الفهرس 
Definition of a MembraneOnly 14 pages are availabe for public view
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Abstract
The main objective of the present thesis is the production of a low cost, high performance, nanoporous and anti-bacterial ceramic membrane by gelcasting technique for water purification. This method is a new forming process assessed with microwave as a polymerization support. Such forming process is adopted to replace the existing traditional forming methods that need high energy or high firing temperature above 1500°C to produce such sintered alumina/mullite bodies. Different ceramic slurries containing 45-55 wt.-% solid loading have been prepared by using suitable amount 0.6 wt.- of the APC (ammonium polycaboxylate) dispersant to disperse and stabilize alumina or alumina/silica particles to produce alumina or mullite ceramic supports, respectively. The premix solutions were made from 15 wt.-% methylacrylamide (MAM) monomer and methylene bis-acrylamide (MBAM) cross linker. The weight ration of monomer to crosslinker was 4.55:1 for MAM and MBAM. It is found that the optimum temperature for obtaining higly porous ceramic support with higher densities and mechanical properties is 1500°C for 4 hr. and the solid loading was 55% for alumina support and 45% for mullite support. The separation efficiency of ceramic membranes could be significantly improved by constructing a top separation layer with metal oxide nanofibres such as titanate nanofibres. Titanate nanofibers in this study were prepared via a hydrothermal reaction between a concentrated NaOH solution and an inorganic titanium salt. Neutralized using HCl solution has been occurred for the final powder and then firing at 600° C for 3 hr to obtain titanium oxide in the anatase form. Transmission electron microscopy (TEM), Scanning electron microscope (SEM), X-ray diffraction (XRD) and UV/visible spectra have been used to investigate the size,morphology and properties of titania nanofibre In order to increase antibacterial efficiency, each filter is treated with silver nanoparticles after it has been fired by dip coating or spray coating then dried at 200°C for 2 hr. The antibacterial efficiency of Ag/TiO2 and TiO2 nanofibers were measured and compared with the ceramic commercial membrane by zone of inhibition test. Accordingly, the following conclusions could be drawn:- 1. The gelcasting forming process in combination with microwave as a polymerization support is capable of producing well sintered alumina or mullite ceramic bodies with complex shapes and well defined microstructural and mechanical properties. 2. Alumina support of ceramic membrane prepared by gelcasting has porosity 58%, strength 18MPa and pore size near to 0.1780µm when solid loading is 55% as well as sintering temperature is 1500°C. 3. Mullite support of ceramic membrane prepared by gelcasting has porosity 48%, strength 22MPa and pore size near to 0.1780µm when solid loading is decreased to 45% and sintering temperature is 1500°C. 4. Titania nanofibres have been prepared by hydrothermal method with diameter ranged from 50 to20 nm. 5. Silver nanoparticle (with diameter ranged from 136nm to 11nm) was successfully prepared and deposited on the surface of titania nanofibres by polyol synthesis. 6. The bacterial efficiency of the ceramic membrane increased after deposition of silver on tiatania nanofibres and show efficiency towards gram negative/ positive bacteria with degree more than that of commercially ceramic membranes.