Impact of environmental conditions on the sorption behavior of 60Co and 152+154EU radionuclides onto polyaniline/zirconium aluminate composite

Polyaniline/zirconium aluminate composite (PANI/ZAI) was synthesized as a novel sorbent by sol-gel hydrolysis method and characterized using Fourier Transform Infrared Spectra, Scanning Electron Microscope, X-ray Diffraction, Differential Thermal Analysis and Thermal Gravimetric Analysis. Sorption of 152+154EU and Co-60 radionuclides were achieved taking into account important parameters including initial pH of the medium, contact time, initial metal ion concentration and temperature. A comparative study between zirconium aluminate and PANI/ZAI composite for the sorption of Eu152+154 and Co-60 was implemented. The obtained data revealed that the sorption process is significantly improved using PANI/ZAI composite. The distribution coefficient values (K-d) for 152+154EU onto PANI/ZAI and zirconium aluminate were found to be 13,671 and 7226 mL/g, respectively, and for Co-60, the value of K-d increased from 4037 to 6023 mL/g. Langmuir isotherm model was applicable for the sorption process and the maximum sorption capacity of PANI/ZAI was 175.7 and 140.3 mg/g for Eu152+154 and Co-60, respectively. From the regeneration process, it was established that the regenerated PANI/ZAI can be used for several cycles (six cycles) until completely exhausted. The desorption percent in the first cycle using 0.3 mol/L HNO3 was 91.2 and 95.4% for 152+154EU and Co-60 respectively. Findings of the present work highlight the potential use of PANI/ZAI as a novel, effective and recyclable sorbent for the removal of Co-60 and 152+154EU radioisotopes from the liquid phase. (C) 2019 Elsevier B.V. All rights reserved.