Вплив мікроструктури модифікованого діатоміту на його адсорбційні властивості
The effect of microstructural changes caused by chemical modification of diatomite with aluminosilicate nanoparticles on its adsorption properties with respect to fluorine has been elucidated.The surface modification of diatomite with aluminosilicate is accompanied with significant changes in its st...
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| Дата: | 2017 |
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| Автори: | , |
| Формат: | Стаття |
| Мова: | Англійська |
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Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine
2017
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| Онлайн доступ: | https://www.cpts.com.ua/index.php/cpts/article/view/414 |
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| Назва журналу: | Chemistry, Physics and Technology of Surface |
Репозитарії
Chemistry, Physics and Technology of Surface| _version_ | 1856543887397486592 |
|---|---|
| author | Datsko, T. Ia. Zelentsov, V. I. |
| author_facet | Datsko, T. Ia. Zelentsov, V. I. |
| author_sort | Datsko, T. Ia. |
| baseUrl_str | |
| collection | OJS |
| datestamp_date | 2022-06-29T10:15:09Z |
| description | The effect of microstructural changes caused by chemical modification of diatomite with aluminosilicate nanoparticles on its adsorption properties with respect to fluorine has been elucidated.The surface modification of diatomite with aluminosilicate is accompanied with significant changes in its structure and chemical properties – a growth of specific surface area, a shift of electro-superficial properties and an increase of adsorption capacity for fluorine. Moreover, some kind of synergism takes place after modification: adsorption capacity of aluminosilicate species grafted on the diatomite surface is higher than that of bulk aluminosilicate.The surface-chemical modification of diatomite has been carried out by heating it in a NaOH solution and subsequent treatment with a solution of aluminum salt and after that with ammonia. Amorphous surface silica partially dissolves during the treatment with NaOH and due to addition of an aluminum salt it forms an aluminosilicate compound. The obtained product is further denoted as DMA.The increase in the specific surface area of DMA is connected with variation of the ratio of the micro- and mesopores through the filling of the large mesopores with aluminosilicate and its own microporous structure increment; the specific surface area gets 81.8 m2/g, which is 2.5 times larger than the corresponding value of the initial unprocessed diatomite (37.5 m2/g). Partial substitution of Si atoms in silicates of diatomite surface by Al atoms creates as a result of their different valences an excess negative charge, and pHPZC of the sorbent surface shifts to higher values compared to initial diatomite sample that facilitates the attraction of more negatively charged ions from solution. Both these phenomena lead to that adsorption capacity of modified diatomite (DMA) with respect to fluorine is considerably increased from 10 to 58 mmol/g.Aluminosilicate in the DMA composition has 1.3 times greater adsorption capacity with respect to fluorine compared to bulk synthetic aluminosilicate. Since the reactive sites responsible for the adsorption are essentially surface aluminum ions, it is expected that their concentration is closely associated with the content of Al2O3 in aluminosilicate. It is easy to understand that not all the silica in diatomite matrix, but the surface only was subjected to the substitution of Si atoms with Al, so the surface aluminosilicate composition must contain the increased ratio of Al2O3/ SiO2; it is 0.5 according to some calculation compared to the volume ratio which is 0.33; besides, the surface aluminosilicate is more or less uniformly distributed on the pore material surface, so more aluminum sites are accessible for interaction with fluoride ions. Furthermore, molecular aluminum and silicon precursors are preferentially grafted on sites that enable the formation of Al(IV) coordination form, and deposited aluminum species on silica are Al(IV) tetrahedrally coordinated species. This specific surface site connectivity eventually enables the formation of Br?nsted acid sites. Such acid sites may be formulated as bridging hydroxyls in connection with Al(IV) species, such as pseudo-bridging silanol in Al/SiO2, therefore more fluorine is involved in complexes with Al.Apparently,all of the above facts together should be responsible for an increased adsorption capacity of the surface aluminosilicate in the DMA composition. |
| first_indexed | 2025-07-22T19:32:53Z |
| format | Article |
| id | oai:ojs.pkp.sfu.ca:article-414 |
| institution | Chemistry, Physics and Technology of Surface |
| language | English |
| last_indexed | 2025-12-17T12:07:44Z |
| publishDate | 2017 |
| publisher | Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine |
| record_format | ojs |
| spelling | oai:ojs.pkp.sfu.ca:article-4142022-06-29T10:15:09Z Effect of microstructure of modified diatomite on its adsorption properties Влияние микроструктуры модифицированного диатомита на его адсорбционные свойства Вплив мікроструктури модифікованого діатоміту на його адсорбційні властивості Datsko, T. Ia. Zelentsov, V. I. diatomite chemical-structural modification nano-sized aluminosilicate fluorine adsorption диатоміт хімічно-структурна модифікація нанорозмірні алюмосилікати фтор адсорбція The effect of microstructural changes caused by chemical modification of diatomite with aluminosilicate nanoparticles on its adsorption properties with respect to fluorine has been elucidated.The surface modification of diatomite with aluminosilicate is accompanied with significant changes in its structure and chemical properties – a growth of specific surface area, a shift of electro-superficial properties and an increase of adsorption capacity for fluorine. Moreover, some kind of synergism takes place after modification: adsorption capacity of aluminosilicate species grafted on the diatomite surface is higher than that of bulk aluminosilicate.The surface-chemical modification of diatomite has been carried out by heating it in a NaOH solution and subsequent treatment with a solution of aluminum salt and after that with ammonia. Amorphous surface silica partially dissolves during the treatment with NaOH and due to addition of an aluminum salt it forms an aluminosilicate compound. The obtained product is further denoted as DMA.The increase in the specific surface area of DMA is connected with variation of the ratio of the micro- and mesopores through the filling of the large mesopores with aluminosilicate and its own microporous structure increment; the specific surface area gets 81.8 m2/g, which is 2.5 times larger than the corresponding value of the initial unprocessed diatomite (37.5 m2/g). Partial substitution of Si atoms in silicates of diatomite surface by Al atoms creates as a result of their different valences an excess negative charge, and pHPZC of the sorbent surface shifts to higher values compared to initial diatomite sample that facilitates the attraction of more negatively charged ions from solution. Both these phenomena lead to that adsorption capacity of modified diatomite (DMA) with respect to fluorine is considerably increased from 10 to 58 mmol/g.Aluminosilicate in the DMA composition has 1.3 times greater adsorption capacity with respect to fluorine compared to bulk synthetic aluminosilicate. Since the reactive sites responsible for the adsorption are essentially surface aluminum ions, it is expected that their concentration is closely associated with the content of Al2O3 in aluminosilicate. It is easy to understand that not all the silica in diatomite matrix, but the surface only was subjected to the substitution of Si atoms with Al, so the surface aluminosilicate composition must contain the increased ratio of Al2O3/ SiO2; it is 0.5 according to some calculation compared to the volume ratio which is 0.33; besides, the surface aluminosilicate is more or less uniformly distributed on the pore material surface, so more aluminum sites are accessible for interaction with fluoride ions. Furthermore, molecular aluminum and silicon precursors are preferentially grafted on sites that enable the formation of Al(IV) coordination form, and deposited aluminum species on silica are Al(IV) tetrahedrally coordinated species. This specific surface site connectivity eventually enables the formation of Br?nsted acid sites. Such acid sites may be formulated as bridging hydroxyls in connection with Al(IV) species, such as pseudo-bridging silanol in Al/SiO2, therefore more fluorine is involved in complexes with Al.Apparently,all of the above facts together should be responsible for an increased adsorption capacity of the surface aluminosilicate in the DMA composition. Рассмотрено влияние изменений микроструктуры, вызванных структурно-химическим модифицированием диатомита наночастицами алюмосиликата, на его адсорбционную способность по отношению к фтору. Показано, что адсорбционная емкость модифицированного диатомита превышает таковую для исходного, необработанного образца в 5.5 раз: наблюдается своего рода синергизм в адсорбционных свойствах модифицированного диатомита: адсорбционная емкость алюмосиликата, привитого на поверхность диатомита, превышает в 1.3 раза адсорбционную емкость синтетического объемного алюмосиликата. Обсуждаются возможные причины этого явления. Розглянуто вплив змін мікроструктури, викликаних структурно-хімічним модифікуванням діатоміту наночастинками алюмосилікату, на його адсорбційну здатність що до фтору. Показано, що адсорбційна ємність модифікованого діатоміту перевищує таку для вихідного, необробленого зразка в 5.5 разів: спостерігається свого роду синергізм в адсорбційних властивостях модифікованого діатоміту: адсорбційна ємність алюмосилікату, щепленого на поверхню диатоміту, перевищує в 1.3 рази адсорбційну ємність синтетичного об'ємного алюмосилікату. Обговорюються можливі причини цього явища. Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine 2017-02-01 Article Article application/pdf https://www.cpts.com.ua/index.php/cpts/article/view/414 10.15407/hftp08.01.065 Chemistry, Physics and Technology of Surface; Vol. 8 No. 1 (2017): Chemistry, Physics and Technology of Surface / Himia, Fizika ta Tehnologia Poverhni; 65-72 Химия, физика и технология поверхности; Том 8 № 1 (2017): Химия, физика и технология поверхности; 65-72 Хімія, фізика та технологія поверхні; Том 8 № 1 (2017): Хімія, фізика та технологія поверхні; 65-72 2518-1238 2079-1704 10.15407/hftp08.01 en https://www.cpts.com.ua/index.php/cpts/article/view/414/411 Copyright (c) 2017 T. Ia. Datsko, V. I. Zelentsov |
| spellingShingle | диатоміт хімічно-структурна модифікація нанорозмірні алюмосилікати фтор адсорбція Datsko, T. Ia. Zelentsov, V. I. Вплив мікроструктури модифікованого діатоміту на його адсорбційні властивості |
| title | Вплив мікроструктури модифікованого діатоміту на його адсорбційні властивості |
| title_alt | Effect of microstructure of modified diatomite on its adsorption properties Влияние микроструктуры модифицированного диатомита на его адсорбционные свойства |
| title_full | Вплив мікроструктури модифікованого діатоміту на його адсорбційні властивості |
| title_fullStr | Вплив мікроструктури модифікованого діатоміту на його адсорбційні властивості |
| title_full_unstemmed | Вплив мікроструктури модифікованого діатоміту на його адсорбційні властивості |
| title_short | Вплив мікроструктури модифікованого діатоміту на його адсорбційні властивості |
| title_sort | вплив мікроструктури модифікованого діатоміту на його адсорбційні властивості |
| topic | диатоміт хімічно-структурна модифікація нанорозмірні алюмосилікати фтор адсорбція |
| topic_facet | diatomite chemical-structural modification nano-sized aluminosilicate fluorine adsorption диатоміт хімічно-структурна модифікація нанорозмірні алюмосилікати фтор адсорбція |
| url | https://www.cpts.com.ua/index.php/cpts/article/view/414 |
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