PHOTO-REDUCTION KINETICS OF MnO2 IN AQUATIC ENVIRONMENTS CONTAINING HUMIC ACIDS

https://doi.org/10.22146/ijc.21645

Narsito Narsito(1*), Sri Juari Santosa(2), Setya Lastuti(3)

(1) Graduate Studies in Environmental Chemistry, Department of Chemistry, Universitas Gadjah Mada, Sekip Utara, Yogyakarta, 55281
(2) Graduate Studies in Environmental Chemistry, Department of Chemistry, Universitas Gadjah Mada, Sekip Utara, Yogyakarta, 55281
(3) Institute for Environmental Health Engineering, Yogyakarta
(*) Corresponding Author

Abstract


The kinetics of photo-reduction of manganese(IV) oxide, MnO2 in aqueous medium, in the presence of humic acid has been investigated, including the possibility for the involvement of such radicals in the reduction. Results showed that in aqueous medium, the efficiency of the photo-reduction of MnO2 producing a soluble ionic Mn(II) was governed strongly by an internal electron transfer within an intermediate of HA-MnO2 anion complex, resulted in the chemical adsorption of humic acid on MnO2 surface. It was observed that under solar radiation and atmosphere containing oxygen, the rate of MnO2 reduction increased considerably, by factors of about 46 and 2 respectively. Moreover, there was evidence that some radicals certainly played a role in the photo-reduction of MnO2, since radical scavenger addition significantly decreased the reduction efficiency of MnO2. In the present of an excess of propanol-2, however, which was expected to remove all OH radicals present, only about 60 % decrease in reduction efficiency were observed, suggesting that radicals other than OH radical are involved in the reduction of MnO2. It was observed further that the presence of iron(III) in MnO2 up to 1 % (w/w) did not alter the reduction efficiency of MnO2.


Keywords


MnO2 kinetics; photo-reduction; aquatic; humic acids

Full Text:

Full Text Pdf


References

[1] Christian, G. D. and Feldman, F. J., 1970, Atomic Absorption Spectroscopy : Application in Agriculture, Biology, and Medicine, John Wiley & Sons, New York.

[2] Drum, D. A., Baumann, S. L. and Shugar, G. J., 2001, Environmental Field Testing and Analysis Ready Reference Handbook, McGraw Hill Inc., New York.

[3] Kaim, W. and Schwederski, B.,1994, Bioinorganic Chemistry : Inorganic Elements in the Chemistry of Life : An Introduction and Guide, John Wiley & Sons, Chichester.

[4] Bohn, H. L., McNeal, M. L. and O'Connor, G. A., 1979, Soil Chemistry, John Wiley & Sons, New York.

[5] Sunda, W. G., Huntsman, S. A. and Harvey, G. R., 1983, Nature, 301, 234 - 236.

[6] Scott, D. T., and D. C. Harneir, 2000, Enhancement of Fresh Water Manganese Oxide Photo-reduction in the Presence of Fulvic Acids, Proceedings of 10th International Humic Substances Society, IHSS 10, 24 -28 July 2000, Toulouse, France.

[7] Tarchitzky, J., Chen, Y. and Banin, A., 1993, Soil Sci. Soc. Am. J., 57, 367 - 372.

[8] Kipton, H., Powel, J. and Town, R. M.,1992, Anal. Chim. Acta, 267, 47 - 54.

[9] Narsito, Santosa, S. J. and Lastuti, S., 2004, Berkala Ilmiah MIPA, 14 (3), 41 – 63.

[10] Wittbrodt, P.R. and Palmer, C.D., 1995, Environ. Sci. Technol., 30, 2470-2477.

[11] Xie, H., Wang, Y. Cai, W. J. Zafiron, O. C., and Zepp, R. G., 2000, Photochemical Alteration on Dissolved Organic Matter : Effects on Concentration and Acidities of Ionizable Sites in Dissolved Organic Matter in the Satilla Riverof Georgia, USA, Proceedings of 10th International Meeting of the International Humic Substances Society, IHSS, 24 - 28 July 2000, Toulouse, France, 253 -256.

[12] Cederbaum, A. I. and Cohen, G.,1987, Microsomal Oxidation of Hydroxyl radical scavenging Agent, pp. 81 - 82, dalam Greenwald, R. A., 1987, CRC Handbook of Metods for Oxygen Radical Research, CRC Press Inc., Florida.

[13] Mailhot, G., Brand, N. Astruc, M. and Bolte, M., 2002, App. Organomet. Chem., 16, 27 - 33.

[14] Stumm, W. and Morgan, J. J., 1996, Aquatic Chemistry, A Wiley Interscience Publication, John Wiley & Sons, Inc., New York.



DOI: https://doi.org/10.22146/ijc.21645

Article Metrics

Abstract views : 759 | views : 674


Copyright (c) 2010 Indonesian Journal of Chemistry

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

 


Indonesian Journal of Chemistry (ISSN 1411-9420 / 2460-1578) - Chemistry Department, Universitas Gadjah Mada, Indonesia.

Web
Analytics View The Statistics of Indones. J. Chem.