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Title: Incorporation of Chromate into Calcium Carbonate Structure During Coprecipitation

Authors:
; ; ; ;
Publication Date:
Research Org.:
Subsurface Biogeochemical Research (SBR)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER)
OSTI Identifier:
1154169
Resource Type:
Journal Article
Resource Relation:
Journal Name: Water, Air, and Soil Pollution; Journal Volume: 179; Journal Issue: 1-4
Country of Publication:
United States
Language:
English

Citation Formats

Bin,Hua, Baolin,Deng, Edward C.,Thornton, John,Yang, and James E.,Amonette. Incorporation of Chromate into Calcium Carbonate Structure During Coprecipitation. United States: N. p., 2007. Web. doi:10.1007/s11270-006-9242-7.
Bin,Hua, Baolin,Deng, Edward C.,Thornton, John,Yang, & James E.,Amonette. Incorporation of Chromate into Calcium Carbonate Structure During Coprecipitation. United States. doi:10.1007/s11270-006-9242-7.
Bin,Hua, Baolin,Deng, Edward C.,Thornton, John,Yang, and James E.,Amonette. Mon . "Incorporation of Chromate into Calcium Carbonate Structure During Coprecipitation". United States. doi:10.1007/s11270-006-9242-7.
@article{osti_1154169,
title = {Incorporation of Chromate into Calcium Carbonate Structure During Coprecipitation},
author = {Bin,Hua and Baolin,Deng and Edward C.,Thornton and John,Yang and James E.,Amonette},
abstractNote = {},
doi = {10.1007/s11270-006-9242-7},
journal = {Water, Air, and Soil Pollution},
number = 1-4,
volume = 179,
place = {United States},
year = {Mon Feb 05 00:00:00 EST 2007},
month = {Mon Feb 05 00:00:00 EST 2007}
}
  • To assess treatment technologies and establish regulatory framework for chromate-contaminated site remediation, it is imperative to know the exact chromium speciation in soil matrices. In an earlier study, Thornton and Amonette (1999) reported that some chromate in the bulk particles was not accessible to gaseous reductants or solution-phase extractants, based on XANES studies. We hypothesized that part of this non-extractable chromate may reside in the structure of minerals such as calcium carbonate. To test this hypothesis, a number of calcium carbonate precipitates were prepared in the presence of various concentrations of chromate during the precipitation, which could coprecipitate chromate, ormore » by adding chromate after the precipitation was completed. Hydrochloric acid was used to dissolve calcium carbonate and therefore extract the coprecipitated and surface attached chromate. The results showed that the coprecipitated chromate was non-extractable by hot alkaline solution or phosphate buffer, but could be solubilized by HCl in proportional to the amount of calcium carbonate dissolved. The X-ray diffraction experiments revealed that the coprecipitation of chromate with calcium carbonate had an influence on its crystal structure: the higher the chromate concentration, the greater the ratio of vaterite to calcite.« less
  • The reaction process and the optimum preparation conditions of the M-type calcium ferrite by the chemically coprecipitated method were studied using differential thermal, thermogravimetric, and x-ray analyses. It is found that the formation mechanism using the coprecipitated method is the same as that of the solid-state reaction, and the precursor CaO {center dot} 2Fe{sub 2}O{sub 3} cannot be avoided, but it could be formed at lower temperature. The defect based on the replacement of Ca{sup 2 +} by La{sup 3 +}, the charge compensation by Fe{sup 2 +}, and release of oxygen is supported by the DTA/TGA and conductivity data.more » The conductivity is suggested to occur through a hopping mechanism.« less