The aim of the present study is to synthesize dispersible reduced graphene oxide (RGO) via functionalization with metals and metal oxides and explore their potential applications in water purification. Graphene-based metal and metal oxide composites were synthesized hydrothermally using sodium borohydride as a reducing agent and sodium sorbate as a stabilizer. Single (Ag, Cu₂O, and Fe₃O₄) and bimetallic (Ag-Cu₂O, Ag-Fe₃O₄, and Cu₂O-Fe₃O₄) nanoparticles were incorporated on the surface of RGO. The synthesized composites were characterized by various analytical methods. The inactivation of E. coli, the catalytic degradation of 4-nitrophenol, and the adsorption of As(V) were examined using the RGO composites.