Sorption of phosphate onto mesoporous <it>γ</it>-alumina studied with in-situ ATR-FTIR spectroscopy
<p>Abstract</p> <p>Background</p> <p>Due to the extensive use of phosphates in industry, agriculture and households, the phosphate - γ-alumina interactions are important for understanding its detrimental contribution to eutrophication in lakes and rivers. In situ Fourie...
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| Format: | Article |
| Language: | English |
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BMC
2012-04-01
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| Series: | Chemistry Central Journal |
| Online Access: | http://journal.chemistrycentral.com/content/6/1/26 |
| _version_ | 1819349884041428992 |
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| author | Zheng Ting-Ting Sun Zhong-Xi Yang Xiao-Fang Holmgren Allan |
| author_facet | Zheng Ting-Ting Sun Zhong-Xi Yang Xiao-Fang Holmgren Allan |
| author_sort | Zheng Ting-Ting |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Due to the extensive use of phosphates in industry, agriculture and households, the phosphate - γ-alumina interactions are important for understanding its detrimental contribution to eutrophication in lakes and rivers. In situ Fourier transform infrared (FTIR) spectroscopy can provide more detailed information on the adsorbate-adsorbent interaction and the formation of hydrogen bonds.</p> <p>Results</p> <p>In situ ATR-FTIR spectroscopy was used to identify phosphate complexes adsorbed within the three-dimensional network of mesoporous γ-alumina at pH 4.1 and 9.0. The integrated intensity between 850 cm-1 and 1250 cm-1 was used as a relative measure of the amount of adsorbed phosphate. The integrated intensity proved to be about 3 times higher at pH 4.1 as compared with the corresponding intensity at pH 9.0. The adsorption of phosphate at the two pH conditions could be well described by the Langmuir adsorption isotherm at low concentrations and the empirical Freundlich adsorption isotherm for the whole concentration range, viz. 5 – 2000 μM.</p> <p>Conclusions</p> <p>From the band shape of infrared spectra at pH 4.1 and pH 9.0, it was proposed that the symmetry of the inner-sphere surface complex formed between phosphate and γ-alumina was C1 at the lower pH value, whilst the higher value (9.0) implied a surface complex with C2v or C1 symmetry. The difference in adsorbed amount of phosphate at the two pH values was ascribed to the reduced fraction of ≡ AlOH2+ surface sites and the increased fraction of ≡ AlO- sites upon increasing pH from 4 to 9.</p> |
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| format | Article |
| id | doaj.art-31a9acb312ec447689e341c96b1cae09 |
| institution | Directory Open Access Journal |
| issn | 1752-153X |
| language | English |
| last_indexed | 2024-12-24T19:07:36Z |
| publishDate | 2012-04-01 |
| publisher | BMC |
| record_format | Article |
| series | Chemistry Central Journal |
| spelling | doaj.art-31a9acb312ec447689e341c96b1cae092022-12-21T16:43:04ZengBMCChemistry Central Journal1752-153X2012-04-01612610.1186/1752-153X-6-26Sorption of phosphate onto mesoporous <it>γ</it>-alumina studied with in-situ ATR-FTIR spectroscopyZheng Ting-TingSun Zhong-XiYang Xiao-FangHolmgren Allan<p>Abstract</p> <p>Background</p> <p>Due to the extensive use of phosphates in industry, agriculture and households, the phosphate - γ-alumina interactions are important for understanding its detrimental contribution to eutrophication in lakes and rivers. In situ Fourier transform infrared (FTIR) spectroscopy can provide more detailed information on the adsorbate-adsorbent interaction and the formation of hydrogen bonds.</p> <p>Results</p> <p>In situ ATR-FTIR spectroscopy was used to identify phosphate complexes adsorbed within the three-dimensional network of mesoporous γ-alumina at pH 4.1 and 9.0. The integrated intensity between 850 cm-1 and 1250 cm-1 was used as a relative measure of the amount of adsorbed phosphate. The integrated intensity proved to be about 3 times higher at pH 4.1 as compared with the corresponding intensity at pH 9.0. The adsorption of phosphate at the two pH conditions could be well described by the Langmuir adsorption isotherm at low concentrations and the empirical Freundlich adsorption isotherm for the whole concentration range, viz. 5 – 2000 μM.</p> <p>Conclusions</p> <p>From the band shape of infrared spectra at pH 4.1 and pH 9.0, it was proposed that the symmetry of the inner-sphere surface complex formed between phosphate and γ-alumina was C1 at the lower pH value, whilst the higher value (9.0) implied a surface complex with C2v or C1 symmetry. The difference in adsorbed amount of phosphate at the two pH values was ascribed to the reduced fraction of ≡ AlOH2+ surface sites and the increased fraction of ≡ AlO- sites upon increasing pH from 4 to 9.</p>http://journal.chemistrycentral.com/content/6/1/26 |
| spellingShingle | Zheng Ting-Ting Sun Zhong-Xi Yang Xiao-Fang Holmgren Allan Sorption of phosphate onto mesoporous <it>γ</it>-alumina studied with in-situ ATR-FTIR spectroscopy Chemistry Central Journal |
| title | Sorption of phosphate onto mesoporous <it>γ</it>-alumina studied with in-situ ATR-FTIR spectroscopy |
| title_full | Sorption of phosphate onto mesoporous <it>γ</it>-alumina studied with in-situ ATR-FTIR spectroscopy |
| title_fullStr | Sorption of phosphate onto mesoporous <it>γ</it>-alumina studied with in-situ ATR-FTIR spectroscopy |
| title_full_unstemmed | Sorption of phosphate onto mesoporous <it>γ</it>-alumina studied with in-situ ATR-FTIR spectroscopy |
| title_short | Sorption of phosphate onto mesoporous <it>γ</it>-alumina studied with in-situ ATR-FTIR spectroscopy |
| title_sort | sorption of phosphate onto mesoporous it γ it alumina studied with in situ atr ftir spectroscopy |
| url | http://journal.chemistrycentral.com/content/6/1/26 |
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