Aqueous photocatalytic oxidation of lignin and humic acids with supported TiO2
The photocatalytic oxidation (PCO) of UV-irradiated aqueous solutions containing humic acids and lignin was studied. The photocatalyst TiO2 was attached to buoyant hollow glass microspheres and glass plates. A maximum oxidation efficiency as low as 1.1 and 2.54 mg W−1h−1 for humic acids and lignin,...
Saved in:
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley
2006-01-01
|
| Series: | International Journal of Photoenergy |
| Online Access: | http://dx.doi.org/10.1155/IJP/2006/85927 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1841524653736067072 |
|---|---|
| author | Elina Portjanskaja Sergei Preis Juha Kallas |
| author_facet | Elina Portjanskaja Sergei Preis Juha Kallas |
| author_sort | Elina Portjanskaja |
| collection | DOAJ |
| description | The photocatalytic oxidation (PCO) of UV-irradiated aqueous solutions containing humic acids and lignin was studied. The photocatalyst TiO2 was attached to buoyant hollow glass microspheres and glass plates. A maximum oxidation efficiency as low as 1.1 and 2.54 mg W−1h−1 for humic acids and lignin, respectively, was achieved in neutral and alkaline media with 25 gm−2 of the buoyant catalyst. In acidic media, efficiency was even lower. The photocatalytic efficiency with the photocatalyst attached to glass plates was about 3 to 4 times higher than that for the buoyant catalyst. Ferrous ions added to acidic solutions did not increase the rate of PCO of humic acids. However the addition of Fe2+ ions, up to 0.05 mM, to the lignin solution leads to a dramatic increase, about 25%, in PCO efficiency. A further increase in ferrous ion concentration results in a decrease in the PCO efficiency of lignin. Proceeding most likely by a radical mechanism, the efficiency of PCO of humic acids did not benefit from an excessive presence of hydroxyl radical promoters, such as hydrogen peroxide, although the reaction rate increased. However, PCO of lignin in the acidic medium, where OH.-radical formation is suppressed, benefited from the introduction of hydrogen peroxide due to promoted radical formation. |
| format | Article |
| id | doaj-art-a6d65037d76a441f8e3cdba2786e9033 |
| institution | Kabale University |
| issn | 1110-662X 1687-529X |
| language | English |
| publishDate | 2006-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | International Journal of Photoenergy |
| spelling | doaj-art-a6d65037d76a441f8e3cdba2786e90332025-02-03T05:47:45ZengWileyInternational Journal of Photoenergy1110-662X1687-529X2006-01-01200610.1155/IJP/2006/8592785927Aqueous photocatalytic oxidation of lignin and humic acids with supported TiO2Elina Portjanskaja0Sergei Preis1Juha Kallas2Department of Chemical Engineering, Tallinn University of Technology, Ehitajate tee 5, Tallinn 19086, EstoniaDepartment of Chemical Technology, Lappeenranta University of Technology, P.O. Box 20, Lappeenranta 53851, FinlandDepartment of Chemical Technology, Lappeenranta University of Technology, P.O. Box 20, Lappeenranta 53851, FinlandThe photocatalytic oxidation (PCO) of UV-irradiated aqueous solutions containing humic acids and lignin was studied. The photocatalyst TiO2 was attached to buoyant hollow glass microspheres and glass plates. A maximum oxidation efficiency as low as 1.1 and 2.54 mg W−1h−1 for humic acids and lignin, respectively, was achieved in neutral and alkaline media with 25 gm−2 of the buoyant catalyst. In acidic media, efficiency was even lower. The photocatalytic efficiency with the photocatalyst attached to glass plates was about 3 to 4 times higher than that for the buoyant catalyst. Ferrous ions added to acidic solutions did not increase the rate of PCO of humic acids. However the addition of Fe2+ ions, up to 0.05 mM, to the lignin solution leads to a dramatic increase, about 25%, in PCO efficiency. A further increase in ferrous ion concentration results in a decrease in the PCO efficiency of lignin. Proceeding most likely by a radical mechanism, the efficiency of PCO of humic acids did not benefit from an excessive presence of hydroxyl radical promoters, such as hydrogen peroxide, although the reaction rate increased. However, PCO of lignin in the acidic medium, where OH.-radical formation is suppressed, benefited from the introduction of hydrogen peroxide due to promoted radical formation.http://dx.doi.org/10.1155/IJP/2006/85927 |
| spellingShingle | Elina Portjanskaja Sergei Preis Juha Kallas Aqueous photocatalytic oxidation of lignin and humic acids with supported TiO2 International Journal of Photoenergy |
| title | Aqueous photocatalytic oxidation of lignin and humic acids with supported TiO2 |
| title_full | Aqueous photocatalytic oxidation of lignin and humic acids with supported TiO2 |
| title_fullStr | Aqueous photocatalytic oxidation of lignin and humic acids with supported TiO2 |
| title_full_unstemmed | Aqueous photocatalytic oxidation of lignin and humic acids with supported TiO2 |
| title_short | Aqueous photocatalytic oxidation of lignin and humic acids with supported TiO2 |
| title_sort | aqueous photocatalytic oxidation of lignin and humic acids with supported tio2 |
| url | http://dx.doi.org/10.1155/IJP/2006/85927 |
| work_keys_str_mv | AT elinaportjanskaja aqueousphotocatalyticoxidationofligninandhumicacidswithsupportedtio2 AT sergeipreis aqueousphotocatalyticoxidationofligninandhumicacidswithsupportedtio2 AT juhakallas aqueousphotocatalyticoxidationofligninandhumicacidswithsupportedtio2 |