## 4 Conclusions  
In-situ fabrication of highly porous photocatalytic membranes based on ternary 1% CuO/TiO2@GCN (1:9) embedded in CA via phase inversion method was achieved successfully. The presence of ternary 1% CuO/TiO2@GCN (1:9) nanocomposite within the membrane was confirmed by various characterizations techniques, such as XRD, FTIR, XPS and EDS. The absence of visible clustering of 1% CuO/TiO2@GCN (1:9) nanocomposite within the CA membrane proved uniform dispersion was accomplished as observed on SEM micrographs (with 200 nm resolution). The crystallinity of CA with an amorphous structure showed completely structural transition accredited to the embedding of 1% CuO/TiO2@GCN (1:9) nanocomposite with exposed (101) and (002) peaks from TiO2 and GCN, respectively, proving successful embedding of 1% CuO/TiO2@GCN (1:9) within CA membrane. The modified CA membranes containing different weight contents of 1% CuO/TiO2@GCN (1:9) nanocomposites proved to elevate hydrophilicity, porosity, and the shrinkage nature of the membranes and thus, reducing the energy consumption of the membrane filtration system. The modified CA membrane showed the ability to self-clean with the aid of 1% CuO/TiO2@GCN (1:9) photocatalyst absorbing visible light and generating reactive radicals, thereby degrading traces of contaminants attached to the surface. The following supporting information can be downloaded at [[https://www.mdpi.com/article/10.3390/app12031649/s1](https://www.mdpi.com/article/10.3390/app12031649/s1)]([https://www.mdpi.com/article/10.3390/app12031649/s1](https://www.mdpi.com/article/10.3390/app12031649/s1)), S1: Method description: Preparation of TiO2 nanoparticles. S2: Method description: Preparation of CuO/TiO2 nanoparticles. S3: Method description: Preparation of CuO/TiO2@GCN nanoparticles. S4: Method description: Preparation of cellulose acetate membranes. Figure S1: Systematic illustration for the fabrication of CA-based membranes embedded with ternary 1% CuO/TiO2@GCN (1:9) nanocomposite. Figure S2: Filtration setup equipped with a medium power mercury lamp (165 W) and vacuum pump (100 W). S7: TEM  
Figure 12: Proposed mechanism for photodegradation of KP using CTG—500 membrane. and SEM analysis of 1% CuO/TiO2@GCN nanocomposite. Figure S3: (a) TEM micrograph and (b) SEM of 1% CuO/TiO2@GCN (1:9) nanocomposite, SEM elemental mapping of (c) Cu, (d) Ti, (e) C, (f) O and (g) EDX spectrum of 1% CuO/TiO2@GCN (1:9). 58: Optical properties analyses of the various materials. Figure S4: UV/Vis spectra of (a) unmodified TiO2 and 1% CuO/TiO2@GCN (1:9) nano-composite and (b) their extrapolated energy bandgaps based on Kubelka-Munk method. S9: Method description of the analyses of membrane properties. S10: Method description of how the efficiency of the photocatalytic membrane was evaluated. S11: Description on how the electrical consumption was calculated. Table S1: The water quality characteristics of the different water matrixes used in this work. Figure S5: Series of steps for recycling the membranes and (d) ATR-FTR spectra of fresh CTG-500 membrane and after several cycles. Figure S6: Chromatograms of (a) uncatalyzed and (b) photodegraded KP after 5 h; (c) mass spectrum for a peak at retention time 3.09 min. Figure S7: Proposed photodegradation pathway and the intermediates of KP. Conceptualization, L.E.M. ; methodology, L.E.M. ; software, L.E.M. and L.H. ; formal analysis, L.E.M., L.H. and V.P.C. ; investigation, L.E.M. ; validation, L.E.M., L.H. and V.P.C. ; resources, V.P.C., Z.N.T. and J.M. ; data curation, L.E.M., L.H. and V.P.C. ; Writing Original Draft, L.E.M., L.H. and V.P.C. ; writing--review and edit, L.H., V.P.C., Z.N.T. and J.M. ; visualization, L.H., V.P.C., Z.N.T. and J.M. ; supervision, L.H., V.P.C., Z.N.T. and J.M. ; project administration, L.H., V.P.C., Z.N.T. and J.M. ; funding acquisition, L.H., V.P.C., Z.N.T. and J.M. All authors have read and agreed to the published version of the manuscript.