Development of sulfonated polystyrene resin-supported tungsten oxide for Pb²⁺ ion sequestration

A sulfonated polystyrene resin-supported tungsten oxide (SO₃-PSWO) was synthesized and evaluated for its efficiency in removing lead (Pb²⁺) from aqueous solutions. Morphology, phase purity, structural properties, thermal stability, and elemental composition of SO₃-PSWO, are evaluated using SEM, XRD, FTIR, TGA, and CHNS analyzers. The ICP-OES technique was utilized for quantitative measurements of the Pb²⁺ ions. The influence of key parameters such as pH, adsorbent dose, contact time, metal ion concentration, temperature, and interference of competing ions on Pb²⁺ removal is systematically investigated. Under optimum conditions (pH 3.5-5.5), SO₃-PSWO achieved a maximum Pb²⁺ removal efficiency of 99.7% within one hour and demonstrated an exceptional adsorption capacity of 386 mg g^-1, as described by the Langmuir isotherm model. Kinetic analysis revealed a pseudo-second-order mechanism, highlighting chemisorption as the predominant process. Thermodynamic studies indicated an exothermic and spontaneous adsorption behavior. With its easy synthesis, cost-effectiveness, rapid kinetics, high adsorption capacity, and superior efficiency, SO₃-PSWO emerges as a promising material for the remediation of Pb²⁺ contamination in water treatment applications.