Preparation of Halloysite/Ag2O Nanomaterials and Their Performance for Iodide Adsorption

摘要

Halloysite/Ag2O (Hal/Ag2O) nanomaterials were prepared by growing Ag2O nanoparticles on the surface of nanotubular halloysite using silver nitrate solution under alkaline conditions. The nanomaterials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and N-2 adsorption. Good dispersion of Ag2O nanoparticles with average sizes of 6.07 +/- 2.5 nm and 8.04 +/- 3.8 nm was achieved in the nanomaterials when using different concentrations of alkali. The nanomaterial with 6.36% Ag2O (Hal/Ag2O-2) exhibited rapid adsorption to iodide (I-); adsorption equilibrium can be reached within 100 min. The adsorption capacity of I- on Hal/Ag2O-2 is 57.5 mg/g, which is more than 143 times higher than that of halloysite. The nanomaterial also showed a better adsorption capacity per unit mass of Ag2O due to the better dispersion and less coaggregation of Ag2O in the nanomaterial than in the pure Ag2O nanoparticles. Importantly, Hal/Ag2O-2 exhibited high selectivity for I-, and its I- removal efficiency was hardly affected by the coexistence of Cl-, Br-, or SO42-, as well as the initial pH of the solution. With an excellent adsorption performance, the prepared Hal/Ag2O nanomaterial could be a new and efficient adsorbent capable of the adsorption of radioactive I- from aqueous solution.

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