Synthesis of Na-2-mica from metakaolin and its cation exchange properties

Tatsuya Kodama; Takayuki Higuchi; Tadaaki Shimizu; Ken-ichi Shimizu; Sridhar Komarneni; Wilfried Hoffbauer; Hartmut Schneider

doi:10.1039/B101186N

Tatsuya Kodama,†*^a Takayuki Higuchi,^a Tadaaki Shimizu,^b Ken-ichi Shimizu,^b Sridhar Komarneni,^c Wilfried Hoffbauer^d and Hartmut Schneider^e

Author affiliations

* Corresponding authors

^a Department of Chemistry & Chemical Engineering, Faculty of Engineering, Niigata University, 8050 Ikarashi 2-nocho, Niigata, Japan

^b Graduate School of Science and Technology, Niigata University, 8050 Ikarashi 2-nocho, Niigata, Japan

^c Materials Research Laboratory and Department of Agronomy, The Pennsylvania State University, University Park, PA, USA

^d Institute of Inorganic Chemistry, University of Bonn, Bonn, Germany

^e Ceramic Department, Institute of Materials Research, German Aerospace Research Establishment-DLR, Köln, Germany

Abstract

Na-2-mica of the ideal composition of Na₂Mg₆Al₂Si₆O₂₀F₄·xH₂O was prepared from a mixture of NaF, magnesium nitrate, SiO₂ and calcined kaolinite (the latter serving as a cost-effective aluminosilicate source) at 800 °C and was found to excel in Sr removal from solutions at room temperature. This mica was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and ²⁷Al and ²⁹Si magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy. Fundamental studies of nNa⁺ → Mⁿ⁺ (Mⁿ⁺ = Sr²⁺, Ca²⁺, Li⁺, K⁺ and Cs⁺) equilibria revealed a high selectivity and large capacity for Sr²⁺ ion uptake. A relatively low-temperature heat treatment (200 °C) of the Sr-exchanged mica resulted in collapse of the hydrated interlayer spacings of the mica, which will be useful to immobilize strontium in the stable unhydrated phase. This selective Sr-ion exchanger is expected to be useful for ⁹⁰Sr removal and its immobilization.

Article information

https://doi.org/10.1039/B101186N

Article type

Paper

Submitted

06 Feb 2001

Accepted

15 May 2001

First published

04 Jul 2001

Download Citation

J. Mater. Chem., 2001,11, 2072-2077

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