Adsorption Characteristics of Various Heavy Metals at the Oxide-Solution Interface: Effect of Complex Formation

摘要

The adsorption characteristics of various divalent heavy metals onto hydrous solids were examined when strong polydentate complex forming agents were present in equivalent or excessive amounts. The adsorption characteristics of the 'free' metals and uncomplexed organic ligands were also studied and compared to the complexed metals. The ligand adsorption characteristics were found to strongly influence the adsorption of metal complexes, and evidence indicates that hydrogen bonds are formed between specific acidic surface groups and various organic functional groups. It was found that the adsorption of uncomplexed and complexed organic ligands was enhanced in the lower pH region. Data were incorporated into a predictive model for various polyacetic amino acids and their metal complexes. Predicted results and actual data were compared and shown to support the validity of the model.