Effective and environmental retention of some radioactive elements (U (VI), Sr (II), and Ba (II)) within bentonite/zeolite hybrid structure; equilibrium and realistic study

Abstract

Bentonite/zeolite hybrid structure was synthesized as adsorbent material for promising retention of U (VI), Sr (II), and Ba (II) as toxic radionuclides in water. The retention of U (VI) and Ba (II) show slight partialities to be described with the Pseudo-First order model and the adsorption of Sr (II) is of slightly higher fitting with Pseudo-Second order model. The equilibrium modeling demonstrated retention processes according to Langmuir assumption with expected qmax of 172.26 mg/g, 123 mg/g, and 187.9 mg/g for U (VI), Ba (II), and Sr (II), respectively. The calculated energies for the retention of U (VI) (1.18 KJ/mol), Ba (II) (0.84 KJ/mol), and Sr (II) (1.24 KJ/mol) suggesting physisorption mechanisms. The retention reactions are of exothermic nature with spontaneous properties. The studied BE/Z hybrid structure is of excellent recyclability properties and is of promising efficiency in reducing Sr (II) and U (VI) from the groundwater sample.