Organic micropollutant desorption in various water matrices - Activated carbon pore characteristics determine the reversibility of adsorption

Aschermann, Geert; Schröder, Corinna; Zietzschmann, Frederik; Jekel, Martin

doi:10.1016/j.chemosphere.2019.124415

Cited by 19 publications

(13 citation statements)

References 22 publications

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“…Additionally, the reduced adsorption capacity of the bioregenerated GAC can also be related to the release of melamine previously adsorbed. The release of adsorbed melamine may be hindered by the presence of dissolved (and adsorbed) organic matter due to pore blockage, which would lead to desorption hysteresis (Aschermann et al, 2019a(Aschermann et al, , 2019b. This effect is stronger in microporous GACs (Aschermann et al, 2019b), as is the case for the GAC used in this experiment .…”

Section: Limiting Factors For Bioregenerationmentioning

confidence: 86%

“…The release of adsorbed melamine may be hindered by the presence of dissolved (and adsorbed) organic matter due to pore blockage, which would lead to desorption hysteresis (Aschermann et al, 2019a(Aschermann et al, , 2019b. This effect is stronger in microporous GACs (Aschermann et al, 2019b), as is the case for the GAC used in this experiment . Our desorption isotherm shows that melamine adsorption was fully reversible in the presence of inactivated melamine degrading biomass (Figures 4.7 and S4.2).…”

Section: Limiting Factors For Bioregenerationmentioning

confidence: 86%

“…The n value obtained for the adsorption isotherm was used as input, together with the desorption data, to determine the desorption Freundlich constant (𝐾𝐾 𝑓𝑓,𝑎𝑎𝑒𝑒𝑎𝑎 , in L/g) similar to the procedure followed by Aschermann et al (2019b). The purpose of this approach is to compare adsorption and desorption affinities based on a single coefficient (𝐾𝐾 𝑓𝑓 ).…”

Section: Melamine Adsorption and Desorption Isothermmentioning

confidence: 99%

“…The faster adsorption observed for the bioregenerated GAC compared to nonbioregenerated GAC supports the hypothesis of melamine desorption hysteresis due to pore blockage. Pore blockage is likely to happen in the smallest pore fraction of the GAC (Aschermann et al, 2019b). This means that melamine only desorbs from adsorption sites in the larger pore fraction and hence those are the pores subject to bioregeneration.…”

Section: Melamine Adsorption Ratementioning

confidence: 99%

“…GAC bioregeneration can be negatively impacted by NOM only if pore blockage prevents micropollutants desorption. This effect is more influenced by GAC pore size distribution than by NOM composition (Aschermann et al, 2019b(Aschermann et al, , 2019a. Aschermann et al (2019b) compared micropollutants adsorption using ACs with different pore size distributions and concluded that pore blockage limited micropollutants desorption from microporous AC, whereas adsorption was still fully reversible in mesoporous AC.…”

Section: Natural Organic Matter and Micropollutants Adsorptionmentioning

confidence: 99%

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Micropollutants removal with activated carbon : Adsorption and regeneration by biodegradation

Piai¹

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Hydrophilic organic micropollutants are commonly detected in source water used for drinking water production. Effective technologies to remove these micropollutants from water include adsorption onto granular activated carbon in fixed-bed filters. The ratedetermining step in adsorption using activated carbon is usually the adsorbate diffusion inside the porous adsorbent. The presence of mesopores can facilitate diffusion, resulting in higher adsorption rates. We used two different types of granular activated carbon, with and without mesopores, to study the adsorption rate of hydrophilic micropollutants. Furthermore, equilibrium studies were performed to determine the affinity of the selected micropollutants for the activated carbons. A pore diffusion model was applied to the kinetic data to obtain pore diffusion coefficients. We observed that the adsorption rate is influenced by the molecular size of the micropollutant as well as the granular activated carbon pore size.

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Section: Limiting Factors For Bioregenerationmentioning

confidence: 86%