Seaweed Biochar Captures 120.5 mg CO2 per Gram
Lab tests show the marine-derived material outperforms untreated versions, though it has not yet been validated outside the laboratory.
Updated on Nov. 4, 2026 in Environmental
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Researchers Yuanling Li, Tao Wang, Jinyu Zhu, Siyu Duan, and Lina Liu developed a biochar made from seaweed that captures carbon dioxide, reported in Biochar X in 2026. The work is research-stage, not a deployed product.
Why it matters
Harmful brown seaweed blooms frequently wash ashore in massive quantities, creating coastal pollution and economic burdens, and marine algae do not compete with arable farmland the way terrestrial biomass does. Turning that waste stream into a carbon-capture material points to a feedstock that avoids the land-use trade-offs of crop-based biochar.
The optimized material has an internal surface area of nearly 570 square meters per gram and loses only 1.1 percent of its capture performance across nine cycles, compared with up to 17 percent loss for biochar produced without chemical activation. The lifecycle assessment puts total energy demand at roughly 6.24 megajoules per kilogram of captured carbon dioxide, yielding a net removal of 0.29 kilograms of CO2 equivalent per kilogram trapped.
The players
Yuanling Li, Tao Wang, Jinyu Zhu, Siyu Duan, and Lina Liu
The research team that developed the seaweed-derived carbon dioxide capture material and reported it in Biochar X.
The details
Raw seaweed is treated with potassium hydroxide, a strong alkaline chemical, before being heated to 400 degrees Celsius to form biochar, a porous carbon material. The chemical step opens a dense network of tiny pores, which is what gives the material its very large internal surface area for gas molecules to stick to. Applying the chemical after heating instead produced far weaker capture, which the authors attribute to the order of treatment.
Timeline
2026: Study published in Biochar X by Li et al.
The Tech Race
Biochar has been studied mainly as a soil amendment and carbon store made from agricultural and forestry residues, which raises land-use questions at scale. This seaweed-based approach positions marine algae as an alternative feedstock, though the source does not compare it directly against competing sorbent materials.
The material is at the laboratory stage and is not available to users, and the source gives no timeline for pilot or commercial use. Its practical relevance depends on whether coastal communities and carbon-capture developers can source and process seaweed at scale.
The takeaway
Watch for follow-up work testing the material under real flue-gas conditions and over more than nine regeneration cycles. Whether seaweed can supply feedstock without the land-use trade-offs of crop-based biochar will depend on that data.
Further reading
For broader context on how carbon removal materials are being developed, explore the Environmental section.
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