Вплив способу іммобілізації ?-циклодекстрину на сорбційні властивості модифікованих кремнеземів
The purpose of this work is to study the influence of ?-cyclodextrin immobilization method on the sorption of benzoic acid from aqueous solutions by highly dispersed amorphous silicas. Silicas with large specific surface area, high reactivity of functional groups, hydrolytic, chemical and radiation...
Збережено в:
| Дата: | 2019 |
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| Автори: | , , , , |
| Формат: | Стаття |
| Мова: | Російська |
| Опубліковано: |
Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine
2019
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| Теми: | |
| Онлайн доступ: | https://www.cpts.com.ua/index.php/cpts/article/view/501 |
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| Назва журналу: | Chemistry, Physics and Technology of Surface |
Репозитарії
Chemistry, Physics and Technology of Surface| Резюме: | The purpose of this work is to study the influence of ?-cyclodextrin immobilization method on the sorption of benzoic acid from aqueous solutions by highly dispersed amorphous silicas. Silicas with large specific surface area, high reactivity of functional groups, hydrolytic, chemical and radiation stability are widely used oxide matrices for synthesis of new materials with predicted sorption specificity. The surface immobilization of organic compounds that form “key-lock” or “host-guest” complexes is one of the effective ways to make the silica sorption affinity for specific substances. Benzoic acid and its functional derivatives are used in the synthesis of herbicides, pesticides, polymers, preservatives, resins, plasticizers, dyes, drugs, and cosmetics. They have a harmful effect on living organisms even at low concentrations in water. Therefore the extraction of trace amounts of aromatic organic substances from aqueous objects is an important task of environmental science. Silicas modified by ?-cyclodextrin adsorption and its chemical fixing on the surface of aerosil A-300, silochrome C-120 and silica gel KSKG-4 were synthesized. Using elemental, chemical and thermogravimetric analysis, pH-metry, IR spectroscopy, low-temperature nitrogen adsorption-desorption, spectrophotometry, and sorption measurements, the structure and physicochemical properties of resulting functional materials were characterized. An increase in the acidity of silanol groups in the series A-300 < C-120 < KSKG-4 with silica structure ordering was found. The sorption affinity of modified silicas to benzoic acid grows by two orders of magnitude, and the distribution coefficients – in 30–150 times. The results of benzoic acid sorption studies were analyzed using the Lagergren kinetic model and the Langmuir and Freundlich equilibrium adsorption models. The processes that occur when ?-cyclodextrin-containing silicas contact with benzoic acid solutions were identified. It has been shown that desorption of ?-cyclodextrin prevents the formation of inclusion complexes in the surface layer of silicas. No correlation was found between porous structure of silicas and strength of ?-cyclodextrin retention on their surface. The use of silicas chemically modified with ?-cyclodextrin for extraction of benzoic acid and its functional derivatives from aqueous solutions, including that in cyclic sorption-desorption mode, was demonstrated. |
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