The Application of TiO₂/ZrO₂-Modified Nanocomposite PES Membrane for Improved Permeability of Textile Dye in Water

This study investigates the modification of polyethersulfone (PES) membranes with 1 wt% titanium dioxide (TiO₂), zirconium dioxide (ZrO₂) and a nanocomposite of TiO₂/ZrO₂. The aim was to efficiently remove Rhodamine B (RhB) from water using a threefold approach of adsorption, filtration and photodegradation. Among the modified membranes (TiO₂, ZrO₂ and TiO₂/ZrO₂), the TiO₂/ZrO₂-PES nanocomposite membrane showed a better performance in rejection of RhB than other membranes with the rejection efficiency of 96.5%. The TiO₂/ZrO₂-PES membrane was found to possess a thicker selective layer and reduced mean pore radius, which contributed to its improved rejection. The TiO₂/ZrO₂ nanocomposite membrane also showed high bulk porosity and a slightly lower contact angle of 69.88° compared to pristine PES with a value of 73°, indicating an improvement in hydrophilicity. Additionally, the TiO₂/ZrO₂-PES nanocomposite membrane demonstrated a relatively lower surface roughness (Sa) of 8.53 nm, which offers the membrane antifouling properties. The TiO₂/ZrO₂-PES membrane showed flux recovery ratio (FRR), total fouling (R_t), reversible fouling (R_r) and irreversible fouling (R_ir) of 48.0%, 88.7%, 36,8% and 52.9%, respectively. For the photocatalytic degradation performance, the removal efficiency of RhB followed this order TiO₂ > TiO₂/ZrO₂ > ZrO₂ (87.6%, 85.7%, 67.8%). The tensile strength and elongation were found to be compromised with the addition of nanoparticles and nanocomposites. This indicates the necessity to further modify and optimise membrane fabrication to achieve improved mechanical strength of the membranes. At low pressure, the overall findings suggest that the TiO₂/ZrO₂ nanocomposite has the potential to offer significant improvements in membrane performance (water flux) compared to other modifications.