A Prussian blue analog-based copper-aluminum layered double hydroxide for cesium removal from water: fabrication, density functional theory-based molecular modeling, and the adsorption mechanism

Xindai Li; Kexin Shao; Guangming Xu; Meng Xia; Xinyao Liu; Zhaorong Shang; Fuqiang Fan; Junfeng Dou

doi:10.1039/d3cp03879c

A Prussian blue analog-based copper-aluminum layered double hydroxide for cesium removal from water: fabrication, density functional theory-based molecular modeling, and the adsorption mechanism

Phys Chem Chem Phys. 2024 Jan 3;26(2):1113-1124. doi: 10.1039/d3cp03879c.

Authors

Xindai Li^{1

2}, Kexin Shao^{1

2}, Guangming Xu^{1

2}, Meng Xia¹, Xinyao Liu¹, Zhaorong Shang³, Fuqiang Fan⁴, Junfeng Dou^{1

2}

Affiliations

¹ College of Water Sciences, Beijing Normal University, Beijing 100875, P. R. China. doujf@bnu.edu.cn.
² Engineering Research Center for Groundwater Pollution Control and Remediation Ministry of Education, College of Water Sciences, Beijing Normal University, Beijing 100875, P. R. China.
³ Nuclear and Radiation Safety Center, Ministry of Ecology and Environment, Beijing 100082, China.
⁴ Advanced Institute of Natural Sciences, Beijing Normal University at Zhuhai, Zhuhai 519087, P. R. China. ffan02@bnu.edu.cn.

PMID: 38098463
DOI: 10.1039/d3cp03879c

Abstract

A new type of adsorbent, a Prussian blue analog-based copper-aluminum layered double hydroxide (PBA@CuAl-LDH), was successfully synthesized using a one-step method for the removal of radioactive Cs⁺ from wastewater. The adsorption performance, characteristics and the underlying adsorption mechanism of PBA@CuAl-LDH were systematically examined. The results showed that PBA@CuAl-LDH exhibited excellent adsorption performance, with a maximum adsorption capacity of 109.2 mg g^-1. Over 85% of PBA@CuAl-LDH can be recycled, and the material exhibited only a 6.6% loss in adsorption performance. The adsorption process was well-fitted using the pseudo-second-order kinetic model and the Freundlich isotherm model, revealing the surface heterogeneity of the composite adsorbent. A molecular model of PBA@CuAl-LDH was constructed by combining density functional theory and multiple instrumental characterization techniques. Our results indicate that PBA crystals can be generated between layers and on the surface. Ion exchange was revealed as the main adsorption mechanism of Cs⁺ by PBA@CuAl-LDH. Specifically, the interstitial spaces of the PBA crystals generated between the layers and on the surface played an important role in ion exchange. These findings provide concrete theoretical support for radioactive pollution control and have significant value in directing the fabrication of cesium removal materials and their future engineering application.