakthrough curve analyses using gas mixtures containing both CO2 and CH₄ at varying concentrations. These experiments assess the materials’ dynamic adsorption performance and selectivity under realistic process conditions. To facilitate large-scale implementation and overcome pressure drop issues commonly associated with powdered materials, the project has developed and optimized two shaping strategies: 3D-printed adsorbents and adsorbent incorporation into alginate beads. These approaches enhance the mechanical stability, processability, and overall applicability of the materials in industrial biogas upgrading systems.
Expected Impact
GRACE advances the development of sustainable, high-performance adsorbents for CO2 capture and biogas upgrading by combining green synthesis, advanced characterization, and industrial shaping strategies. The project enhances understanding of CO2 adsorption mechanisms, providing fundamental insight into gas–solid interactions through solid-state NMR, XPS, computational modeling, operando analyses, and gas adsorption measurements. These insights support the rational design of selective and durable sorbents bridging molecular science and industrial application. GRACE’s outcomes are expected to improve process efficiency and reduce CO2 emissions, contributing to the EU Green Deal and Circular Economy goals, while laying a foundation for continued innovation in sustainable carbon management and more climate-conscious industrial practices.
Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far
DESIGN OF SUSTAINABLE ADSORBENTS
i) PMO-based adsorbents:
• Investigated the silylation reactions of monoradicals and biradicals and their incorporation into PMO frameworks.
• Explored the amine synthesis of amine-derived organosilane precursors.
• Explored the preparation of sustainable surfactants derived from fatty alcohols as structure-directing agents.
• Prepared PMOs containing aromatic amines (e.g. aniline and vinylaniline) via post-modification approaches.
• Designed fluorine-functionalized PMOs through condensation reactions of fluorine-containing organosilane precursors.
ii) N-doped mesoporous carbon adsorbents:
• Synthesized mesoporous carbons through nanocasting using nitrogen-rich precursors such as 1,10-phenanthroline, D-glucosamine, urea, and melamine.
• Demonstrated that some of these materials also act as catalysts for the oxygen reduction reaction (ORR), relevant to fuel cell applications.
iii) Biochars:
• Developed sponge-like N-doped biochars via chitosan dissolution, freeze-drying, and pyrolysis; optimized pyrolysis temperature to enhance CO2 adsorption–separation performance while minimizing energy use.
• Produced N-doped biochars via microwave-assisted pyrolysis, comparing this energy-efficient route with conventional pyrolysis to understand structural and adsorption enhancements.
iv) Amino-derived polysaccharides:
• Processed waste crab shells through selective deproteinization and demineralization to tune textural properties while preserving their natural porous architecture for CO2 adsorption.
UNRAVELING THE STRUCTURE–PROPERTY RELATIONSHIPS IN CO2 SORBENTS
i) Non-modified and fluorine-derived PMOs:
• Characterized materials by XRD, TEM, FTIR, EA, TGA, solid-state NMR, and gas adsorption isotherms.
• Evaluated their performance for CO2, N2, and H2O adsorption.
ii) Biochars:
• Characterized by Raman spectroscopy, XPS, EA, XRD, SEM, TGA, and TGA-IR.
• Evaluated for CO2, N2, and CH₄ adsorption–separation.
• Performed preliminary solid-state NMR studies to investigate CO2–biochar surface interactions.
• Correlated structural and chemical features with gas adsorption–separation performance.
iii) N-doped mesoporous carbon adsorbents:
• Characterized by Raman spectroscopy, EA, XRD, TEM, TGA, and TXRF.
• Evaluated for CO2 adsorption–separation and ORR catalytic activity.
iv) Amino-derived polysaccharides:
• Characterized by FTIR, EA, XRD, solid-state NMR, SEM, and TGA.
• Correlated structural features with CO2 adsorption performance.
• Established the CO2 adsorption mechanism through a combined solid-state NMR and computational modeling approach.
STRUCTURING ADSORBENT MATERIALS – PROOF OF CONCEPT
3D Printing:
• Developed 3D-printable alkali-activated aluminosilicate composites incorporating biochars and activated carbon adsorbents.
• Optimized ink formulations and printing parameters to achieve desired structural integrity and porosity.
• Integrated industrial residues (e.g. red mud, biomass fly ash) into inks, reinforcing circular economy principles.
• Tested 3D-printed structures for CO2 adsorption under dynamic breakthrough conditions.
Alginate Spheres:
• Incorporated metal–organic frameworks (MOFs) into alginate beads.
• Evaluated MOF/alginate beads for CO2 and CH₄ adsorption up to 20 bar.
• Assessed CO2/CH₄ separation performance of the MOF/alginate beads under dynamic breakthrough conditions.
i) PMO-based adsorbents:
• Investigated the silylation reactions of monoradicals and biradicals and their incorporation into PMO frameworks.
• Explored the amine synthesis of amine-derived organosilane precursors.
• Explored the preparation of sustainable surfactants derived from fatty alcohols as structure-directing agents.
• Prepared PMOs containing aromatic amines (e.g. aniline and vinylaniline) via post-modification approaches.
• Designed fluorine-functionalized PMOs through condensation reactions of fluorine-containing organosilane precursors.
ii) N-doped mesoporous carbon adsorbents:
• Synthesized mesoporous carbons through nanocasting using nitrogen-rich precursors such as 1,10-phenanthroline, D-glucosamine, urea, and melamine.
• Demonstrated that some of these materials also act as catalysts for the oxygen reduction reaction (ORR), relevant to fuel cell applications.
iii) Biochars:
• Developed sponge-like N-doped biochars via chitosan dissolution, freeze-drying, and pyrolysis; optimized pyrolysis temperature to enhance CO2 adsorption–separation performance while minimizing energy use.
• Produced N-doped biochars via microwave-assisted pyrolysis, comparing this energy-efficient route with conventional pyrolysis to understand structural and adsorption enhancements.
iv) Amino-derived polysaccharides:
• Processed waste crab shells through selective deproteinization and demineralization to tune textural properties while preserving their natural porous architecture for CO2 adsorption.
UNRAVELING THE STRUCTURE–PROPERTY RELATIONSHIPS IN CO2 SORBENTS
i) Non-modified and fluorine-derived PMOs:
• Characterized materials by XRD, TEM, FTIR, EA, TGA, solid-state NMR, and gas adsorption isotherms.
• Evaluated their performance for CO2, N2, and H2O adsorption.
ii) Biochars:
• Characterized by Raman spectroscopy, XPS, EA, XRD, SEM, TGA, and TGA-IR.
• Evaluated for CO2, N2, and CH₄ adsorption–separation.
• Performed preliminary solid-state NMR studies to investigate CO2–biochar surface interactions.
• Correlated structural and chemical features with gas adsorption–separation performance.
iii) N-doped mesoporous carbon adsorbents:
• Characterized by Raman spectroscopy, EA, XRD, TEM, TGA, and TXRF.
• Evaluated for CO2 adsorption–separation and ORR catalytic activity.
iv) Amino-derived polysaccharides:
• Characterized by FTIR, EA, XRD, solid-state NMR, SEM, and TGA.
• Correlated structural features with CO2 adsorption performance.
• Established the CO2 adsorption mechanism through a combined solid-state NMR and computational modeling approach.
STRUCTURING ADSORBENT MATERIALS – PROOF OF CONCEPT
3D Printing:
• Developed 3D-printable alkali-activated aluminosilicate composites incorporating biochars and activated carbon adsorbents.
• Optimized ink formulations and printing parameters to achieve desired structural integrity and porosity.
• Integrated industrial residues (e.g. red mud, biomass fly ash) into inks, reinforcing circular economy principles.
• Tested 3D-printed structures for CO2 adsorption under dynamic breakthrough conditions.
Alginate Spheres:
• Incorporated metal–organic frameworks (MOFs) into alginate beads.
• Evaluated MOF/alginate beads for CO2 and CH₄ adsorption up to 20 bar.
• Assessed CO2/CH₄ separation performance of the MOF/alginate beads under dynamic breakthrough conditions.
Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)
RESULTS BEYOND THE STATE OF THE ART
The GRACE project has advanced the field of sustainable adsorbent materials for CO2 capture and biogas upgrading, achieving results that go beyond the current state of the art. By integrating green synthesis, advanced characterization, and industrial structuring, the project delivered a comprehensive approach to developing efficient and environmentally responsible gas separation materials.
SCIENTIFIC AND TECHNOLOGICAL ADVANCES
GRACE established sustainable synthetic routes for several classes of adsorbents—including PMO-based materials, N-doped mesoporous carbons, biochars, and amino-derived polysaccharides—many of which were produced from renewable or waste-derived sources. The use of microwave-assisted synthesis and energy-efficient pyrolysis substantially reduced energy consumption and reaction times compared to conventional methods.
Functionalization with amine groups enhanced CO2 affinity and selectivity, while fluorine-containing PMOs displayed improved hydrophobicity and moisture tolerance. Notably, certain bridged PMOs also demonstrated potential for hormone capture from real wastewater samples, broadening their applicability beyond gas separation. Meanwhile, N-doped carbons exhibited multifunctional behavior, serving not only as CO2 adsorbents but also as electrocatalysts for the oxygen reduction reaction (ORR), highlighting their potential in fuel cell technologies.
A major scientific contribution of GRACE lies in advancing the mechanistic understanding of CO2 adsorption across different material families. By combining advanced characterization techniques, including solid-state NMR, XPS, operando TGA-IR, gas adsorption isotherms, and/or computational modeling, the project generated new insight into how surface chemistry and pore architecture govern CO2–adsorbent interactions. This knowledge underpins the rational design of next-generation sorbents with improved selectivity, regeneration capacity, and durability.
On the application side, GRACE demonstrated scalable structuring strategies through 3D-printed aluminosilicate composites and MOF/alginate beads, addressing key engineering challenges such as pressure drop and mechanical stability. Both systems were successfully tested under dynamic CO2/CH₄ breakthrough conditions, showing promising performance for biogas upgrading.
POTENTIAL IMPACTS AND FUTURE NEEDS
The project’s outcomes contribute to the development of eco-efficient gas separation technologies, aligning with the EU Green Deal and Circular Economy objectives. GRACE promotes resource efficiency through waste valorization and establishes methodologies for green materials development with strong industrial relevance.
To ensure further progress and broader uptake, several needs were identified:
• Optimization of PMO precursor synthesis, as current yields remain low, limiting isotopic labeling strategies for amino-derived precursors.
• Further tuning of PMO pore structure, since materials with smaller pores and high organization remain challenging to produce.
• Comprehensive techno-economic and life-cycle assessments to quantify the environmental and cost advantages of the developed adsorbents.
• Scale-up and commercialization by developing scalable manufacturing processes for 3D-printed adsorbents and establishing strategic partnerships with industry to facilitate technology transfer and commercialization.
Overall, GRACE demonstrates that sustainable synthesis and advanced characterization can converge to deliver high-performance, low-impact CO2 adsorbents. The project provides both fundamental understanding and technological proof of concept, laying the foundation for scalable, circular, and climate-friendly CO2 capture solutions that support Europe’s transition toward a carbon-neutral industry.
The GRACE project has advanced the field of sustainable adsorbent materials for CO2 capture and biogas upgrading, achieving results that go beyond the current state of the art. By integrating green synthesis, advanced characterization, and industrial structuring, the project delivered a comprehensive approach to developing efficient and environmentally responsible gas separation materials.
SCIENTIFIC AND TECHNOLOGICAL ADVANCES
GRACE established sustainable synthetic routes for several classes of adsorbents—including PMO-based materials, N-doped mesoporous carbons, biochars, and amino-derived polysaccharides—many of which were produced from renewable or waste-derived sources. The use of microwave-assisted synthesis and energy-efficient pyrolysis substantially reduced energy consumption and reaction times compared to conventional methods.
Functionalization with amine groups enhanced CO2 affinity and selectivity, while fluorine-containing PMOs displayed improved hydrophobicity and moisture tolerance. Notably, certain bridged PMOs also demonstrated potential for hormone capture from real wastewater samples, broadening their applicability beyond gas separation. Meanwhile, N-doped carbons exhibited multifunctional behavior, serving not only as CO2 adsorbents but also as electrocatalysts for the oxygen reduction reaction (ORR), highlighting their potential in fuel cell technologies.
A major scientific contribution of GRACE lies in advancing the mechanistic understanding of CO2 adsorption across different material families. By combining advanced characterization techniques, including solid-state NMR, XPS, operando TGA-IR, gas adsorption isotherms, and/or computational modeling, the project generated new insight into how surface chemistry and pore architecture govern CO2–adsorbent interactions. This knowledge underpins the rational design of next-generation sorbents with improved selectivity, regeneration capacity, and durability.
On the application side, GRACE demonstrated scalable structuring strategies through 3D-printed aluminosilicate composites and MOF/alginate beads, addressing key engineering challenges such as pressure drop and mechanical stability. Both systems were successfully tested under dynamic CO2/CH₄ breakthrough conditions, showing promising performance for biogas upgrading.
POTENTIAL IMPACTS AND FUTURE NEEDS
The project’s outcomes contribute to the development of eco-efficient gas separation technologies, aligning with the EU Green Deal and Circular Economy objectives. GRACE promotes resource efficiency through waste valorization and establishes methodologies for green materials development with strong industrial relevance.
To ensure further progress and broader uptake, several needs were identified:
• Optimization of PMO precursor synthesis, as current yields remain low, limiting isotopic labeling strategies for amino-derived precursors.
• Further tuning of PMO pore structure, since materials with smaller pores and high organization remain challenging to produce.
• Comprehensive techno-economic and life-cycle assessments to quantify the environmental and cost advantages of the developed adsorbents.
• Scale-up and commercialization by developing scalable manufacturing processes for 3D-printed adsorbents and establishing strategic partnerships with industry to facilitate technology transfer and commercialization.
Overall, GRACE demonstrates that sustainable synthesis and advanced characterization can converge to deliver high-performance, low-impact CO2 adsorbents. The project provides both fundamental understanding and technological proof of concept, laying the foundation for scalable, circular, and climate-friendly CO2 capture solutions that support Europe’s transition toward a carbon-neutral industry.