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Title: The influence of humic acid and colloidal silica on the sorption of U(VI) onto SRS Sediments Collected from the F/H Area - 15499

Abstract

Between 1955 and 1988, the F/H Area Seepage Basins located in the center of SRS received approximately 6,814,000 m{sup 3} of acidic waste solutions containing radionuclides and dissolved metals. Uranium (VI) is a key contaminant of concern in groundwater associated with the basins. The pump-and-treat water treatment unit designed and built in 1997 to remove metals and radionuclides eventually became less effective, prompting research for new remedial alternatives. The pump-and-treat system was discontinued in 2004, replaced with a funnel-and-gate system in which base solutions are injected at the gates to raise pH. To take advantage of the potential formation of uranium silicate minerals, Florida International University - Applied Research Center (FIU-ARC), in collaboration with Savannah River National Laboratory (SRNL), is conducting an investigation into a base containing sodium silicate to evaluate whether these solutions have sufficient alkalinity to correct the acidic nature of the aquifer sediments. The research was extended to investigate if U(VI) is bound to colloidal silica and if any synergy exists between humic acid (HA) and colloidal Si that would influence the removal of uranium. Humic substances (HS) are a major component of soil organic matter and are known for their abilities to influence the migration behaviormore » and fate of heavy metals. Studies showed that HA function as an important ion exchange and metal-complexing ligand, carrying a large number of functional groups with high complexing capacity that can greatly affect the mobility behavior of actinides in natural systems. The study investigates if there are any synergistic interactions between U(VI) ions, humic acid and colloidal silica under oxidized conditions and studies the influence of HA and Si on the sorption of U(VI) onto sediments collected from the F/H Area. The experiments also evaluated the effects of different environmental variables such as pH, presence of U(VI) and varying concentrations of HA on the sorption behavior of U(VI) in multi-component batch systems in the pH range between 3 and 8. Several background sediment samples were collected at SRS from archived cores obtained during installation of the well FSB 91C and used for preparation of triplicate samples. The experimental matrix was set up as follows: - Batch 1: Si (3.5 mM) + U (VI) (0.5 ppm) (no sediments and no HA); - Batch 2: Si (3.5 mM) + U (VI) (0.5 ppm) + HA (10 ppm) (no sediments); - Batch 3: U (VI) (0.5 ppm) + HA (10 ppm) (no Si and no sediments); - Batch 4: Sediments + Si (3.5 mM) + U (VI) (0.5 ppm) (no HA); - Batch 5: Sediments + Si (3.5 mM) + U (VI) (0.5 ppm) + HA; - Batch 6: Sediments + U (VI) (0.5 ppm) + HA, (no Si); - Batch 7: Sediments + U (VI) (0.5 ppm) (no Si and no HA). All samples were prepared in triplicate 50-mL conical tubes. All control and experimental tubes were vortexed and kept on a shaker for 24 h at 100 rpm and room temperature. Results showed that the sediment-bearing batches typically exceeded the performance of non-sediment batches. Results showed that the sorption of U(VI) onto sediments was influenced by the pH and the presence of HA. At low pH 3, the addition of HA slightly enhances U(VI) sorption compared to the HA-free samples. This result is consistent with other studies; in the acidic pH range, the addition of HA slightly enhances U(VI) sorption relative to the HA-free system. Conversely, in the pH range of 4 to 7, the sorption of U(VI) on Si was reduced in the presence of HA in comparison to the system without HA. In subsequent experiments the concentration of HA will be increased to 50 ppm. (authors)« less

Authors:
;  [1];  [2]; ;  [1]
  1. Applied Research Center, Florida International University, 10555 W Flagler St., EC 2100, Miami, FL 33174 (United States)
  2. Savannah River National Laboratory, Savannah River Site, Aiken, SC 29808 (United States)
Publication Date:
Research Org.:
WM Symposia, Inc., PO Box 27646, 85285-7646 Tempe, AZ (United States)
OSTI Identifier:
22824389
Report Number(s):
INIS-US-19-WM-15499
TRN: US19V0962069435
Resource Type:
Conference
Resource Relation:
Conference: WM2015: Annual Waste Management Symposium, Phoenix, AZ (United States), 15-19 Mar 2015; Other Information: Country of input: France; 8 refs.; available online at: http://archive.wmsym.org/2015/index.html
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; ACID NEUTRALIZING CAPACITY; AQUIFERS; COLLOIDS; CONCENTRATION RATIO; GROUND WATER; HEAVY METALS; HUMIC ACIDS; ION EXCHANGE; LIQUID WASTES; ORGANIC MATTER; PH VALUE; RADIOISOTOPES; SAVANNAH RIVER; SEDIMENTS; SILICA; SILICATE MINERALS; SODIUM SILICATES; SOLUTIONS; SORPTION; TEMPERATURE RANGE 0273-0400 K; TUBES; URANIUM; URANIUM SILICATES; WATER TREATMENT

Citation Formats

Gonzaleza, Hansell, Katsenovich, Yelena, Denhamb, Miles, Gudavallia, Ravi, and Lagos, Leonel. The influence of humic acid and colloidal silica on the sorption of U(VI) onto SRS Sediments Collected from the F/H Area - 15499. United States: N. p., 2015. Web.
Gonzaleza, Hansell, Katsenovich, Yelena, Denhamb, Miles, Gudavallia, Ravi, & Lagos, Leonel. The influence of humic acid and colloidal silica on the sorption of U(VI) onto SRS Sediments Collected from the F/H Area - 15499. United States.
Gonzaleza, Hansell, Katsenovich, Yelena, Denhamb, Miles, Gudavallia, Ravi, and Lagos, Leonel. 2015. "The influence of humic acid and colloidal silica on the sorption of U(VI) onto SRS Sediments Collected from the F/H Area - 15499". United States.
@article{osti_22824389,
title = {The influence of humic acid and colloidal silica on the sorption of U(VI) onto SRS Sediments Collected from the F/H Area - 15499},
author = {Gonzaleza, Hansell and Katsenovich, Yelena and Denhamb, Miles and Gudavallia, Ravi and Lagos, Leonel},
abstractNote = {Between 1955 and 1988, the F/H Area Seepage Basins located in the center of SRS received approximately 6,814,000 m{sup 3} of acidic waste solutions containing radionuclides and dissolved metals. Uranium (VI) is a key contaminant of concern in groundwater associated with the basins. The pump-and-treat water treatment unit designed and built in 1997 to remove metals and radionuclides eventually became less effective, prompting research for new remedial alternatives. The pump-and-treat system was discontinued in 2004, replaced with a funnel-and-gate system in which base solutions are injected at the gates to raise pH. To take advantage of the potential formation of uranium silicate minerals, Florida International University - Applied Research Center (FIU-ARC), in collaboration with Savannah River National Laboratory (SRNL), is conducting an investigation into a base containing sodium silicate to evaluate whether these solutions have sufficient alkalinity to correct the acidic nature of the aquifer sediments. The research was extended to investigate if U(VI) is bound to colloidal silica and if any synergy exists between humic acid (HA) and colloidal Si that would influence the removal of uranium. Humic substances (HS) are a major component of soil organic matter and are known for their abilities to influence the migration behavior and fate of heavy metals. Studies showed that HA function as an important ion exchange and metal-complexing ligand, carrying a large number of functional groups with high complexing capacity that can greatly affect the mobility behavior of actinides in natural systems. The study investigates if there are any synergistic interactions between U(VI) ions, humic acid and colloidal silica under oxidized conditions and studies the influence of HA and Si on the sorption of U(VI) onto sediments collected from the F/H Area. The experiments also evaluated the effects of different environmental variables such as pH, presence of U(VI) and varying concentrations of HA on the sorption behavior of U(VI) in multi-component batch systems in the pH range between 3 and 8. Several background sediment samples were collected at SRS from archived cores obtained during installation of the well FSB 91C and used for preparation of triplicate samples. The experimental matrix was set up as follows: - Batch 1: Si (3.5 mM) + U (VI) (0.5 ppm) (no sediments and no HA); - Batch 2: Si (3.5 mM) + U (VI) (0.5 ppm) + HA (10 ppm) (no sediments); - Batch 3: U (VI) (0.5 ppm) + HA (10 ppm) (no Si and no sediments); - Batch 4: Sediments + Si (3.5 mM) + U (VI) (0.5 ppm) (no HA); - Batch 5: Sediments + Si (3.5 mM) + U (VI) (0.5 ppm) + HA; - Batch 6: Sediments + U (VI) (0.5 ppm) + HA, (no Si); - Batch 7: Sediments + U (VI) (0.5 ppm) (no Si and no HA). All samples were prepared in triplicate 50-mL conical tubes. All control and experimental tubes were vortexed and kept on a shaker for 24 h at 100 rpm and room temperature. Results showed that the sediment-bearing batches typically exceeded the performance of non-sediment batches. Results showed that the sorption of U(VI) onto sediments was influenced by the pH and the presence of HA. At low pH 3, the addition of HA slightly enhances U(VI) sorption compared to the HA-free samples. This result is consistent with other studies; in the acidic pH range, the addition of HA slightly enhances U(VI) sorption relative to the HA-free system. Conversely, in the pH range of 4 to 7, the sorption of U(VI) on Si was reduced in the presence of HA in comparison to the system without HA. In subsequent experiments the concentration of HA will be increased to 50 ppm. (authors)},
doi = {},
url = {https://www.osti.gov/biblio/22824389}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2015},
month = {7}
}

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