Application of mesopores copper hexacyanoferrate (II) nanomaterials for cesium adsorption

Abstract

Mesopores of copper hexacyanoferrate (II) (M-CuHCF-II) nanomaterials used for the cesium (Cs⁺) removal were synthesized by the chemical coprecipitation method. M-CuHCF-II has a cubic structure (space group F-43m), a surface area of 12.80 m²/g, and a pore width of about 34.49 nm. At pH=6, the adsorption capacity of Cs⁺ ions by CuHCF-II reached the maximum within 15 minutes. Langmuir, Redlich–Peterson, and Sips models are suitable to describe the adsorption of Cs⁺ ions by M-CuHF-II materials. The maximum absorption capacity of M-CuHCF-II was determined at 318 K corresponding to the value of 197.72 mg g^-1. The Gibbs free energy change (ΔG°) of Cs⁺ adsorption process with ranging values from -37.47 to -40.74, and ΔH⁰ = -8.28 (kJ mol^-1) at temperatures from 298–348 K. Na⁺, NH₄⁺, Ca²⁺, and K⁺ ions in solution affect the removal of Cs⁺ ions when they occur at high concentrations. M-CuHCF-II materials are easy to prepare, low-cost, have high adsorption capacity for Cs⁺ ions, and are easy to apply. In addition, the adsorption mechanism of Cs⁺ ions by M-CuHCF-II is also proposed and discussed.