Study of precipitates formed on iron reactors following the removal of copper from water

The presence of heavy metals, e.g. Cu in groundwater as a result of acid mine drainage (AMD) poses a threat to the environment. In order to remove cationic copper from solutions simulating the AMD, iron reactors were applied as zero-valent iron. The precipitates formed on the surface of the reactors and their specific surface area were determined. Affinity of copper in ionic form with reactors was investigated. The results show that for iron reactor immersed in solution of initial pH 3, copper oxides as well as iron oxides and carbonates (to lower extent) were formed. More reaction products were generated in case of higher pH (initial pH = 6). These were mainly: copper and iron oxides, Cu0, and probably iron sulfates and carbonates. These precipitates caused an increase in specific surface of the reactors. In both cases (mainly for the reactor immersed in a solution of lower pH) the surface of the reactors was not covered entirely with a coating. The sorption study indicated that copper ions may be retained on the surface of reactors only at higher pH, because the pH at point of zero charge of iron reactors was ca. 6.2.