Seaweed Biochar Captures Carbon Dioxide Efficiently
Chemically activated brown seaweed biochar traps 120.5 milligrams of carbon dioxide per gram in a new study.
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 from seaweed that captures carbon dioxide at 120.5 milligrams per gram after potassium hydroxide pre-treatment. The findings were published in Biochar X in 2026.
Why it matters
Harmful brown seaweed blooms frequently wash ashore in large quantities, causing coastal pollution and economic burdens. Because marine algae do not compete with arable farmland the way terrestrial biomass does, converting this material into a carbon capture medium offers a potential alternative use.
Laboratory measurements show the optimized biochar has an internal surface area of nearly 570 square meters per gram and loses only 1.1 percent of its capture performance across nine adsorption and regeneration cycles, compared with a 17 percent loss for biochar produced without chemical activation. The lifecycle assessment estimates a total energy demand of roughly 6.24 megajoules per kilogram of captured carbon dioxide, and the source does not describe performance at industrial scale.
The players
Yuanling Li
Lead-listed author of the study published in Biochar X, who worked with colleagues Tao Wang, Jinyu Zhu, Siyu Duan, and Lina Liu on the seaweed biochar research.
Biochar X
A peer-reviewed journal that published the research describing the seaweed-derived carbon dioxide capture material.
The details
Potassium hydroxide was applied to raw seaweed before thermal treatment at 400 degrees Celsius to produce the biochar. Applying the chemical after heating instead achieved only 40.0 milligrams per gram, showing that the order of treatment matters.
Timeline
2026: Study published in Biochar X by Li et al.
The Big Picture
Untreated seaweed biochar in this study captured only 10.9 to 24.1 milligrams per gram, and the new chemically activated version raises that figure to 120.5 milligrams per gram. The result shows that pre-treatment chemistry, not just the choice of biomass, determines how well biochar performs as a carbon capture material.
If the approach scales beyond the laboratory, coastal communities facing seaweed blooms could find a use for material that now creates cleanup costs. The material's capture rate and energy demand would need to be validated under real industrial conditions before any practical application.
The takeaway
Turning harmful coastal algae into a carbon capture material shows how waste biomass can be repurposed, but the strongest results so far come from laboratory conditions. Readers should watch for follow-up studies that test performance at larger scales.
Further reading
For related coverage of carbon removal approaches, see the Environmental section.
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