**20. PAN-ATAL, PS-BMT ion exchangers**

Chen and Zhao [113] prepared the chelating resin PAN-ATAL by immobilization of crosslinked polyacrylnitrile (PAN) (7% DVB) with 2-amino-2-thiazole (ATAL) selective towards noble metals, i.e Pd(II), Ru(II), Ir(IV) and Rh(III) ions, for which the sorption capacity values were 230.7 mg Pd(II)/g, 147.1 mg Ir(IV)/g, 137.6 mg Ru(IV)/g and 72.1 mg Rh(III)/g of the resin. The affinity of chelating macroporous resin PS-BMT (where PS – the cross-linked chlorome‐ tylated polystyrene (10% DVB), BMT – 2,5-dimercapto-1,3,4-thiadiazole) for Pd(II), Au(III) and Pt(IV) ions from chloride solutions was studied by Qu et al. [114]. The sorption capacity for Au(III) ions 5.8 mmol/g is much higher than for Pd(II) ions 0.19 mmol/g and Pt(IV) ions 0.033 mmol/g which is associated with gold(III) chlorocomplexes coordination by two donor N and S atoms of the resin and reduction of gold(III) to a metallic form. However, in the case of PdCl4 2- and PtCl6 2- complexes, only one donor atom – sulfur atom takes part in bonding.
