Preparation, characterisation and properties of sulphoxide modified polystyrene resins for solid-phase extraction of PtIV, RuIII and RuIV from hydrochloric acid

New sulphoxide modified resins were synthesized using poly(styrene-co-divinylbenzene) (PS-DVB) as matrix. Infrared spectroscopy and elemental analysis were used for characterisation. Solid-phase extraction of PtIV, RuIII and RuIV from acidic chloride solutions was performed via batch experiments. Influence of spacer length between sulphoxide and matrix (ethylene, hexamethylene), substitution of sulphoxide (R1: ethyl, hexyl, phenyl) and bead size of PS-DVB (spherical beads: d50 < 155 μm, d50 < 80 μm; powder: d50 < 30 μm) on adsorption was investigated subjected to acidity. Experimental results showed that ethyl substituted sulphoxide immobilised onto ground PS-DVB and hexamethylene spacer exhibited best adsorption properties. Different kinetic models and isotherms were fitted to the experimental data to identify extraction mechanism. PtIV was quantitative sorbed at [HCl] ⩽ 0.1 mol/L whereas RuIII and RuIV sorption ranged between 90% and 95% at [HCl] ⩾ 5 mol/L. Desorption was reached using a solution of 0.5 M thiourea (Tu) in 0.1 M HCl at 90 °C. Separation of PtIV and RuIII occurred at [HCl] ⩽ 0.1 mol/L whereas PtIV was extracted and RuIII remained in solution. A further separation was achieved by extracting PtIV and RuIV at 5 M HCl followed by sequential elution of PtIV with concentrated HCl and RuIV with 0.5 M Tu in 0.1 M HCl at 90 °C.