Modeling uranium transport in acidic contaminated groundwater with base addition

Journal Article · Sat Jan 01 04:00:00 EST 2011 · Journal of Hazardous Materials

DOI:https://doi.org/10.1016/j.jhazmat.2011.04.022· OSTI ID:1015092

Zhang, Fan ^[1]; Luo, Wensui ^[2]; Parker, Jack C. ^[3]; Brooks, Scott C ^[2]; Watson, David B ^[2]; Jardine, Philip ^[3]; Gu, Baohua ^[2]

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1. Institute of Tibetan Plateau Research, Chinese Academy of Sciences
2. ORNL
3. University of Tennessee, Knoxville (UTK)

This study investigates reactive transport modeling in a column of uranium(VI)-contaminated sediments with base additions in the circulating influent. The groundwater and sediment exhibit oxic conditions with low pH, high concentrations of NO{sub 3}{sup -}, SO{sub 4}{sup 2-}, U and various metal cations. Preliminary batch experiments indicate that additions of strong base induce rapid immobilization of U for this material. In the column experiment that is the focus of the present study, effluent groundwater was titrated with NaOH solution in an inflow reservoir before reinjection to gradually increase the solution pH in the column. An equilibrium hydrolysis, precipitation and ion exchange reaction model developed through simulation of the preliminary batch titration experiments predicted faster reduction of aqueous Al than observed in the column experiment. The model was therefore modified to consider reaction kinetics for the precipitation and dissolution processes which are the major mechanism for Al immobilization. The combined kinetic and equilibrium reaction model adequately described variations in pH, aqueous concentrations of metal cations (Al, Ca, Mg, Sr, Mn, Ni, Co), sulfate and U(VI). The experimental and modeling results indicate that U(VI) can be effectively sequestered with controlled base addition due to sorption by slowly precipitated Al with pH-dependent surface charge. The model may prove useful to predict field-scale U(VI) sequestration and remediation effectiveness.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1015092
• Journal Information: Journal of Hazardous Materials, Journal Name: Journal of Hazardous Materials Journal Issue: 1-3 Vol. 190; ISSN 0304-3894
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CATIONS
DISSOLUTION
HYDROLYSIS
ION EXCHANGE
KINETICS
Oak Ridge IFRC
PRECIPITATION
REACTION KINETICS
REINJECTION
SEDIMENTS
SIMULATION
SORPTION
SULFATES
TITRATION
TRANSPORT
URANIUM