NEW SELECTIVE RESINS WITH GUANIDYL GROUPS

Conditions of reaction between nitrile groups of acrylonitrile/vinyl a cetate/divinylbenzene (ANNA/DVB) copolymer and aminoguanidine bicarbon ate (AGB) leading to N-substituted amides have been optimized. It has been found that the highest concentration of amino groups can be achie ved carrying out aminolysis in the presence of a butanol/water mixture as solvent, Resin obtained under such conditions has 2.20 mmol/g of a mino groups and 2.40 g/g water regain. Modified resins display a small er average pore diameter (5.6 nm) than starting AN/VA/DVB copolymer (1 1.2 nm), indicating that the pore surface is covered with amide gel. W hen water is used as solvent in aminolysis reaction the degree of modi fication is smaller and the structure of the resulting resin is simila r to that of the starting copolymer. Sorption of Cu(II) on obtained re sins is high and proportional to amino group concentration, whereas so rption of Au(CN)(2)(-) under alkaline conditions in the presence of ex cess KCN depends on the structure of the acrylic resin but not on amin o group content. Resins which have been modified with AGB in the prese nce of a butanol/water mixture are 9-times (49.3 mg/g of dry resin) mo re effective in gold cyanide removal than those modified in water. Oth er polymers such as: methacrylic acid/trimethylolpropane trimethacryla te (TMPMA), glycidyl methacrylate/TMPMA, glycidyl methacrylate/trimeth ylolpropane triacrylate and vinylbenzylchloride/styrene/divinylbenzene have been investigated as matrices for aminoguanidine ligands. In the case of the latter polymer, containing 2 wt% of crosslinking agent, s orption of gold cyanide is 55.0 mg/g. (C) 1998 Elsevier Science B.V. A ll rights reserved.