Understanding the interactions between ranitidine and magadiite: Influence of the interlayer cation

Synthetic sodium silicates are widely applied in environmental remediation for the adsorption of organic and inorganic pollutants. In this work, sodium magadiite (Na-mag) and the H+, K+, Ca2+ and Mg2+ exchanged forms were evaluated for their ability to remove ranitidine from aqueous solution. Na-mag was prepared by hydrothermal synthesis using silicon oxide and sodium hydroxide. The samples were characterized by X-ray diffraction, near and Fourier transform-infrared spectroscopy (NIR and FTIR), Raman spectroscopy, thermogravimetric analysis, energy dispersive spectrometry and transmission electronic microscopy. The nature of the interlayer cation influenced the amount of ranitidine adsorbed from aqueous solution at pH 6.0 and 298 K. The adsorption mechanism was based on both cationic exchange between the interlayer cations of magadiite and ranitidine and hydrogen bonding between the ranitidine neutral molecules and silanol groups of the mineral. The data highlight the good performance of the sodium and potassium forms of magadiite for ranitidine removal. (C) 2019 Elsevier Ltd. All rights reserved.