Some of the more promising materials in the environmental field are nanostructured metal oxides, mainly due to their physicochemical properties derived from their molecular structure. These properties depend largely of the synthesis process used to obtain it. For this reason, the next chapter discusses the synthesis methods that have been widely used and developed to create nanostructured metal oxides to be used as adsorbent materials of heavy metal ions from aqueous media. The manganese oxides have been broadly studied at present for the removal of heavy metal ions of model water or wastewater due to its features, such as due to its nanometric particle size, geometric shape of the particles, crystal structure, high specific surface area, and specificity. This chapter focuses on how the different synthesis pathways used to get metal oxides of iron and manganese affect their surface, structural, and physicochemical properties and improve their performance in the adsorption of heavy metal ions.