1. Inorganic Membranes, Mesa+ Institute for Nanotechnology, University of Twente, P. O. Box 217 7500, AE Enschede, The Netherlands
2. Environment and Water Directorate, Ministry of Science and Technology, Baghdad, Iraq
3. Department of Civil Engineering and Management, University of Twente, P. O. Box 217, 7500, AE Enschede, The Netherlands
4. Department of Water Engineering & Management, University of Twente, P. O. Box 217, 7500, AE Enschede, The Netherlands