Effect of modification of granulated activated carbons with ozone on their properties

Belyaeva, O. V.; Krasnova, T. A.; Семенова, С. А.

doi:10.1134/s1070427211040070

Cited by 7 publications

(5 citation statements)

References 6 publications

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“…A loss of SBET and pore volume below 10% was observed when ozone-enriched air (40 mgL -1 ) was used at 100ºC (12.7% burn-off). Belyaeva et al [28] studied the modification of commercial granular activated carbons with 1.5% ozone in air at 25ºC. A short treatment time (1 h) led to a significant increase of SBET (from 683 to 885 m 2 g -1 ) and total pore volume because of the "etching" of the surface of meso and macropores, which resulted in the formation of new micropores.…”

Section: Introductionmentioning

confidence: 99%

“…Rivera-Utrilla and Sánchez-Polo [29] also observed a decrease in the surface area of commercial activated carbons when treated with ozone in gas phase at 25ºC for 20-120 min due to the ozone attack and the increase of oxygenated groups, these last preventing the diffusion of nitrogen during BET test by obstructing micropore entrances. Some works [19,20,[27][28][29][30] also showed that ozone oxidation of carbon materials brings about a noticeable increase of the surface oxygen content due to the formation of oxygen-containing functional groups.…”

Section: Introductionmentioning

confidence: 99%

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Ozone as oxidation agent in cyclic activation of biochar

Jiménez-Cordero

Heras

Alonso-Morales

et al. 2015

Fuel Processing Technology

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Granular activated carbons were produced from grape seed biochar by cyclic activation with ozone. In each cycle, char was first oxidized by exposure to ozone and then subjected to high temperature in inert atmosphere to desorb oxygen groups formed. The study assessed the influence of operating conditions in the development of porosity, from a starting biochar with narrow microporosity (SBET: 47 m 2 g-1 , SDA: 505 m 2 g-1) prepared by flash pyrolysis of grape seed at 800ºC. The variables studied were the number of cycles applied and the oxidation and desorption temperatures (250-275 and 850-950 ºC, respectively). High oxidation temperatures led to higher burn-off, which was also found to increase with the number of activation cycles. The burn-off needed to achieve a high surface area was lower than in conventional physical activation. After 7-9 activation cycles, activated carbons with SBET higher than 1200 m 2 g-1 and SDA above 1500 m 2 g-1 were obtained. The use of ozone resulted in mainly microporous activated carbons (0.37-0.52 cm 3 g-1) with very low contribution of mesopores (<0.04-0.07 cm 3 g-1). The mean micropore size increased with the number of activation cycles due to pore widening, while mesopore mean size decreased along the cycles. The activated carbons showed a unique granular morphology with a hollow core and a porous shell, which is maintained even after 10 activation cycles. Figure 5. Micro and mesopore volume development with number of activation cycles.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ozone as oxidation agent in cyclic activation of biochar

Jiménez-Cordero

Heras

Alonso-Morales

et al. 2015

Fuel Processing Technology

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“…Activation can be performed by different methods, such as mechanical or thermal, chemical, or a combination of both (i.e., physiochemical) [67], and it can also be biological [69]. These include several methods and their combinations, such as chemical treatment, air oxidation, electrochemical oxidation, and plasma, microwave, and ozone treatment for enhancing the adsorption performance of AC [70][71][72][73][74]. However, for AC prepared for anionic dye adsorption, the chemical-activation technique (using activating agents, such as zinc chloride or phosphoric acid) [75] is mostly preferred (Figure 6) because of its faster activation time, higher carbon yield, simplicity, lower operating temperature, and well-developed pore structure.…”

Section: Thermal Modificationsmentioning

confidence: 99%

Sustainable Adsorbents from Plant-Derived Agricultural Wastes for Anionic Dye Removal: A Review

et al. 2022

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The extensive use of dyes in numerous industries results in massive dye discharge in the wastewater, which is a major cause of water pollution. Globally, the consumption of dyes is near seven hundred thousand tons across different sectors, of which around 10–15% goes into the wastewater. Among the dye kinds, anionic dyes make up the main proportion, having a 32–90% share in the wastewater. Different plant-derived wastes, which are sustainable given their natural abundance, effectiveness, and low cost, are frequently proposed for dye separation. However, these adsorbents are inherently more suitable for cationic dyes than anionic dyes. In recent years, the modification of these wastes has been progressively considered to suit them to anionic dye removal. These modifications involve mechanical, thermal, or chemical treatments, or combinations. These attempts propose two-way benefits, as one abundant waste is being used to cure another severe problem, and eventually both could be diminished. This review has a key focus on the evaluation of plant-derived adsorbents and their modifications, and particularly for anionic dye adsorption. Overall, the mechanism of adsorption and the suitability of the current methods are discussed, and their future potential is explored.

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“…Several studies have shown that modifying activated carbon can significantly improve its physical and chemical characteristics, which in turn enhance adsorption selectivity and capacity . Activated carbon modification is generally implemented using acid treatment, base treatment, microwave irradiation, ozone oxidation, impregnation with hydrophilic chemicals, and grafting of hydrophilic functional groups connected to the activated carbon surface. , Acid treatment or base treatment is usually performed by immersing the activated carbon in different solutions, which is followed by filtration and drying. However, the drying process of wet-modified activated carbon is extremely prone to cause fires if the temperature increase due to heat accumulation exceeds its ignition temperature. , The increasing number of applications in the activated carbon modification industry and the frequent occurrence of combustion in the process of modifying activated carbon have necessitated additional studies on the safety research and combustion prevention …”

Section: Introductionmentioning

confidence: 99%

“… 9 Several studies have shown that modifying activated carbon can significantly improve its physical and chemical characteristics, which in turn enhance adsorption selectivity and capacity. 10 Activated carbon modification is generally implemented using acid treatment, 11 base treatment, 12 microwave irradiation, 13 ozone oxidation, 14 impregnation with hydrophilic chemicals, and grafting of hydrophilic functional groups connected to the activated carbon surface. 15 , 16 Acid treatment or base treatment is usually performed by immersing the activated carbon in different solutions, which is followed by filtration and drying.…”

Section: Introductionmentioning

confidence: 99%

Spontaneous Combustion Characteristics of Activated Carbon Modified via Liquid Phase Impregnation during Drying

Li,

Zhang,

Lyu

et al. 2023

ACS Omega

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Spontaneous combustion characteristics are important issues for the safe operation of the wet-modified activated carbon drying process. The spontaneous combustion characteristics of activated carbon modified via liquid phase impregnation were fully investigated in this study. The modified activated carbon was prepared using columnar activated carbon and 4-amino-1,2-butanediol solution. Physical properties and surface functional group analyses were performed for activated carbon before and after modification. The ignition temperature of activated carbon before and after modification was then characterized using the methods of GB/T20450–2006, thermogravimetry–derivative thermogravimetry (TG-DTG), and TG–mass spectrometry (TG-MS). At the same time, the activation energy of activated carbon before and after modification was calculated by using thermodynamic analysis. Furthermore, a new self-designed test platform was introduced to investigate the spontaneous combustion characteristics of wet-modified activated carbon under the drying temperatures of 150, 175, 180, and 210 °C. The results show that the specific surface area of Brunauer, Emmett, and Teller (BET) is decreased by 368 m 2 ·g –1 , the total volume of pore size is decreased by 0.17 cm 3 ·g –1 , and the content of oxygen-containing functional groups is decreased by 0.071 mmol/g compared with row activated carbon. The ignition temperatures of the sample before modification characterized by the three methods are 483, 596, and 599 °C, respectively. The ignition temperatures of the sample after modification are 489, 607, and 611 °C, respectively. The activation energy of the modified activated carbon is increased by 35 kJ/mol compared to the original activated carbon. It is concluded that the temperature that triggers the modified activated carbon combustion during the drying process is between 175 and 180 °C, and the heat is mainly gathered at the longitudinal center of the combustion chamber through the investigation of spontaneous combustion experiments. The results in this study can contribute to safe production to prevent combustion in the process of modifying activated carbon during the drying process.

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Effect of modification of granulated activated carbons with ozone on their properties

Cited by 7 publications

References 6 publications

Ozone as oxidation agent in cyclic activation of biochar

Ozone as oxidation agent in cyclic activation of biochar

Sustainable Adsorbents from Plant-Derived Agricultural Wastes for Anionic Dye Removal: A Review

Spontaneous Combustion Characteristics of Activated Carbon Modified via Liquid Phase Impregnation during Drying

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