Synthesis, characterization and photolytic degradation activity of poly-o-toluidine–thorium(IV)molybdophosphate cation exchanger: Analytical application in metal ion treatment

• Synthesis of a novel wastewater detoxicant poly-o-toluidine–thorium(IV)molybdophosphate
• Crystalline hybrid cation exchanger with ion exchange capacity of 1.22 meq g− 1 (K+ ions)
• Highly selective for Hg2 + and Pb2 + ions in various solvent systems
• The limit of detection and limit of quantification were found to be 0.72 and 2.40 μg L− 1 respectively for Hg2 + ions.
• Photocatalytic degradation of Congo red dye using the exchanger

A new hybrid cation exchanger poly-o-toluidine–thorium(IV)molybdophosphate (POT-TMP) has been synthesized using sol–gel method by the incorporation of inorganic precipitates of thorium(IV)molybdophosphate into the matrices of organic poly-o-toluidine. The product formation was optimized by varying the synthesis conditions at pH of 1.0. Ion exchange capacity, pH titration, effect of calcinations, chemical stability and distribution behavior of the exchanger were also studied. Activation energy calculated from Arrhenius plot using Broido equation was found to be 7.94 KJ mol− 1 at 50 °C. The distribution coefficient values of metal ions determined in different solvent media show the selectivity of the hybrid exchanger for Hg2 + and Pb2 + ions. The analytically important separations of metal ions have been successfully achieved using columns packed with this exchanger. The practical utility of the material was shown by qualitative as well as quantitative determination of Pb2 + and Hg2 + in the synthetic mixtures and industrial effluents. The limit of detection (LOD) evaluated for Pb2 + and Hg2 + was found to be 1.53 and 0.72 μg L− 1 respectively. The photocatalytic degradation of Congo red dye using the composite under natural sunlight shows that about 74% of Congo red dye was degraded within 8 h of photo irradiation.