Electrochemically Selective Separation of Cesium Ion Using a Silicomolybdate Doped Polyaniline Composite

Abstract

Rational design of efficient adsorbents for recovering Cs + from complex brines is crucial for the sustainable industrial supply of cesium resources. Herein, a novel silicomolybdate doped polyaniline composite (SiMo 12 −PANI) was facilely prepared and used for extracting Cs + via the electrochemical process for the first time. Silicomolybdic acid contains abundant oxygen sites and can be used as a receptor of Cs + . The morphology and chemical structure of the composite were fully characterized, and the effects of potential, ion concentration, and solution pH in the electrochemical separation Cs + process were further studied. The results revealed that the SiMo 12 −PANI electrode exhibited a relatively fast ad/desorption kinetics of Cs + due to the intensifying effect of the electric field. The adsorption capacity can be increased from 14.4 mg•g −1 to 24.9 mg•g −1 at the initial cesium concentration of 50 mg•L −1 , and the desorption ratio was also improved. In particular, the separation factors of Cs + over K + , Rb + , Ca 2+ , and Mg 2+ can reach 11.7−16, 2.1−2.3, 205−726, and 622−708, respectively. XPS results confirmed that the excellent selectivity for Cs + was achieved by ultra-affinity of oxygen donors toward Cs + , and the reversible capture and release of Cs + may be achieved by the driving force of the electric field and the redox reaction between Mo 6+ and Mo 5+ . It is expected that our work may provide a green and sustainable approach for selective recovery of Cs + from complex solutions using a novel silicomolybdate doped polyaniline composite via an electrochemical process.