Fe(III) recovery from HCl solutions using amberlite XAD‐7 resin impregnated with a tetraalkyl phosphonium ionic liquid

Fe(III) is efficiently extracted from concentrated HCl solutions using Amberlite XAD‐7 impregnated with tetraalkyl phosphonium chloride ionic liquid (IL) (synthesis of extractant‐impregnated resin, EIR). The sorption efficiency is controlled by metal speciation and IL loading in the EIR. Sorption isotherms in mono‐component solutions are described by the Langmuir equation, while the extended Langmuir equation perfectly fits sorption isotherms from binary Fe(III)/Zn(II) solutions. The thermodynamic study confirms the endothermic nature of the sorption. Uptake kinetics are fitted by the pseudo‐second order rate equation. While temperature and metal concentration have a relatively limited effect on kinetics, the IL content more significantly affects the mass transfer of Fe(III). Water, sodium sulphate, nitric acid, and sulphuric acid almost completely desorb Fe(III) from loaded EIRs. Resin recycling was tested for eight cycles without significant decrease of the sorption and desorption efficiencies.