EARTH

[2901-14-07] Modifying neutralization treatment with oxidation and sulfidization for selective precipitation and recovery of iron, copper, and zinc from industrial heavy metal wastewater

○Li Pang Wang¹, Yan Jhang Chen¹ (1. National Taipei University of Technology)

Chairman：Kyoungkeun Yoo （Korea Maritime and Ocean University）, Wei Sheng Chen (National Cheng Kung University)

Keywords:industrial wastewater treatment, selective precipitation, copper, zinc, recovery

The most widely used method for the treatment of industrial wastewater containing heavy metals nowadays is neutralization. However, it must be accompanied with the treatment of produced metal hydroxide precipitates. This study proposed a process that modified the conventional lime neutralization treatment method with oxidation and sulfidization to selectively precipitate iron (Fe), copper (Cu), and zinc (Zn) from industrial wastewater for recovery. A real industrial wastewater sample containing high concentrations of Fe, Cu, and Zn was utilized. First of all, lime neutralization was applied to the industrial wastewater to observe the precipitation behaviors of Fe, Cu, and Zn. Next, hydrogen peroxide (H₂O₂) oxidation, sodium hydrosulfide (NaHS) sulfidization, and the integration with lime neutralization were carried out to separately precipitate Fe, Cu, and Zn from the industrial wastewater. Finally, an integrated treatment process for selectively precipitating Fe, Cu, and Zn from the industrial wastewater was proposed. The result of a consecutive experiment for the proposed process showed that Fe, Cu, and Zn in the industrial wastewater were removed and separated into individual precipitates, which were suitable for subsequent metal smelting processes.