Kiet Le Anh Cao

CO2回収に向けて，低コストかつ高効率な吸着材の開発が求められている．なかでも，バイオマス由来多孔質カーボン材料は，細孔構造を柔軟に制御でき，かつ製造コストも低いことから，有望な材料として注目されている．本研究では，環境調和型活性化剤であるK2CO3を用い，スプレードライ法と炭素化を組み合わせることで，クラフトリグニン（クラフト法により得られるリグニン）由来多孔質カーボンの持続可能な合成法を提案した．K2CO3は，従来のKOHと比較して毒性および腐食性が低く，装置の長期使用や大規模応用に適している．さらに，CO2吸着に有利なミクロ孔構造を形成するとともに，廃棄物管理の簡素化にも寄与する．本手法では，炭素化と活性化を一段階で同時に行うことにより，プロセスの簡略化と効率向上を実現した．得られた多孔質カーボンは，298 Kにおいて4.54 mmol/gのCO2吸着容量を示し，KOH活性化材料と同等の性能を示した．さらに，活性化条件と細孔構造の相関解析により，超微細ミクロ孔がCO2吸着に重要な役割を果たすことを明らかにした．本研究で対象とするCO2吸着プロセスは，将来的なCO2変換技術における前処理段階として重要な役割を担うものである．

Nanostructured particles with nanoscale architectures have attracted considerable attention as potential candidates for applications in environmental catalysis, energy conversion, and advanced functional materials. In particular, macroporous particles are of interest due to their high specific surface areas and the possibility of enhanced mass transport within their structures, which may contribute to improved performance in various applications. However, it remains challenging to quantitatively characterize key structural features of such macroporous particles─including pore connectivity, tortuosity, and porosity─using conventional analytical techniques alone. In this study, we explore the construction of model macroporous particles in a virtual environment based on experimentally obtained particle properties and structural descriptors derived from real macroporous particles synthesized via spray drying of a colloidal solution containing primary nanoparticles and template particles. The parameters used for the model construction include particle diameter, pore size, porosity, template embedding depth, and pore overlap ratio. The digitally generated particles were able to reproduce key features of the experimentally observed pore morphology and porosity to a reasonable extent, suggesting that the proposed modeling approach can serve as a useful tool for geometry-based reconstruction of macroporous particle structures.

Spray-dried TEMPO-oxidized cellulose nanofiber (TOCN)-Fe₃O₄ (TF) composite particles were fabricated using TOCNs of distinct fiber lengths, where the long TOCNs were approximately 3 times longer (around 1 μm) than the short TOCNs (approximately 350 nm). The objective was to elucidate how nanofiber aspect ratio governs particle morphology, magnetic performance, and bioaffinity. SEM and TEM analyses revealed that both TOCN types formed spherical particles (approximately 2-3 μm) with fibrous surface textures, yet the Fe₃O₄ distribution varied significantly. Short TOCNs promoted dense fiber entanglement within droplets, effectively entrapping Fe₃O₄ nanoparticles inside the particle core, whereas long TOCNs facilitated Fe₃O₄ migration toward the particle surface. Despite similar ζ-potentials (-44 to -49 mV) and superparamagnetic hysteresis behavior, surface Fe₃O₄ accessibility strongly influenced biofunctional response without altering magnetization. These findings provide a scalable strategy for designing bioactive magnetic cellulose composites with customizable surface reactivity for biosensing, biocatalysis, and magnetic separation in biomedical field.

The accelerating rise of atmospheric CO ₂ remains a central driver of global climate change, highlighting the urgent need for scalable and energy‐efficient carbon capture technologies. Porous carbons are among the most promising solid adsorbents due to their high surface area, chemical stability, and tunable pore structures, which facilitate efficient CO ₂ adsorption and low regeneration energy. Lignin is a renewable aromatic by‐product of the pulp and paper industry, which offers exceptional promise as a sustainable carbon source due to its abundance (50–70 Mt/year), high carbon content (>60 wt%), and rich aromatic structure. Unlike previous reviews broadly covering biomass‐derived carbons, this review focuses on recent advances in lignin‐derived porous carbons for CO ₂ capture, correlating preparation strategies with structural evolution and adsorption performance. Chemical activation, templating, and hybrid methods enable precise control of ultramicropores (2 capture using lignin‐derived porous carbons.