Membrane application is widespread in water filtration to remove natural organic matter (NOM), especially humic acid. However, there is a significant concern in membrane filtration, which is fouling, which will cause a reduction in the membrane life span, a high energy requirement, and a loss in product quality. Therefore, the effect of a TiO₂/PES mixed matrix membrane on different concentrations of TiO₂ photocatalyst and different durations of UV irradiation was studied in removing humic acid to determine the anti-fouling and self-cleaning effects. The TiO₂ photocatalyst and TiO₂/PES mixed matrix membrane synthesised were characterised using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray powder diffraction (XRD), scanning electron microscope (SEM), contact angle, and porosity. The performances of TiO₂/PES membranes of 0 wt.%, 1 wt.%, 3 wt.%, and 5 wt.% were evaluated via a cross-flow filtration system regarding anti-fouling and self-cleaning effects. After that, all the membranes were irradiated under UV for either 2, 10, or 20 min. A TiO₂/PES mixed matrix membrane of 3 wt.% was proved to have the best anti-fouling and self-cleaning effect with improved hydrophilicity. The optimum duration for UV irradiation of the TiO₂/PES mixed matrix membrane was 20 min. Furthermore, the fouling behaviour of mixed matrix membranes was fitted to the intermediate blocking model. Adding TiO₂ photocatalyst into the PES membrane enhanced the anti-fouling and self-cleaning properties.

The severe water pollution from effluent dyes threatens human health. This study created pH-magnetic-photocatalytic polymer microspheres to conveniently separate the photocatalyst nanoparticles from the treated water by applying an external magnetic field. While fabricating magnetic nanoparticles’ (MNPs) microspheres, incorporating 0.5 wt.% iron oxide (Fe₃O₄) showed the best magnetophoretic separation ability, as all the MNPs microspheres were attracted toward the external magnet. Subsequently, hybrid organic–inorganic polyoxometalates (HPOM), a self-synthesized photocatalyst, were linked with the functionalized magnetic nanoparticles (f-MNPs) to prepare augmented magnetic-photocatalytic microspheres. The photodegradation dye removal efficiency of the augmented magnetic-photocatalytic microspheres (f-MNPs-HPOM) was then compared with that of the commercial titanium dioxide (TiO₂) photocatalyst (f-MNPs-TiO₂). Results showed that f-MNPs-HPOM microspheres with 74 ± 0.7% photocatalytic removal efficiency better degraded methylene orange (MO) than f-MNPs-TiO₂ (70 ± 0.8%) at an unadjusted pH under UV-light irradiation for 90 min. The excellent performance was mainly attributed to the lower band-gap energy of HPOM (2.65 eV), which required lower energy to be photoactivated under UV light. The f-MNPs-HPOM microspheres demonstrated excellent reusability and stability in the photo-decolorization of MO, as the microspheres retained nearly the same removal percentage throughout the three continuous cycles. The degradation rate was also found to follow the pseudo-first-order kinetics. Furthermore, f-MNPs-HPOM microspheres were pH-responsive in the photodegradation of MO and methylene blue (MB) at pH 3 (acidic) and pH 9 (alkaline). Overall, it was demonstrated that using HPOM photocatalysts in the preparation of magnetic-photocatalytic microspheres resulted in better dye degradation than TiO₂ photocatalysts.

This study investigated the potential of acid-pretreated rice husk ash (RHA) sourced alkaline earth metal silicates for lauric acid (LA) adsorption. The synthesized materials were characterized using BET, FTIR, XRD, EDS, and SEM analyses, demonstrating that metal cation size had a notable effect on surface area, pore structure, crystallinity, and particle aggregation. Magnesium silicate (MS-1.0), with its smaller atomic radius, exhibited the highest surface area and the most porous structure among the samples. Calcium silicate (CS-1.0) displayed a moderate surface area with a mesoporous structure, while strontium silicate (SS-1.0), having the largest atomic radius, exhibited the lowest surface area, a predominantly macroporous structure and the highest degree of particle aggregation. The synthesized alkaline earth metal silicates were tested for LA adsorption performance and compared using the analytical hierarchy process (AHP). CS-1.0 demonstrated the highest LA removal efficiency (59.94% ± 11.24%) and adsorption capacity (8.68 ± 1.60 mmol/g), while MS-1.0 had the lowest removal efficiency (17.64 ± 3.28%) and adsorption capacity (2.60 ± 0.50 mmol/g). Interestingly, the production yield increased from MS-1.0 to CS-1.0 and SS-1.0. Through the AHP method, CS-1.0 was identified as the best-performing adsorbent in this study, considering both adsorption efficiency and production yield with the highest priority value of 0.9603.

Polyoxometalates (POM), Na₂C₆H₄NO₂. [PW₁₂O₄₀] have been synthesized under hydrothermal conditions and characterized. The SEM result indicates that morphology of photocatalyst was homogeneous. The performance of POM was then tested on photocatalytic degradation of methylene blue at different operating conditions. The degradation of methylene blue was dependent on several parameters, such as its initial concentration, HPOM loading and temperature. Langmuir–Hinshelwood model is usually used to describe the kinetics of this photocatalytic process. It was found that rate constant, k_app decreased with increasing initial concentrations of methylene blue. However, as increases in HPOM loading improved methylene blue degradation. The activation energy obtained was low due to this photocatalytic process being less dependent on temperature.

This research aims to fabricate and analyze asymmetric polylactic acid (PLA) membranes and evaluate their performance in the removal of methyl orange (MO) dye through a microfiltration process. The asymmetric PLA membranes were synthesized via the non-solvent induced phase separation (NIPS) method. A polymer solution containing 14 wt.% PLA dissolved in 86 wt.% N,N-dimethylacetamide (DMAc) was prepared with varying amounts of TiO₂ (0, 0.5, and 1.0 wt.%). The cast membranes were immersed in a coagulant bath consisting of methanol and distilled water in an 80:20 ratio. Several characterization methods were employed: membrane porosity was measured using the gravimetric method and hydrophilicity was assessed by water contact angle. Membrane performance was evaluated in terms of water flux and permeability under a transmembrane pressure of 1 bar, as well as the removal efficiency of methyl orange dye. In addition, the photocatalytic activity of the membranes was investigated to determine its effect on dye removal. The results showed that membrane porosity decreased with increasing TiO₂ content (from 53.7% to 45.1%), while water contact angle also decreased (from 72.7° to 56.1°), indicating improved hydrophilicity. The incorporation of TiO₂ enhanced water flux (11,526.8–14,628.4 L/m²h), permeability (5763.4–7314.2 L/m²h·bar), and methyl orange removal efficiency (65–69.8%). Furthermore, photocatalytic reactions further improved dye removal efficiency with increasing TiO₂ content (up to 84.3%).