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

• Published in: Minerals (Basel) 2022-03, Vol.12 (3), p.304
• Main Authors: Yu, Wenlin, Dong, Qinpeng, Yu, Wenbin, Qin, Zonghua, Nie, Xin, Wan, Quan, Chen, Xiuli
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; Ag2O; Aqueous solutions; Coexistence; Dispersion; Electron microscopy; Experiments; halloysite; iodide; Iodides; Iodine; Morphology; nanomaterial; Nanomaterials; Nanoparticles; Nanotechnology; nanotube; radionuclides; Selectivity; Silver; Silver nitrate; Transmission electron microscopy; X-ray diffraction
• ISSN: 2075-163X; 2075-163X
• DOI: 10.3390/min12030304

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 N2 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.