Comparative adsorption of diclofenac sodium and losartan potassium in organophilic clay-packed fixed-bed: X-ray photoelectron spectroscopy characterization, experimental tests and theoretical study on DFT-based chemical descriptors

Author(s)

de Andrade, Julia Resende ^[1] ; Oliveira, Maria Fernanda ^[1] ; Sehn Canevesi, Rafael Luan ^[2] ; Landers, Richard ^[3] ; Carlos da Silva, Meuris Gurgel ^[1] ; Adeodato Vieira, Melissa Gurgel ^[1]

Affiliation

^[1] Univ Estadual Campinas, Sch Chem Engn, Cidade Univ Zeferino Vaz, BR-13083970 Campinas, SP - Brazil

^[2] Univ Lorraine, Inst Jean Lamour, ENSTIB, UMR CNRS, 7198, 27 Rue Philippe Seguin, BP 21042-88051, Epinal 9 - France

^[3] Univ Estadual Campinas, Inst Phys Gleb Wataghin, Cidade Univ Zeferino Vaz, BR-13083970 Campinas, SP - Brazil

• Document type: Journal article
• Source: JOURNAL OF MOLECULAR LIQUIDS; v. 312, AUG 15 2020.
• Web of Science Citations: 0

Abstract

Diclofenac sodium (DS) and losartan potassium (LP) are pharmaceuticals extensively used worldwide and contaminants of emerging concern. This work aims to examine the monocomponent continuous adsorption of DS and LP in fixed-beds packed with the organophilic clay, Spectrogel.The external surface of Spectrogel was studied by X-ray photoelectron spectroscopy (XPS) prior and post application as adsorbent. Continuous tests were conducted for the effects of flow rate (0.4-1.0 mL/min) and inlet concentration (0.05-0.15 mmol/L). Both DS- and LP-systems best operated at 0.4 mL/min and 0.15 mmol/L condition, which provided the highest breakthrough adsorption capacities (0.0047 mmol/g for DS and 0.0013 mmol/g for LP) and the lowest mass transfer zones (4.3 cm for DS and 4.4 cm for LP). Five different models were applied to describe the breakthrough curves and Dual site diffusion approach showed high suitability (R-2 > 0.97). The DS adsorption performance by Spectrogel was contrasted with other materials. Density functional theory (DFT) computations were combined with experimental findings to clarify the particularities of DS and LP adsorption. Greater hydrophobicity, lower water solubility, reduced steric hindrance effects and greater chemical molecular reactivity were some of the factors attributed to the enhanced DS adsorption onto Spectrogel compared to LP. (C) 2020 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 16/05007-1 - Removal of residual drug in aqueous solution by alternative adsorbents
• Grantee: Meuris Gurgel Carlos da Silva
• Support Opportunities: Regular Research Grants