Synthesis of a novel dithiooxamide–formaldehyde resin and its application to the adsorption and separation of silver ions

In this study, a new chelating resin of dithiooxamide (rubeanic acid)–formaldehyde (DTOF) has been synthesized by the reaction of dithiooxamide and formaldehyde. Also a well-known chelating resin of thiourea (thiooxamide)–formaldehyde (TUF) has been prepared by the reaction of thiourea and formaldehyde. DTOF and TUF chelating resins were used in the adsorption, separation and concentration of silver ions by batch and column techniques. These resins were characterized using FTIR and elemental analysis. It was found that DTOF resin has silver adsorption capacity of 3333.3 mg g−1 or 30.86 mmolg g−1 and TUF resin has the capacity of 1428.6 mg g−1 or 13.22 mmol g−1. DTOF resin showed more affinity to silver ions according to Cu(II), Zn(II), Ni(II) and Co(II) base metal ions than TUF resin. It was also demonstrated that DTOF resin can be used in the separation and concentration of silver ions.