Interactions between Cationic Dye Toluidine Blue and Fibrous Clay Minerals
Interactions between cationic dyes and negatively charged mineral surfaces have long attracted great attention from clay mineralogists, environmental scientists, and chemical engineers. In this study, the interactions between a cationic dye toluidine blue (TB) and palygorskite and sepiolite were inv...
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MDPI AG
2021-06-01
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| Online Access: | https://www.mdpi.com/2073-4352/11/6/708 |
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| author | Qingfeng Wu Kristen Carlson Qi Cheng Xisen Wang Zhaohui Li |
| author_facet | Qingfeng Wu Kristen Carlson Qi Cheng Xisen Wang Zhaohui Li |
| author_sort | Qingfeng Wu |
| collection | DOAJ |
| description | Interactions between cationic dyes and negatively charged mineral surfaces have long attracted great attention from clay mineralogists, environmental scientists, and chemical engineers. In this study, the interactions between a cationic dye toluidine blue (TB) and palygorskite and sepiolite were investigated under different experimental conditions. The results showed that in addition to cation exchange, the specific surface area (SSA) of the minerals, particularly the formation of dimer molecules on the surface of both minerals, also accounted for the much higher TB uptake in comparison to their cation exchange capacities (CEC). The TB molecules were sorbed to the external surfaces, as no d-spacing expansion was observed in X-ray diffraction analyses. FTIR analyses showed strong interactions between the C=N or N-(CH<sub>3</sub>)<sub>2</sub> group and the mineral surfaces, suggesting net electrostatic interactions if either of these functional groups bears a positive charge. Results from molecular dynamic simulations suggested dense monolayer TB formation on palygorskite because of its limited SSA and large CEC values. In comparison, a loosely dimeric formation was revealed on sepiolite for its large SSA and limited CEC values. Therefore, palygorskite is a better carrier for the sorption of cationic dyes, as evidenced by Maya blue paintings. |
| first_indexed | 2024-03-10T10:14:48Z |
| format | Article |
| id | doaj.art-8a2a43eff7c64a388f6683149623715f |
| institution | Directory Open Access Journal |
| issn | 2073-4352 |
| language | English |
| last_indexed | 2024-03-10T10:14:48Z |
| publishDate | 2021-06-01 |
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| series | Crystals |
| spelling | doaj.art-8a2a43eff7c64a388f6683149623715f2023-11-22T00:56:52ZengMDPI AGCrystals2073-43522021-06-0111670810.3390/cryst11060708Interactions between Cationic Dye Toluidine Blue and Fibrous Clay MineralsQingfeng Wu0Kristen Carlson1Qi Cheng2Xisen Wang3Zhaohui Li4School of Physics and Optoelectronic Engineering, Yangtze University, 1 Nanhuan Road, Jingzhou 434023, ChinaDepartment of Geosciences, University of Wisconsin—Parkside, 900 Wood Road, Kenosha, WI 53144, USASchool of Physics and Optoelectronic Engineering, Yangtze University, 1 Nanhuan Road, Jingzhou 434023, ChinaDepartment of Chemistry, California State University, Sacramento, CA 95819, USADepartment of Geosciences, University of Wisconsin—Parkside, 900 Wood Road, Kenosha, WI 53144, USAInteractions between cationic dyes and negatively charged mineral surfaces have long attracted great attention from clay mineralogists, environmental scientists, and chemical engineers. In this study, the interactions between a cationic dye toluidine blue (TB) and palygorskite and sepiolite were investigated under different experimental conditions. The results showed that in addition to cation exchange, the specific surface area (SSA) of the minerals, particularly the formation of dimer molecules on the surface of both minerals, also accounted for the much higher TB uptake in comparison to their cation exchange capacities (CEC). The TB molecules were sorbed to the external surfaces, as no d-spacing expansion was observed in X-ray diffraction analyses. FTIR analyses showed strong interactions between the C=N or N-(CH<sub>3</sub>)<sub>2</sub> group and the mineral surfaces, suggesting net electrostatic interactions if either of these functional groups bears a positive charge. Results from molecular dynamic simulations suggested dense monolayer TB formation on palygorskite because of its limited SSA and large CEC values. In comparison, a loosely dimeric formation was revealed on sepiolite for its large SSA and limited CEC values. Therefore, palygorskite is a better carrier for the sorption of cationic dyes, as evidenced by Maya blue paintings.https://www.mdpi.com/2073-4352/11/6/708dimersinteractionsmechanismpalygorskitesepiolitetoluidine blue |
| spellingShingle | Qingfeng Wu Kristen Carlson Qi Cheng Xisen Wang Zhaohui Li Interactions between Cationic Dye Toluidine Blue and Fibrous Clay Minerals Crystals dimers interactions mechanism palygorskite sepiolite toluidine blue |
| title | Interactions between Cationic Dye Toluidine Blue and Fibrous Clay Minerals |
| title_full | Interactions between Cationic Dye Toluidine Blue and Fibrous Clay Minerals |
| title_fullStr | Interactions between Cationic Dye Toluidine Blue and Fibrous Clay Minerals |
| title_full_unstemmed | Interactions between Cationic Dye Toluidine Blue and Fibrous Clay Minerals |
| title_short | Interactions between Cationic Dye Toluidine Blue and Fibrous Clay Minerals |
| title_sort | interactions between cationic dye toluidine blue and fibrous clay minerals |
| topic | dimers interactions mechanism palygorskite sepiolite toluidine blue |
| url | https://www.mdpi.com/2073-4352/11/6/708 |
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