Cellulose acetate-Sn(IV) molybdophosphate: A biopolymer supported composite Exchanger for the removal of selected heavy metal ions

Abstract

Cellulose acetate-tin(IV) molybdophosphate (CATMP) composite exchanger was prepared by mixing biopolymer celluloseacetate with its inorganic counterpart tin(IV) molybdophosphate (TMP) using sol‑gel method. The physical characterization of the as synthesized exchanger was carried out by FTIR, XRD, BET, TGA-DTG and SEM-EDX techniques. Chemical properties such as ion exchange capacity, chemical stability, pH and distribution behavior were carried out. The average IEC of the composite material, as determined by batch equilibrium, was found to be 2.43 meq/g for Na⁺ ion; higher than its inorganic counterpart, i.e. 1.41 meq/g. This exchanger was also found to be stable in water, acids and organic solvents, but unstable in basic medium. The distribution study (K_d) of the exchanger in different solvent systems showed promising separation potential of the exchanger towards metal ions of analytical interest from a given mixture of toxic heavy metal ions. The sorption studies revealed that the material was selective for Cr(III) and Cd(II) ions and moderately selective for Co(II) ion in solvents employed in this work. Its selectivity was examined by achieving some important binary separations of metal cations on its column indicating its promising application in environmental pollution abatement.

KEY WORDS: Cation exchanger, Biopolymer, Organic-inorganic hybrid, Sol–gel method, Binary distribution

Bull. Chem. Soc. Ethiop. 2020, 34(2), 259-276

DOI: https://dx.doi.org/10.4314/bcse.v34i2.5