Modified Alkali Activated Zeolite Foams with Improved Textural and Mechanical Properties
Natural zeolites are crystalline hydrated alkali metal and alkaline earth metal aluminosilicates with unique ion-exchange and sorption properties. The exceptional structure of pores gives natural zeolites several application possibilities, especially for water treatment and construction. For a wider...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-05-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/10/5/483 |
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| author | Kateřina Hrachovcová Zdeněk Tišler Eliška Svobodová Jan Šafář |
| author_facet | Kateřina Hrachovcová Zdeněk Tišler Eliška Svobodová Jan Šafář |
| author_sort | Kateřina Hrachovcová |
| collection | DOAJ |
| description | Natural zeolites are crystalline hydrated alkali metal and alkaline earth metal aluminosilicates with unique ion-exchange and sorption properties. The exceptional structure of pores gives natural zeolites several application possibilities, especially for water treatment and construction. For a wider use of natural zeolites, such as catalysis, properties—especially chemical, textural, and mechanical—need to be modified. In this study, the basic natural zeolite foam was synthesized by alkali activation of natural zeolite with an activator (KOH + Na<sub>2</sub>SiO<sub>3</sub>) and foamed by hydrogen peroxide solution. Other foams were prepared by a partial replacement of the natural zeolite with CaO, MgO, and metakaolin (MK) and alkali activated and foamed in the same manner as the basic natural zeolite foam. Other properties of the foams were modified by acid leaching. The aim of the study was to compare the basic alkali activated zeolite foam with the CaO, MgO, and MK modified zeolite foams and determine the effect of the CaO, MgO, and MK modification and the subsequent leaching of the alkali activated zeolite foams on the textural, mechanical, and chemical properties. Properties of alkali activated zeolite foams were determined by Hg porosimetry, N<sub>2</sub> physisorption, NH<sub>3</sub>-TPD, XRF, XRD, and strength analyses. From the data, it is apparent that all modified samples have an increase of pore volume in the mesoporous region and the partial replacement by MgO or CaO significantly increased surface area up to 288.2 m<sup>2</sup>/g while increasing the strength several times. The obtained data showed an improvement in properties and extension of the potential applicability of modified zeolite foams in the chemical industry, especially for catalytic and sorption applications. |
| first_indexed | 2024-03-10T19:36:26Z |
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| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-10T19:36:26Z |
| publishDate | 2020-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-382b4bc535fe49f7930c0cb8349f58fd2023-11-20T01:40:29ZengMDPI AGMinerals2075-163X2020-05-0110548310.3390/min10050483Modified Alkali Activated Zeolite Foams with Improved Textural and Mechanical PropertiesKateřina Hrachovcová0Zdeněk Tišler1Eliška Svobodová2Jan Šafář3Unipetrol Centre for Research and Education, a.s., Areál Chempark 2838, Záluží 1, 436 70 Litvínov, Czech RepublicUnipetrol Centre for Research and Education, a.s., Areál Chempark 2838, Záluží 1, 436 70 Litvínov, Czech RepublicUnipetrol Centre for Research and Education, a.s., Areál Chempark 2838, Záluží 1, 436 70 Litvínov, Czech RepublicUnipetrol Centre for Research and Education, a.s., Areál Chempark 2838, Záluží 1, 436 70 Litvínov, Czech RepublicNatural zeolites are crystalline hydrated alkali metal and alkaline earth metal aluminosilicates with unique ion-exchange and sorption properties. The exceptional structure of pores gives natural zeolites several application possibilities, especially for water treatment and construction. For a wider use of natural zeolites, such as catalysis, properties—especially chemical, textural, and mechanical—need to be modified. In this study, the basic natural zeolite foam was synthesized by alkali activation of natural zeolite with an activator (KOH + Na<sub>2</sub>SiO<sub>3</sub>) and foamed by hydrogen peroxide solution. Other foams were prepared by a partial replacement of the natural zeolite with CaO, MgO, and metakaolin (MK) and alkali activated and foamed in the same manner as the basic natural zeolite foam. Other properties of the foams were modified by acid leaching. The aim of the study was to compare the basic alkali activated zeolite foam with the CaO, MgO, and MK modified zeolite foams and determine the effect of the CaO, MgO, and MK modification and the subsequent leaching of the alkali activated zeolite foams on the textural, mechanical, and chemical properties. Properties of alkali activated zeolite foams were determined by Hg porosimetry, N<sub>2</sub> physisorption, NH<sub>3</sub>-TPD, XRF, XRD, and strength analyses. From the data, it is apparent that all modified samples have an increase of pore volume in the mesoporous region and the partial replacement by MgO or CaO significantly increased surface area up to 288.2 m<sup>2</sup>/g while increasing the strength several times. The obtained data showed an improvement in properties and extension of the potential applicability of modified zeolite foams in the chemical industry, especially for catalytic and sorption applications.https://www.mdpi.com/2075-163X/10/5/483natural zeoliteclinoptilolitealkali activationacid leachinginorganic foam |
| spellingShingle | Kateřina Hrachovcová Zdeněk Tišler Eliška Svobodová Jan Šafář Modified Alkali Activated Zeolite Foams with Improved Textural and Mechanical Properties Minerals natural zeolite clinoptilolite alkali activation acid leaching inorganic foam |
| title | Modified Alkali Activated Zeolite Foams with Improved Textural and Mechanical Properties |
| title_full | Modified Alkali Activated Zeolite Foams with Improved Textural and Mechanical Properties |
| title_fullStr | Modified Alkali Activated Zeolite Foams with Improved Textural and Mechanical Properties |
| title_full_unstemmed | Modified Alkali Activated Zeolite Foams with Improved Textural and Mechanical Properties |
| title_short | Modified Alkali Activated Zeolite Foams with Improved Textural and Mechanical Properties |
| title_sort | modified alkali activated zeolite foams with improved textural and mechanical properties |
| topic | natural zeolite clinoptilolite alkali activation acid leaching inorganic foam |
| url | https://www.mdpi.com/2075-163X/10/5/483 |
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