Removal of phenolic compounds from aqueous solution using MgCl2-impregnated activated carbons derived from olive husk: the effect of chemical structures

Activated carbon (BC) prepared from olive oil solid waste (olive husk) by slow pyrolysis was chemically activated using MgCl2 (BC-MgCl2). The BC and BC-MgCl2 were used as adsorbents for removal of three phenolic compounds, namely, phenol (P), p-methoxyphenol (PMP) and p-nitrophenol (PNP), from aqueo...

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Bibliographic Details
Published in:Water science and technology 2020-06, Vol.81 (11), p.2351
Main Authors: Hamadneh, Imad, Abu-Zurayk, Rund A., Al-Dujaili, Ammar H.
Format: Article
Language:English
Subjects:
Activated carbon
Adsorbents
Adsorption
Aqueous solutions
Biomass
Endothermic reactions
Entropy
Fourier transforms
Isotherms
Kinetics
Magnesium chloride
Molecular structure
Nitrophenol
Nonsteroidal anti-inflammatory drugs
Olive oil
p-Nitrophenol
Phenolic compounds
Phenols
Polarity
Pyrolysis
Removal
Solid wastes
Uptake
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Summary:Activated carbon (BC) prepared from olive oil solid waste (olive husk) by slow pyrolysis was chemically activated using MgCl2 (BC-MgCl2). The BC and BC-MgCl2 were used as adsorbents for removal of three phenolic compounds, namely, phenol (P), p-methoxyphenol (PMP) and p-nitrophenol (PNP), from aqueous solution. The uptake of these three phenolic compounds by the BC and BC-MgCl2 was better expressed by the Langmuir and Dubinin–Radushkevich (D-R) isotherm models than by the Freundlich isotherm, and the kinetics of the adsorption process followed the pseudo-second order kinetic model. The maximum monolayer adsorption capacity of P, PMP and PNP were increased from 24.938, 45.455 and 61.728 on BC to 43.860, 98.039 and 121.951 mg/g on BC-MgCl2 by factors of 1.76, 2.16 and 1.98, respectively. Therefore, the chemical activation of BC by MgCl2 is indeed of importance for improving its adsorption performances. For both adsorbents, the adsorption phenomenon for different substituted phenols is a strong function of solubility, polarity, molecule structure, and size. At the tested temperatures (25, 35 and 45 °C), the negative values of ΔG° and positive values of ΔH° and ΔS° for the adsorption of P, PMP and PNP on BC and BC-MgCl2 demonstrated that the adsorption was a spontaneous, endothermic and entropy-increasing process.
ISSN:0273-1223
1996-9732
DOI:10.2166/wst.2020.297