CaltechAUTHORS
  A Caltech Library Service

Arsenic Adsorption and Oxidation at Manganite Surfaces. 1. Method for Simultaneous Determination of Adsorbed and Dissolved Arsenic Species

Chiu, Van Q. and Hering, Janet G. (2000) Arsenic Adsorption and Oxidation at Manganite Surfaces. 1. Method for Simultaneous Determination of Adsorbed and Dissolved Arsenic Species. Environmental Science and Technology, 34 (10). pp. 2029-2034. ISSN 0013-936X. http://resolver.caltech.edu/CaltechAUTHORS:20170314-154330918

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item: http://resolver.caltech.edu/CaltechAUTHORS:20170314-154330918

Abstract

Arsenic occurs in the +III oxidation state as a metastable species in oxic waters. Under oxic conditions, As(III) is both more mobile in natural waters and less efficiently removed by water treatment processes than As(V). Other oxidants, however, can react with As(III) more rapidly than oxygen. The oxidation of As(III) by manganite occurs on the time scale of hours. Here, a method is introduced for the rapid determination of the total and dissolved concentrations of arsenic species in this heterogeneous system; adsorbed arsenic concentrations are calculated by difference. The oxidation reaction is quenched by the addition of ascorbic acid to effect the reductive dissolution of manganite and concomitant release of adsorbed As(III) and As(V) into solution. Once in solution, As(III) and As(V) are separated using anion-exchange chromatography. Comparison of dissolved and total concentrations of As(III) and As(V) clearly illustrates that the overall conversion rate of As(III) to As(V) in this system would be overpredicted based solely on dissolved As(III) concentrations and underpredicted based solely on dissolved As(V) concentrations. The overall conversion of As(III) to As(V) was more rapid at pH 4 than at pH 6.3 and was unaffected by the presence of boric acid at 95 μM or 3 mM. However, the presence of 200 μM phosphate (at pH 4) decreased the overall rate of conversion of As(III) to As(V). Comparison of total and dissolved As(III) concentrations during the reaction time course demonstrates that the effects of pH and phosphate on adsorbed As(III) concentrations are generally consistent with these kinetic observations.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/es990788pDOIArticle
http://pubs.acs.org/doi/abs/10.1021/es990788pPublisherArticle
Additional Information:© 2000 American Chemical Society. Publication Date (Web): April 9, 2000. This project was funded by the National Science Foundation (BES-9753074 and BES-98696136). We thank Prof. James J. Morgan for helpful discussions of this work and Mr. Brian R. King for assistance with sampling.
Funders:
Funding AgencyGrant Number
NSFBES-9753074
NSFBES-98696136
Record Number:CaltechAUTHORS:20170314-154330918
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20170314-154330918
Official Citation:Arsenic Adsorption and Oxidation at Manganite Surfaces. 1. Method for Simultaneous Determination of Adsorbed and Dissolved Arsenic Species Van Q. Chiu and Janet G. Hering, Environmental Science & Technology 2000 34 (10), 2029-2034 DOI: 10.1021/es990788p
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:75118
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:16 Mar 2017 17:36
Last Modified:16 Mar 2017 17:36

Repository Staff Only: item control page