Background:
The nanocomposites are formed by introducing inorganic nano-clusters, fullerenes, clays, metals,
oxides with numerous organic polymers. The assembly of these materials exhibits better properties such as catalytic, thermal
stability and adsorption properties, etc. than the individual materials.
Objective:
The nanocomposite synthesized here by sol-gel method was primarily evaluated for cation exchange properties
viz, elution concentration, elution behavior, effect of temperature on ion-exchange capacity. The synthesized composite was
used as an electro-active component for fabrication of Hg2+ ion selective membrane electrode.
Method :
The sol-gel technique was used to synthesize multi-walled carbon nanotubes Zr(IV) phosphate composite cation
exchanger. By the technique of solution casting the material as an electroactive part was used for the fabrication of mercury
ion-selective membrane electrode. The potential response of the electrode was also investigated as a function of membrane
composition and plasticizer.
Results:
The composite cation exchanger exhibited 1.8 meq g-1 ion-exchange capacity (IEC). It retained almost 65 % of its
initial IEC upto a temperature of 400 °C. Distribution studies showed the selective nature of the composite for Hg(II) ions.
The ion-selective membrane electrode exhibited typical Nernstian response towards Hg2+ ions in the concentration range
1×10-1
-1×10-7 M.
Conclusion:
The results discussed reveal that a new cation composite exchanger-multi-walled carbon nanotubes Zr (IV)
phosphate exhibited excellent cation exchange properties and was found to be preferentially selective towards the Hg2+ ions.
It was also used as an indicator electrode in the titration of Hg2+ using ethylenediaminetetraacetic acid as a titrant.
Organic-inorganic Composite Cation-exchanger: Poly-o-toluidine Zr(IV) Phosphate-based Ion-selective Membrane Electrode for the Potentiometric Determination of Mercury