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Öğe A combined DFT, Monte Carlo, and MD simulations of adsorption study of heavy metals on the carbon graphite (111) surface(Elsevier, 2022) Khnifira, M.; Boumya, W.; Attarki, J.; Mahsoune, A.; Sadiq, M.; Abdennouri, M.; Kaya, S.This work investigated the adsorption mechanism of heavy metals: silver (Ag), mercury (Hg), cadmium (Cd), palladium (Pd), and zinc (Zn) on the carbon graphite (111) surface based on density functional theory (DFT), Metropolis Monte Carlo (MMC), and the molecular dynamics (MD) simulation methods. The obtained results from the adsorption of these species showed that the process is spontaneous and exothermic in nature. The maximum adsorption capacities were obtained in neutral to low acid medium, and the interaction between Hgcarbon graphite was more favored than other systems. These findings showed that carbon graphite was more efficient in the removal of the studied metals. Moreover, this study better explains the adsorption mechanism of heavy metals onto carbon graphite and gives a theoretical basis for the wider application of graphite adsorbent in the removal of heavy metals. This paper provides theoretical support for heavy metals removal in various mediums and also provides some new ideas for the secondary utilization of quantum chemical descriptors and molecular dynamics simulation methods.Öğe Adsorption characteristics of dopamine by activated carbon: Experimental and theoretical approach(Elsevier B.V., 2023) Khnifira, M.; Boumya, W.; Attarki, J.; Mahsoune, A.; Abdennouri, M.; Sadiq, M.; Kaya, S.In this work, we investigate the adsorption mechanism of dopamine (DP) drug using an activated carbon (AC) type through experimental and theoretical data. Experiment series were carried out at different initial values of solution pH, temperature, reaction time and initial drug concentration. The effect of protonation and deprotonation of DP molecule was also investigated. The equilibrium isotherm data were evaluated using the Dubinin-Radushkevich, Langmuir, Temkin and Freundlich models. Elovich, pseudo-first and pseudo-second order kinetic models were used to analyze kinetic data. Here we also used molecular dynamic (MD) simulation and DFT-based computational methods to reach information about the electronic properties of DP drug and its adsorption mechanism that have not been experimentally observed. Experimental results show that the Elovich kinetic model and Langmuir model best describe the adsorption phenomenon. In parallel, the experimental analysis revealed that the adsorption process is spontaneous and endothermic. Dopamine adsorption on AC occurs quickly and is pH and temperature-dependent. Frontier molecular orbital (FMO) energies for neutral, deprotonated and protonated forms of DP were determined and thoroughly explained. The basic medium significantly impacts DP drug adsorption behavior, which has the greatest adsorption energy when the pH is less than 12. It was found that DP adsorption occurs in a bidentate geometry by forming strong bonds between molecular oxygens and carbon atoms on the AC surface. Based on theoretical calculations interaction mechanisms of DP on the AC (001) surface were proposed. © 2023 Elsevier B.V.Öğe Adsorption mechanism investigation of methylthioninium chloride dye onto some metal phosphates using Monte Carlo dynamic simulations and DFT calculations(Elsevier, 2023) Attarki, J.; Khnifira, M.; Boumya, W.; Mahsoune, A.; Lemdek, E. M.; Sadiq, M.; Abdennouri, M.In this study, Monte Carlo dynamics (MCD) simulations and DFT has been used to investigate the adsorption performance of methylthioninium chloride (MC), known as methylene blue, on Zn3(PO4)2 (11-4), Fe3(PO4)2 (111), Co3(PO4)2 (012) and Ca3(PO4)2 (130) surfaces. In order to understand the chemical properties of MC and its interaction mechanism with the adsorbent surfaces, quantum chemical (QC) descriptors were calculated based on lowest unoccupied molecular orbital energy (ELUMO) and highest occupied molecular orbital energy (EHOMO). On the other hand, the dynamic descriptors were calculated using the Adsorption Locator module. The small gap energy (Delta Egap) value indicated that the MC molecule is highly reactive. As a results, the obtained adsorption configurations show that MC adsorbed parallelly on all surfaces. The dynamic descriptors indicate exothermic and spontaneous adsorption due to negative adsorption energy (Eads) in various mediums. Also, the MC dye adsorption was high, especially in an acidic medium. Therefore, the MC/Co3(PO4)2 complex has a higher adsorption energy obtained as -3067.51, -878.87 and -403.95 kcal/mol, respectively, in acidic, neutral and basic mediums. While, both Fe3(PO4)2 and Co3(PO4)2 surfaces has a low value of dEads/dNiMC, that explained the more easily adsorbed MC molecule. The most stable adsorption configurations show that the interaction between the adsorbate and the surfaces is a chemisorption. This result is confirmed by the radial distribution function (RDF) analysis.Öğe Adsorption mechanisms investigation of methylene blue on the (001) zeolite 4A surface in aqueous medium by computational approach and molecular dynamics(Elsevier, 2022) Khnifira, M.; El Hamidi, S.; Sadiq, M.; Simsek, S.; Kaya, S.; Barka, N.; Abdennouri, M.The cationic methylene blue (CMB) and its pmtonated forms have been studied by computational tools to predict their adsorption behavior on zeolite 4A. The interaction nature has been exhaustively studied in terms of energy gap (Delta E-g), global reactivity descriptors, Fukui functions, adsorption energy, density of states and natural bond orbital analysis. It was found that the protonated CMB (N36N35) molecule is less stable, more electmphilic and very reactive. The highest contribution to the lowering of the stabilization energy (E-2) for all systems was mainly due to the intramolecular charge transfer from the lone pair of the nitrogen atoms as a donor orbital to pi* as an acceptor orbital. DFT calculations revealed that N36 and N35 site of CMB was faced with a lower energy gap (Delta E-g) and chemical hardness (eta) as well as a higher electron accepting power compared to other sites. Monte Carlo molecular modeling simulation (MCMM) confirmed the predominant of electrostatic interactions and p-p electron coupling. The studied compounds prefer to have configurations that facilitate p-p interaction, which is evident from the parallel orientation of CMB with zeolite surface. The dynamic parameters show that the adsorption of methylene blue is exothermic and spontaneous chemisorption.Öğe Adsorption of methylene blue cationic dye onto brookite and rutile phases of titanium dioxide: Quantum chemical and molecular dynamic simulation studies(Elsevier, 2021) Khnifira, M.; El Hamidi, S.; Mahsoune, A.; Sadiq, M.; Serdaroglu, G.; Kaya, S.; Qourzal, S.This study reports the statistical physics modeling of the methylene blue cationic dye (MBCD) adsorption in aqueous solution on TiO2 surface. In order to comprehend the adsorption performance, theoretical investigations were done to collect extensive information about the chemical and physical properties of the molecules using quantum chemical parameters (QCP). Also, molecular dynamic and quantum descriptors were applied to better understand the dye adsorption on different phases of TiO2 (i.e., bmokite and rutile). The molecular structures of MBCD acts as good electron donators to an empty d orbital of TiO2 due to the availability of electrons in both the lone pair on the N atoms and 't electrons of the aromatic rings. The reactivity of optimized molecular structures was confirmed by the quantum chemical descriptors. Modeling results showed that the adsorption was performed with a horizontal position of MBCD molecules on both surfaces. Overall, the TiO2 showed the highest adsorption energies for protonated MBCD (N36N35) (-886.533 kcal/mol (MBCD/rutile-TiO2)) > -626.428 kcal/mol (MBCD/brookite-TiO2)), which implies that these sites prompt the adsorption on both surfaces. The analysis of the adsorption energy values showed an exothermic chemisorption process, which could be governed by steric parameters according to the results obtained with the molecular dynamics modeling.
