Extraction and separation of Fe(III) from heavy metal wastewater using P204 solvent impregnated resin

The extraction and separation of Fe(III) from heavy metal wastewater generated in zinc smelting process were studied using solvent impregnated resin containing CL-P204. The influence of pH and temperature on absorbing heavy metal cations by static adsorption was investigated. The batch tests on adsorption equilibrium, kinetics and elution efficiency were carried out to evaluate the performance of CL-P204. Column operations for extraction and separation of Fe(III) by CL-P204 were performed for further optimization of process parameters and feasibility evaluation. The reaction mechanism of Fe(III) and CL-P204 was analyzed through saturation capability, slope analysis and infrared spectroscopy (IR). The results show that the separation of Fe(III) from heavy metal wastewater using CL-P204 can be achieved through process of adsorption and desorption at a flow rate of 1.53 ml·min⁻¹·cm⁻², pH 0.8 and temperature of 25 °C. The experimental data of Fe(III) adsorption by CL-P204 have a satisfactory fit with Langmuir adsorption equation and Freundlich adsorption isotherms. The probable molecular formula of extracted complex is Fe[R₂(R₂H)], and the adsorption reaction equation is concluded as following: \({\text{Fe}}^{3 + } + 4{\text{RH}}\mathop \Leftrightarrow \limits^{{K_{\text{ex}} }} {\text{Fe}}[{\text{R}}_{2} ({\text{R}}_{2} {\text{H}})] + 3{\text{H}}^{ + } \) (K _ex, extraction equilibrium constant). This study will supply the fundamentals for treatment of heavy metal wastewater.