Turning Sargassum waste into a high-performance material for carbon capture

Huge blooms of Sargassum can create critical environmental and financial issues when the seaweed accumulates alongside coastlines. A brand new research means that this troublesome marine biomass may as an alternative turn into a helpful useful resource for capturing carbon dioxide.

Researchers have developed a porous biochar from Sargassum tenerrimum that mixes excessive CO2 adsorption capability, speedy uptake, and robust regeneration stability. The important thing was modifying the seaweed with potassium hydroxide, or KOH, earlier than changing it to biochar at a average temperature of 400 °C.

“Our outcomes present that waste Sargassum may be remodeled right into a extremely efficient carbon adsorbent when its pore construction and floor chemistry are engineered collectively,” mentioned corresponding writer Lina Liu of Nankai College. “The essential level isn’t merely creating extra pores. We additionally have to protect the floor chemical teams that work together with CO2.”

The research, revealed in Biochar X, examined how pyrolysis temperatures from 400 to 700 °C and completely different sequences of KOH modification affected the properties of Sargassum-derived biochar.

The most effective-performing materials, known as Sar-KOH, was produced by treating the uncooked seaweed with KOH earlier than pyrolysis at 400 °C. It achieved a CO2 adsorption capability of 120.5 mg per gram at 313 Ok, considerably larger than the untreated biochars examined within the research. After 9 adsorption and regeneration cycles, the fabric retained 98.9% of its authentic capability.

Microscopic and floor analyses helped clarify the efficiency. KOH activation dramatically elevated the biochar’s particular floor space to 569.66 m²/g, in contrast with just one.14 m²/g for untreated biochar produced at 400 °C. The ensuing materials contained a extremely developed community of micropores, together with plentiful pores smaller than 0.7 nanometers.

These extraordinarily small pores are notably favorable for bodily trapping CO2 molecules. On the identical time, utilizing the comparatively average pyrolysis temperature of 400 °C helped protect hydroxyl teams on the biochar floor. These teams can work together with CO2 via hydrogen bonding.

The researchers due to this fact recognized a twin adsorption mechanism: micropores present plentiful websites for bodily adsorption, whereas hydroxyl teams strengthen chemical interactions with CO2.

The sequence of remedy proved particularly essential. Making use of KOH after the seaweed had already been transformed to biochar produced a fabric with a CO2 capability of solely 40.0 mg/g. Treating the biomass earlier than pyrolysis allowed KOH to work together extra successfully with the carbon construction because it fashioned, creating a way more in depth porous community.

Sar-KOH additionally captured CO2 rapidly, reaching adsorption equilibrium in roughly 11 minutes, in contrast with 26 to twenty-eight minutes for untreated biochars.

Past carbon seize, the strategy gives a possible route for making productive use of marine biomass related to dangerous macroalgal blooms. As an alternative of treating collected Sargassum solely as waste, it may function a renewable feedstock for carbon-based adsorbents.

The researchers observe that further work remains to be wanted earlier than sensible deployment, together with evaluating efficiency below practical gasoline mixtures and optimizing materials manufacturing and regeneration at bigger scales.

By linking waste valorization with carbon seize, the research gives a technique for designing sustainable adsorbents whereas addressing an more and more seen marine biomass drawback.

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Journal reference: Li Y, Wang T, Zhu J, Duan S, Liu L. 2026. Tailoring the porosity and floor chemistry of Sargassum biochar for enhanced CO₂ seize. Biochar X 2: e021 doi: 10.48130/bchax-0026-0019  

https://www.maxapress.com/article/doi/10.48130/bchax-0026-0019  

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Concerning the Journal: 

Biochar X (e-ISSN: 3070-1686) is an open entry, online-only journal goals to transcend conventional disciplinary boundaries by offering a multidisciplinary platform for the alternate of cutting-edge analysis in each elementary and utilized features of biochar. The journal is devoted to supporting the worldwide biochar analysis group by providing an modern, environment friendly, {and professional} outlet for sharing new findings and views. Its core focus lies within the discovery of novel insights and the event of rising functions within the quickly rising subject of biochar science. 

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