Adsorption of Cs ions using a temperature-responsive polymer/magnetite/zeolite composite adsorbent and separation of the adsorbent from water using high-gradient magnetic separation

摘要

Magnetite-zeolite composites (MZCs) and an MZC modified with poly(N-isopropylacrylamide) (PNIPAM) (PMZ) were prepared in this study as adsorbents for Cs+ ions. The ratios of the removal of these magnetic adsorbents from suspensions using high-gradient magnetic separation (HGMS) were examined. The structures of these adsorbents were examined using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetry. From these measurements, it was confirmed that the magnetite was deposited on the zeolite for the MZC samples and PNIPAM was immobilized on an MZC for the PMZ sample. The saturated amount of Cs+ adsorption of the zeolite, MZCs, and the PMZ were almost the same at 0.66, 0.68, and 0.65 mmol/g, respectively. The ratios of the removal of the zeolite, an MZC (10.7 wt% magnetite loading), and the PMZ (at 20 degrees C and 50 degrees C) adsorbents from suspensions using HGMS were 33, 85, 92, and 96 wt%, respectively. It was concluded that the PMZ adsorbent was the most effective for the adsorption of Cs+ and could be removed most effectively from suspensions using HGMS at 50 degrees C.