Document Detail


Influence of clay minerals on the reduction of Cr6+ by citric acid.
MedLine Citation:
PMID:  18022670     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The influence of clay minerals on the reduction of Cr6+ by citric acid was investigated at pH values 4.0, 4.5 and 5.0 at 25 degrees C. The results indicate that montmorillonite and illite greatly accelerate the reduction reactions at pH 4.0 and 4.5, but their effects are dramatically reduced at pH 5.0. The role of clay minerals in accelerating the reactions is in the order: illite>montmorillonite>>kaolinite, which has a positive correlation with the amount of Mn2+ adsorbed on the surfaces of these minerals. With light, Fe(3+) also significantly increases reaction rates. Ethylenediaminetetraacetic acid (EDTA) greatly suppresses the acceleration of the reduction reactions by these minerals, indicating that EDTA competes with citric acid for Mn2+. Thus, the formation of complexes between Mn(2+) and citric acid could be a prerequisite for the acceleration of the reductions of Cr6+ by clay minerals. In addition, there is no relationship between the specific surface area of clay minerals and the reduction rate of Cr6+ by citric acid.
Authors:
Yeqing Lan; Chen Li; Jingdong Mao; Jun Sun
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-11-26
Journal Detail:
Title:  Chemosphere     Volume:  71     ISSN:  0045-6535     ISO Abbreviation:  Chemosphere     Publication Date:  2008 Mar 
Date Detail:
Created Date:  2008-03-04     Completed Date:  2008-05-28     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0320657     Medline TA:  Chemosphere     Country:  England    
Other Details:
Languages:  eng     Pagination:  781-7     Citation Subset:  IM    
Affiliation:
College of Sciences, Nanjing Agricultural University, Nanjing 210095, PR China. lanyq102@njau.edu.cn
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MeSH Terms
Descriptor/Qualifier:
Adsorption
Aluminum Silicates / chemistry*
Catalysis
Chromium / chemistry*
Citric Acid / chemistry*
Edetic Acid / chemistry
Iron / chemistry
Kinetics
Magnesium / chemistry
Oxidation-Reduction
Chemical
Reg. No./Substance:
0/Aluminum Silicates; 1302-87-0/clay; 60-00-4/Edetic Acid; 7439-89-6/Iron; 7439-95-4/Magnesium; 7440-47-3/Chromium; 77-92-9/Citric Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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