Removal of Toxic Heavy Metal Ions (Pb, Cr, Cu, Ni, Zn, Co, Hg, and Cd) from Waste Batteries or Lithium Cells Using Nanosized Metal Oxides: A Review

How to remove harmful heavy metal ions from waste batteries or lithium cells efficiently has been the focus of scholars. More and more metal oxides had been used to deal with the pollution of heavy metal caused by waste batteries in recent years. Nanostructured metal oxides have great potential because of their large comparative areas. The adsorption for these heavy metal ions can be further improved by using modified metal oxides as adsorbents. At present, iron oxide is widely used in this field. Other metal oxides have also been studied in removing these heavy metal ions. Compared to other metal oxides, the adsorbents made of iron oxide are easy to be separated from the reaction system. pH value in the solution can affect the activity of adsorption sites on metal oxides adsorbents and change the distribution of ions in solution. As a result, pH value can significantly influence the adsorption of metal oxides adsorbents for heavy metal ions from waste batteries or lithium cells.