Scientists develop low-cost carbon capture technology

Chinese researchers from Tianjin University have developed a novel all-organic mixed-matrix membrane, which acts like a "CO2-specific sieve" for industrial flue gas — allowing carbon dioxide to pass through quickly, ensuring long-term material durability, and being suitable for large-scale industrial manufacturing.

The research team's findings, led by professors Jiang Zhongyi and He Guangwei, were published recently in the international academic journal Nature Energy, offering a brand-new low-cost solution for carbon capture from industrial flue gas.

"This breakthrough addresses a long-standing challenge in developing membranes that are both highly effective at separating carbon dioxide and easy to manufacture," said Yu Miao, a professor from the University at Buffalo in the United States. "It opens a promising pathway toward more energy-efficient and affordable carbon capture from industrial emissions."

Steel, cement and coal-fired power are pillar industries for modern infrastructure development, but their production processes generate large volumes of carbon dioxide. According to data from the International Energy Agency, part of these carbon emissions stem from chemical reactions inherent in the production process itself, which cannot be fully eliminated even by improving energy efficiency.

Together, steel and cement sectors account for around 14 percent of global energy and industrial process-related emissions.

For low-concentration flue gas from these industries, conventional carbon capture technologies typically cost $40 to $120 per metric ton of CO2. High costs and high energy consumption have long been the biggest barriers to large-scale industrial application of carbon capture, leaving many hard-to-abate industries without viable decarbonization options, He said.

Tests under simulated industrial flue gas conditions showed that the membrane's CO2 permeability increased by an order of magnitude, breaking existing academic records.

"Covalent organic framework mixed-matrix membranes not only deliver high carbon capture performance and reduced energy consumption, but can also be manufactured on a large scale like plastic films," he said.

"This is more than just an improvement in laboratory performance — it directly responds to the real-world constraints that have long held back membrane-based carbon capture from industrial application," he added.

A preliminary techno-economic analysis, under defined process and cost conditions, estimated the membrane's carbon capture cost at around $38 per ton of CO2, which is below the lower limit of the cost range for low-concentration industrial flue gas carbon capture published by the IEA.

"Next-generation membrane separation technology is a key innovation direction driving industrial low-carbon transformation. Lower capture costs will make carbon capture commercially viable in more hard-to-abate industries," the IEA noted in a related technical report.

Notably, the captured and recovered carbon dioxide is not useless waste. It has two main application pathways.

One is geological sequestration, where CO2 is injected into deep saline aquifers or depleted oil and gas fields to achieve permanent emission reduction, according to He's team.

The second is resource recycling, whereby it can be injected into oil fields for enhanced oil recovery to boost hydrocarbon production, or used as a raw material to produce chemical products such as methanol, biodegradable plastics and construction materials.

After purification, it can also serve as food-grade carbon dioxide for beverage processing and cold-chain preservation, creating additional economic benefits while cutting emissions.

For heavy industries, lower capture costs mean emission reductions can be achieved without imposing excessive cost pressure on production, cutting greenhouse gas emissions while safeguarding industrial competitiveness.

For the general public, cheaper industrial decarbonization and recyclable carbon resources translate to cleaner air and more stable prices for essential industrial goods, as emission reduction costs will not be fully passed on to end consumers.

The research team also noted that the technology still needs to go through multiple key milestones before full industrial application, including large-scale material production, development of membrane modules, and long-term operation verification under real industrial flue gas conditions.

"Going forward, our efforts will focus on the development of large-area mixed-matrix membranes and the reduction of membrane material costs," he added.

"Our next step will be to carry out verification in real industrial scenarios, starting with industries with relatively concentrated emission sources."

If successfully scaled up, this carbon capture membrane is expected to become a cost-effective decarbonization tool for hard-to-abate industries, supporting national and global carbon reduction goals while ensuring the stability of core industrial supply chains, according to the team.

Zhang Jiashuo contributed to this story.

yandongjie@chinadaily.com.cn