A novel iron modified montmorillonite composite and its enhanced performance for tetracycline hydrochloride adsorption

Iron-modified montmorillonite (Mt) composites with controlled interlayer spacing were successfully synthesized through Fentonlike process with the addition of different concentrations of Rhodamine B (RhB). The physicochemical properties of the resulting samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). It was worth noting that the adsorption efficiency of the composite for tetracycline hydrochloride (TC) increased with the increase of the RhB concentration during preparation. The maximum adsorption capacity of the as-prepared composite toward TC was 192.4 mg/g, which was much higher than that of the Mt (144.9 mg/g). Moreover, the as-prepared adsorbent showed high adsorption capacity of TC in a wide pH range of 3.0-9.0. The adsorption process followed the pseudo-second-order equation and the Langmuir isotherm model, suggesting the mono-layer chemisorption of the adsorption process. The present work may provide a new strategy for the design and fabrication of functional clay-based materials.