MOFs: A Tailor-made Solution for a Global CO2 Problem
The super-adsorbents with the highest CO2 capacity and low-energy demands will be in the frontline of Carbon Capture Technologies
Our ever-increasing technological and convenient lives are threatening the very home that sustains us. The destructive impact of our high energy-driven lifestyles is playing out in many forms, from flooding, droughts & forest fires to melting glaciers & rising sea levels. Evidence of these drastic effects has come to the fore recently, manifesting in the form of unprecedented wildfires in both the Arctic circle and Amazon rainforest.
Carbon dioxide (CO2) and other pollutant gases emitted to the atmosphere can absorb solar radiation. The ‘blanket’ effect associated with these emissions results in the planet getting hotter is known as the Greenhouse Effect. Irrespective of the link between CO2 emissions and global warming; fossil fuel combustion is still our main energy source for electricity generation, transportation, and manufacturing.
Alarmingly, if we stick to our current path of fossil fuel utilization, total annual worldwide carbon dioxide emissions are forecast to increase by ca. 15% by the year 2050, equivalent to an additional 2 billion SUVs worth of CO2 annually!
As a society, we are now at a crossroads; continue on our convenient but short-sighted path of irresponsible CO2 pollution; or start developing and implementing effective strategies to deal with these emissions.
Realisation & Action
Thankfully, we are waking up to the magnitude of this global problem. Various international agreements have been implemented to tackle the growing issues surrounding greenhouse gas emissions and global warming, such as:
The Kyoto Protocol (1997)
The Paris Agreement (2015)
A report provided by the Intergovernmental Panel on Climate Change (IPCC), has defined critical targets which must be met to limit global mean surface temperature increase. The IPCC is estimating that anthropogenic CO2 emissions (pre-2011) will need to undergo a reduction of 45% by 2030, reaching net-zero by 2050. Such a goal demands rapid, far-reaching, and unprecedented changes in all aspects of society. To realise these objectives, various CO2 abatement initiatives are being considered, such as:
Energy conservation strategies
Implementation of low carbon / carbon neutral fuels
Alternative renewable energies
Carbon capture storage (CCS) and carbon capture utilisation (CCU)
What is CCS/CCU?
CCS (Carbon Capture and Storage) and CCU (Carbon Capture and Utilisation) technologies are both very promising approaches for removing CO2 from large stationary sources. Both technologies are capable of removing the majority of carbon dioxide emitted at large industrial process facilities such as oil refineries, cement plants, and power plants. Carbon dioxide is initially ‘captured’ at source, compressed, and dealt with in different ways.
During CCS, CO2 is transported to a suitable site where it can be stored indefinitely via several methods such as geological storage, mineral storage, or bacterial degradation. CCU differs in that captured CO2 is used to produce higher-value chemicals such as biofuels, plastics, concretes, and chemical feedstocks.
One of the most challenging aspects of CCS/CCU involves the capture and separation of CO2 from industrial gas streams. Various ‘mature’ technology solutions currently exist on the market, including absorption and cryogenic separation. However, the high operating costs and associated environmental impacts of these processes have limited their deployment; leaving the door open to alternative and more efficient methods. The direct removal of CO2 via adsorption technologies represents a promising solution over traditional CCS and CCU methods. Adsorption-based processes can boast high CO2 removal efficiencies with significantly reduced operating costs, affording an attractive option for the future of carbon dioxide capture.
Benefits of MOFs for carbon capture
To date, the low CO2 capacities and CO2/N2 selectivities of conventional sorbents have posed the main obstacles to the successful deployment of adsorption-based processes in CCS / CCU.
Metal Organic Frameworks (MOFs) are tailormade super-adsorbents materials that are highly tuned for CO2 capture. They represent a disruptive technology platform with huge potential in the gas storage and separation industries.
Metal organic frameworks enjoy many advantages over traditional adsorbents (zeolites, aluminas, silicates, and activated carbons). The existence of tailored open metal sites has resulted in MOF having the highest known capacity for CO2, making them prime candidates for carbon capture. By specifically selecting MOFs with low heats of carbon dioxide adsorption, very low regeneration energy requirements can be attained whilst maintaining extremely high CO2 selectivities. In fact, MOF-based systems can have up to half the energy requirements of an amine-based solution. The structures themselves can be tuned to repel competing adsorbate species e.g. H2O, simultaneously enhancing hydrothermal stability and selectivity.
MOF Technologies’ Role
MOF Technologies envisage that MOFs will enable the use of our natural resources in a more efficient manner and will improve the quality of our lives. Towards this aim, we have dedicated our efforts to unlock the huge potential of MOFs and develop viable CCS solutions, a critical element for the overall strategy to mitigate the threat of climate change. As the pioneers in developing MOF applications, we are taking MOF-based carbon capture from concept to reality.
MOF Tech has developed MOFs specially engineered for CO2. We have tailored the physicochemical properties of our materials to ensure that they deliver unrivalled selectivity and storage capacities. We have already proven the feasibility of this technology at a lab-scale and now seeking a development partner to accelerate its in-field pilot demonstration. It’s our vision that through such collaborative approaches, MOFs will continue to be a game-changing weapon in the fight against CO2 pollution.
The Big Picture
To tackle the problems associated with climate change, we must not rely solely on a single CO2 abatement strategy, but rather combine the benefits of multiple complimentary approaches. If global warming was a jigsaw puzzle, renewable energy, clean fuels, energy efficiency, CCS and CCU would form the major pieces to the solution. The MOF pieces for CCS and CCU are already on the table ready to be utilised, they merely need to be uncovered and put in place sooner rather than later.