Statistical modeling and optimization of dexamethasone adsorption from aqueous solution by Fe3O4@NH2-MIL88B nanorods: Isotherm, Kinetics, and Thermodynamic

Mohammad Hassan Mahmoudian; Ali Azari; Anis Jahantigh; Maryam Sarkhosh; Mahmood Yousefi; Seyed Ali Razavinasab; Maryam Afsharizadeh; Fatemeh Mohammadi Shahraji; Abbas Pour Pasandi; Ali Zeidabadi; Tayebeh Ilaghinezhad Bardsiri; Mohammad Ghasemian

doi:10.1016/j.envres.2023.116773

Statistical modeling and optimization of dexamethasone adsorption from aqueous solution by Fe3O4@NH2-MIL88B nanorods: Isotherm, Kinetics, and Thermodynamic

Environ Res. 2023 Nov 1;236(Pt 2):116773. doi: 10.1016/j.envres.2023.116773. Epub 2023 Aug 3.

Affiliations

¹ Research Center for Environmental Pollutants, Department of Environmental Health Engineering, Faculty of Health, Qom University of Medical Sciences, Qom, Iran.
² Workplace Health Promotion Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Sirjan School of Medical Sciences, Sirjan, Iran. Electronic address: azari.hjh@gmail.com.
³ Department of Environmental Health Engineering, School of Public Health, Zabol University of Medical Sciences, Zabol, Iran.
⁴ Department of Environmental Health Engineering, Mashhad University of Medical Sciences, Mashhad, Iran.
⁵ Department of Environmental Health Engineering, School of Public Health, Iran University of Medical Sciences, Tehran, Iran.
⁶ Sirjan School of Medical Sciences, Sirjan, Iran.
⁷ Tehran Sewerage Company, Operation Manager of West Tehran Wastewater Treatment Plant, Tehran, Iran.

PMID: 37543125
DOI: 10.1016/j.envres.2023.116773

Abstract

The presence of pharmaceutical compounds in the environment poses a significant threat to human and aquatic animal health. Dexamethasone (DEX), a synthetic steroid hormone with endocrine-disrupting effects, is one such compound that needs to be effectively removed before discharging into the environment. This research presents a novel approach utilizing magnetically recyclable Fe₃O₄@NH₂-MIL_88B NRs as an efficient adsorbent for the treatment of DEX from aqueous solutions. The synthesized adsorbent was characterized by X-ray diffraction (XRD), scanning microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), diffuse reflectance spectra (DRS), and Fourier transform infrared spectroscopy (FTIR). Response surface methodology based on central composite design (RSM-CCD) was employed to optimize DEX removal efficiency by determining the optimal conditions, including pH, adsorbent dose, time, and DEX concentration. Under the optimized conditions (pH: 5.53, adsorbent dose: 0.185 g/L, time: 16.068 min, and DEX concentration: 33.491 mg/L), Fe₃O₄@NH₂-MIL_88B NRs revealed remarkable DEX adsorption efficiency of 91 ± 1.34% and adsorption capacity of 180.01 mg/g. The Langmuir isotherm and pseudo-second-order kinetic model were found to fit well with the experimental data, indicating a monolayer and chemical adsorption process. Thermodynamic analysis revealed that the adsorption process was spontaneous and endothermic. The study also investigated the inhibitory effect of background ions on DEX removal by Fe₃O₄@NH₂-MIL_88B NRs. Magnesium exhibited superior competitive ability with dexamethasone to occupy the active sites of the adsorbent compared to other background ions. The reuse of the adsorbent over ten consecutive cycles resulted in a 39.46% decrease in removal efficiency. The Fe₃O₄@NH₂-MIL_88B NRs are surrounded by abundant amounts of functional groups and π-electrons bands that can play a key role in the adsorption and separation of DEX from aqueous environments. The promising results obtained under real conditions highlight the potential of Fe₃O₄@NH₂-MIL_88B NRs as a practical and efficient adsorbent for the removal of DEX and other similar corticosteroids from aqueous solutions.

Keywords: Adsorption; Central composite design; Dexamethasone; Fe(3)O(4)@NH(2)-MIL(88B) NRs; Optimization”.