Anion Intercalation and Anion Exchange in Bismuth Compounds

  • PDF / 286,017 Bytes
  • 6 Pages / 595 x 842 pts (A4) Page_size
  • 40 Downloads / 224 Views

DOWNLOAD

REPORT


DD6.10.1

Anion Intercalation and Anion Exchange in Bismuth Compounds Masamichi Tsuji, Makoto Yamaguchi1, and Satoshi Murao2 Tokyo Institute of Technology, Research Center for Carbon Recycling and Energy, Tokyo, JAPAN. 1Institute of Research and Innovation, Kashiwa Laboratory, Chiba, JAPAN. 2National Institute of Advanced Industrial Science and Technology, Institute for Geo-resources and Environment, JAPAN.

ABSTRACT Bismuth nitrate basic, which chemical content is given by 4BiNO3(OH)2.BiO(OH), was studied for anion-intercalation or anion-exchange properties. A crystal structure of the bismuth nitrate basic has not been known. In the present study, its XRD pattern was indexed using a possible orthorhombic system having the lattice parameters of ao=3.021(1) nm, bo=3.029(1) nm and co=0.9572(3) nm. This compound was found to incorporate CH3COO-, halides and several oxyanions including CO32-. Incorporation of these anions by this solid was evidenced by broadening of infrared absorption band by NO3-, suggesting involvement with NO3- ions. Intercalation of CO32- by the bismuth nitrate basic in full extent yielded a bismutite represented by the chemical composition Bi2O2CO3. The bismuth nitrate basic will serve as a new host for anion-intercalation and anion-exchange.

INTRODUCTION A bismutite compound Bi2O2CO3 and its divalent cation substituted bismutite-type compounds (Bi1-x,Mx)2(O1-x,(OH)x)2CO3.nH2O have been discovered to show very high affinity towards SeO32 ions [1,2]. These compounds carry CO32 ions as a mobile charge between the + Bi2O22 or (Bi1-x,Mx)2(O1-x,(OH)x)22+ layers. The interlayer distance is 0.68 nm, which is substantially shorter than that of layered double hydroxides (LDHs) or hydrotalcite-like compounds (0.78 nm). SeO32 is exclusively exchanged with CO32 having the similar geometry. Other oxyanions such as SO42 , SeO42 , NO3 and NO2 ions are not exchanged with CO32 ions between the layers by steric hindrance. Such steric hindrance does not occur in LDHs having larger interlayer distance and space for accommodation of anions. This results in low anion selectivity of LDHs [2]. LDHs have been extensively studied as anion intercalation and anion-exchange materials. They are represented by the chemical composition of [M1-x2+Nx3+(OH)2]x+ [Ax/mm-.nH2O]x . The x value denotes substitution of trivalent cations N, and ranges from 0.2 to 0.45 [3-9]. A large substitution of 0.45 by Al3+ has been reported in the brucite layers of Mg2+, Ni2+, Zn2+, Co2+ and Cu2+ [8]. In the course of our study, the present authors found a new bismuth compound, bismuth nitrate basic, showing anion uptake, which chemical content is given by 4BiNO3(OH)2.BiO(OH) on a basis of chemical analysis. This compound was studied as a candidate material for new

DD6.10.2

anion-intercalation and anion-exchange properties by powder XRD data and infrared spectroscopy in the present work.

EXPERIMENTAL A. Materials and anion intercalation/anion exchange Bismuth nitrate basic and other bismuth compounds were supplied by Wako Pure Chemicals Co. Ltd.

Data Loading...