Résumé:
Enhancement of the adsorptive properties of commercial activated carbons by simple
surface modifications using chemical agents and their application to methylene blue,
bemacid blue N-TF dyes, and nickel(II) ion removal from their aqueous solutions was the
aim of this study. Impregnations in 10% KOH (MAC-K) for 24 h and concentrated H
2
SO
4
(MAC-S) for 2 h, applied to Merck activated carbon, and NaOH (RHAC-N) with different
strength applied to Riedel- de Haen activated carbon in order to functionalize and to mod-
ify their surfaces were investigated. These treatments were found to increase the adsorption
capacity of the considered pollutants significantly relative to their untreated state of up to
250.00 mg/g for methylene blue, 11.47 mg/g for nickel(II) ions, and 312.00 mg/g for
bemacid blue ET-L by MAC-K, MAC-S, and RHAC-N, respectively. Three well-known
model equations namely Langmuir, Freundlich, and Temkin were used to analyze the
adsorption equilibrium data. Parameters influencing adsorption capacity such as contact
time, adsorbent dosage, pH, and temperature were studied. FT-IR and DRX analysis were
performed for chemical functionalities; pH
zpc
, methylene blue accessible area, iodine
number, and morphological analysis by scanning electron microscopy determination were
also performed to characterize the prepared adsorbents. Adsorption kinetics was found to
comply with the pseudo-second-order with a good correlation factor (
R
2
= 0.99) and with
intra-particle diffusion as the rate-determining steps. This study showed that surface
functionalization of activated carbon could prove to be a very useful method in removing
toxic substances from wastewater and the environment.
