In this book, we investigated 2 types of separation method for trace metals in aqueous solution. One is to establish a magnetic separation method and the other is to establish a flotation method. In the present book, the experimental results concerning the subjects mentioned above are described in the following chapters. In chapter 2, the study on the formation of ferromagnetic bimetallic nanoparticles and their application in trace metal ion collection will be described. In chapter 3, magnetic removal of cesium and strontium ions using poly -glutamic-acid coated Fe3O4 particles with and without the aid of zeolite will be described. In chapter 4, the study of multielemental adsorption on activated carbon will be described. And finally, in chapter 5, a flotation technique using poly - glutamic acid as flotation agent for removal of fine particles such as activated carbon particles will be described. Furthermore, metal ions adsorbed activated carbon particles can be removal by thismethod.