## 3 Results and Discussion  
### Membrane Morphology  
The nanostructure morphology of a membrane has a great effect on its photocatalytic performance for wastewater treatment. Polymer templates are considered effective structure-directing agents for the control of the nanostructure morphology. They not only effectively induce the organized structure of a membrane, but also have no negative impact on the membrane performance due to its complete degradation upon calcination. Since the hydrophilic TiO\({}_{2}\) precursor TTIP has high affinity toward hydrophilic materials, it interacts strongly with the hydrophilic POEM chains. A POEM/TTIP hybrid was thus successfully formed during the sol-gel process. Since the low-viscosity POEM/TTIP solution can easily penetrate the macroporous Al\({}_{2}\)O\({}_{3}\) membrane, its presence will influence the nanostructure morphology and, subsequently, the membrane performance. Our previous study showed that polymeric template/TTIP solution could be penetrated into the pore structure of macroporous Al\({}_{2}\)O\({}_{3}\) support and it caused non-uniform photocatalytic film on the ceramic support [15]. With the help of a PVP coating on the Al\({}_{2}\)O\({}_{3}\) membrane [6; 15], the penetration of the POEM/TTIP solution deep inside the membrane was prevented and a TiO\({}_{2}\) thin film was thereby successfully obtained. During calcination at 450 \({}^{\circ}\)C, TTIP was transformed into crystalline TiO\({}_{2}\), while the organic POEM, PVP, and solvents were all completely decomposed. The synthesized TiO\({}_{2}\) film on the Al\({}_{2}\)O\({}_{3}\) membrane was found to be highly crystalline and well organized [15; 18]. The surface of the TiO\({}_{2}\) structure on the FTO glass and Al\({}_{2}\)O\({}_{3}\) membrane was characterized by SEM analysis (Figure 2). A uniform TiO\({}_{2}\) film prepared with the aid of POEM was successfully synthesized on a flat FTO glass substrate. Owing to the nonporous substrate and strong interactionsbetween TTIP and POEM, the TiO\({}_{2}\) film exhibits a well-organized morphology, as shown in Figure 2a. The bare membrane with a pore size of approximately 100 nm is clearly observed in Figure 2b. Large Al\({}_{2}\)O\({}_{3}\) crystals are also observed in the magnified surface image in Figure 2c. The morphology of the POEM-directed TiO\({}_{2}\) structure on the Al\({}_{2}\)O\({}_{3}\) membrane in Figure 2d is similar to that of the bare membrane. This is attributable to the formation of a very thin TiO\({}_{2}\) film resulting from the low-viscosity POEM/TTIP solution. In the enlarged image shown in Figure 2e, the Al\({}_{2}\)O\({}_{3}\) crystals appear well covered with uniform and well-connected TiO\({}_{2}\) nanoparticles consisting of the POEM/TTIP hybrid. The distribution of TiO\({}_{2}\) on Al\({}_{2}\)O\({}_{3}\) membrane was investigated with EDS analysis (Figure 3). The Ti elemental mapping image of TiO\({}_{2}\) structure prepared by the POEM template revealed that TiO\({}_{2}\) was homogeneously distributed on the entire surface of Al\({}_{2}\)O\({}_{3}\) membrane. The aggregation of photocatalysts on membrane should be prevented for effective photocatalysis and high permeate flux. It is widely known that the uniform distribution of photocatalyst without aggregation increases the surface area, thereby leading to the large number of active sites for photocatalysis. In addition, it is favorable for high permeate flux. Thus, the uniform distribution of TiO\({}_{2}\) on membrane without severe aggregation might contribute to the enhanced performance of photocatalytic membrane. The cross-sectional SEM images in Figure 4a,b show the macroporous structure of the bare Al\({}_{2}\)O\({}_{3}\) membrane. Figure 4c,d reveals that the cross-section of the TiO\({}_{2}\)-deposited Al\({}_{2}\)O\({}_{3}\) membrane is not significantly different from that of the bare membrane as a result of the deposition of a very thin TiO\({}_{2}\) film, as seen in the magnified image in Figure 4d.