## 1 Introduction  
The demand for advanced water treatment technologies is increasing for the treatment of high-strength wastewater, such as industrial wastewater including complex water pollutants. Membrane technology is a promising way to enhance wastewater treatment efficiency as it can produce great effluent (permeate) quality with a smaller footprint than that afforded by conventional wastewater treatment processes [1; 2; 3]. However, the polymeric membranes widely adopted in wastewater treatment applications display relatively low thermal and chemical resistance. There has been an upsurge of interest in ceramic membranes for the treatment of high-strength wastewater, for which polymeric membranes are not suitable [4; 5]. Ceramic membranes consisting of metal oxides usually exhibit high membrane porosity, membrane permeability, and narrow distribution of the membrane pore size. These unique properties allow for superior separation characteristics and antifouling behavior than those of polymeric membranes. Photocatalytic membrane reactors (PMRs) combine photocatalytic reactors with membrane filtration units [6; 7]. As the photocatalytic membrane is combined with oxidation promoters, such as UV irradiation, the membrane plays an important role as a support for the photocatalytic materials and as a selective barrier to degrade organic contaminants. The TiO\({}_{2}\) materials are often considered as coating materials on ceramic support for the photocatalytic membrane because of their high photocatalytic activity and thermal/chemical stability at low environmental toxicity [8; 9; 10]. The TiO\({}_{2}\) coating on the ceramic support has been reported to provide high water permeability with relatively low fouling rate to polymeric membrane [11; 12]. The photo-degradation activity of nanostructured ceramic membranes functionalized in situ have been found to be very effective for wastewater treatment [9]. Thus, the photocatalytic layer on the membrane is expected to reduce the extent of membrane fouling while producing an excellent permeate quality due to the selective photocatalytic degradation of organic compounds on the catalytic membrane surface [13]. In addition, the intrinsic properties of the ceramic membrane against certain chemical reagents allow for the photocatalytic membrane to withstand the concomitant attack of the strong oxidants produced during photocatalytic processes, e.g., hydroxyl radicals [14]. The hierarchically porous nanostructure of the catalyst film on the ceramic membrane plays a critical role in determining the photocatalytic membrane performance. The morphology of the photocatalyst film on the membrane support has been found to be an important factor determining the membrane surface reactivity [15]. The introduction of surface-directing agents on the ceramic support has allowed the control of its porous structure [6; 8; 15; 16]. For example, the porous structure of a photocatalyst film was enhanced using a Pluronic block copolymer for high organic dye removal efficiency [16]. [PERSON] et al. [17] found that the mesoporous and narrow pore size distribution of photocatalyst films improve the wastewater treatment efficiency significantly. A grafted copolymer-based composite membrane exhibited excellent properties in terms of organic-compound degradation efficiency [15]. Homopolymers can also be used with great potential to improve the photocatalytic membrane reactivity. The photocatalytic activity of TiO\({}_{2}\) composite membranes has been significantly enhanced by introducing hydrophobic homopolymers consisting of polyvinyl chloride (PVC) as a polymer template in the membrane support [6]. Nevertheless, developing photocatalytic membranes with uniform distribution of catalytic materials on ceramic support with fine-tuned nanostructure is still major challenge.