Assessment of chromite ore wastes for methylene blue adsorption: Isotherm, kinetic, thermodynamic studies, ANN, and statistical physics modeling

Esmaeil Allahkarami; Ebrahim Allahkarami; Majid Heydari; Amirreza Azadmehr; Abbas Maghsoudi

doi:10.1016/j.chemosphere.2024.142098

Assessment of chromite ore wastes for methylene blue adsorption: Isotherm, kinetic, thermodynamic studies, ANN, and statistical physics modeling

Chemosphere. 2024 Apr 25:358:142098. doi: 10.1016/j.chemosphere.2024.142098. Online ahead of print.

Authors

Esmaeil Allahkarami¹, Ebrahim Allahkarami², Majid Heydari³, Amirreza Azadmehr⁴, Abbas Maghsoudi³

Affiliations

¹ Department of Petroleum Engineering, Faculty of Petroleum, Gas and Petrochemical Engineering, Persian Gulf University, Bushehr, Iran.
² Department of Chemical Technology, Iranian Research Organization for Science and Technology, Tehran, Iran.
³ Department of Mining Engineering, Amirkabir University of Technology, Tehran, Iran.
⁴ Department of Mining Engineering, Amirkabir University of Technology, Tehran, Iran. Electronic address: A_azadmehr@aut.ac.ir.

PMID: 38677606
DOI: 10.1016/j.chemosphere.2024.142098

Abstract

This research investigates the adsorption potential of chrysotile and lizardite, two minerals derived from chromite ore wastes, for the uptake of Methylene Blue (MB) dye from waste streams. The characterization of these minerals involves XRD, XRF, FTIR, and SEM. Results confirm the dominance of polymorphic magnesium silicate minerals, specifically chrysotile and lizardite, in the samples. The FTIR spectra reveal characteristic vibration bands confirming the presence of these minerals. The SEM analysis depicts irregular surfaces with broken and bent edges, suggesting favorable morphologies for adsorption. N₂ adsorption-desorption isotherms indicate mesoporous structures with Type IV pores in both adsorbents. The Central Composite Design approach is employed to optimize MB adsorption conditions, revealing the significance of contact time, adsorbent mass, and initial MB concentration. The proposed models exhibit high significance, with F-values and low p-values indicating the importance of the studied factors. Experimental validation confirms the accuracy of the models, and the optimum conditions for MB adsorption are determined. The influence of solution acidity on MB uptake is investigated, showing a significant enhancement at higher pH values. Isothermal studies indicate Langmuir and Freundlich models as suitable descriptions for MB adsorption onto chrysotile and lizardite. The maximum adsorption capacities of MB for chrysotile and lizardite were found to be 352.97 and 254.85, respectively. Kinetic studies reveal that the pseudo-first-order model best describes the adsorption process. Thermodynamic analysis suggests an exothermic and spontaneous process. Statistical physics models further elucidate the monolayer nature of adsorption. Additionally, an artificial neural network is developed, exhibiting high predictive capability during training and testing stages. The reusability of chrysotile and lizardite is demonstrated through multiple regeneration cycles, maintaining substantial adsorption potential. Therefore, this research provides comprehensive insights into the adsorption characteristics of chrysotile and lizardite, emphasizing their potential as effiective and reusable sorbents for MB uptake from wastewater.

Keywords: ANN; Adsorption; Chromite ore wastes; Methylene blue; Statistical physics modeling.