Feasibility and the Mechanism of Desorption of Phenolic Compounds from Activated Carbons

Abstract

The desorption efficiency (DE) of phenols, including pnitrophenol, p-chlorophenol, p-hydroxybenzoic acid, phenol, and hydroquinone, from activated carbons (ACs), has been investigated with a variety of solvents to gain insight into the feasibility and mechanism of phenols desorption. Ultrasound (US), microwaves (MW), and flow mode have been used to facilitate phenols desorption. It was found that the basicity, polarity, and hydrogen bonds of solvents synergistically affected phenols desorption. The preferred solvents (Lewis basic solvents, acetic acid, and alcohols) gave highly efficient elution. Increasing the alkaline or/and hydrogen bonding interactions, by adding ammonia or urea, enhanced desorption in most solvents. Moreover, although US and MW heating slightly improved desorption, complete desorption was easily achieved in a flow mode. It is demonstrated, herein, that phenols adsorption on the ACs is a reversible physical process, thus proving the feasibility of phenols desorption with proper solvents. Comparison of diffuse reflectance infrared Fourier transform (DRIFT) spectra and porosity property measurements of pristine, loaded, and eluted ACs confirmed our results. It can, therefore, be stated that our procedure can be used to dispose of secondary pollution while cutting post-treatment costs, thanks to the recovery of valuable compounds and AC recycling.

On the potential of pristine Cocos nucifera L . tissues for green desalination

“…The desorption trends of salinity in the DW are shown in figure 3. This desorption study has two points of relevance for investigation: (i) to predict the ease of desorption/regeneration for subsequent reuse of the various samples and (ii) to inform on the strength of chemisorption by which the sorbed Cl − could be held without possible re-elution into the water [45]. Therefore, the higher the magnitude and rate of the desorption, the ease with which the regeneration (less energy demand and faster process) would ensue, albeit the lower the reliability of Cl − adsorption, resulting in less efficient removal.…”

Metabolomic analysis and ecofriendly enrichment of sunflower meal extract

“…Desorption studies are less abundant, and the literature has emphasized that it has been challenging to achieve efficient desorption of phenols. 69,70 For some time, it was believed that many phenolic compounds would be irreversibly linked to the adsorbent, especially AC. 66 However, more recent studies were able to achieve complete desorption of adsorbed phenols 69,71 disproving this belief.…”

“…69,70 For some time, it was believed that many phenolic compounds would be irreversibly linked to the adsorbent, especially AC. 66 However, more recent studies were able to achieve complete desorption of adsorbed phenols 69,71 disproving this belief. Ge et al, 69 in an extensive study about the desorption of phenolic compounds from different adsorbents, recommended the use of alkaline ethanol for better desorption results.…”

“…66 However, more recent studies were able to achieve complete desorption of adsorbed phenols 69,71 disproving this belief. Ge et al, 69 in an extensive study about the desorption of phenolic compounds from different adsorbents, recommended the use of alkaline ethanol for better desorption results. According to the researchers, alkaline pH favored the formation of phenolic salts, increasing the desorption efficiency.…”