TITLE:
Thermodynamic Modeling of Uranium (VI) Reductive Immobilization in Groundwater of NPCC Sludge Storages (Novosibirsk, Russia)
AUTHORS:
Olga L. Gaskova, A. E. Boguslavsky, A. V. Safonov
KEYWORDS:
Uranium Wastes, Bacterialreduction, Nitrogen, Sulfur, Thermodynamic Model
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.6 No.11,
November
30,
2018
ABSTRACT: The Biochemical Reduction Of Both Nitrate And Sulfate In U-Containing Aquifers Of The Novosibirsk Plant Of Chemical Concentrates (NPCC) Was Investigated Experimentally And Thermodynamically. It Was Observed That Decrease In Eh Up To -397 Mv Has A Distinct Effect On The Denitrification And Uranium Precipitation As UO2(S). Nitrate Was Denitrified With A Temporary Accumulation Of The Intermediate Nitrite On The Day 4th. According To The X-Ray Fluorescence Analysis And Thermodynamic Calculations, More Than Half Of The Uranium Is Deposited In The First Stage As UO2+X oxides, And The Rest, Together With The Sulfides In The Reducing Environment. Findings Suggest That Accurately Thermodynamic Predicting Of Groundwater NO3-; And SO42- Fate Is Primarily Limited By Failing To Account For A Kinetic Of Redox Fluctuations In The Experiment: 1) Measured Eh +190 Mv Is Low Despite The High Amount Of Nitrates (1124 Mg/L), But NH4+ Predominates In Solution According To Calculations, 2) Sulfate Reduction Lagged Behind Nitrate Reduction By Approximately 50 Days Unlike Model Simulation.