**11. Ion exchangers of functional amine and guanidine groups**

Resins of functional amine and guanidine functional groups were successfully used in sorption of Pd(II), Pt(IV) and Au(III) ions from chlorides solutions (initial concentration of each metal was 24 mM). The highest selectivity towards the above-mentioned ions and the possibility of practical application of their recovery are exhibited by the ion exchangers A2 (Au – 99.7; Pt – 108; Pd – 54.3 mg/g), B2 (Au – 94.1; Pt – 104.8; Pd – 48.7 mg/g) and AG2 (Au – 85,1; Pt – 64; Pd – 49.2 mg/g) and BG2 (Au – 74.3; Pt – 76.2; Pd – 48.5 mg/g). The sorption mechanism of Pd(II), Pt(IV) and Au(III) chloro complexes is the combination of coordination interactions of electron nitrogen pair and electrostatic interactions of these ions with the protonated group –NH2 [83].

**Ion exchanger Application Additional Information Ref.**

Sorption capacities (mmol/g): Pd(II) – 0.78 (pH = 0); Pt(IV) – 0.71 (pH = 0); Ru(III) – 0.685 (1.5 M HCl); Rh(III) – 0.615 (2 M HCl); Ag(I) – 0 (pH = 0) and increase with increasing solution pH, Ir(III) – 0 (pH = 0); Au(III) and Os(VI) are reduced during the contact with the resin; Cu(II), Bi(III), Hg(II), Fe(III) and Al(III) are not retained by the resin; Desorption: 4 M and 9 M HCl as well as 5 % N,N-diphenylthiourea in ethanol

Selectivity series: Pd(II) > Au(III) >> Ir(IV) > Os(IV) > Pt(IV) > Ru(III) > Rh(III); Desorption: acidified 5% (NH2)2CS

Sorption capacities for Au(III), Pd(II), Ru(III), Os(VI), Pt(IV) and Ir(IV) equalled to 5.38, 3.67, 3.46, 3.10, 2.46 and 2.24 mmol/g, respectively

[77]

[79]

[80]

) adding 0.2 M EDTA [82].

Separation of Pd(II), Rh(III), Pt(IV), Ru(III), Ir(III), Au(III), Os(VI), as well as Cu(II), Bi(III), Hg(II), Fe(III) and Al(III)

Preconcentration and separation of noble metal ions in the amount of 0.001 M in the presence of Zn(II), Co(II), Cu(II), Fe(III), Ni(II) and Cd(II) from acidic solutions of the proportion of noble metal to base metal: 1:1, 1:10, 1:100

Pre-concentration and recovery of Au(III), Pd(II), Ru(III), Os(VI), Pt(IV) and Ir(IV) in the presence of Zn(II), Fe(III), Cu(II) and Ni(II) from chloride solutions

**10. Ion exchangers of functional (amino)pyridine groups**

eliminated using 2 M HCl and those from iron (> 200 mg Fe/dm3

**11. Ion exchangers of functional amine and guanidine groups**

**Table 1.** Examples of the chelating ion exchangers of thiosemicarbazide, piperazine and tetrazine functional groups

Resins of pyridine [81] and α-aminopyridine groups on the polyphenylethylene support [82] were successfully used for the separation of technetium and platinum metals from diluted chloride solutions and in concentration of Pt(IV), Pd(II) and Ir(III) (*on-line* FAAS). Technetium ions were eluted using concentrated solutions of hydrochloric acid but platinum metals (Ru(III), Rh(III) and Pd(II)) by means of 0.1 M NH2CSNH2 in 1 M HCl [81] or 0.5 M HCl – 0.5 M HClO4 – 0.5 M Mg(ClO4)2 [82]. Most interferences coming from noble-metal ions were

Resins of functional amine and guanidine functional groups were successfully used in sorption of Pd(II), Pt(IV) and Au(III) ions from chlorides solutions (initial concentration of each metal

Resin of thiosemicarbazide functional groups

12 Ion Exchange - Studies and Applications

Resin of amine and 1,2,4,5-tetraazine functional groups

Resin of 1-(2 aminethylene) piperazine functional groups

and their characteristic.

In the case of the ion exchangers of the same functional groups: amine (D1, D2, D3, D4) and guanidine (D1G, D2G, D3G, D4G) but on the basis of copolymer VBC/AN/DVB (copolymer D), the studies of Pd(II), Pt(IV), Au(III), Cu(II), Ni(II) and Fe(III) ion removal from single and multi-component chloride solutions (0.1–3.0 M HCl) showed that the highest selectivity towards metal ions is exhibited by the resin D4 (sorption capacity 190 mg Au(III)/g, 245 mg Pt(IV)/g and 280 mg Pd(II)/g of the resin), and the selectivity series towards Pd(II) ions is as follows: D4 (117 mg/g) >> D1 > D4G > D1G > D2 = D3G > D2G > D3 (25 mg/g). Recovery of noble metals from multi-component solutions with ten greater excess of Cu(II), Ni(II) and Fe(III) ions was > 95 % [84].
