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Title: Physical-Chemical Treatment of Metals and Radionuclides in the Saturated Zone Using Colloidal Buffers - 12515

Abstract

There are numerous acidic plumes throughout the DOE complex and the nation as a whole. Low aquifer pH is a major concern since many important radionuclides (Pu, Ra, Sr, Tc) and metals (Cd, Co, Cs, Mn, Ni, Pb, Zn) strongly sorb to iron hydroxides and aluminosilicates under neutral to alkaline conditions, but are mobile in acidic plumes. To effectively use natural and enhanced attenuation (NEA) for management of these contaminants, we must be able to raise aquifer pH and maintain it at background levels until the external acid loading to the aquifer has dissipated. Geochemical modeling showed that a permeable reactive barrier (PRB) formed by injection of colloidal Mg(OH){sub 2} would last much longer than colloidal Ca(OH){sub 2} due to the much lower solubility of Mg(OH){sub 2}. Assuming a 1,000 meq/L suspension of colloidal Mg(OH)2 could be effectively distributed, the PRB could last over twenty years before rejuvenation was required. Preliminary bench-scale treatability studies were conducted to demonstrate the efficacy of increasing the aquifer pH using a colloidal pH buffer. Laboratory studies demonstrated that three different colloidal Mg(OH){sub 2} suspensions (concentration varied from 1,000 to 1,250 meq/L) could be transported through the columns packed with aquifer sand without significant permeabilitymore » loss. The time before suspension breakthrough into the column effluent varied with surface treatment, indicating the Mg(OH)2 retention and PRB longevity could be controlled by varying the suspension surface treatment. (authors)« less

Authors:
;  [1];  [2]
  1. North Carolina State University, Raleigh, NC 27695 (United States)
  2. EOS Remediation, LLC. Raleigh, NC 27607 (United States)
Publication Date:
Research Org.:
WM Symposia, 1628 E. Southern Avenue, Suite 9-332, Tempe, AZ 85282 (United States)
OSTI Identifier:
22293729
Report Number(s):
INIS-US-14-WM-12515
TRN: US14V1385115253
Resource Type:
Conference
Resource Relation:
Conference: WM2012: Waste Management 2012 conference on improving the future in waste management, Phoenix, AZ (United States), 26 Feb - 1 Mar 2012; Other Information: Country of input: France; 7 refs.
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 54 ENVIRONMENTAL SCIENCES; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; IRON HYDROXIDES; MAGNESIUM HYDROXIDES; MANAGEMENT; METALS; RADIOISOTOPES; SIMULATION; SUSPENSIONS

Citation Formats

Lai, Yenjung, Borden, Robert C., and Alperin, Ed. Physical-Chemical Treatment of Metals and Radionuclides in the Saturated Zone Using Colloidal Buffers - 12515. United States: N. p., 2012. Web.
Lai, Yenjung, Borden, Robert C., & Alperin, Ed. Physical-Chemical Treatment of Metals and Radionuclides in the Saturated Zone Using Colloidal Buffers - 12515. United States.
Lai, Yenjung, Borden, Robert C., and Alperin, Ed. Sun . "Physical-Chemical Treatment of Metals and Radionuclides in the Saturated Zone Using Colloidal Buffers - 12515". United States.
@article{osti_22293729,
title = {Physical-Chemical Treatment of Metals and Radionuclides in the Saturated Zone Using Colloidal Buffers - 12515},
author = {Lai, Yenjung and Borden, Robert C. and Alperin, Ed},
abstractNote = {There are numerous acidic plumes throughout the DOE complex and the nation as a whole. Low aquifer pH is a major concern since many important radionuclides (Pu, Ra, Sr, Tc) and metals (Cd, Co, Cs, Mn, Ni, Pb, Zn) strongly sorb to iron hydroxides and aluminosilicates under neutral to alkaline conditions, but are mobile in acidic plumes. To effectively use natural and enhanced attenuation (NEA) for management of these contaminants, we must be able to raise aquifer pH and maintain it at background levels until the external acid loading to the aquifer has dissipated. Geochemical modeling showed that a permeable reactive barrier (PRB) formed by injection of colloidal Mg(OH){sub 2} would last much longer than colloidal Ca(OH){sub 2} due to the much lower solubility of Mg(OH){sub 2}. Assuming a 1,000 meq/L suspension of colloidal Mg(OH)2 could be effectively distributed, the PRB could last over twenty years before rejuvenation was required. Preliminary bench-scale treatability studies were conducted to demonstrate the efficacy of increasing the aquifer pH using a colloidal pH buffer. Laboratory studies demonstrated that three different colloidal Mg(OH){sub 2} suspensions (concentration varied from 1,000 to 1,250 meq/L) could be transported through the columns packed with aquifer sand without significant permeability loss. The time before suspension breakthrough into the column effluent varied with surface treatment, indicating the Mg(OH)2 retention and PRB longevity could be controlled by varying the suspension surface treatment. (authors)},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2012},
month = {7}
}

Conference:
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