High-gravity intensified preparation of D201 resin-hydrated iron oxide nanocomposites for Cr(VI) removal

In this study, D201 resin-hydrated iron oxide (HFO) nanocomposites were prepared for the first time for Cr(VI) removal in a high-gravity rotating packed bed (RPB), and then D201-HFO nanocomposites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The results show that HFO nanoparticles embedded in D201 resin exhibit an average particle size of 10.34 nm, a narrow particle size distribution and excellent dispersibility. The use of 0.05 g of D201-HFO nanocomposite prepared in the RPB (D201-HFO-R) leads to efficient removal of Cr(VI) from 10 mg/L to below 50 ppb, and it has a higher reaction rate constant (k = 0.959 h(-1)) than that prepared in a stirred tank reactor (STR). D201-HFO-R nanocomposites also exhibit higher competitive adsorption of Cr(VI) against CO32-, NO3- and SO42-. Notably, it still shows good removal efficiency for Cr(VI) after five adsorption-regeneration cycles. The removal mechanism of Cr(VI) by D201-HFO-R mainly involves complexation and electrostatic attraction. This study provides a simple and facile method to prepare D201-HFO nanocomposites in the RPB for wastewater treatment. (C) 2021 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.