Superhydrophilic TiO ₂ /WO _2.72 Nanocomposites Boost PES Membranes Performance for Natural Spring Water Decontamination

Abstract This study explores the embedment of TiO 2 nanoparticles, WO 2.72 nanoparticles, or TiO 2 /WO 2.72 nanocomposites into PES membranes to improve dead‐end ultrafiltration of natural spring water, using dye rejection, antifouling, and photocatalytic degradation capabilities as performance indicators. TiO 2 , WO 2.72 , or TiO 2 /WO 2.72 are incorporated into the PES matrix at different ratios (1, 1.5, and 2 wt.%). The prepared materials are characterized using several techniques, including XPS, XRD, FTIR, SEM, EDS, BET, UV–vis DRS, AFM, and Raman spectroscopy. Density Functional Theory (DFT) calculations show that WO 2.72 strongly adsorbs methyl orange (MO) dye compared to TiO 2 surfaces. The high adsorption energy (−6.89 eV) of the WO 2.72 surface and MO facilitates subsequent photocatalytic degradation. The adsorption energy for TiO 2 is −1.52 eV, indicating a lower affinity for MO. Thus, TiO 2 /WO 2.72 nanocomposites are inferred to have a higher affinity for MO than TiO 2 nanoparticles. Experimental data corroborate that the nanocomposite outperformed either nanoparticle alone. When treating real spring water, TiO 2 /WO 2.72 modified membranes show a substantial enhancement in water flux, dye rejection, and antifouling, and rejected over 99% of both bovine serum albumin (BSA) and Congo red dye (CR). The fluorescence excitation emission matrix (FEEM) of natural spring water confirms the presence of tryptophan‐like, fulvic acid‐like, and humic acid‐like substances, while the UV 254 absorbance confirms their reduction after treatment with 2 wt.% TiO 2 /WO 2.72 membrane. The bare PES and 2 wt.% (TiO 2 and WO 2.72 ) modified membranes show resistance to organic fouling. Overall, modification of PES (dead‐end ultrafiltration) membranes with TiO 2 /WO 2.72 nanocomposite presents a remarkable improvement in rejection ability, antifouling properties, and photocatalytic degradation capabilities. This enhancement makes TiO 2 /WO 2.72 nanocomposites a potential membrane additive to achieve reactive membranes for sustainable water purification solutions.