Efficient removal of crystal violet dye from aqueous solutions using sodium hydroxide-modified avocado shells: kinetics and isotherms modeling

Autor: Mohamed Ait Haki, Abdelaziz Imgharn, Nouh Aarab, Abdelghani Hsini, Abdelillah Essekri, Mohamed Laabd, Habiba El Jazouli, Maria Elamine, Rajae Lakhmiri, Abdallah Albourine
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Water Science and Technology, Vol 85, Iss 1, Pp 433-448 (2022)
Druh dokumentu: article
ISSN: 0273-1223
1996-9732
DOI: 10.2166/wst.2021.451
Popis: The main objective of this study is to optimize a new composite for the depollution of contaminated water. The sodium hydroxide-modified avocado shells (NaOH-AS) were firstly prepared, characterized by field-emission-scanning-electron-microscopy (FE-SEM), X-ray energy dispersive spectroscopy (EDS) and Fourier transforms infrared (FT-IR) spectroscopy, and applied for efficient removal of crystal violet dye (CV) in wastewater. In addition, the adsorption in a batch system of CV dye on the NaOH-AS material was studied. Therefore, we accomplished a parametric study of the adsorption by studying the effect of several important parameters on the decolorizing power of the used material, namely, initial pH, contact time, initial CV dye concentration, temperature, and the ionic strength effect on the CV dye adsorption process were systematically assessed. The highest adsorption efficiency of CV dye (>96.9%) by NaOH-AS was obtained at pH >8. The pseudo-second-order kinetic model gave the best description of the adsorption kinetic of CV dye on the AS and NaOH-AS adsorbents. In addition, the mass transfer of CV dye molecules from the solution to the adsorbent surface occurred in three sequential stages (boundary layer diffusion, intraparticle diffusion and adsorption equilibrium). The adsorption isotherm data were best fitted with the Freundlich model. The adsorption capacity of AS increased from 135.88 to 179.80 mg g−1 after treatment by 1 M NaOH. The thermodynamic study showed that CV dye adsorption onto NaOH-AS was an exothermic and feasible process. The electrostatic interactions acted as the only forces governing the CV adsorption mechanism. The NaOH-AS demonstrated a satisfactory reusability. Therefore, we can state that the as-developed NaOH-AS material has a potential application prospect as an efficient adsorbent for CV dye from wastewaters. HIGHLIGHTS NaOH-AS is an efficient adsorbent for removal of crystal violet dye from aqueous solutions.; Equilibrium data were well described by Freundlich isotherm model.; The maximum uptake capacity was found to be 179.80 mg/g.;
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