Rice husk-based activated carbon honeycomb monolith for biogas upgrading and CO2 capture from flue gases


Ortega-Ortiz H. Bernardo M. Matos I. Fonseca I. Mota J.P.B. Jandosov J. Ribeiro R.P.P.L.
March 2026Springer

Adsorption
2026#32Issue 3

Structured adsorbents offer important advantages over conventional bead- or pellet-shaped materials used in fixed-bed gas separation processes. In particular, monolithic architectures can reduce pressure drop and enhance mass and heat transfer, leading to improved process performance. In this work, an activated carbon honeycomb monolith (ACHM) was produced from rice husk through extrusion, carbonization and CO2 activation. The material was characterized by N2 physisorption at 77 K, mercury porosimetry and scanning electron microscopy (SEM), confirming a hierarchical porous structure. Thermogravimetric analysis indicated thermal stability up to 873 K. Adsorption equilibrium isotherms of carbon dioxide (CO2), methane (CH4) and nitrogen (N2) were obtained at 303, 323, 348 and 373 K using a manometric method. The ACHM exhibited a higher affinity towards CO2, followed by CH4 and N2. The adsorption equilibrium data were accurately correlated using the Dual-Site Langmuir and Toth models. Dynamic single component breakthrough experiments were performed and the results fitted to a mathematical model to determine mass and heat transfer parameters. These were subsequently used to predict the multicomponent breakthrough curves, which consisted in binary mixtures of CO2/N2 and CO2/CH4. The CO2/N2 and CO2/CH4 selectivities at 1 bar and 303 K were ca. 18 and 4, respectively, demonstrating the good potential of the rice husk-based ACHM for adsorption-based processes targeting CO2 removal from flue gases and biogas.

Adsorption , Circular economy , Structured adsorbent , Waste valorization

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Department of Chemistry, NOVA School of Science and Technology, LAQV-REQUIMTE, NOVA University of Lisbon, Caparica, 2829-516, Portugal
Institute of Combustion Problems, Laboratory of Nanobiotechnology, 172, Bogenbay Batyr St, Almaty, 050000, Kazakhstan

Department of Chemistry
Institute of Combustion Problems

10 лет помогаем публиковать статьи Международный издатель

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