TiO2 Membrane Research Articles

Visible-light-activated Fe2O3–TiO2 nanoparticles enhance biofouling resistance of polyethersulfone ultrafiltration membranes against marine algae Chlorella vulgaris

This study investigated the modification of polyethersulfone (PES) ultrafiltration membranes with TiO2 and Fe2O3–TiO2 nanoparticles to enhance their hydrophilicity and biofouling resistance against the marine microalgae Chlorella vulgaris. It is a common freshwater and marine microalga that readily forms biofilms on membrane surfaces, leading to significant flux decline and increased operational costs in ultrafiltration processes. The microalgae cells and their extracellular polymeric substances (EPS) adhere to the membrane surface, creating a dense fouling layer that impedes water permeation. The modified membranes were characterized using contact angle measurements, scanning electron microscopy, and pure water flux/resistance tests. Short-term ultrafiltration experiments evaluated the membranes’ antifouling performance by measuring flux decline, flux recovery ratio, and relative flux reduction during C. vulgaris filtration. The TiO2 membrane showed improved hydrophilicity and antifouling over the pristine PES membrane, while the Fe2O3–TiO2 nanocomposite membrane exhibited the best performance. It reduced the water contact angle and showed only a 5% relative flux reduction compared to 60% for the pristine membrane. SEM images confirmed reduced microalgal deposition on the nanocomposite surface. Long-term tests with microalgal cells under dark and visible light conditions in saline water further assessed the membranes’ biofouling resistance. The Fe2O3–TiO2 membrane maintained 59 L/m2 h water flux under visible light after immersion in the microalgal solution, outperforming the pristine (38 L/m2 h) and TiO2 (52 L/m2 h) membranes. This superior antifouling was attributed to photocatalytic generation of reactive oxygen species inhibiting microalgal adhesion. This study demonstrates a promising strategy for mitigating biofouling in membrane-based water treatment and desalination processes.

TiO2-embedded dual-layer mullite hollow fiber membranes for efficient removal of Persistent organic pollutants from wastewater

Persistent organic pollutants (POPs) are toxic pollutants that harm the environment and ecosystems. This study presents a novel approach to develop a dual-layer hollow fiber ceramic membrane for phenolic compound removal. A co-extrusion-based phase inversion process and co-sintering techniques were employed to fabricate the membrane, and the effects of TiO2 loadings on the outer layer were investigated. Characterization techniques, including FTIR, SEM, EDX, and zeta potential analysis, were used to analyze the mullite and TiO2 powders and membranes. The membrane’s performance was evaluated through rejection tests of POPs at various concentrations (10, 500, and 1000 ppm) and fouling assessments were conducted. The results showed that the M−MT0.6 membrane, with a mean pore size of 0.0245 μm, effectively rejected benzoic acid (81.45 %), gallic acid (91.45 %), and hydroquinone (74.49 %) from wastewater, achieving the highest permeate flux (1320.50 L/m2·h) for gallic acid at 10 ppm. Additionally, M−MT0.6 exhibited minimal fouling over a 1-h filtration cycle, with the lowest fouling rate (35.1 %) recorded at 1000 ppm for BA, attributed to effective backwashing. However, higher fouling rates were observed at 10 ppm for BA (90.10 %) and HQ (83.50 %). Overall, this study demonstrates the potential of the novel membrane for effective removal of POPs from industrialwastewater.

Assessing the Stability and Photocatalytic Efficiency of a Biodegradable PLA‐TiO2 Membrane for Air Purification

AbstractThe potential of a biodegradable polylactic acid (PLA)‐TiO2 membrane for air purification is investigated, utilizing the environmentally friendly solvent Cyrene. Through the integration of TiO2 nanoparticles within a PLA matrix, the membrane is used to degrade ethanol as a model volatile organic compound (VOC) under UV light. Scanning Electron Microscopy (SEM), Energy Dispersive X‐ray Analysis (EDX), and UV–vis spectrophotometry confirm the porous structure of the membrane, the even distribution of TiO2, and its effective band gap of 3.06 eV, respectively. Ethanol adsorption is best described by the Langmuir isotherm model, suggesting monolayer coverage on a homogeneous surface. Photocatalytic tests demonstrate that the membrane decomposes ethanol (6800 ppm) within 14 min under UV light, generating acetaldehyde, acetic acid, formaldehyde, and formic acid as intermediates, and ultimately producing CO2 and water. Reusability tests indicate a decrease in decomposition time over successive cycles due to increased TiO2 exposure from the gradual degradation of PLA. However, this degradation poses challenges for continuous use, compromising the membrane's long‐term durability.

Thin-Layer TiO2 Membrane Fabrication by Condensed Layer Deposition.

A novel approach to the fabrication of thin-film supported metal oxide membranes was investigated. Nanocoatings were obtained by the condensed layer deposition of TiO2 on tubular microporous supports, applying multiple consecutive layers of TiO2/polyaniline. The surface, cross-sectional structure, and morphology of the materials were investigated by electron microscopy. Their membrane-related properties were explored by permeability measurements, rejection, and fouling analysis, using polyethylene glycol (PEG) as test molecules. The SEM images showed that TiO2 was successfully deposited on the surface, creating a layer with partial coverage of the support after each layer was deposited; consequently, the permeability of the membranes decreased gradually. Overall, the results of the flux and permeability of the membranes confirmed the coating. The transmembrane pressure (TMP) increased with each coating layer, while the rejection of the membrane showed gradual improvement.

TiO2-based nitrogen dioxide gas sensor with transparent ordered micro-hollow bump structure prepared by 3D heterogeneous integration technology

This study produces the TiO2 membrane for a transparent ordered micro-hollow-bump (TOMHB) structure using a micro electro mechanical system (MEMS) and 3D heterogeneous integration (HI). The SEM image shows that the diameter and depth of each MHB are 12.5 μm and 8.5 μm. The TEM image shows that a 70 nm-thick TiO2 membrane is uniformly coated onto the MHB using atomic layer deposition (ALD). For NO2 gas sensing, the TiO2 TOMHB gas sensor is measured with and without UV irradiation at a working temperature for the sensor of room temperature, and a measurement time from NO2 injection to exhaust of about 5 min. Without UV irradiation, the gas response is good but the response time is slow and difficult-recoverable. With UV irradiation, the TiO2 TOMHB gas sensor has a fast response and recovery time. Four consecutive stability experiments show that the sensor response has an average value of 9.5 % for NO2 4.25 ppm. The average response time is 7 s and the average recovery time is 144 s. In addition, the TiO2 TOMHB gas sensor is a good selective for NO2 gas. These results show that the TiO2 TOMHB NO2 gas sensor has good stability, reproducibility and selectivity.

Rational regulation of post-electrodialysis electrochromic anion exchange membranes via TiO2@Ag synergistically strengthens visible-light photocatalytic anti-contamination activity

Membrane-contamination during electrodialysis (ED) process is still a non-negligible challenge, while irreversible consumption and unsustainability have become the main bottlenecks limiting the improvement of anion exchange membranes (AEMs) anti-contamination activity. Here, we introduce a novel approach to design AEMs by chemically assembling 4-pyndinepropanol with bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO) in an electrochromic-inspired process. Subsequently, the co-mingled TiO2@Ag nanosheet with the casting-solution were sprayed onto the surface of the substrate membrane to create a micrometer-thick interfacial layer. The addition of Ag nanoparticles (NPs) enhances the active sites of TiO2, resulting in stronger local surface plasmon resonance (LSPR) effects and reducing its energy band gap limitation (From 3.11 to 2.63 eV). Post-electrodialysis electrochromic AEMs incorporating TiO2@Ag exhibit synergistic enhancement of sunlight absorption, effectively suppressing photogenerated carrier binding and promoting migration. These resultant-membranes demonstrate significantly improved bacterial inhibition properties (42.0-fold increase for E. coli) and degradation activity (7.59-fold increase for rhodamine B) compared to pure TiO2 membranes. Importantly, they maintain photocatalytic activity without compromising salt-separation performance or stability, as the spraying process utilizes the same substrate materials. This approach to rational design and regulation of anti-contamination AEMs offers new insights into the collaborative synergy of color-changing and photocatalytic materials.

Empowering TiO2–coated PVDF membranes stability with polyaniline and polydopamine for synergistic separation and photocatalytic enhancement in dye wastewater purification

Photocatalytic membranes are effective in removing organic dyes, but their low UV resistance poses a challenge. To address this, self-protected photocatalytic PVDF membranes were developed using polyaniline (PANI) and polydopamine (PDA), whaich are anti-oxidation polymers, as interlayers between the membrane and TiO2. PVDF membranes were first modified by a self-polymerization layer of either PANI or PDA and then coated with titanium dioxide (TiO2). The TiO2 remained firmly attached to the PANI and PDA layer, regardless of sonication and prolonged usage. The PANI and PDA layers enhanced the durability of PVDF membrane under UV/TiO2 activation. After 72 h of irradiation, PVDF–PDA–TiO2 and PVDF–PANI–TiO2 membranes exhibited no significant change. This process improved both separation and photocatalytic activity in dye wastewater treatment. The PVDF–PDA–TiO2 and PVDF–PANI–TiO2 membranes showed enhanced membrane hydrophilicity, aiding in the rejection of organic pollutants and reducing fouling. The modified membranes exhibited a significant improvement in the flux recovery rate, attributed to the synergistic effects of high hydrophilicity and photocatalytic activity. Specially, the flux recovery rate increased from 17.7% (original PVDF) to 56.3% and 37.1% for the PVDF–PDA–TiO2 membrane and PVDF–PANI–TiO2 membrane. In dye rejection tests, the PVDF‒PDA‒TiO2 membrane achieved 88% efficiency, while the PVDF‒PANI‒TiO2 reached 95.7%. Additionally, the photodegradation of Reactive Red 239 (RR239) by these membranes further improved dye removal. Despite an 11% reduction in flux, the PVDF–PDA–TiO2 membrane demonstrated greater durability and longevity. The assistance of PANI and PDA in TiO2 coating also improved COD removal (from 33 to 58–68%) and provided self-protection for photocatalytic membranes, indicating that these photocatalytic membranes can contribute to more sustainable wastewater treatment processes.

Promoted adsorption-photocatalysis synergistic removal of contaminants via surface regulation by a tree-like nanofiber membrane substrate

Photocatalysis represents a promising strategy for wastewater treatment, but the widely used powder photocatalysts are still limited by sluggish interfacial mass transfer and chemical processes. In this study, a tree-like PVDF nanofiber membrane (T-PVDF) was explored to enhance the photocatalytic activity of TiO2 and TiO2/BiOI heterojunction through different pathways. TiO2 was first integrated into the T-PVDF substrate via a one-step electrospinning method. The dendritic architecture greatly favored the contaminant adsorption on the catalytic surface and thus boosted the photodegradation of RhB under UV or visible light irradiation. Especially for the visible light driven dye-sensitive photocatalysis, the integrated TiO2@T-PVDF outperformed the powder TiO2 and pristine PVDF membrane anchored TiO2 by 17.9 and 2.4 times, respectively. In addition, the construction of TiO2/BiOI heterojunction on the T-PVDF substrate was realized by further growing BiOI nanosheets via a solvothermal method. The irregular growth of BiOI on the multiscale nanofiber substrate formed a rough surface with unexpected high hydrophobicity, which allowed the accumulation of high-concentrated O2 at the catalytic interfaces. This greatly boosted the O2 reduction and inhibited the competitive H2 evolution under visible light irradiation, resulting in 3.8-fold higher reaction kinetics than that obtained for hydrophilic powder TiO2/BiOI heterojunction.

Immobilization of Bi2WO6 on Polymer Membranes for Photocatalytic Removal of Micropollutants from Water - A Stable and Visible Light Active Alternative.

In this work, bismuth tungstate Bi2WO6 is immobilized on polymer membranes to photocatalytically remove micropollutants from water as an alternative to titanium dioxide TiO2. A synthesis method for Bi2WO6 preparation and its immobilization on a polymer membrane is developed. Bi2WO6 is characterized using X-ray diffraction and UV-vis reflectance spectroscopy, while the membrane undergoes analysis through scanning electron microscopy, X-ray photoelectron spectroscopy, and degradation experiments. The density of states calculations for TiO2 and Bi2WO6, along with PVDF reactions with potential reactive species, are investigated by density functional theory. The generation of hydroxyl radicals OH• is investigated via the reaction of coumarin to umbelliferone via fluorescence probe detection and electron paramagnetic resonance. Increasing reactant concentration enhances Bi2WO6 crystallinity. Under UV light at pH 7 and 11, the Bi2WO6 membrane completely degrades propranolol in 3 and 1 h, respectively, remaining stable and reusable for over 10 cycles (30 h). Active under visible light with a bandgap of 2.91eV, the Bi2WO6 membrane demonstrates superior stability compared to a TiO2 membrane during a 7-day exposure to UV light as Bi2WO6 does not generate OH• radicals. The Bi2WO6 membrane is an alternative for water pollutant degradation due to its visible light activity and long-term stability.

Effect Of UV-Assisted Titanium Dioxide (TiO2) Photocatalysis on Viable Airborne Bacteria and Fungi in The Seasoning Powder Industry

Titanium dioxide (TiO2) has been known to have anti-microbial activity against fungi, bacteria, and viruses. The application of TiO2 in the membrane attached to the air conditioner was expected to minimize airborne microorganisms. This study contribution to investigate the efficacy of UV-assisted TiO2 photocatalysis in controlling airborne microorganisms in the seasoning powder industry. TiO2 was coated to the non-woven membrane and attached with a UV lamp inside the air conditioner. When the AC was on, the Ti3+ was released into the air. Enumeration of airborne microorganisms was conducted by opening the agar plates for 15 min at several food processing facilities, followed by incubating agar plates for 72 hours at 30 °C. The result shows dry processing facility had the highest number of initial airborne bacteria while the wet production facility had the highest number of initial airborne fungi. Interestingly, the number of airborne microorganisms fluctuated in the packaging facility related to the number of people going inside and outside. On the contrary, the number of airborne microorganisms was deficient in empty rooms, which indicated that the number of airborne microorganisms might be related to people and products. Overall, airborne microorganisms were reduced after 60 min of irradiation. Therefore, it is recommended to irradiate the facilities for 60 min before production start. SEM images and EDAX analysis results show TiO2 was detected after 160 h. However, it was recommended to change the TiO2 membrane after one month. This research was expected to contribute to controlling airborne microorganisms during food production in food processing facilities.

Microplastic Removal in Krueng Aceh River Water Using Ultrafiltration Membrane from Polyethersulfone Polymer (PES)

The Company's input pipes contained microplastics, per the preliminary test findings. While the water yield produced by PDAM Tirta Daroy contains 150 particles/L, the Tirta Daroy Drinking Water Area has 275 particles/L. Microplastics found in the water pose a major risk to living beings if they are consumed. This work aims to characterize the properties, flux, and polyethersulfone (PES) membrane rejection coefficient, which were made utilizing the phase inversion technique with a solvent and additives called N,N-dimethylformamide (DMF). In Sungai Krueng Aceh, titanium dioxide (TiO2) is utilized to filter out microplastics from the water. Results of Scanning Electron Microscopy (SEM) examination of Membrane Morphology demonstrate that the resulting membrane is an asymmetrical membrane of two layers, the upper layer relatively thin and the lower layer porous. When compared to the PES membrane when it was 15% DMF/TiO2, the 20% DMF/TiO2 membrane exhibits a finger-like cross-sectional structure called a macrovoid) with more and larger numbers. Analysis of the microplastic rejection coefficients proved the effectiveness of PES, DMF, and TiO2 membranes in removing microplastics. Results of tests on the effectiveness of rejecting microplastics after undergoing process filtration with a microplastic rejection coefficient of 94% and 14.2 particles/L utilizing a 20% PES/DMF/TiO2 membrane Performance of PES membranes: The PES membrane with 20% DMF/TiO2 has a water flux of 0.467 L/m2.hour compared to 15% DMF/TiO2 0.733 L/m2.hour. This study's findings on membrane Ultrafiltration have the potential to be used as a water filter standard in PDAM.

Synthesis and performance of ultrafiltration membranes incorporated with different oxide nanomaterials: experiments and modeling

Abstract In membrane filtration technology, membrane fouling is the primary obstacle to optimizing efficiency and results in a short membrane lifetime and high operating costs. By incorporating nanomaterials into the membrane synthesis process, a mixed-matrix membrane with significantly enhanced characteristics and performance may be obtained. Graphene oxide (GO), aluminum oxide (Al2O3), tin oxide (SnO2), and titanium oxide (TiO2) were incorporated into a polyethersulfone (PESU) membrane. The water permeability of the modified membranes showed improvements when compared with the pure membrane. It increased from 65 L/m2 h bar for the pristine membrane (PES-1) to 143.6, 83.68, 92.12, 75.43 L/m2 h bar for Al2O3 (PES-2), TiO2 (PES-3), SnO2 (PES-4), and GO (PES-5) membranes, respectively. It was discovered that the membrane's surface hydrophilicity was significantly and directly affected by the incorporation of nanoparticles. Fouling parameters include Rr (Reversible fouling ratio), Rir (irreversible fouling ratio), Rt (total fouling ratio), and Frr (flux recovery ratio) and were measured to determine the membrane's fouling tendency. The results showed that the membrane's propensity for fouling could be reduced when nanoparticles were incorporated into it. The experimental results are best explained by the cake layer and both standard and intermediate blocking mechanism models, as determined by the traditional single fouling models.

Modified ceramic membranes for the treatment of highly saline mixtures utilized in vacuum membrane distillation

Membrane Distillation processes could enable the treatment of highly saline solutions and facilitate minimal (MLD) or zero liquid discharge (ZLD) applications. Ceramic membranes can be a robust alternative to polymeric membranes if they are chemically modified to exhibit hydrophobic qualities to prevent wetting, particularly for vacuum membrane distillation (VMD). This study found that the thin top layer of asymmetrically structured ceramic membranes is robust enough for highly saline and abrasive suspensions and that TiO2 membranes outperform Al2O3 membranes in respect to the mass transport due to their larger support pore size and lower thermal conductivity. A maximum permeate flux of 35 kg/(m2 h) with exceptionally high rejections were measured in VMD using a saline brine with a concentration of 350 g NaCl per kg H2O. Furthermore, a VMD mass transfer model was successfully adopted (based on the Dusty Gas Model) to facilitate the calculation of the mass transfer through asymmetrically structured TiO2 membranes. Model deficiencies such as the underestimation of polarization effects were discussed, and correction factors integrated accordingly. This was done to establish a mass transfer modelling fundament for asymmetrical ceramic membranes used in MD that can be extended in future works and possibly serve as a tool for membrane optimization.

Cu-doped mesoporous TiO2 photocatalyst for efficient degradation of organic dye via visible light photocatalysis

A solvothermal method was used to synthesize the mesoporous TiO2, (1-3w %) Cu-doped mesoporous TiO2 membrane with the help of a bioreactor. To understand the physicochemical composition of all synthesized nanomaterials, the structure, morphology and crystallinity of the materials were studied using X-ray diffractometer (XRD), Field emission scanning electron microscopy (FESEM), Fourier transform-infrared (FTIR), Energy dispersive X-ray spectroscopy (EDS) and cyclic voltammetry (CV). Under artificial light source (500 W mercury bulb) irradiations, the nano catalysts' catalytic effectiveness was examined for the azo dyes, namely Congo red. Cu-doping causes a shift in the light absorption of mTiO2 from the ultraviolet to the visible region. The 3w% Cu-doped mTiO2 photocatalyst exhibits lower band gap energy (2.6eV) than TiO2 which is 3.2 eV to efficiently utilize solar energy. As a result, the light absorption was shifted towards the visible spectrum. The recommended mTiO2 and (1, 2, 3) w% Cu-doped mTiO2 photocatalysts were used to photodegrade Congo red and methylene blue. For the degradation of CR, the mTiO2 photocatalyst exhibited 61% and 3w% Cu-doped mTiO2 demonstrated 99% photocatalytic performance after 50 min. A variety of scavengers were also utilized to distinguish the active species by catching the radicals and holes created during the process of photocatalytic degradation. CV indicates the presence of Cu2+ and Cu1+ in Cu-doped mTiO2. Oxygen vacancies and the electronegative surface of Cu1+ seem to perform the photocatalytic reduction of CR.

Construction of V2O5-WO3/TiO2 nanocones catalyst layer on SiC ceramic membrane for efficient removal of NO and dust

In this work, TiO2 nanocones grown on SiC membrane was used as the support of V2O5-WO3 species to prepare V2O5-WO3/TiO2@SiC (VWTi(C-X)@SiC) catalytic membrane for dust filtration and NH3-SCR denitration. On account of the large specific surface area, abundant surface acid sites and prominent redox property, the optimized VWTi(C-550)@SiC catalytic membrane shows >90% NO removal efficiency at the temperature of 280–360 °C, which are much higher than VWTi(P-550)/SiC catalytic membrane (TiO2 nanoparticles prepared by traditional vacuum coating titanium sol method was used as the support of V2O5-WO3 species, NO conversion <80% at whole tested temperature). Additionally, VWTi(C-550)@SiC displays superior stability during the SO2 + H2O resistance and 300 h long-term test at 300 °C, and exhibits an excellent dust filtration performance (2.5 μm SiO2 particles interception rate exceeded 99.99%) under all test conditions. More importantly, the structure of nanocones decrease the influence of tensile stresses due to the different thermal expansion coefficients of TiO2 and SiC membranes, which significantly suppress the fall of VWTi catalyst layer from the surface of SiC during pulse-jet cleaning. Among above results, it can be concluded that the optimized VWTi(C-550)@SiC catalytic membrane shows a prosperous application prospect for the simultaneously dust filtration and NH3-SCR denitration of medium–high temperature flue gas.

Self-assembly graphene oxide membrane embedded with CPU@PAA@TiO2 for enhancing the dyes separation and photocatalytic self-cleaning performance

Low separation efficiency and poor reusability have become the most important factors restricting the development of membranes in water purification. Herein, a photocatalytic self-cleaning graphene oxide (GO) membrane with a unique intercalated structure of CPU@PAA@TiO2 (CPU: CNS@PDA@UiO-66-NH2, PAA: polyacrylic acid, CNS: carbon nanospheres, PDA: polydopamine) was prepared by simple vacuum filtration self-assembly. The water channels formed by photocatalysis nano-filler CPU@PAA@TiO2 and the dense laminated structure of GO layer existed in the membrane at the same time. The core-shell CPU has a larger photocatalytic area than UiO-66-NH2. Moreover, the crosslinking modification of CPU, PAA, and TiO2 leads to an excellent water flux, dye separation performance, and photocatalytic activity of composite membranes. The water flux of GO/CPU/PAA/TiO2 membrane was 230.48 L ∙ m−2∙ h−1∙ bar−1, and the flux of three dyes was over 220 L ∙ m−2∙ h−1∙ bar−1 while the removal rates were over 99.5%. After 120 min of visible light irradiation, the GO/CPU/PAA/TiO2 membrane exhibited an enhanced degradation (94.21%) for methylene blue because of the suitable band-gap alignment and synergistic effect between CPU and TiO2. In addition, the GO/CPU/PAA/TiO2 membrane exhibited excellent acid/alkaline-stability and reusability in dye filtration and photocatalytic performance. The results indicated that the GO/CPU/PAA/TiO2 membrane has great potential in water purification and photocatalytic self-cleaning.

Ultrathin TiO2 Blocking Layers via Atomic Layer Deposition toward High-Performance Dye-Sensitized Photo-Electrosynthesis Cells

The collection of solar energy in chemical bonds via dye-sensitized photoelectrosynthesis cells (DSPECs) is a reliable solution. Herein, atomic layer deposition (ALD) introduced ultrathin blocking layers (BLs) between a mesoporous TiO2 membrane and fluorine-doped tin oxide (FTO), and much improved photoelectrochemical water oxidation performance was well documented. Samples with different BL thicknesses deposited on FTO were obtained by ALD. In the photoanode, polypyridyl Ru(II) complexes were used as photosensitizers, and Ru(bda)-type was used as a catalyst during water oxidation. Under one sun irradiation, the BL (i) increased the photocurrent density; (ii) slowed down the open-circuit voltage decay (OCVD) by electrochemical measurement; (iii) increased the photo-generated electron lifetime roughly from 1 s to more than 100 s; and (iv) enhanced the water oxidation efficiency from 25% to 85% with 0.4 V of applied voltage bias. All this pointed out that the ALD technique-prepared layers could greatly hinder the photogenerated electron–hole pair recombination in the TiO2-based photoanode. This study offers critical backing for the building of molecular films by the ALD technique to split water effectively.

Polymer-based TiO2 membranes: An efficient route for recalcitrant dye degradation

Methyl orange (MO) is a poisonous, carcinogenic, and genotoxic azo dye with high chemical stability, high solubility in water, and very low biodegradability. The removal is difficult by conventional water purification methods. The degradation of MO with photocatalytic membrane reactors loaded with TiO2 nanoparticles(NPs) is reported in some publications, and the degradation efficiency is less than 50%. The present study presents the use of titanium dioxide nanoparticles deposited on the surface of nanofiltration membranes to assess the photocatalytic degradation of reactive dye. The morphological analyses showed the presence of a thin titanium dioxide layer on the surface of the membranes. In addition, the photocatalytic membranes with 0.25 wt% of TiO2 showed an interesting photocatalytic activity over four hours, with 82.3% of the MO degraded. The degradation followed a pseudo-second-order kinetics model, and the reusability of the prepared membranes was also verified.

Decreasing of Mangan (II) in The Water Using Membrane of Moringa Seed Powder-TiO2 with Variation of Mass TiO2

Mn (II) is a metal ion commonly used in steel alloys, pigment industries, welding, fertilizers, pesticides, ceramics, and electronics. According to the Regulation of the Minister of Health No. 32 of 2017, the permissible content of Manganese in dug well water is 0.5 mg/L. The purpose of this study was to determine the concentration of Mn (II) ions in water before and after passing through a Moringa Seeds Powder (MSP)-TiO2 membrane 20:1; 20:3; 20:5; 20:7; 20:9 and measure the percentage decrease in the concentration of Mn (II) ions in water after through the MSP-TiO2 membrane. The object of this research is a 55 ppm Mn (II) ion artificial sample at a flow rate of 0.56 mL/minute for 90 minutes with 90-watt radiation UV. The concentration of Mn (II) ion was measured by visible spectrophotometric method, the morphology of MSP, TiO2, and MSP-TiO2 membranes was characterized by SEM-EDX, and its diffraction spectra by X-Ray diffraction. The results obtained that the initial Mn(II) was 55.06 ± 0.031 ppm, the concentration of Mn (II) ions with the MSP-TiO2 membrane of mass MSP-TiO2 were 20:1; 20:3; 20:5; 20:7; 20:9 respectively 36.47±0.00; 44.16±1.15; 44.31±1.04; 44.94±0.94; 42.27±2.61 ppm. The percentage of decrease concentration of Mn (II) ion are 34.19±0.44%; 21.37±0.43%; 20.94±0.85%; 19.24±0.86%; and 19.66±0.86%. The highest percentage decrease in Mn (II) ion concentration was 34.15±0.44% in the variation of mass MSP-TiO2 20:1. This study concludes that the MSP-TiO2 membrane has the potential to reduce the concentration of Mn (II) ions in water.

Methylene blue rejection and antifouling properties of different carbonaceous additives-based polyvinylidene fluoride membrane

In the present study, various polyvinylidene fluoride (PVDF)-based membranes were successfully fabricated via non-solvent induced phase separation (NIPS) method utilising different carbon-based materials as additive. The incorporation of reduced graphene oxide (rGO), multi-walled carbon nanotubes (MWCNTs) and GO-MWCNTs hybrid along with titanium dioxide (TiO2) definitely affect the fabricated membrane’s morphology, hydrophilicity, porosity, filtration performance and antifouling properties. Based on dead-end filtration measurement, rGO-based PVDF/TiO2 membrane presented excellent pure water flux (2446.887 L/m2h) with membrane permeability of 1143.850 L/m2hMPa compared to other membranes. Furthermore, the inclusion of rGO and TiO2 also resulted in the highest methylene blue (MB) dye rejection rate (∼92%) compared to MWCNTs (62.22%) and GO-MWCNTs (86.69%). It was believed that steric hindrance effect played a major role in enhancing dye rejection performance of PVDF@rGO/TiO2 membrane. Interestingly, in terms of antifouling properties, PVDF@GO-MWCNTs/TiO2 possessed better antifouling properties as indicated by its higher flux recovery ratio (FRR) value of 95.30%. The existence of hydration layer on membrane surface endowed by oxygen-functional groups prevents the contaminant accumulation thus resulted high FRR value.