Synthesis of MWCNTs-TiO₂ photocatalytic nanocomposite membrane via In-situ colloidal precipitation method for methyl orange removal

This research aims to examine the performance of photocatalytic nanocomposite membrane for methyl orange dye (MO) removal. Multiwalled carbon nanotubes (MWCNTs) and titanium dioxide (TiO₂) are used as nanofillers to produce photocatalytic membranes via insitu colloidal precipitation method. The weight ratio of MWCNT:TiO₂ were manipulated at 10:0, 5:5, and 0:10 with nanomaterials concentration of 0.1 g/L. The membranes were characterized by surface hydrophilicity, porosity and pore size, and surface charge. The membrane performance was assessed using dead-end membrane filtration method to determine water permeability, dye rejection, and fouling propensity. Pure TiO₂ membrane improved water permeability by 22.57% due to increasing hydrophilicity and large porosity. For dye rejection, pristine membrane outperformed the nanocomposite membranes with a rejection of 25.52% due to the small membrane pore size by sieve mechanism. Lastly, all the nanocomposite membranes showed better antifouling properties with higher normalized flux for pure MWCNTs (0.6822), TiO₂ (0.6781), MWCNT/TiO₂ (0.7239) membranes relative to the pristine membrane (0.6039). The pure TiO₂ membrane has the highest improvement in flux recovery (19.87%) due to dye photodegradation under UV light assisted in membrane cleaning and defouling. Overall, this study demonstrates that photocatalytic nanocomposite membrane can be produced via in-situ colloidal precipitation method.