Monodisperse Fe3O4 microspheres have great potential in many fields, including magnetic separation, drug delivery and catalysis. In the present work, we first investigated various parameters affecting solvothermal synthesis of Fe3O4 microspheres in ethylene glycol (MEG), and then successfully synthesized magnetic Fe3O4 microspheres of ca. 034 mu m by treatment of the concentrated mixture of FeCl3 center dot 6H(2)O (13.7 mmol) and NaOAc (43.9 mmol) in 9 ml of MEG at 198 degrees C for 14h. This formula significantly reduces the production cost of Fe3O4 microspheres and the resulting waste. Upon ethylenediamine tetraacetate (EDTA) modification, the Cu2+ adsorption capacity of Fe3O4 microspheres obviously increases from negligible to 4.5-7.9 mg/g. In combination with EDTA as a versatile chelating agent, EDTA-modified Fe3O4 microspheres are potential magnetic adsorbents for removal of trace heavy metal ions from waste water. (C) 2014 Elsevier Ltd. All rights reserved.