Wyniki wyszukiwania - Biblioteka Nauki

1

Thermal analysis of activated carbons from biomass

100%

Bartkowiak M. , Orszulak G. , Doczekalska B.

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2018

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tom No. 104

96--100

EN

Thermal analysis was applied in investigation of activated carbons (ACs) from different biomass: beech and hornbean wood, pine cones, walnut shell, miscanthus giganteus, corn stalks and switchgrass. The precursors were pyrolysed at the temperature of 600°C. Carbonizates were activated with potassium hydroxide at the temperature of 750°C for 15 minutes. On the basis of thermogravimetric analysis (TGA) it was found that activated carbons obtained from different types of biomass show different resistance to thermal degradation process. The thermostability of activated carbons from biomass of annual plants is smaller compared to the thermal resistance of carbons adsorbents from wood.

2

Activated carbons from common nettle as potential adsorbents for CO2 capture

100%

Szymańska A. , Skoczek A. , Przepiórski J.

Polish Journal of Chemical Technology

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2019

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tom Vol. 21, nr 1

59--66

EN

Activated carbons (ACs) prepared from common nettle (Urtica Dioica L.) were studied in terms of carbon dioxide adsorption. ACs were prepared by KOH chemical activation in a nitrogen atmosphere at temperatures (ranging from 500 to 850°C). The pore structure and the surface characterization of the ACs were specified based on adsorption-desorption isotherms of nitrogen measured at –196°C and carbon dioxide at 0°C. The specific surface area was calculated according to the BET equation. The pore volume was estimated using the DFT method. The highest values of the specific surface area (SSA) showed activated carbons produced at higher carbonization temperatures. All samples revealed presence of micropores and mesopores with a diameter range of 0.3–10 nm. The highest value of the CO2 adsorption, 4.22 mmol/g, was found for the material activated at 700°C.

3

The simplex optimization for high porous carbons preparation

100%

Sreńscek-Nazzal J. , Michalkiewicz B.

Polish Journal of Chemical Technology

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2011

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tom 13

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nr 4

63-70

EN

The microporous carbon materials were prepared by chemical activation of Polish coal with potassium hydroxide using the simplex design method for planning the experiments. The experimental parameters were varied to identify the optimum conditions. Coal can be an excellent starting material for the preparation of high porous carbons for natural gas storage. The porosity of the resultant carbons was characterized by nitrogen adsorption (-196°C). Methane adsorption was investigated in a volumetric laboratory installation at range pressures from 1 to 3.5 MPa (25°C).The best results of methane storage capacity (557 cm3 · g-1) were obtained when using an impregnation ratio 3.41/1 KOH/precursor and temperature at 592°C, (SLANG = 2091 m2 · g-1). The parameters of the preparation of high porosity and high methane adsorption carbon were determined by a fast and simple method.

4

Wpływ aktywacji chemicznej stopów magazynujących typu Mg-Ni na ich właściwości elektrochemiczne

100%

Majchrzycki W. , Wieczorek I. , Sierczyńska A. , Jankowska E.

Przemysł Chemiczny

|

2003

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tom T. 82, nr 8-9

576-579

5

Chemical activation effect on the mechanical response of mortars based on dune sand

88%

Ladjel D. , Zairi M. , Belagraa L.

Mining Science

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2020

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tom Vol. 27

61--71

EN

The main qualities sought for a mortar are usually; the high compactness, good sealing or impermeability, better mechanical strength and long-term durability. The different methods of accelerating setting and hardening of the mortar as well as the desired characteristics are of great importance with regard to the use of mortars and their different applications in civil engineering. This work is a contribution to improving the properties of mortars at fresh and hardened state by different activation techniques in particular chemical alkaline activators method. The properties of chemically activated mortars using alkaline solutions (KOH and NaOH) at dosages of 0, 2 and 4% was investigated in this experimental program using a based cement matrix with dune sand and blended cement type CEM II/ B grade 42. The results obtained showed the beneficial effect of the chemical activation modes mainly, an improvement of the mechanical response (compressive strength) at young age and in the long term.

6

Preparation of sorbents from selected polymers

88%

Ciesińska W. , Makomaski G. , Zieliński J. , Brzozowska T.

Polish Journal of Chemical Technology

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2011

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tom 13

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nr 1

51-54

EN

In this work, the results of studies on the preparation of sorbents from selected polymers were presented. The polymers were carbonized and subsequently physically activated by steam or carbon dioxide, or alternatively, chemically activated with potassium hydroxide. For the obtained materials, a specific area was evaluated by means of low-temperature nitrogen adsorption and benzene adsorption, iodine number was also determined. The obtained results indicated a possibility to procure hydrophobic sorbents of microporous structure. Sorbents having the best properties, i.e. the specific area of above 2000 m2/g were produced from poly(ethylene terephthalate) and phenol-formaldehyde resin.

7

Removal of methylene blue from aqueous solutions via adsorption on activated biocarbon obtained from post-extraction residue

88%

Przytulska A. , Gargol M. , Gil-Kowalczyk M. , Nowicki P.

Physicochemical Problems of Mineral Processing

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2022

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tom Vol. 58, iss. 2

art. no. 146709

EN

This paper deals with adsorption of a cationic dye – methylene blue - on the activated biocarbon obtained via chemical activation of horsetail herb post-extraction residue. The effects of initial dye concentration, temperature, solution pH, as well as the phase contact time on the adsorption effectiveness have been tested. The adsorbent prepared was characterized based on the results of elementary analysis, surface area measurements, thermal analysis as well as determination of the acid-base nature of its surface. It has been shown that micro/mesoporous horsetail herb-based activated biocarbon exhibits a significantly higher ability to methylene blue uptake than the commercial activated carbon prepared from peat. It has been also found that the adsorption capacity increases with the increasing initial dye concentration in the solution and the phase contact time. The maximum adsorption toward methylene blue was found at pH=12 and at temperature of 40 C. A better fit to the experimental data was obtained with a Langmuir isotherm than Freundlich one, whereas better fit of the kinetic data was achieved using the pseudo-second order model.

8

Factor Affecting Microwave Assisted Preparation of Activated Carbon from Local Raw Materials

88%

Elsayed M. A. , Zalat O. A.

International Letters of Chemistry, Physics and Astronomy

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2015

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tom Vol. 47

15--23

EN

This study illustrates the preparation of activated carbon (AC) from Corn Cob (CC) via microwave assisted K2CO3&enspactivation. The effect of operational parameters including chemical impregnation ratio (0.25-1.25), microwave power (90 – 800 W) and irradiation time (1 – 9 min) on the carbon yield and adsorption capability of derived Corn Cob Activated Carbon (CCAC) were investigated. The results indicated that the optimum conditions were as follows: microwave power of 600W, microwave radiation time of 5 min and the impregnation ratio of K2CO3&enspwas 0.75 g/g. The optimum conditions resulted in CCAC with a maximum adsorption capacity of 275.32 mg/g for MB and carbon yield of 27.09%. The BET surface area, Langmuir surface area and total pore volume were determined to be 765 m2/g, 834 m2/g and 0.43 cm3/g, respectively.

9

Preparation and characterization of activated carbons from biomass material – giant knotweed (Reynoutria sachalinensis)

75%

Fałtynowicz H. , Kaczmarczyk J. , Kułażyński M.

Open Chemistry

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2015

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tom 13

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nr 1

EN

Activated carbons from biomass material of giant knotweed Reynoutria sachalinensis (F. Schmidt ex Maxim.) Nakai were obtained. Use of this plant for manufacturing activated carbon has not been studied yet. Therefore, the first activated carbons of giant knotweed origin are described. Both physicochemical (by steam and CO2) and chemical (by KOH) activation methods were applied. Influences of temperature (500, 600, 700 and 800°C), burn-off [10, 25 and 50 wt. % (daf)] and KOH concentration on pores surface area and volume distribution of the obtained activated carbons were explored. Porosity of the elaborated sorbents was determined by benzene and carbon dioxide sorption measurements. Sorbents obtained by steam activation were micro- and mesoporous with surface area and volume of pores increasing with temperature and burn-off to V = 0.351 cm3 g-1 and S = 768 m2 g-1 at 800°C at 50% burn-off. Carbon dioxide activation resulted with notably microporous activated carbons with porous texture parameters also increasing with burn-off to V = 0.286 cm3 g-1 and S = 724 m2 g-1 at 50% burn-off. The highest BET surface area of 2541 m2 g-1 was achieved when chemical (KOH) activation was performed using KOH to char ratio 4:1.

10

Charakterystyki pojemnościowe wielościennych nanorurek węglowych aktywowanych związkami alkalicznymi

75%

Jurewicz K. , Babeł K.

Karbo

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2006

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tom Nr 4

206-213

PL

W celu poprawy parametrów pojemnościowych wielościennych nanorurek węglowych (MWCNTs), wytworzonych metodą katalitycznego rozkładu acetylenu z wykorzystaniem stałego roztworu CoxMg(1-x)O, poddano je procesowi aktywacji chemicznej za pomocą KOH lub NaOH. W wyniku aktywacji z KOH, stosując moduł 4:1 uzyskano ponad dwukrotny wzrost powierzchni BET do 577 m2/g, głównie w zakresie mezoporowatym. Przyrost powierzchni mikroporowatej i dalszy wzrost powierzchni do 684 m2/g, uzyskano przy wyższym module KOH (5:1). W efekcie przeprowadzonych modyfikacji zanotowano istotną poprawę pojemności MWCNTs. Dla elektrod ujemnych w środowisku zasadowym sięga ona dwóch rzędów wielkości (77 F/g). Nie zaobserwowano prostej korelacji między zmianami strukturalnymi, a przyrostem pojemności, co wskazuje na istotny udział pseudopojemności. Aktywacja za pomocą NaOH, choć mniej efektywna (350 m2/g), pozwoliła uzyskać korzystną strukturę dla zastosowań w środowisku aprotycznym. MWCNTs, także po ich aktywacji, charakteryzuje wysoka dynamika wymiany ładunku, co predysponuje je na materiał elektrodowy dla kondensatorów dużej mocy.

EN

In order to improve capacitance parameters of multi-wall carbon nanotubes (MWCNTs) obtained by catalytic acethylene decomposition with solid solution of CoxMg(1-x)O, they were subject to activation process with KOH or NaOH. As a result of activation with KOH at 4:1 module, more than a double increase of BET surface to 577 m2/g was obtained, mainly in mesopore range. Higher microporous surface and further increase of BET surface to 684 m2/g was achieved at KOH (5:1) module. In consequence of such modifications, considerable improvement of MWCNTs capacitance was observed. For negative electrodes in alkaline environment , it reaches two order of magnitude higher value ( 77 F/g). No simple correlation between structural changes and capacitance increase was defined which, in turn, indicates considerable contribution of pseudocapacity. Activation with NaOH, although less efficient (350 m2/g), allowed to obtain advantageous structure for use in aprotic environment MWCNTs, also after activation, reveal high charge exchange dynamics and this feature makes them suitable as an electrode material for high power supercapacitors.

11

Adsorption of bisphenol a from aqueous solutions by activated tyre pyrolysis char – Effect of physical and chemical activation

75%

Kuśmierek K. , Świątkowski A. , Kotkowski T. , Cherbański R. , Molga E. , Kuśmierek K. , Świątkowski A. , Kotkowski T. , Cherbański R. , Molga E.

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nr 2

12

Modyfikacja chemiczna węgli aktywnych dla układów magazynowania energii

75%

Wolak E.

Inżynieria i Aparatura Chemiczna

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2013

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tom Nr 5

496--497

PL

Przedmiotem badań były węgle aktywne otrzymane z surowców pochodzenia roślinnego (pyłowy węgiel aktywny z węgla drzewnego aktywowanego parą wodną, węgiel aktywny z pestek brzoskwiń otrzymany przez ich kar- bonizację i aktywację ditlenkiem węgla oraz węgiel aktywny wytworzo¬ny w skali przemysłowej z łupin orzechów kokosowych aktywowany parą wodną), które poddano dodatkowej aktywacji za pomocą KOH. W wyniku tej aktywacji otrzymano materiał sorpcyjny o znacznie rozwiniętej strukturze mikro- i mezoporowatej oraz o zmienionym charakterze powierzchni, co wpłynęło na znaczne polepszenie własności sorpcyjnych względem metanolu. Otrzymany materiał można z powodzeniem wykorzystać do celów magazynowania energii.

EN

Investigations dealing with active carbons obtained from vegetable precursors (activated carbon dust from charcoal activated by water vapour, activated carbon from peach stones obtained by their carbonization and activation using carbon dioxide, and finally commercial activated carbon produced from coconut shells activated by water vapour) additionally modified by KOH were carried out. As a result of this activation the sorptive material with significantly developed micro- and mesoporous structure and modified surface was obtained. The activation resulted in significant improvement of methanol sorption properties. The obtained carbon adsorbent can be advantageously used for heat storage purposes.

13

Otrzymywanie węgli aktywnych z wierzby energetycznej. Cz. 2, Aktywacja chemiczna

75%

Jasieńko-Hałat M. , Grusiecka M.

Przemysł Chemiczny

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2010

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tom T. 89, nr 7

966-969

14

Adsorption of lead ions onto chemically activated carbon from waste tire char and optimization of the process using response surface methodology

75%

Rutto H. , Seidigeng T. , Malise L.

Archives of Environmental Protection

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2019

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tom Vol. 45, no. 4

92--103

EN

Tires play an important role in the automobile industry. However, their disposal when worn out has adverse effects on the environment. The main aim of this study was to prepare activated carbon from waste tire pyrolysis char by impregnating KOH onto pyrolytic char. Adsorption studies on lead onto chemically activated carbon were carried out using response surface methodology. The effect of process parameters such as temperature (°C), adsorbent dosage (g/100 ml), pH, contact time (minutes) and initial lead concentration (mg/l) on the adsorption capacity were investigated. It was found out that the adsorption capacity increased with an increase in adsorbent dosage, contact time, pH, and decreased with an increase in lead concentration and temperature. Optimization of the process variables was done using a numerical optimization method. Fourier Transform Infrared Spectra (FTIR) analysis, X-ray Diffraction (XRD), Thermogravimetric analysis (TGA) and scanning electron microscope were used to characterize the pyrolytic carbon char before and after activation. The numerical optimization analysis results showed that the maximum adsorption capacity of 93.176 mg/g was obtained at adsorbent dosage of 0.97 g/100 ml, pH 7, contact time of 115.27 min, initial metal concentration of 100 mg/and temperature of 25°C. FTIR and TGA analysis showed the presence of oxygen containing functional groups on the surface of the activated carbon produced and that the weight loss during the activation step was negligible.

15

Otrzymywanie węgli aktywnych z wierzby energetycznej. Cz. 3, Aktywacja związkami sodu i potasu

63%

Jasieńko-Hałat M. , Majewski D.

Przemysł Chemiczny

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2012

|

tom T. 91, nr 7

1412-1415

PL

Przeprowadzono badania nad otrzymywaniem węgli aktywnych ze wstępnie karbonizowanej (500°C) wierzby energetycznej przez aktywację chemiczną związkami Na i K (temp. aktywacji 800°C, stopień impregnacji 2 g związku/g prekursora). Strukturę porowatą otrzymanych materiałów scharakteryzowano na podstawie izoterm sorpcji C₆H₆ i CO₂ w temp. 25°C. Określono wpływ rodzaju czynnika aktywującego, a w przypadku stosowania NaOH, także stopnia impregnacji (1–3 g/g) i obniżenia temp. aktywacji do 700°C na strukturę porowatą otrzymanych adsorbentów. Zdolność stosowanych związków do rozwijania objętości i powierzchni porów adsorpcyjnych w badanym surowcu jest zróżnicowana i maleje w kolejności: NaOH, KOH, K₂CO₃ i Na₂CO₃. Wszystkie otrzymane adsorbenty charakteryzują się strukturą mikroporowatą. Przy aktywacji surowca NaOH wzrost stopnia impregnacji powoduje wyraźne rozwinięcie układu porowatego, natomiast obniżenie temperatury aktywacji nie wpływa znacząco na parametry struktury porowatej otrzymanych adsorbentów.

EN

Activated C was prepd. by pyrolysis of willow (Salix spp.) wood at 500°C after chem. activation with Na and K compds. (2 g/g, 800°C). The adsorbent prepd. by activation with NaOH showed the highest pore vol. (0.9 cm³/g) and sp. surface (2000 m²/g) as detd. by sorption of PhH and CO₂ at 25°C. An increase in impregnation ratio (1–3 g/g) resulted in better development of microporous structure. The activation temp. (700–800°C) did not play any significant role.

16

Active carbons from plum stones

63%

Pawlicka A. , Doczekalska B. , Bartkowiak M.

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2012

|

tom 79

17

Ammoxidized active carbons as adsorbents for pollution from liquid and gas phases

63%

Pietrzak R. , Nowicki P. , Wachowska H.

|

nr 2

449-452

EN

The influence of modification by pre- and post-treatment of active carbons with ammonia on adsorption abilities from liquid and gas phases has been tested. Carbon materials with different surface chemistry were obtained by chemical activation of Polish brown and subbituminous coal. The products were microporous active carbon samples of well developed surface area (SBET from 1579 to 2,922 m²/g), containing from 0.3 to 7.4 wt% of nitrogen. The results obtained in our study have, moreover, proven that a suitable choice of the modification procedure for coals can produce activated carbons with high capacity of iodine adsorption (to 2,100 mg/g) and high nitrogen dioxide adsorption ability, reaching to 55.1 mg NO₂/g.

18

Isotherm studies of malachite green removal by yarn processing sludge-based activated carbon

63%

Tang S. H. , Zaini M. A. A.

Chemistry-Didactics-Ecology-Metrology

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2019

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tom R. 24, NR 1-2

127--134

EN

Adsorption is an effective wastewater treatment technique which has been widely used in various industrial applications. However, the high operation cost involving commercial activated carbon in industrial processes is the main drawback. Sewage sludge is an auspicious precursor of activated carbon owing to its high carbon content, rich functional groups, low cost, high availability and abundance. This research was aimed to establish the feasibility of converting yarn processing sludge into activated carbon by KI + KOH activation and char at 700 °C for 1 h. The effect of preparation strategies on the properties of sludge-based adsorbents (SBA) was reviewed. The applications of SBAs in the removal of dyes and model pollutants were discussed. The results from this study proved that the preparation of yarn processing sludge-based activated carbon via KI + KOH activation is feasible and effective in the adsorption of dye. This paper provides further insight on the preparation methods of sludge-based adsorbents and dye wastewater treatment using these adsorbents.

19

Grzyby i odpady grzybowe jako nowe prekursory do otrzymywania adsorbentów węglowych

63%

Koźlarek N. , Bazan-Woźniak A. , Pietrzak R.

Wiadomości Chemiczne

|

2022

|

tom [Z] 76, 3-4

221--236

EN

Undesirable changes in the bacteriological, physical and chemical properties of water are a consequence of introduction of excessive amounts of inorganic and organic materials to it. These pollutants limit or prevent the use of water for drinking, food production and household purposes. The greatest amounts of pollutants enter the watersystem with sewage. Also the pesticides,surfactants, organic dyes, artificial fertilizers along with municipal and industrial waste can easily enter water system and threaten the organisms living there. Another, equally important problem is the pollution of atmospheric air. Emission of solid liquid or gas pollutants to the atmosphere has been proved to have significant impact on human health, climate and nature. That is why the search for new and more effective technologies for the environment purification is a continuous challenge. Recently, increasingly often carbon materials are used as effective adsorbents of pollutants from liquid and gas phases.

20

Chemical activation of Polish anthracites with solid sodium hydroxide

63%

Pająk J. , Kozak S. , Lachowski A.

Karbo

|

2006

|

tom Nr 1

35-38

EN

Two Polish anthracites were activated by mixing with sodium hydroxide and heating under flowing gas up to 780°C. Microporous carbons were obtained. Several NaOH/anthracite ratios, several schemes of thermal treatment and two gases: nitrogen and carbon dioxide were used. Porosity development is strongly dependant on NaOH/anthracite ratio. A part of NaOH is consumed due to reactions with inorganics constituting mineral matter of anthracite The anthracite with low content of mineral matter and higher C/H atomic ratio is more suitable as microporous carbon precursor. Carbon dioxide atmosphere has negative effect on activation with solid NaOH.

PL

Badano proces aktywacji chemicznej dwóch polskich antracytów poprzez zmieszanie próbek ze stałym wodorotlenkiem sodu i ogrzewanie w przepływie gazu w temperaturze 780°C. Otrzymano mikroporowate węgle aktywne. Aby uzyskać informacje dotyczące przebiegu procesu i wpływu poszczególnych parametrów, zastosowano różne schematy obróbki cieplnej przy użyciu dwóch gazów: azotu i CO2. Badano również wpływ stosunku wagowego NaOH do próbki węgla na porowatość produktu aktywacji. Produkty aktywacji charakteryzowano głównie na podstawie pomiarów izotermy sorpcji azotu. Stwierdzono, że poprzez zwykłe fizyczne zmieszanie (bez impregnacji) antracytu z wodorotlenkiem sodu i ogrzanie tej mieszaniny w przepływie azotu do temperatury 780°C można otrzymać mikroporowate węgle aktywne o porowatości około 0,9 cm3/g i mikroporowatości powyżej 88 %. Porowatość produktu aktywacji zależy od prekursora i od parametrów procesu aktywacji. Optymalny stosunek wagowy NaOH do antracytu wynosi około 3:1, ale w przypadku antracytu o dużej zawartości substancji mineralnych stosunek ten powinien być wyższy, gdyż NaOH reaguje z tymi substancjami, obniżając ich zawartość w węglu aktywnym. Dwutlenek węgla wywiera negatywny wpływ na przebieg aktywacji antracytów za pomocą stałego wodorotlenku sodu.