Effects of pore structure and temperature on VOC adsorption on activated carbon

Chiang, Yu‐Chun; Chiang, Pen‐Chi; Huang, Chin‐Pao

doi:10.1016/s0008-6223(00)00161-5

Cited by 355 publications

(142 citation statements)

References 12 publications

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“…Chiang (Chiang, 2001) studied the influence of pore structure on AC's adsorptive properties and concluded that the adsorptive capacity was related to the pore size, shape, and distribution. Using benzene and toluene as adsorbates, Lillo-Ródenas (LilloRódenas et al, 2005) studied the adsorption behavior of AC in low concentrations and concluded that the adsorption capacity of AC was closely related to pore structure.…”

Section: Introductionmentioning

confidence: 99%

Effects of activated carbon surface properties on the adsorption of volatile organic compounds

Sun

et al. 2012

Journal of the Air & Waste Management Association

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Physical and chemical properties of activated carbon (AC) were analyzed to investigate the effects of adsorbate properties on AC adsorption performance. Fixed-bed adsorption experiments were conducted with toluene, acetone, and xylene as adsorbates. From the results, the adsorption capacities of the three adsorbates had the following order: xylene > toluene > acetone. The correlation between experimental data and adsorbate properties was also analyzed. The results showed that different functional groups corresponding to the properties of adsorbates influenced the adsorptive properties of AC differently. The adsorption capacity of AC increased linearly as the molecular weight, dynamic diameter, boiling point, and density of the adsorbate increased. However, adsorption capacity decreased as the polarity index and vapor pressure of the adsorbate increased. For adsorption onto three types of AC, the adsorption energies of the three adsorbates had the following order: xylene > toluene > acetone.Implications: This paper focused on the research on adsorption behavior of activated carbon based on adsorbate properties. Adsorption experiments were conducted under the same condition while the adsorbates were toluene, acetone, and xylene, respectively. Correlation analysis between experimental data and adsorbate properties was conducted. The different groups have different influence on the adsorptive properties of ACs. The adsorption capacity of activated carbon increases with the increase of adsorbate molecular weight, dynamic diameter, boiling point, and density, and that this relationship is linear. The relationship between adsorption capacity and the polarity index and vapor pressure of adsorbate shows an opposite trend, and the adsorption capacities and adsorption energies of three kinds of activated carbon for these three adsorbates had the following order: xylene > toluene > acetone.

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Section: Introductionmentioning

confidence: 99%

Effects of activated carbon surface properties on the adsorption of volatile organic compounds

Sun

et al. 2012

Journal of the Air & Waste Management Association

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“…1 Schematic diagram and cross-sectional micrograph (under x1 K magnification) of the assembly of P-25TiO 2 / BEN-PVAG/GP bilayer system classification, both BEN and BEN-PVAG composite demonstrated type IV adsorption isotherms with type 4 hysteresis loops, indicative of the existence of the mesoporous structures. The broad hysteresis loop of H4 type indicates the formation of slit-like pores associated with the capillary condensation in mesoporous behaviour (Chiang et al 2001;Thommes 2010). Clearly, addition of PVAG sharply decreased the adsorption isotherm which indicated a significant decrease in its BET surface area.…”

Section: Resultsmentioning

confidence: 95%

Role of bentonite adsorbent sub-layer in the photocatalytic-adsorptive removal of methylene blue by the immobilized TiO2/bentonite system

Ngoh

Nawi

2016

Int. J. Environ. Sci. Technol.

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An immobilized clay composite (BEN-PVAG) on a glass plate (GP) was fabricated using bentonite powder (BEN) and glutaraldehyde cross-linked polyvinyl alcohol (PVAG) as the adsorbent and adhesive, respectively. The immobilized bentonite composite (BEN-PVAG) was characterized using SEM, EDX, FTIR, and BET analysis. The adsorption capacity of BEN-PVAG was examined using methylene blue (MB) as the model pollutant. The results indicated that the adsorption of MB onto BEN-PVAG obeyed pseudo-second-order kinetics. In addition, the adsorption of MB by the immobilized BEN-PVAG was controlled by intra-particle diffusion. In contrast, the adsorption of MB by the suspended BEN-PVAG composite was dominated by film diffusion. The immobilized BEN-PVAG was then applied as the adsorbent sublayer for the fabrication of P-25TiO 2 /BEN-PVAG/GP bilayer system where P-25TiO 2 was deposited as the top layer. The fabricated bilayer system exhibited synergistic photocatalytic-adsorptive removal of MB upon irradiation with a light source, while experiment in the dark yielded only adsorption process. The rate of the synergistic photocatalytic-adsorptive removal of MB by the P-25TiO 2 / BEN-PVAG/GP was 5.3 times faster than the suspended P-25TiO 2 . The result implied the positive impact of the BEN-PVAG adsorbent sub-layer on the immobilized P-25TiO 2 photocatalyst. Most important, the immobilized P-25TiO 2 /BEN-PVAG/GP provided a convenient reuse of the catalyst over time where the treated water could be directly discharged without the need of filtration.

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“…The molecular diameter of VOCs was between approximately 3 Å and 8.5 Å (Chang, 2002). For surface adsorption, the ratio of pore diameter to the diameter of adsorbate is a key parameter, and the proportion of micropores (<20 Å) of AC is critical to the effective adsorption of VOCs (Wu and Yuo, 2007;Mauguet et al, 2005;Chiang et al, 2001;Yamamoto et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Adsorption–desorption characteristics of methyl ethyl ketone with modified activated carbon and inhibition of 2,3-butanediol production

Nien

Chang²,

Chang

2015

Journal of the Air & Waste Management Association

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Activated carbon (AC) is seldom applied for recovering ketone-based volatile organic compounds because of safety concerns. Adsorption of methyl ethyl ketone (MEK) with AC is a highly exothermic reaction that potentially causes fires in AC beds. Moreover, 2,3-butanediol (BDO) is produced in the desorbed solvent, causing yellowing and odor of the recovered solvent. This study applied a continuous adsorption-desorption apparatus for evaluating the operating capacities and BDO concentration in recovered MEK containing modified and original ACs. AC-1 (TAKETA-G2X) was used as the target for modification. The experimental results indicate that using MgO as the modifier increases the ignition point by 12°C and that applying KNO 3 as the modifier reduces the AC ignition point by 28°C (compared with AC-1). The BDO concentration of the desorbed MEK solvent can be reduced by increasing the loading of the modifying agent (Ethanolamine) (Im-1: 3.1 wt%; Im-5: 6.2 wt%). Moreover, applying the AC pretreated with nitrogen (Im-6) as adsorbent significantly reduces the BDO concentration (from 0.123 wt% to 0.073 wt%). Because desorption and purging procedures were performed in N 2 atmospheres, the BDO concentrations of the desorbed MEK solvents were relatively low and ranged from 0.032 wt% to 0.043 wt%. When the MEK concentration was reduced to 2000 ppm, lower BDO concentrations (0.012-0.022 wt%) were measured in the recovered MEK solvent. The way to modify activated carbon and a better desorbing sequence to effectively inhibit the oxidation of MEK to BDO are developed. The results obtained indicate that the BDO concentration in the desorbed solvent was lower than the original MEK solvent (0.023 wt%). Different approaches can be applied simultaneously to achieve high inhibition effects; however, carbon adsorption performance may be negatively affected.Implications: The study is motivated to improve the quality of recovered solvent and reduce fire hazards, particularly when AC is applied for adsorbing a ketone-based solvent (e.g., MEK). The experimental results indicate that the BDO concentration in the recovered solvent can be reduced and the ignition point of AC can be increased by modifying the AC with an appropriate agent.

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Effects of pore structure and temperature on VOC adsorption on activated carbon

Cited by 355 publications

References 12 publications

Effects of activated carbon surface properties on the adsorption of volatile organic compounds

Effects of activated carbon surface properties on the adsorption of volatile organic compounds

Role of bentonite adsorbent sub-layer in the photocatalytic-adsorptive removal of methylene blue by the immobilized TiO2/bentonite system

Adsorption–desorption characteristics of methyl ethyl ketone with modified activated carbon and inhibition of 2,3-butanediol production

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