Magnetic manganese dioxide as an amphoteric adsorbent for removal of harmful inorganic contaminants from water
- Autor: Calderon, C. / Franzreb, M. / Valenzuela, F. / Höll, W. (2010)
Relative & Functional Polymers 70 (2010), 8, 516–520
- Datum: 2010
Calderon, C. / Franzreb, M. / Valenzuela, F. / Höll, W. (2010): „Magnetic manganese dioxide as an amphoteric adsorbent for removal of harmful inorganic contaminants from water“. In: Relative & Functional Polymers 70 (2010), 8, 516–520
Manganese dioxide (δ-MnO2) with magnetic properties has been synthesized by precipitation of MnO2 in the presence of magnetite. The resulting material has a particle size distribution between 0.5 and 5 μm. Magnetization of the material is in the order of magnitude of that of magnetite. Therefore a solid–liquid separation by means of moderate magnetic fields is possible.
Due to the properties of δ-MnO2 the point of zero charge of the surface is about 2.5. Therefore, the adsorbent is almost exclusively a cation exchanger although sorption of oxoanions is also possible. Sorption experiment with Cd2+, Ni2+, and Pb2+ ions revealed a preferred sorption. Alkaline earth ions such as Ca2+ affect the uptake only at high concentrations. Because of the small particles and the respective large specific surface, sorption is fast.