Adsorption of Silver and Gold Ions from their Aqueous Solutions using a Magnetic Chelating Resin Derived from a Blend of Bisthiourea/Thiourea/Glutaraldehyde

A magnetic chelating resin was obtained from copolymerization of a blend of bisthiourea/thiourea/glutaraldehyde in the presence of magnetite (Fe3O4). The uptake of Ag(I) and Au(III) by the resin using batch and column techniques was studied. The maximum uptake capacity showed 6.2 and 5.78 mmol/g for Ag(I) and Au(III), respectively. Breakthrough curves showed critical bed height values of 0.03 cm and 0.04 cm for Ag(I) and Au(III), respectively, indicating the higher affinity of resin to Ag(I) relative to Au(III). Regeneration of the resins was achieved using acidified thiourea at efficiency of 98% over five cycles with no appreciable change in durability. The investigated resin was found to be able to remove 13 different metal ions from a real wastewater matrix at efficiency of 91%.