Characterization, kinetics and thermodynamics of biosynthesized uranium nanoparticles (UNPs)

The present study was carried out to explore the potential of the isolated bacterial strains isolated from Gabal El Sela in Eastern Dessert, Egypt for biosynthesis of uraninite nanoparticles intracellularly. The most potent bacterial strains associated (intra) with uranium nanoparticles were characterized by transmission electron microscope (TEM), Fourier transform infrared (FTIR) and Energy Dispersive X-ray (EDX). Studying factors affecting biosynthesis of uranium nanoparticles indicated that the optimum conditions were 6000 ppm uranium concentrations at pH 7.0 and temperature 30 °C ± 1 after five days with 10% biomass under shaking conditions and the maximum uranium uptake by MAM - U9 cells was 3300 ppm (55%) from uranyl nitrate solution and 3600 ppm (72%) from Sela rock sample. Results of TEM micrograph show those uranium nanoparticles (UNPs) with size ranging from 2.9 to 21.13 nm inside cells. The kinetics, isotherm and thermodynamics parameters of uranium uptaken by bacterial strain MAM -U9 have been determined and found to be a first order process (R² = 9935), follows Langmuir isotherm (R_L² = 0.998) and the thermodynamics of ΔG = -9.715 kJmol^-1, ΔH = 16.987 kJmol^-1 and ΔS = 0.0881 kJmol^-1K^-1 at 30 °C.