Biosorption of U(VI) by the green algae Chlorella vulgaris in dependence of pH value and cell activity
| Autor: | Johannes Raff, Manja Vogel, B. Li, Gert Bernhard, Alix Günther, André Rossberg |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
inorganic chemicals
Water Pollutants Radioactive Environmental Engineering TRLFS Biomass Chlorophyceae chemistry.chemical_element Fresh Water Chlorophyta complex mixtures Oxalate chemistry.chemical_compound Environmental Chemistry Waste Management and Disposal sorption biology Chemistry technology industry and agriculture Biosorption Hydrogen-Ion Concentration Uranium biology.organism_classification Phosphate green algae Pollution EXAFS uranium(VI) Green algae Chlorella vulgaris ATR-FTIR Nuclear chemistry |
| Zdroj: | Science of the Total Environment 409(2010)2, 384-395 |
| ISSN: | 0048-9697 |
| DOI: | 10.1016/j.scitotenv.2010.10.011 |
| Popis: | Biosorption of uranium(VI) by the green alga Chlorella vulgaris was studied at varying uranium concentrations from 5 μM to 1 mM, and in the environmentally relevant pH range of 4.4 to 7.0. Living cells bind in a 0.1 mM uranium solution at pH 4.4 within 5 min 14.3 ± 5.5 mg U/g dry biomass and dead cells 28.3 ± 0.6 mg U/g dry biomass which corresponds to 45% and 90% of total uranium in solution, respectively. During 96 h of incubation with uranium initially living cells died off and with 26.6 ± 2.1 mg U/g dry biomass bound similar amounts of uranium compared to dead cells, binding 27.0 ± 0.7 mg U/g dry biomass. In both cases, these amounts correspond to around 85% of the initially applied uranium. Interestingly, at a lower and more environmentally relevant uranium concentration of 5 μM, living cells firstly bind with 1.3 ± 0.2 mg U/g dry biomass to 1.4 ± 0.1 mg U/g dry biomass almost all uranium within the first 5 min of incubation. But then algal cells again mobilize up to 80% of the bound uranium during ongoing incubation in the time from 48 h to 96 h. The release of metabolism related substances is suggested to cause this mobilization of uranium. As potential leachates for algal-bound uranium oxalate, citrate and ATP were tested and found to be able to mobilize more than 50% of the algal-bound uranium within 24 h. Differences in complexation of uranium by active and inactive algae cells were investigated with a combination of time-resolved laser-induced fluorescence spectroscopy (TRLFS), extended X-ray absorption fine structure (EXAFS) spectroscopy and attenuated total reflection Fourier transform infrared (ATR–FTIR) spectroscopy. Obtained results demonstrated an involvement of carboxylic and organic/inorganic phosphate groups in the uranium complexation with varying contributions dependent on cell status, uranium concentration and pH. |
| Databáze: | OpenAIRE |
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