Explainer: Carbon capture materials (sorbents, membranes) — a practical primer for teams that need to ship

Global carbon capture capacity surpassed 50 million tonnes per annum in 2024, yet this represents barely 0.1% of the 36.8 gigatonnes of CO₂ emitted annually. The gap between current capacity and what climate models demand—upwards of 7 gigatonnes by 2050—underscores a critical materials science challenge. For teams building or deploying carbon capture systems, the choice between solid sorbents, liquid amines, and membrane-based separation is not merely academic: it determines capital expenditure, energy penalties, operational flexibility, and ultimately whether projects can attract financing in an increasingly competitive landscape.

Why It Matters

North America sits at the epicenter of the carbon capture buildout. As of Q4 2024, the U.S. Department of Energy had allocated over $3.7 billion to carbon capture demonstration projects, while Canada's federal investment tax credit offers up to 60% coverage for direct air capture (DAC) equipment. The Inflation Reduction Act's enhanced 45Q tax credit—now offering $180 per tonne for DAC and $85 per tonne for point-source capture—has fundamentally altered project economics. In 2025, the North American pipeline includes more than 120 proposed capture facilities representing over 200 million tonnes of potential annual capacity.

Yet the materials that enable this capture remain the limiting factor. Amine-based solvents, which dominate approximately 85% of operational facilities, impose energy penalties of 25–40% on power plants. Next-generation solid sorbents promise to reduce regeneration energy by 30–50%, but face degradation challenges under real-world flue gas conditions. Membrane technologies offer modular scalability but struggle with selectivity-permeability trade-offs that limit their application to high-CO₂ concentration streams.

For sustainability teams, procurement officers, and engineering leads, understanding these trade-offs is no longer optional. The difference between selecting a proven but energy-intensive amine system versus betting on an emerging sorbent technology can mean the difference between a bankable project and a stranded asset.

Key Concepts

Carbon Capture Technology Classes

Carbon capture systems separate CO₂ from mixed gas streams through three primary mechanisms. Absorption uses liquid solvents (typically amines like monoethanolamine) that chemically bind CO₂, then release it upon heating. Adsorption employs solid sorbents—including metal-organic frameworks (MOFs), zeolites, and amine-functionalized silicas—that capture CO₂ on their surfaces. Membrane separation relies on polymer or inorganic barriers that preferentially allow CO₂ to pass while blocking other gases.

Materials Characterization

Rigorous characterization underpins sorbent and membrane development. Key measurements include surface area (via BET analysis), pore size distribution, CO₂ uptake capacity (typically measured in mmol/g), and adsorption kinetics. For membranes, selectivity (the ratio of CO₂ permeability to N₂ permeability) and permeance (flux per unit driving force) define performance. Characterization under realistic conditions—humid flue gas, trace contaminants like SO₂ and NOₓ—reveals degradation mechanisms that laboratory idealized tests miss.

Benchmark KPIs

Industry benchmarks center on several critical metrics. Working capacity measures the usable CO₂ uptake between adsorption and desorption conditions, typically targeting >2 mmol/g for economically viable sorbents. Regeneration energy should fall below 2.5 GJ per tonne CO₂ to compete with optimized amine systems. Cycle stability requires materials to maintain >90% capacity after 1,000+ adsorption-desorption cycles. For membranes, targets include CO₂/N₂ selectivity >50 and CO₂ permeance >1,000 GPU (gas permeation units).

Scale-Up Challenges

Laboratory breakthroughs routinely fail at scale. Synthesizing MOFs at kilogram quantities often introduces defects absent in milligram batches. Forming sorbent powders into pellets or monoliths can reduce effective surface area by 20–40%. Heat and mass transfer limitations in large contactors create performance gaps between lab isotherms and field capture rates. Membrane module design must balance surface area with pressure drop and fouling resistance.

Catalysis and Sorbent Regeneration

Catalytic enhancement of CO₂ adsorption and desorption kinetics represents an emerging frontier. Incorporating catalytic sites—such as carbonic anhydrase mimics or metal nanoparticles—can accelerate CO₂ binding by orders of magnitude, reducing contactor sizes. However, catalyst stability under regeneration temperatures (80–150°C for most solid sorbents) and resistance to poisoning by flue gas impurities remain active research areas.

What's Working and What Isn't

What's Working

Amine scrubbing at scale: Despite energy penalties, amine-based capture has proven operational reliability across dozens of facilities. The Boundary Dam project in Saskatchewan has captured over 4 million tonnes since 2014, demonstrating that first-generation technology can function at utility scale. Operational learnings—including solvent management, corrosion mitigation, and emissions control—provide a foundation for next-generation deployments.

Temperature-swing adsorption for DAC: Climeworks and Carbon Engineering have demonstrated that solid sorbent systems can operate in direct air capture configurations. Climeworks' Orca and Mammoth facilities in Iceland use amine-functionalized filter materials with low-temperature geothermal regeneration, achieving capture costs that have declined from >$600/tonne in 2021 to approximately $400/tonne in 2025.

Hybrid membrane-absorption systems: Combining membranes for bulk CO₂ enrichment with absorption for final polishing leverages the strengths of both approaches. MTR (Membrane Technology and Research) has deployed Polaris membranes at the National Carbon Capture Center in Alabama, demonstrating 90% capture rates from coal flue gas when integrated with downstream amine scrubbing.

MOF commercialization pathways: Companies like Svante and Mosaic Materials have moved metal-organic framework sorbents from laboratory curiosities toward commercial viability. Svante's VeloxoTherm process, using proprietary structured adsorbent beds, has been validated at the Husky Lloydminster Ethanol Plant in Saskatchewan.

What Isn't Working

Material stability under real conditions: Laboratory sorbents tested with pure CO₂ often degrade rapidly when exposed to humid flue gas containing SO₂, NOₓ, and particulates. Amine-functionalized materials can oxidize, while some MOFs hydrolyze or lose crystallinity. The gap between idealized and realistic performance metrics routinely exceeds 50%.

Heat integration economics: Solid sorbent systems require significant heat input for regeneration. Many proposed projects assume access to low-cost waste heat that proves unavailable or variable in practice. Without favorable heat integration, regeneration energy costs can double, undermining project economics.

Membrane module manufacturing at scale: While laboratory membrane films achieve impressive selectivity and permeance, translating these into robust modules that operate for years without replacement remains challenging. Membrane compaction under pressure, plasticization by CO₂, and fouling by particulates limit real-world performance.

Supply chain bottlenecks: Specialty sorbent precursors—including organic linkers for MOFs and high-purity amines—face constrained global supply. The 2024 surge in DAC project announcements outpaced sorbent manufacturing capacity, creating 12–18 month lead times for some materials.

Key Players

Established Leaders

1. Shell Cansolv: Provides amine-based capture technology deployed at Quest (Alberta) and multiple refineries, with over 20 million tonnes of cumulative capture experience.

2. Mitsubishi Heavy Industries (MHI): Offers the KM CDR Process, with installations at Petra Nova (Texas) and partnerships spanning North American industrial facilities.

3. Fluor Corporation: Licenses Econamine FG Plus technology, with deployments at cement plants and power stations across the continent.

4. Linde Engineering: Delivers turnkey CO₂ capture and purification systems integrated with industrial gas supply chains.

5. Honeywell UOP: Develops advanced solvents and process intensification solutions for post-combustion capture in refining and petrochemical applications.

Emerging Startups

1. Svante (Vancouver, BC): Commercializes solid sorbent technology using rapid-cycle temperature-swing adsorption, with pilot validation at multiple industrial sites.

2. Climeworks (with North American expansion): Swiss-based DAC leader expanding into the U.S. market, targeting multi-megatonne projects with solid sorbent systems.

3. CarbonCapture Inc. (Los Angeles, CA): Develops modular DAC systems using novel sorbent materials, with a pilot facility in Wyoming.

4. Mosaic Materials (Oakland, CA): Pioneers diamine-appended MOFs with high CO₂ selectivity, backed by strategic partnerships with oil majors.

5. Membrane Technology and Research (Newark, CA): Advances Polaris membrane technology for industrial flue gas applications, with National Carbon Capture Center validations.

Key Investors & Funders

1. U.S. Department of Energy (Office of Fossil Energy and Carbon Management): Largest public funder, with $3.7 billion allocated to regional DAC hubs and demonstration projects.

2. Breakthrough Energy Ventures: Bill Gates-backed fund with investments in Climeworks, CarbonCapture Inc., and other frontier capture technologies.

3. Lowercarbon Capital: Active in early-stage carbon removal investments, funding materials science startups developing next-generation sorbents.

4. Oil majors (Occidental, Chevron, ExxonMobil): Strategic investors providing both capital and offtake agreements for captured CO₂, particularly for enhanced oil recovery and permanent sequestration.

5. Canada Growth Fund: Government-backed entity offering C$15 billion for clean technology deployment, including carbon capture projects.

Examples

1. Quest Carbon Capture and Storage (Alberta, Canada): Operated by Shell since 2015, Quest captures approximately 1.2 million tonnes of CO₂ annually from the Scotford Upgrader using Shell Cansolv amine technology. The project has achieved 99.99% capture uptime and demonstrated that integrated CCS can operate reliably in cold climates. Crucially, Quest's operational data has informed sorbent degradation models and helped de-risk subsequent North American projects.

2. Project Bison (Wyoming, USA): CarbonCapture Inc. is developing a multi-phase DAC facility targeting 5 million tonnes per year by 2030. Phase 1, operational in 2024, uses modular sorbent-based systems that can be manufactured off-site and deployed rapidly. The project benefits from Wyoming's Class VI well permitting streamlining and low-cost renewable electricity, achieving projected capture costs below $250/tonne at full scale.

3. National Carbon Capture Center Membrane Demonstrations (Alabama, USA): MTR's Polaris membranes have been tested at the Southern Company-operated facility using actual coal-fired power plant flue gas. Results from 2023–2024 campaigns demonstrated 90% CO₂ capture with <10% energy penalty when combined with downstream polishing, validating membrane technology for high-CO₂ industrial streams.

Action Checklist

• Conduct a flue gas characterization study to identify contaminants (SO₂, NOₓ, particulates, humidity) that may degrade sorbent or membrane performance
• Evaluate waste heat availability and temperature profiles to determine feasibility of temperature-swing adsorption versus alternative regeneration approaches
• Request accelerated aging test data from sorbent vendors demonstrating >1,000 cycle stability under realistic conditions
• Model the impact of supply chain constraints on project timelines; identify secondary sorbent suppliers or membrane manufacturers
• Engage with 45Q tax credit advisors to optimize capture system design for maximum credit qualification
• Develop a sorbent replacement and disposal plan addressing end-of-life material handling and potential recycling pathways
• Benchmark proposed system energy penalty against DOE targets (<2.5 GJ/tonne) to ensure project competitiveness
• Establish monitoring protocols for real-time sorbent performance tracking, enabling predictive maintenance and capacity forecasting
• Assess Class VI well permitting timelines in target geographies to align capture system commissioning with sequestration availability
• Build relationships with strategic offtake partners (enhanced oil recovery operators, concrete producers, or permanent storage developers) to secure CO₂ disposition pathways

FAQ

Q: What is the cost difference between solid sorbents and traditional amine systems? A: Capital costs for solid sorbent systems currently run 20–40% higher than conventional amine scrubbers due to specialized contactor designs and less mature manufacturing. However, operational costs can be 15–30% lower when favorable heat integration is available, as solid sorbents typically regenerate at 80–120°C versus 120–150°C for amines. Levelized capture costs converge at approximately $50–80/tonne for point-source applications, with project-specific heat availability being the decisive factor.

Q: How do membrane systems compare to sorbents for direct air capture? A: Membranes face fundamental thermodynamic challenges in DAC applications due to the low CO₂ concentration (~420 ppm) in ambient air. Achieving adequate driving force across the membrane requires either vacuum on the permeate side (energy-intensive) or very large membrane areas (capital-intensive). Current DAC deployments overwhelmingly favor solid sorbents, though hybrid approaches using membranes for initial enrichment before sorbent capture are under investigation.

Q: What are the primary failure modes for MOF-based sorbents? A: Metal-organic frameworks can fail through several mechanisms: hydrolysis (water molecules disrupting metal-ligand bonds), oxidative degradation of organic linkers, thermal decomposition during regeneration, and poisoning by acidic flue gas components. Careful MOF selection—prioritizing water-stable frameworks like zeolitic imidazolate frameworks (ZIFs) or aluminum-based MOFs—and upstream flue gas conditioning can mitigate these risks.

Q: How should teams evaluate sorbent vendor claims? A: Require vendors to provide performance data under conditions matching your specific flue gas composition, including humidity and contaminants. Insist on accelerated cycling tests (minimum 500 cycles) at relevant temperatures. Request references from operating facilities with similar gas streams. Validate working capacity claims using independent laboratory characterization if possible. Be skeptical of performance metrics derived solely from pure CO₂ or dry gas testing.

Q: What policy developments are most likely to impact sorbent and membrane deployment in North America? A: The continuation and potential expansion of the 45Q tax credit remains the single largest policy driver. EPA's proposed Class VI well permitting acceleration and state-level CO₂ pipeline siting reforms will influence where capture facilities can practically sequester CO₂. Canada's carbon pricing trajectory (currently C$80/tonne, rising to C$170/tonne by 2030) creates additional economic incentive for capture deployment, particularly in Alberta's industrial heartland.

Sources

• U.S. Department of Energy, Office of Fossil Energy and Carbon Management. "Carbon Capture and Storage Program: FY2024 Project Portfolio." Washington, DC, 2024.

• International Energy Agency. "CCUS in Clean Energy Transitions." IEA Publications, Paris, 2024.

• National Academies of Sciences, Engineering, and Medicine. "Negative Emissions Technologies and Reliable Sequestration: A Research Agenda." The National Academies Press, Washington, DC, 2019.

• Global CCS Institute. "Global Status of CCS 2024." Melbourne, Australia, 2024.

• Rochelle, G.T. "Amine Scrubbing for CO₂ Capture." Science, vol. 325, no. 5948, 2009, pp. 1652–1654.

• Siegelman, R.L., et al. "Porous Materials for Carbon Dioxide Separations." Nature Materials, vol. 20, 2021, pp. 1060–1072.

• Canada Energy Regulator. "Carbon Capture, Utilization and Storage in Canada." Calgary, AB, 2024.