Preparation, characterisation and sorptive properties towards noble metals of the resins from poly(vinylbenzyl chloride) copolymers

In this paper, we described a convenient synthetic route towards crosslinked poly(vinylbenzyl chloride) resins bearing diamine and guanidine ligands. A series of 24 resins were synthesised from an expanded gel (A), and porous (B, C) vinylbenzyl chloride copolymers using alkyldiamines (1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane and 1,6-diaminohexane) and cyanamide. The resins contain amine and guanidine functionality of 3.1-5.7 mmol/g. The resins reveal excellent sorption ability towards gold, palladium and platinum anions from hydrochloric acid solutions which is proportional to anion-exchange capacity. Among all investigated resins A2 and B2 resins show excellent sorption in acidic solution up to 100 mg Au/g, 105 Pt mg/g, respectively. Palladium sorption is about 50% lower than in other noble metals. High distribution coefficients are observed up to 170,000 for palladium, 50,000 for platinum and for gold. The resins with a longer spacer of the hydrophobic methylene between the amnio group and the terminal guanidine group reveal a higher dicyanoaurate sorption from KCN solution at 9.6 pH. The expanded gel resins, AG6, up to 45 mg Au/g show the best sorptive properties.