Introduction of amino groups into polyphosphazene framework supported on CNT and coated Fe3O4 nanoparticles for enhanced selective U(VI) adsorption

• Main Authors: Liu, Yan, Zhao, Zhengping, Yuan, Dingzhong, Wang, Yun, Dai, Ying, Zhu, Yean, Chew, Jia Wei
• Other Authors: School of Chemical and Biomedical Engineering
• Format: Article
• Language: English
• Published: 2021
• Subjects: Engineering::Chemical engineering; Polyphosphazene; Amino
• Online Access: https://hdl.handle.net/10356/150582
• Institution: Nanyang Technological University

A CNT-modified composite (namely, NH2-PZS/CNT/Fe3O4) was prepared and used for the removal of U(VI) from aqueous solution. The composite was synthesized using Fe3O4 nanoparticles with polyphosphazene-based polymer coating on CNTs. Experiments were carried out to investigate the influence of pH, concentration, contact time and temperature on the U(VI) removal process. The maximum adsorption capacity was calculated as 250 mg/g by considering Langmuir isotherm model and the adsorption process was also explained with pseudo-second-order kinetics. Adsorption tests in the presence of competing ions exhibited high selectivity for U(VI). The thermodynamic parameters indicate that the process was spontaneous and endothermic. The interaction mechanism of U(VI) with NH2-PZS/CNT/Fe3O4 was systematically clarified by using X-ray photoelectron spectroscopy (XPS) and Fourier transformation infrared (FTIR). Overall, the prepared NH2-PZS/CNT/Fe3O4 composite, which displayed important advantages such as re-usability, high adsorption capacity and selectivity, is a good adsorbent candidate for the removal of U(VI) from wastewater.