Polyaniline Titanium (IV) Tungstomolybdate Composite Ion Exchanger: Fabrication and Binary Separation Studies for the Removal of Selected Toxic Heavy Metals

Abstract

Environmental pollution by toxic heavy metals is increasing at an alarming rate which demands the development of an appropriate analytical method to investigate and quantify the target analytes. In response to this call, polyaniline Titanium (IV) tungstomolybdate (PANI/TWM) nanocomposite was synthesized by incorporating polyaniline into Titanium (IV) tungstomolybdate using sol–gel method. The material was then characterized using X-ray diffraction (XRD), UV-Vis, Fourier transform infrared (FTIR), Thermogravimetric analysis (TGA-DTA), and Scanning electron microscope (SEM-EDX). It was amorphous with appreciable thermal stability as it retained 65.2% of its ion exchange capacity (IEC) up to 600 ^OC. It acts as a bifunctional strong acid cation exchanger with an IEC of 1.58 meq/g for Na⁺ ions. Moreover, the high distribution coefficients (Kd) of 1572 and 928 mL/g for Pb(II) and Co(II), respectively, indicate its potential to treat these ions in an aqueous matrix selectively. Real sample treatment with the prepared material was undertaken for binary separation of selected metal ions in column mode and practically appreciable efficiency (90.3 to 96.8%) was achieved. Therefore, the synthesized material can be considered as a promising cation exchanger to treat an environmental matrix containing toxic heavy metals.