High-efficiency removal of Cs (I) by vermiculite/zinc hexacyanoferrate (II) composite from aqueous solutions. Issue 2 (April 2023) - Dai, Tianya
Abstract: Aimed to solve the problems of low adsorption capacity, complex preparation and difficult recovery for reported cesium ion adsorbents, a novel high-efficiency Cs + adsorbent of vermiculite/zinc hexacyanoferrate (II) (VMT/ZnHCF) composite was prepared via in situ synthetic method. The structure and properties of this composite were comprehensively characterized using XRD, FTIR, SEM, TEM, and TG-DTA. The maximum Cs + adsorption capacity was recorded to be 378.79 mg/g, and this value was significantly higher than the values recorded for other absorbents. This spontaneous and exothermic adsorption behavior could be explained by the Langmuir isotherm model and the pseudo-second-order kinetic model. In addition, this composite exhibited excellent selective adsorption ability towards Cs + even in solutions containing high concentrations of Na +, K +, Ca 2+, and Mg 2+ . The Cs + adsorption mechanism was analyzed by conducting ion exchange experiments and using XRD, SEM, and XPS techniques. The Cs + adsorption of the VMT/ZnHCF composite was synergistically achieved through the ion exchange of Na + in vermiculite interlayers and Zn 2+ in zinc hexacyanoferrate (II) lattices. A high-efficiency and simple preparation of cesium ion adsorbent has been developed in application of cesium ion wastewater treatment. This work can provide theoretical guidance to realize the non-hazardous treatment of radioactive wastewater. Graphical Abstract: ga1 Highlights: A novel high-efficiency Cs (I) adsorbent of VMT/ZnHCF was prepared via an in situ synthetic method. VMT/ZnHCF obtained a maximum Cs (I) adsorption capacity of 378.79 mg/g significantly superior to other absorbents. VMT/ZnHCF exhibited excellent selective adsorption ability towards Cs (I) in multicomponent metal ion solutions. Cs (I) adsorption behavior is ascribed to synergistic ion exchange of Na + and Zn 2+ in VMT/ZnHCF.