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Bisphenol A (BPA) is an endocrine-disrupting chemical (EDC) that can cause adverse effects on human health. The incorporation of materials as visible light photocatalysts and its energy storage capability allow for the photodegradation of BPA, especially in the absence of a light source. To date, there have been no significant studies regarding energy storage in membrane technology, with only a focus on the suspension form. Hence, this study was conducted to degrade the pollutant through a co-extrusion process using a mixture of copper (II) oxide and tungsten oxide as the photocatalyst and energy storage materials, respectively. Both materials were embedded into polyvinylidene (PVDF) membranes to produce a Cu2O/WO3/PVDF dual-layer hollow fiber (DLHF) membrane. The outer dope extrusion flow rate was set at 3 mL/min, 6 mL/min, and 9 mL/min with photocatalyst:polymer ratios of 0.3, 0.50, and 0.7 Cu2O/WO3/PVDF, respectively. The performance of the membranes for each ratio was evaluated using 2 ppm of BPA with visible light irradiation. The results showed that each membrane's outer and inner layers featured finger-like void structures, while the intermediate part had a sponge-like structure. The membrane with the photocatalyst:polymer ratio of 0.5 was hydrophilic and had a high porosity of 54.97%, resulting in a high flow of 510 L/m2h. Under visible light irradiation, a 0.5 Cu2O/PVDF DLHF membrane with a 6-mL/min outer dope flow rate was able to remove 97.82% of 2-ppm BPA without copper leaching into the water sample. Under dark conditions, the DLHF sample showed the capability of energy storage performance and could drive certain degradation after lighting off up to 70.73% of 2-ppm BPA. The photocatalytic DLHF membrane with the ratio of 0.5 was the most optimal due to its potential morphology and ability to degrade a large amount of BPA. It is important to emphasize that usage of materials with the capability for energy storage can provide a significant contribution toward more practical membranes, so photodegradation can occur even in dark conditions. [ABSTRACT FROM AUTHOR]

The presence of bisphenol A (BPA) in various water sources has potentially led to numerous adverse effects in human such as increased in blood pressure and derangement in liver function. Thus, a reliable treatment for the removing BPA is highly required. This present work aimed to study the efficiency of visible light driven photocatalytic dual-layer hollow fiber (DLHF) membrane for the removal of BPA from water and further investigated its detrimental effects by using an in-vivo model. The prepared membranes were characterized for their morphology, particles distribution, surface roughness, crystallinity and light absorption spectra. The removal of 81.6% and 86.7% in BPA concentration was achieved for N-doped TiO2 DLHF after 360 min of visible and UV light irradiation, respectively. No significant changes for all three groups were observed in liver function test meanwhile the rats-exposed to untreated BPA water shows significance blood pressure increment contrary to rats-exposed to treated BPA water. Similarly, the normal morphology in both jejunum and ileum were altered in rats-exposed to untreated BPA water group. Altogether, the presence of N-doped TiO2 in DLHF are shown to significantly enhance the photocatalytic degradation activity under visible irradiation, which effectively mitigates the effect of BPA in an in-vivo model. [ABSTRACT FROM AUTHOR]

A significant drawback of the traditional photocatalysts such as titanium dioxide (TiO 2) is their inability to absorb visible light from the solar spectrum due to their wide band gap energy. They are only photoactive in the ultraviolet (UV) region which is just a little fraction of the solar spectrum and could be harmful with much exposure to it. Due to its abundance in the solar spectrum, visible light needs to be harnessed for environmental applications. However, we lack visible light driven photocatalysts with long-lasting energy storage capacity for "round-the-clock photocatalytic" (RTCP) applications. For this reason, there is a growing need to find new photocatalysts that can mitigate these bottlenecks. It is evident from some carefully selected published articles (1976–2021) that tungsten oxide (WO 3) and its composites have attracted popularity in recent years because of its outstanding properties and particularly its smaller band gap energy of 2.8 eV. However, pristine WO 3 is limited due to relatively low energy density and smaller specific surface area. These drawbacks can be addressed by developing various WO 3 – based materials to improve their performance. This paper reviews and discusses their recent development in surface advancement, morphology control, modification of nanostructured WO 3 and its composites, and their RTCP energy storage for photocatalytic activities in visible light and the dark for environmental applications. Specific aspects focused on its nature, structure, properties, synthesis, coatings, deposition, approaches at modifying and enhancing its visible light photoactivity for enhanced performance and energy storage potential. [Display omitted] • Synthesis techniques for WO 3 -based photocatalysts are discussed. • Visible light enhancement strategies for WO 3 -based photocatalysts are elaborated. • WO 3 "round the clock photocatalysis" is described. • WO 3 - based photocatalytic memory for environmental applications is reviewed. • WO 3 -based catalysts are promising for continuous day and night photocatalysis. [ABSTRACT FROM AUTHOR]

This present study aims to develop a visible-light driven photocatalytic dual layer hollow fiber (DLHF) membrane for photodegradation activity. Nitrogen-doped TiO 2 DLHF membranes with different loadings of N-doped TiO 2 were successfully fabricated via a single step co-extrusion method. The fabricated membranes were characterized for their morphology and properties. The incorporation of N-doped TiO 2 into membrane matrix has shifted the absorption capability into visible light region with lowest band gap energy obtained was 2.63eV. The photocatalytic performance evaluations of the N-doped TiO 2 DLHF reported 75% and 100% of Reactive Black 5 (RB5) removal were achieved after 360 min of visible and UV light illumination respectively. Altogether, N-doped TiO 2 DLHF exhibits excellent photocatalytic degradation activity under visible and UV light irradiation, hence have a promising potential in removing RB5 and other organic contaminants for water treatment. • The fabrication of visible light driven photocatalytic dual layer hollow fiber via co-extrusion technique. • The incorporation of N-doped TiO 2 into membrane surface successfully expand the photoresponse into the visible light region. • Good photocatalytic activity with 75% and 100% removal of RB5 under visible and UV light irradiation, respectively. • Efficient photocatalytic degradation process of visible-light driven N-doped TiO 2 for contaminants present in the water. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) and reactive black 5 (RB5) dye are among the most persistent and non-biodegradable contaminants in water which require an urgent need for the development of effective removal method. The ubiquitous existence of both contaminants could interfere with the human health and aquatic environmental balance. Photocatalytic process as one of advanced oxidation processes (AOPs) has shown high performance for degradation of organic compounds to the harmless materials under sensible condition. Therefore, this study aims to develop a visible-light-driven photocatalyst that can efficiently degrade BPA and RB5 present in household water. N-doped TiO2 were successfully synthesized via simple and direct sol-gel method. The prepared TiO2 nanoparticles were characterized by field emission scanning microscope (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Brunauere Emmette Teller (BET) analysis. The incorporation of nitrogen in TiO2 lattice exhibited excellent optical responses to visible region as revealed by UV-Vis-NIR spectroscopy absorption capability at 400-600 nm. The photocatalytic activity of the N-doped TiO2 nanoparticles was measured by photocatalytic degradation of BPA and RB5 in an aqueous solution under visible-light irradiations. Degradation of BPA and RB5 was 91.3% and 89.1%, respectively after 360 min illumination. The degradation of BPA and RB5 by N-doped TiO2 was increased up to 89.8% and 88.4%, respectively under visible-light irradiation as compared to commercial TiO2 P25. This finding clearly shows that N-doped TiO2 exhibits excellent photocatalytic degradation of BPA and RB5 under visible irradiation, hence have a promising potential in removing various recalcitrant contaminants for water treatment to fulfill the public need to consume clean water.ᅟ [ABSTRACT FROM AUTHOR]

[Display omitted] • TiO 2 -WO 3 @GO/PVDF-DLHF photocatalytic membrane with catalytic memory was fabricated. • 3 wt% photocatalyst loaded membrane achieved 98.62% TOC rejection in visible light. • Good anti-fouling and self-cleaning with water flux of 99.51 L/m2h and FRR of 91.35 % • 3 wt% loaded membrane achieved 68.56% TOC rejection for memory catalysis. • Excellent stability after prolonged use with a TOC rejection of 89.76% Oilfield-produced water (OPW) is a complex wastewater that is difficult to treat causing significant harm to the environment. Photocatalytic membranes are emerging for OPW treatment. However, they suffer significant fouling due to the inability to self-clean during prolonged treatment. They also require continuous photo assistance to sustain the catalytic process. This limits their applications in the absence of light referred to as memory catalysis. This work reported the fabrication of a unique ternary photocatalyst TiO 2 -WO 3 @GO/PVDF dual-layer hollow fiber (DLHF) photocatalytic membranes for photodegradation and memory catalysis of total organic carbon (TOC) in OPW. The photocatalytic membranes were fabricated via phase inversion and co-extrusion method varying (0,1,3,5) wt% of the TiO 2 -WO 3 @GO photocatalyst. The membranes were characterized and their performances for TOC removal under visible light and memory catalysis were evaluated. The membranes exhibited excellent TOC degradation, rejection, anti-fouling, self-cleaning, and catalytic memory. The WO 3 was responsible for electron storage within the system and improved the absorptive capacity of TiO 2 in the visible range while the GO promoted the electron-hole transfer creating abundant active sites for photocatalytic reaction. The 3 wt% loaded membrane showed the best TOC rejection of 98.62 % after 6 h of operation, water and permeate fluxes of 99.51 L/m2h, and 76.54 L/m2h respectively. The membrane showed good catalytic memory in the dark with a TOC rejection of 68.56 % after 6 h, OPW flux recovery ratio (FRR), and TOC rejection of 91.35 % and 89.76 % respectively after 5 cycles of operation under visible light. This work is expected to bring a paradigm shift toward the fabrication of memory catalytic membranes for wastewater treatment. [ABSTRACT FROM AUTHOR]