New insight into the eco-friendly synthesis of MgO NPs using olive pomace extract: combined experimental and DFT study for Congo red adsorption
Abstract
In this study, magnesium oxide nanoparticles (MgO NPs) were synthesized via a green method using olive pomace extract as a natural reducing and stabilizing agent. XRD, FTIR, SEM-EDX, TG/DTG, and BET analyses confirmed the formation of crystalline, quasi-spherical MgO with a cubic structure and an average crystallite size of ∼13 nm. The MgO NPs were applied for the removal of Congo Red (CR) dye from aqueous solutions, achieving 91.5% removal within 30 min and over 95% under optimal conditions (pH ≈ 7, dose = 0.2 g, C 0 = 20 mg L-1, T = 298 K). Equilibrium data fitted the Dubinin-Radushkevich isotherm, and kinetics followed a pseudo-second-order model, indicating chemisorption as the dominant mechanism. Thermodynamic parameters indicated spontaneous (ΔG° = -31.16 to -31.43 kJ mol-1) and exothermic (ΔH° = -27.21 kJ mol-1) adsorption, with increased disorder at the solid-liquid interface (ΔS° = +13.50 J (mol-1 K-1)) and a slight decrease in adsorption at higher temperatures. DFT and MD studies provided molecular-level insights, showing strong electrostatic and charge-transfer interactions between CR sulfonate groups and Mg2+ sites, supported by a low HOMO-LUMO gap (∼2.83 eV) and favorable adsorption configurations. These results demonstrate that green-synthesized MgO NPs from olive pomace are efficient and environmentally friendly adsorbents for dye removal from wastewater.
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BibTeX
@article{mechati2026insight,
title = {{New insight into the eco-friendly synthesis of MgO NPs using olive pomace extract: combined experimental and DFT study for Congo red adsorption}},
author = {Sabrina Mechati and Meriem Zamouche and Hichem Tahraoui and Zakaria Laggoun and Oumnia Rayane Benkouachi and Nasreddine Hadjadj and Nora Cherb and Sonia Cherif and Mohammed Kebir and Mouni Lotfi and Aymen Amine Assadi and Ahmed Amine Azzaz and A Amrane},
journal = {RSC Advances},
year = {2026},
month = oct,
doi = {10.1039/d6ra02871c},
url = {https://hal.science/hal-05741228v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - New insight into the eco-friendly synthesis of MgO NPs using olive pomace extract: combined experimental and DFT study for Congo red adsorption
AU - Sabrina Mechati
AU - Meriem Zamouche
AU - Hichem Tahraoui
AU - Zakaria Laggoun
AU - Oumnia Rayane Benkouachi
AU - Nasreddine Hadjadj
AU - Nora Cherb
AU - Sonia Cherif
AU - Mohammed Kebir
AU - Mouni Lotfi
AU - Aymen Amine Assadi
AU - Ahmed Amine Azzaz
AU - A Amrane
PY - 2026
DA - 2026/10/16
JO - RSC Advances
DO - 10.1039/d6ra02871c
UR - https://hal.science/hal-05741228v1
AB - In this study, magnesium oxide nanoparticles (MgO NPs) were synthesized via a green method using olive pomace extract as a natural reducing and stabilizing agent. XRD, FTIR, SEM-EDX, TG/DTG, and BET analyses confirmed the formation of crystalline, quasi-spherical MgO with a cubic structure and an average crystallite size of ∼13 nm. The MgO NPs were applied for the removal of Congo Red (CR) dye from aqueous solutions, achieving 91.5% removal within 30 min and over 95% under optimal conditions (pH ≈ 7, dose = 0.2 g, C 0 = 20 mg L-1, T = 298 K). Equilibrium data fitted the Dubinin-Radushkevich isotherm, and kinetics followed a pseudo-second-order model, indicating chemisorption as the dominant mechanism. Thermodynamic parameters indicated spontaneous (ΔG° = -31.16 to -31.43 kJ mol-1) and exothermic (ΔH° = -27.21 kJ mol-1) adsorption, with increased disorder at the solid-liquid interface (ΔS° = +13.50 J (mol-1 K-1)) and a slight decrease in adsorption at higher temperatures. DFT and MD studies provided molecular-level insights, showing strong electrostatic and charge-transfer interactions between CR sulfonate groups and Mg2+ sites, supported by a low HOMO-LUMO gap (∼2.83 eV) and favorable adsorption configurations. These results demonstrate that green-synthesized MgO NPs from olive pomace are efficient and environmentally friendly adsorbents for dye removal from wastewater.
SN - 2046-2069
ER -