Au (III) uptake by triazine polyamine polymers: Mechanism, kinetic and equilibrium studies

Abstract

Triazine-polyamine polymers were successfully synthesized and adsorption of the gold (III) ions from chloride-containing solutions was carried out by comparing the effect of amine chain lengths in the polymers triazine-ethylenediamine (EDA), triazine-triethylenetetramine (TETA) and triazine-pentaethylene hexamine (PEHA). The second-order kinetic equation provides the best correlation for the adsorption process. Langmuir equation has a good fit for all the adsorption systems. Langmuir monolayer adsorption capacities of the EDA, TETA and PEHA polymers were 548, 1003 and 1086mg/g, respectively. Adsorption mechanism was determined using FTIR, XPS, SEM, SEM Mapping and EDS. Adsorption mechanism is followed by ionic and surface complex formation mechanisms. Hydroxy chloro gold complexes were more interacted with nitrogen atoms of amine groups in polymers than nitrogen atoms in triazine rings. The adsorption capacity did not decrease after using all polymers five times. Furthermore, elution of the adsorbed Au (III) ions was made easily using 3% (m/v) thiourea solution in 1M HCl. From the results, it was concluded that EDA, TETA and PEHA polymers have a high gold uptake capacity and are highly efficient for the recycling of gold.