Porous Structure Properties of Andropogon gerardi Derived Carbon Materials

Howaniec, Natalia; Smoliński, Adam

doi:10.3390/ma11060876

Cited by 8 publications

(5 citation statements)

References 30 publications

(54 reference statements)

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“…It implies that the pressure-enhanced development of smaller pores resulting from the devolatilization, moisture release and partial oxidation of carbon with carbon dioxide under the pressure of up to 2 MPa was counteracted with merging of pores in larger structures under the pressure of 3 MPa. A similar trend was also observed previously for lignite [25,26] and bituminous coal [22,26], as well as biomass chars [21,26] with no carbon dioxide activation, although the limiting values of pressure varied between 2 and 3 MPa for various parent materials. The differences in the values of the total pore volume for chars activated with carbon dioxide under the pressure of 0.1–2 MPa were within the experimental error.…”

Section: Resultssupporting

confidence: 86%

“…The vast literature is available on the application of the temperature and various oxidizing agents [5,7,11,12,13,14,15,16,17] as well as acidic or basic treatment [7,10,18,19,20] in shaping the surface and structural properties of lignite-derived carbon materials. Limited data is, however, available on the effects of pressure as the activation parameter in shaping the porous structure of carbonaceous materials [21,22,23], in particularly lignite [24,25,26]. A few studies considering the development of porous structure of bituminous coals under carbon dioxide atmosphere [27,28] or inert gas [24,29,30] and elevated pressure are available.…”

Section: Introductionmentioning

confidence: 99%

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Combined Effect of Pressure and Carbon Dioxide Activation on Porous Structure of Lignite Chars

Howaniec

2019

Materials

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Lignite is an important natural resource with the application potential covering present and future energy systems, including conventional power plants and gasification systems. Lignite is also a valuable precursor for the production of porous materials of tailored properties for various environmental applications, including the removal of contaminants from gaseous or liquid media. Although the lignite-based activated carbons are commercially available, various approaches to produce carbon materials of desired properties are still being reported, covering temperature, partial oxidation and chemical activation effects on surface and structural properties of these materials. Limited data is, however, available on the effects of pressure as the activation parameter in shaping the porous structure of carbonaceous materials, in particularly lignite-derived. In the study presented the combined effect of carbon dioxide activation and pressure in the range of 1–3 MPa at the temperature of 800 °C on the development of porous structure of lignite chars was reported. The study was also focused on poor-quality resources valorization by using a relatively low calorific value, low volatiles and high ash content lignite as a carbon material precursor. The results showed that the application of pressure in carbon dioxide-activation process at 800 °C results in generation of chars of comparable or higher specific surface area than the carbon materials previously received with demineralization and carbon dioxide activation of lignite. They also proved that the combined pressure and carbon dioxide activation may be effectively applied in conversion of low quality lignite into valuable porous materials.

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Section: Resultssupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Combined Effect of Pressure and Carbon Dioxide Activation on Porous Structure of Lignite Chars

Howaniec

2019

Materials

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“…The positive effect of pressure on porous structure development may be related to the enhanced release of volatiles and moisture, as well as to a partial decomposition of the carbon structure under carbon dioxide atmosphere, high temperature, and elevated pressure. Such effects have been previously reported for biomass-derived chars [39,40], bituminous coal [36,40], and lignite [37,40] when pressure was considered as the sole agent affecting the porous structure development of carbon materials at high temperature; they were also observed for lignite chars under combined activation with pressure and carbon dioxide in the carbonization step [38].…”

Section: Resultssupporting

confidence: 63%

“…In some works, carbon dioxide and steam activation of carbonized olive stones are reported [15,16,17,18,28,32,33,34]. Limited data are available, however, on the use of pressure as an activation agent in tailoring the porous structure of carbon materials, and these works are mainly related to bituminous coal or lignite as precursors [34,35,36,37,38], with a few works devoted to biomass treatment under elevated pressure and temperature for the development of carbon materials of increased porosity [18,39,40].…”

Section: Introductionmentioning

confidence: 99%

Olive Pomace-Derived Carbon Materials—Effect of Carbonization Pressure under CO2 Atmosphere

Howaniec

2019

Materials

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The valorization of waste and by-products from various industrial activities is a must in our world of depleting natural resources and increasing volume of environmentally negative waste materials. The economic utilization of solid biowaste involves predominantly its use as a carbon-neutral energy resource or a precursor of porous carbon materials, with a potential application range including sorption processes, energy storage, and electric engineering. With the considerable number of lignocellulosic residues tested and applied as the most suitable porous material precursors, such as woods, shells, stones, peels, husks, and stalks of various crop plants, there is still space and need for further developments in the valorization of high amounts of other types of biowaste. Here, the olive pomace was considered because of both the vast volume and the environmentally undesired (when stored) phytotoxic effect of its components. While the literature on chemical (acidic and alkali treatment) and physical activation (temperature, carbon dioxide, and/or steam) of various biowaste precursors is considerable, the effects of pressure in the carbonization step are reported rarely, although the results observed are promising. The same applies to reports on the application of olive pomace for porous materials production, which indicate that olive pomace currently seems to be underestimated as a carbon materials precursor. In the study presented, the combined effects of pressure (0.1–3 MPa), temperature (800 °C), and carbon dioxide atmosphere in the carbonization of olive pomace were assessed on the basis of qualitative and quantitative data on micro- and mesoporosity of the carbon materials produced. The results showed the positive effect of increasing the process pressure on the development of a porous structure, and particularly, on the development of supermicropores and ultramicropores under the carbonization conditions applied. Carbon material with the most developed porous structure and the highest share of micropores was obtained under the maximum pressure tested.

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“…Developments in materials and processes for sustainable energy and environmental systems are of special importance in the world of depleting natural resources, serious environmental concerns, increasing energy demand, and disturbances in the global energy market affecting energy supply chains. Numerous advancements have been made so far in various sectors of the economy in terms of low-emission energy-system development, including gasification to synthesis gas and hydrogen-rich gas, with greenhouse gas emission mitigation [ 1 , 2 , 3 , 4 ], energy efficiency improvements, and waste valorization [ 5 , 6 , 7 , 8 ]. This Special Issue intends to present recent developments in various aspects related to materials and processes contributing to the creation of sustainable power systems and environmental solutions.…”

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confidence: 99%