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Title: Chromate reduction and heavy metal fixation in soil

Abstract

In situ reduction of chromates and the fixation of the metals Cr, Pb, Zn, Cu, Cd and Ni in soil was investigated using Fe II and soluble silica. Fe II fulfills two functions. It reduces chromates (CrVI) at soil pH to CrIII and the reaction products, Fe(OH)[sub 3] and Cr(OH)[sub 3], coprecipitate/adsorb heavy metals. In the absence of CrVI iron is added as FeIII. Destabilized silica also fulfills two functions. It reacts with the metal and metal hydroxides and reduces the soil permeability. The leaching rate (mg/m[sup 2]s) of a metal is the product of leachate flow rate ([ell]/M[sup 2]s) and the leachate concentration (mg/[ell]). The leachate flow rate is directly proportional to the hydraulic coefficient (Darcy's Law). Treatment with destabilized silica reduces the hydraulic coefficient of virgin soil (K[sub h] = 10[sup [minus]2]...10[sup [minus]4]) to K[sub h]=10[sup [minus]7] (cm/s) resulting in a flow rate reduction of 3--5 orders of magnitude. Iron plus silica treatment results in a leachate concentration reduction of up to 2 orders of magnitude (Cr:95--99%;Pb:99%;Zn 95--99%; Cd:93--99%; Ni:75--94%). Combined effect of flow rate reduction and leachate concentration reduction results in a potential leaching rate reduction of five to seven orders of magnitude. Iron-silica treatment may bemore » developed into an efficient containment technology, provided the silica gel integrity does not change with time.« less

Authors:
Publication Date:
Research Org.:
Sizemore Technical Services, Inc., Round Rock, TX (United States)
Sponsoring Org.:
DOE; USDOE, Washington, DC (United States)
OSTI Identifier:
6914271
Alternate Identifier(s):
OSTI ID: 6914271; Legacy ID: DE93002266
Report Number(s):
DOE/CH-9214
ON: DE93002266
DOE Contract Number:  
W-31109-ENG-38
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; SOILS; REMEDIAL ACTION; ADSORPTION; CADMIUM; CHROMATES; CHROMIUM; CONTAMINATION; COPPER; IRON IONS; LEAD; NICKEL; PERMEABILITY; PROGRESS REPORT; REDUCTION; SILICA GEL; SILICON OXIDES; SLUDGES; WASTES; ZEOLITES; ZINC; ADSORBENTS; CHALCOGENIDES; CHARGED PARTICLES; CHEMICAL REACTIONS; CHROMIUM COMPOUNDS; DOCUMENT TYPES; ELEMENTS; INORGANIC ION EXCHANGERS; ION EXCHANGE MATERIALS; IONS; MATERIALS; METALS; MINERALS; OXIDES; OXYGEN COMPOUNDS; SILICATE MINERALS; SILICON COMPOUNDS; SORPTION; TRANSITION ELEMENT COMPOUNDS; TRANSITION ELEMENTS 540220* -- Environment, Terrestrial-- Chemicals Monitoring & Transport-- (1990-)

Citation Formats

Schwitzgebel, K. Chromate reduction and heavy metal fixation in soil. United States: N. p., 1992. Web.
Schwitzgebel, K. Chromate reduction and heavy metal fixation in soil. United States.
Schwitzgebel, K. Mon . "Chromate reduction and heavy metal fixation in soil". United States.
@article{osti_6914271,
title = {Chromate reduction and heavy metal fixation in soil},
author = {Schwitzgebel, K.},
abstractNote = {In situ reduction of chromates and the fixation of the metals Cr, Pb, Zn, Cu, Cd and Ni in soil was investigated using Fe II and soluble silica. Fe II fulfills two functions. It reduces chromates (CrVI) at soil pH to CrIII and the reaction products, Fe(OH)[sub 3] and Cr(OH)[sub 3], coprecipitate/adsorb heavy metals. In the absence of CrVI iron is added as FeIII. Destabilized silica also fulfills two functions. It reacts with the metal and metal hydroxides and reduces the soil permeability. The leaching rate (mg/m[sup 2]s) of a metal is the product of leachate flow rate ([ell]/M[sup 2]s) and the leachate concentration (mg/[ell]). The leachate flow rate is directly proportional to the hydraulic coefficient (Darcy's Law). Treatment with destabilized silica reduces the hydraulic coefficient of virgin soil (K[sub h] = 10[sup [minus]2]...10[sup [minus]4]) to K[sub h]=10[sup [minus]7] (cm/s) resulting in a flow rate reduction of 3--5 orders of magnitude. Iron plus silica treatment results in a leachate concentration reduction of up to 2 orders of magnitude (Cr:95--99%;Pb:99%;Zn 95--99%; Cd:93--99%; Ni:75--94%). Combined effect of flow rate reduction and leachate concentration reduction results in a potential leaching rate reduction of five to seven orders of magnitude. Iron-silica treatment may be developed into an efficient containment technology, provided the silica gel integrity does not change with time.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1992},
month = {6}
}

Technical Report:
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