Comparison of Physicochemical Properties of Nitrogen-enriched Activated Carbons Prepared by Physical and Chemical Activation of Brown Coal

Nowicki, Piotr; Pietrzak, Robert; Wachowska, Helena

doi:10.1021/ef800251w

Cited by 43 publications

(33 citation statements)

References 27 publications

(51 reference statements)

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“…With increasing temperature of carbonisation, the number of basic groups increases, although the difference between the samples carbonised at 500 and 700°C is only 0.19 mmol/ g. The activation with CO 2 results in a further increase in the amount of basic surface groups, especially on the surfaces of samples M5A8 and M7A8, activated at 800°C. The strongly basic character of the surfaces of activated carbons obtained is probably a consequence of the fact that the activator applied (CO 2 ) and the high temperature of activation are favourable for generation of basic groups (Nowicki et al 2008). …”

Section: Acid-base Properties Of the Precursor Chars And Activated Cmentioning

confidence: 99%

“…One of the most effective methods for elimination of pollutants is their adsorption by activated carbons (Bansal and Goyal 2005;Guo et al 2013;Nowicki et al 2013). Thanks to their strongly developed porous structure, activated carbons show very good sorption properties, from both liquid and gas phase and that is why they have been applied in many areas (Aysu and Küçük 2015;Kazmierczak et al 2013;Nowicki et al 2008). Continuous broadening of the range of their use leads to increased demands for activated carbon adsorbents, which stimulates the search for new carbon precursors.…”

Section: Introductionmentioning

confidence: 99%

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Removal of NO2 by carbonaceous adsorbents obtained from residue after supercritical extraction of marigold

2015

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Carbonaceous adsorbents were obtained from the residue after supercritical extraction of marigold subjected to physical activation and used as nitrogen dioxide and iodine adsorbents. The effect of carbonisation and activation temperature on the textural parameters, acidbase character of the surface and sorption properties of the activated carbons was tested. The materials obtained were activated carbons of low-developed surface area varying from 2 to 206 m 2 /g, showing clearly basic character of the surface. The results proved that proper selection of the carbonisation and activation procedure of the residue after supercritical extraction of marigold permitted obtaining carbonaceous adsorbents with good capacity toward liquid as well as gas inorganic pollutants. The effectiveness of NO 2 removal was found to depend to large extent on the conditions of adsorption. The preliminary wetting of the adsorbent bed was shown to significantly increase the amount of pollutants removed.

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Section: Acid-base Properties Of the Precursor Chars And Activated Cmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Removal of NO2 by carbonaceous adsorbents obtained from residue after supercritical extraction of marigold

2015

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“…This evidence proves high reactivity of sawdust pellets towards urea. Much less nitrogen (4.6 and 6.8 wt%, respectively) was introduced into the structure of chars SP6 and SP7 (Table 2), which is related to a decrease in the susceptibility to chemical modification caused by the structure ordering upon pyrolysis (Nowicki et al , 2008. Unfortunately, a significant amount of nitrogen functional groups introduced into the precursor and chars underwent decomposition upon further thermal treatment as evidenced by a pronounced decrease in N daf after pyrolysis (SUP6 and SUP7 samples- Table 1), and in particular after activation (SUDAX, SP6UAX and SP7UAX series- Table 1).…”

Section: Pyrolysis 600ºc 700ºcmentioning

confidence: 99%

Nitrogen-enriched activated carbons prepared by the activation of coniferous tree sawdust and their application in the removal of Nitrogen dioxide

Nowicki

Kaźmierczak

Sawicka

et al. 2014

Int. J. Environ. Sci. Technol.

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A technology of obtaining nitrogen-enriched activated carbons from coniferous tree sawdust by direct activation of the precursor and physical activation with CO 2 is described. The effect of activation time, pyrolysis temperature as well as modification with urea on the textural parameters, acid-base character of the surface and sorption properties of activated carbons has been tested. The resulting carbons were characterised by low-temperature nitrogen sorption and determination of the number of surface oxygen groups. The sorption properties of the materials obtained were characterised by nitrogen dioxide adsorption in dry and wet conditions. The final products were nitrogen-enriched microporous activated carbons of medium-developed surface, showing very diverse nitrogen content and acidic-basic character of the surface. The results obtained in our study have proved that through suitable choice of the activation and modification procedure of coniferous tree sawdust, activated carbons can be produced with high capacity towards nitrogen dioxide adsorption, reaching to 69 and 46 mg NO 2 /g in dry and wet conditions, respectively. The results of our study have also shown that the adsorption ability of carbonaceous adsorbents depends both on the method of preparation as well as on the textural parameters and acid-base properties of the adsorbents surface.

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“…Both the natural oxidation process and spontaneous combustion process significantly change the surface properties of coal. [1][2][3][4] Among these properties, changes in the wettability of coal have a great effect on the flotation of fine coals. It is necessary to investigate the changes in the wettability of coal before and after the heating process if an effective flotation of spontaneous combustion coal is hoped.…”

Section: Introductionmentioning

confidence: 99%

Effect of heating process on the wettability of fine coals of various ranks

Xia

Niu

2016

Can J Chem Eng

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Spontaneous coal combustion can produce a condition of heating process because the atmosphere of coal underground is usually poor in oxygen. Even though the spontaneous combustion of coal is prevented by people, the surface properties of coal are greatly changed. The changes in the wettability of coal influence the flotation of fine coals. This paper investigates the effect of the heating process on the wettability of fine coals of various ranks. Lignite, bituminous, and anthracite coals were used as experimental samples. The heating temperature and time were 500 °C and 2 h. X‐ray photoelectron spectroscopy (XPS) and contact angle measurements were used to indicate the changes in wettability of fine coals before and after the heating process. The results showed that the wettability of bituminous coal was significantly increased whereas that of lignite was greatly decreased after the heating process. However, the wettability of anthracite coal was increased only a little after the heating process.

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Comparison of Physicochemical Properties of Nitrogen-enriched Activated Carbons Prepared by Physical and Chemical Activation of Brown Coal

Cited by 43 publications

References 27 publications

Removal of NO2 by carbonaceous adsorbents obtained from residue after supercritical extraction of marigold

Removal of NO2 by carbonaceous adsorbents obtained from residue after supercritical extraction of marigold

Nitrogen-enriched activated carbons prepared by the activation of coniferous tree sawdust and their application in the removal of Nitrogen dioxide

Effect of heating process on the wettability of fine coals of various ranks

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