Alkaline activating agents for activation of rice husk biochar and simultaneous bio-silica extraction

Motlagh, Eisa Khoshnood; Sharifian, Seyedmehdi; Asasian‐Kolur, Neda

doi:10.1016/j.biteb.2021.100853

Cited by 9 publications

(4 citation statements)

References 39 publications

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“…In particular, the organic functional groups of –OH, aliphatic –CH 2 /–CH 3 , aromatic CC, C–O–C, and aromatic C–H , showed a high thermal stability present in all of the activated carbons (Figure d). It was also noted that the activated carbons produced at 900 °C (AC-1-900 and AC-2-900) showed the stronger peak intensities of aromatic CC and C–H …”

Section: Resultsmentioning

confidence: 90%

“…It was also noted that the activated carbons produced at 900 °C (AC-1-900 and AC-2-900) showed the stronger peak intensities of aromatic C�C and C−H. 38 The textural properties, such as specific surface area and pore structure, are essential parameters for evaluating the quality of activated carbon. The microstructures of activated carbons before and after water leaching are shown in Figure 5.…”

Section: Characteristics Of Activated Carbonsmentioning

confidence: 99%

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Closed-Loop K₂CO₃ Activation of Biochar for Coproduction of Microporous Carbon and Syngas

Shen,

Loong,

Chen

et al. 2024

Energy Fuels

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The current work systematically studied the technical feasibility of potassium-looping activation of biochar using K 2 CO 3 for the coproduction of highly microporous carbon and syngas. Compared with the solid mixing method, the impregnation method showed a higher biochar activation efficiency and produced a higher quality of activated carbon. By the impregnation method, a high yield of activated carbon (60 wt %, per biochar mass) was achieved under the optimal conditions, such as an activation temperature of 800 °C, a mass ratio of biochar to K 2 CO 3 (1:1), and a retention time of 3 h. The activated carbon with a high specific surface area (1091 m 2 /g) and a high microporosity (98%) was obtained. Besides, during the biochar activation process, syngas (CO/H 2 molar ratio of 1.0−1.5 and yield of ∼23 wt %) was generated. The yield and surface area of activated carbon were not obviously reduced after water leaching within three cycles. The potassium-looping system was evaluated to recover and reuse biochar activation agent within subsequent cycles.

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Section: Resultsmentioning

confidence: 90%

Section: Characteristics Of Activated Carbonsmentioning

confidence: 99%

Closed-Loop K₂CO₃ Activation of Biochar for Coproduction of Microporous Carbon and Syngas

Shen,

Loong,

Chen

et al. 2024

Energy Fuels

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“…Recent investigations have utilized alkali leaching to extract valuable metals from coal ash. For instance, Pan et al [31] accomplished the extraction of Si and Al utilizing alkali agents, while Motlagh et al [32] effectively recovered biochar and SiO 2 through KOH activation of rice husks, which contained substantial amounts of Si (12-20 wt%) and carbon (30-50 wt%). These methodologies leveraged the chemical properties of Si and Al to facilitate the demineralization of crystalline minerals within alkaline environments.…”

Section: Ash Removal Properties During Chemical Activationmentioning

confidence: 99%

“…Under these alkaline conditions, the mineral phase of coal fly ash, including aluminosilicate and amorphous silica, breaks down and transforms into sodium silicate and sodium aluminosilicate, both of which can dissolved in water or acid [29][30][31]. Additionally, Motlagh et al [32] conducted a KOH activation reaction during the production of biochar using rice husks, which have a high ash content, as a carbon precursor. Rice husks typically contain about 12-20 wt% of Si and 30-50 wt% of carbon.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Activated Carbon from Korean Anthracite: Simultaneous Control of Ash Reduction and Pore Development

Kim,

Lee,

Baek

et al. 2023

Processes

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Anthracite stands as a valuable precursor for carbon materials, owing to its high carbon content. However, producing activated carbon from anthracite presents significant challenges due to its elevated ash content (23–40 wt%) and crystalline nature. The high ash content not only fails to contribute to the activation process but also obstructs pore formation on the carbon surface. To address these challenges, this study explores the preparation of activated carbon from anthracite using KOH activation. This method demonstrates remarkable efficacy in enhancing reactivity beyond the inherent physical properties of anthracite. In contrast to physical activation, the utilization of KOH as a chemical agent substantially enhances the specific surface area, resulting in a production yield of 62% and a specific surface area that reaches up to 1596 m2/g at a KOH/anthracite weight ratio of 4.0. Moreover, rinsing the activated sample with tap water achieves an ash removal rate of about 37.9%, surpassing twice the rate achieved through acid pretreatment (67.0%). A noteworthy observation from this study is the substantial reduction in the content of major ash components, such as silicon (Si) and aluminum (Al), both of which are prominent constituents in anthracite ash. Following KOH activation, their levels decrease by approximately 54% to 65%, respectively. These findings highlight the potential of utilizing available anthracite, even with elevated ash content, as a superior carbon material. Fundamentally, the KOH activation method serves a dual purpose: it effectively reduces ash content and promotes pore creation within a highly alkaline environment. This dual advantage positions the method as a promising approach for the production of top-tier activated carbon.

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A characterization study on toughening natural fibre composites using functionalized barely husk biosilica

Krishnamoorthy,

Nagabhooshanam,

Rao

et al. 2023

Biomass Conv. Bioref.

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Alkaline activating agents for activation of rice husk biochar and simultaneous bio-silica extraction

Cited by 9 publications

References 39 publications

Closed-Loop K₂CO₃ Activation of Biochar for Coproduction of Microporous Carbon and Syngas

Closed-Loop K₂CO₃ Activation of Biochar for Coproduction of Microporous Carbon and Syngas

Preparation of Activated Carbon from Korean Anthracite: Simultaneous Control of Ash Reduction and Pore Development

A characterization study on toughening natural fibre composites using functionalized barely husk biosilica

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Alkaline activating agents for activation of rice husk biochar and simultaneous bio-silica extraction

Cited by 9 publications

References 39 publications

Closed-Loop K2CO3 Activation of Biochar for Coproduction of Microporous Carbon and Syngas

Closed-Loop K2CO3 Activation of Biochar for Coproduction of Microporous Carbon and Syngas

Preparation of Activated Carbon from Korean Anthracite: Simultaneous Control of Ash Reduction and Pore Development

A characterization study on toughening natural fibre composites using functionalized barely husk biosilica

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Product

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Closed-Loop K₂CO₃ Activation of Biochar for Coproduction of Microporous Carbon and Syngas

Closed-Loop K₂CO₃ Activation of Biochar for Coproduction of Microporous Carbon and Syngas