1. Preparation of Zn–Al layered double hydroxide intercalated with carboxymethyl-β-cyclodextrin by anion exchange method and its Ni2+ adsorption property.
- Author
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Kameda, Tomohito, Takaizumi, Mao, Kumagai, Shogo, Saito, Yuko, and Yoshioka, Toshiaki
- Subjects
LAYERED double hydroxides ,CARBOXYMETHYL compounds ,LANGMUIR isotherms ,HYDROXIDES ,ION exchange resins ,ADSORPTION (Chemistry) ,ANIONS ,X-ray spectra - Abstract
Recently, layered double hydroxides (LDHs) have been extensively researched for their anion exchange capabilities and exhibit a layered structure with a host layer of octahedrally coordinated metal cations and a guest layer (interlayer) of anions. In this study, we synthesized a CM-β-CD•Zn–Al LDH by anion exchange method to study the anionization of cyclodextrin (CD) to promote its incorporation into the LDH interlayers and its stability therein. Ni
2+ adsorption by the CMCD•Zn–Al LDH by the anion exchange method was compared with the results co-precipitation method. The X-ray diffraction spectra of NO3 •Zn–Al LDH and CM-β-CD•Zn–Al LDH synthesized by the anion exchange method exhibit that the product peaks were attributable to Z n 6 A l 2 O H 16 C O 3 4 H 2 O and possessed an LDH structure. Furthermore, all CM-β-CD•Zn–Al LDHs exhibited the presence of some CM-β-CD. The CM-β-CD•Zn–Al LDH was hypothesized to be composed of two types of layers: a CM-β-CD layer in which two molecules of CM-β-CD7 - , with cavity axes perpendicular to the LDH host layer, are vertically overlaid, and a NO3 -type Zn–Al LDH layer used as a precursor. CM-β-CD•Zn–Al LDH adsorbed Ni2+ in an aqueous solution. To determine whether Ni2+ adsorption by the CM-β-CD•Zn–Al LDH is driven chemically or physically, we fitted the data to the Freundlich and Langmuir adsorption models; the results showed that Ni2+ adsorption by the CM-β-CD•Zn–Al LDH is consistent with the Langmuir equation and could be considered a chemical adsorption. [ABSTRACT FROM AUTHOR]- Published
- 2021
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