Dual-layer Hollow Fiber Membranes Research Articles

Novel self-cleaning PVDF/MoO3/ZnO/GO dual layer hollow fiber photocatalytic membrane with excellent photocatalytic performance of EDCs removal and energy storage capability

Endocrine-disrupting chemicals (EDCs) have a wide range of detrimental effects on health, particularly on the human endocrine system. Efflux This research study involves the application of - molybdenum trioxide, zinc oxide and graphene oxide (MoO3/ZnO/GO) with polyvinylidene fluoride (PVDF) membrane as photocatalytic dual layer hollow fiber (DLHF) membrane as novel energy storage photocatalytic membrane towards efficient degradation of EDCs under visible light illumination. Ternary MoO3/ZnO/GO was synthesized using hydrothermal method and was embedded on the surface of dual layer hollow fiber membrane by dry-wet spinning method by varying the GO loading at 0.1, 0.25 and 0.5 wt%. The results indicated that the 0.5 PVDF/MoO3/ZnO/GO DLHF photocatalytic membrane exhibited improved wettability, high porosity, good water flux, and exceptional EDCs removal, achieving removal rates of 73.08%, 75.80%, 73.65%, 100%, 95.57%, and 53.50% for 1 mg/L BPA, 1 μg/L BPA, 2 μg/L gabapentin, 1 μg/L diclofenac, 10 μg/L caffeine, and 6 μg/L nonylphenol, respectively after 240 min of light exposure. Besides, energy storage capability achieved 96.07% rejection of 1 mg/L BPA in dark condition while stability and reusability test showed 0.5 PVDF/MoO3/ZnO/GO DLHF achieve 74.02% regeneration efficiency after 3 consecutive cycles. Furthermore, the photocatalytic properties of 0.5 PVDF/MoO3/ZnO/GO DLHF could assure a self-cleaning property and increase its lifetime. The PVDF/MoO3/ZnO/GO DLHF photocatalytic membrane served as a versatile 3-in-1 solution, enhancing photocatalytic degradation and rejection capabilities while also serving as a promising energy storage material with self-cleaning properties for removing EDCs from aquatic environments, regardless with or without the presence of light.

Photodegradation of Bisphenol a in Water via Round-the-Clock Visible Light Driven Dual Layer Hollow Fiber Membrane

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.

Sodium hypochlorite activated dual-layer hollow fiber nanofiltration membranes for mono/divalent ions separation

The tailoring of nanofiltration membranes for the precise separation of mono/divalent ions often involves complicated procedures to modify the surface chemistry and structure. Herein, an efficient sodium hypochlorite (NaClO) activation method is developed to tune the selective layer of cross-linked polyimide (PI)/polyethersulfone (PES) dual-layer hollow fiber membranes. By oxidizing the hydroxyl and imine groups while hydrolyzing the amide groups in the cross-linked structure, the membranes are effectively tailored with the negatively charged surface and a more open pore structure with 0.47 nm mean effective pore size. The NaClO-activated membranes show over 97.85% rejection of Na2SO4 while the NaCl rejection decreases from 93.83% to − 19.85% during treating the mixed ions solutions. The fabricated membranes with high separation efficiency and long-term stability exhibit vast potential for the separation of mono/divalent ions in industries. Moreover, the elaborated NaClO activation mechanism potentially gives fundamentals for the modification of the PI membranes with cross-linked structures for other applications.

Fabrication and characterization of dual-layer hollow fiber membranes incorporating poly(citric acid) grafted GO with enhanced antifouling property for water treatment

ABSTRACT Membrane fouling which occurs during filtration process is a perennial issue and could lead to reduced separation efficiency. In this work, poly(citric acid) grafted graphene oxide (PGO) was respectively incorporated into matrix of single-layer hollow fiber (SLHF) and duallayer hollow fiber (DLHF) membranes, aiming to improve membrane antifouling properties during water treatment. Different loading of PGO ranging from 0 to 1 wt% was first introduced into the SLHF in order to identify the best PGO loading for the DLHF preparation with its outer layer modified by nanomaterials. The findings showed that at the optimized PGO loading of 0.7 wt%, the resultant SLHF membrane could achieve both higher water permeability and bovine serum albumin rejection compared to the neat SLHF membrane. This is owing to the improved surface hydrophilicity and increased structural porosity upon the incorporation of optimized PGO loading. When 0.7 wt% PGO was introduced only to the outer layer of DLHF, the cross-sectional matrix of the membrane was altered, forming microvoids and spongy-like structure (more porous). Nevertheless, the BSA rejection of the membrane was improved to 97.7% owing to the presence of inner selectivity layer that was produced from different dope solution (without PGO addition). The DLHF membrane also demonstrated significantly higher antifouling properties compared to the neat SLHF membrane. Its flux recovery rate is 85%, i.e., 37% better than that of neat membrane. By incorporating hydrophilic PGO into the membrane, the interaction of the hydrophobic foulants with the membrane surface is greatly reduced.

10-Year Historical Development of Dual Layer Hollow Fiber Hemodialysis Membranes

Hollow fiber membranes have been employed to purify blood from within the heart of hemodialysis process, namely dialyzer. In the past 10 years, the interest on the utilization of dual layer hollow fiber (DLHF) membranes has arisen due to the innovative idea of combining adsorption and diffusion processes into one step. This short review outlines the historical development of DLHF hemodialysis membranes that spans from year 2012 to year 2022. The motivation and the outcome from the first and the second generation DLHF hemodialysis membranes are discussed. In addition, the use of DLHF membranes in other hemodialysis-related application is presented. This short review would provide a perspective for membranologists to recognize the issues in DLHF hemodialysis membranes and to work their way to finding the real solutions.

Thin-Film Composite Matrimid-Based Hollow Fiber Membranes for Oxygen/Nitrogen Separation by Gas Permeation.

In recent years, the need to reduce energy consumption worldwide to move towards sustainable development has led many of the conventional technologies used in the industry to evolve or to be replaced by new alternatives. Oxygen is a compound with diverse industrial and medical applications. For this reason, obtaining it from air is one of the most interesting separations, traditionally performed by cryogenic distillation and pressure swing adsorption, two techniques which are very energetically expensive. In this sense, the implementation of membranes in a hollow fiber configuration is presented as a much more efficient alternative to carry out this separation. The aim of this work is to develop cost-effective multilayer hollow fiber composite membranes made of Matrimid and polydimethylsiloxane (PDMS) for the separation of oxygen and nitrogen from air. PDMS is used as a cover layer but can also enhance the performance of the membrane. In order to compare these two materials, three different configurations are studied. First, integral asymmetric Matrimid hollow fiber membranes were produced using the spinning method. Secondly, by using dip-coating method, a PDMS dense selective layer was deposited on a self-made polyvinylidene fluoride (PVDF) hollow fiber support. Finally, the performance of a dual-layer hollow fiber membrane of Matrimid and PDMS was studied. Membrane morphology was characterized by SEM and separation performance of the membranes was evaluated by mixed-gas permeation experiments. The novelty presented in this work is the manufacture of hollow fiber membranes and the way Matrimid is treated. This makes it possible to develop much thinner dense layers than in the case of flat-sheet membranes, which leads to higher permeance values. This is a key factor when implementing this technology on an industrial scale. Membranes prepared in this work were compared to the current state of the art, reporting quite good performance for the dual-layer membrane, reaching O2 permeance of 30.8 GPU and O2/N2 selectivity of 4.7, with a thickness of about 5-10 μm (counting both selective layers). In addition, the effect of operating temperature on the membrane permeances has been studied experimentally; we analyze its influence on the selectivity of the separation process.

Hybrid Inorganic Organic PSF/Hap Dual-Layer Hollow Fibre Membrane for the Treatment of Lead Contaminated Water

Lead (Pb) exposure can be harmful to public health, especially through drinking water. One of the promising treatment methods for lead contaminated water is the adsorption-filtration method. To ensure the cost-effectiveness of the process, naturally derived adsorbent shall be utilised. In this study, hydroxyapatite particles, Ca10(PO4)6(OH)2 (HAP) derived from waste cockle shell, were incorporated into the outer layer of polysulfone/HAP (PSf/HAP) dual-layer hollow fibre (DLHF) membrane to enhance the removal of lead from the water source due to its hydrophilic nature and excellent adsorption capacity. The PSf/HAP DLHF membranes at different HAP loadings in the outer layer (0, 10, 20, 30 and 40 wt%) were fabricated via the co-extrusion phase inversion technique. The performance of the DLHF membranes was evaluated in terms of pure water flux, permeability and adsorption capacity towards lead. The results indicated that the HAP was successfully incorporated into the outer layer of the membrane, as visibly confirmed by microscopic analysis. The trend was towards an increase in pure water flux, permeability and lead adsorption capacity as the HAP loading increased to the optimum loading of 30 wt%. The optimized DLHF membrane displayed a reduced water contact angle by 95%, indicating its improved surface hydrophilicity, which positively affects the pure water flux and permeability of the membrane. Furthermore, the DLHF membrane possessed the highest lead adsorption capacity, 141.2 mg/g. The development of a hybrid inorganic-organic DLHF membrane via the incorporation of the naturally derived HAP in the outer layer is a cost-effective approach to treat lead contaminated water.

Use of Nucleating Agent NA11 in the Preparation of Polyvinylidene Fluoride Dual-Layer Hollow Fiber Membranes.

Polyvinylidene fluoride (PVDF) dual-layer hollow fiber membranes were simultaneously fabricated by thermally induced phase separation (TIPS) and non-solvent induced phase separation (NIPS) methods using a triple orifice spinneret (TOS) for water treatment application. The support layer was prepared from a TIPS dope solution, which was composed of PVDF, gamma-butyrolactone (GBL), and N-methyl-2-pyrrolidone (NMP). The coating layer was prepared from a NIPS dope solution, which was composed of PVDF, N,N-dimethylacetamide (DMAc), and polyvinylpyrrolidone (PVP). In order to improve the mechanical strength of the dual-layer hollow fiber, a nucleating agent, sodium 2,2'-methylene bis-(4,6-di-tert-butylphenyl) phosphate (NA11), was added to the TIPS dope solution. The performance of the membrane was evaluated by surface and cross-sectional morphology, water flux, mechanical strength, and thermal property. Our results demonstrate that NA11 improved the mechanical strength of the PVDF dual-layer hollow fiber membranes by up to 42%. In addition, the thickness of the coating layer affected the porosity of the membrane and mechanical performance to have high durability in enduring harsh processing conditions.

Fabrication of CO2-tolerant SrFe0.8Nb0.2O3-δ/SrCo0.9Nb0.1O3-δ dual-layer 7-channel hollow fiber membrane by co-spinning and one-step thermal process

CO2-tolerant membranes are crucial for oxyfuel combustion systems utilizing oxygen permeable membranes. A newly constructed dual-layer 7-channel hollow fiber membrane consisting of SrFe0.8Nb0.2O3-δ (SFN) porous outer layer and SrCo0.9Nb0.1O3-δ (SCN) hollow fiber inner layer has been successfully fabricated by co-spinning and one-step thermal process (OSTP) approach in this work. The outer layer can have different porous structures depending on the graphite content of the spinning solution. In the OSTP approach, the in-situ reactive sintering of the membrane materials results in the two layers being well adhered and mechanically robust. At 900 °C under 80% CO2-containing in sweeping gas, the oxygen flux of SFN/SCN dual-layer hollow fiber membrane with the porous layer of 91.8 μm was 1.98 mL min−1 cm−2, about 7.1 times as much as the SCN hollow fiber membrane (0.28 mL min−1 cm−2) in the same situations. The porous SFN outer layer was demonstrated to prevent membrane performance degradation effectively. Furthermore, the SFN/SCN dual-layer membrane operated in a 20% CO2-containing atmosphere for at least 200 h, maintaining an oxygen flux of 3.20 mL min−1 cm−2 without degradation. As a result of these findings, the SFN/SCN dual-layer 7-channel hollow fiber membrane has significant application potential in CO2 capture for oxyfuel combustion.

Preparation of BCYF0.10–YDC/BCYF0.10–Ni dual-layer hollow fiber membrane for dry reforming of methane and hydrogen purification

A ceramic hydrogen permeable membrane reactor for dry reforming of methane (DRM) enables both the reaction and separation processes to be carried out simultaneously, producing synthesis gas and pure hydrogen while mitigating greenhouse gas emissions.

Grand Challenges in Fabrication of Nanocomposite Hollow Fiber Membranes

Membrane processes allow scalable and energy-efficient separation of gas and liquid, advance low-carbon purifications in various industrial and environmental applications and enable more resilient economy and society. In pursuit of developing more advanced membranes with continuously improved separating performances, nanofillers have been commonly incorporated into membranes to upgrade membrane properties such as mechanical robustness, antifouling ability, and permeability etc., across all types of popular membrane geometries from flat sheet and spiral wound to hollow fiber. Nanofillers inside hollow fibre membranes have received more attentions due to the unique structural advantages such as a large surface area/volume ratio and compact module designs. The resultant nanocomposite hollow fiber membranes thus combine the structural superiority with specific functions of nanomaterials such as superhydrophilicity or catalytic activity, whereas the development of dual layer hollow fiber membrane allowed further design of both the inner and outer membrane layers with innovative functions. On the other hand, greener and more environmentally friendly membranes fabrication are increasingly important to sustainable membrane technology, for example topics of using natural polymers, solvent free membrane fabrication and nano-pollutions are fervently investigated.

PPSU dual layer hollow fiber mixed matrix membranes with functionalized MWCNT for enhanced antifouling, salt and dye rejection in water treatment

AbstractLoose nanofiltration dual layer hollow fiber membranes (DLHFM) were prepared from polyphenylsulfone (PPSU) with a thin contact mixed matrix membrane (MMM) outer layer containing functionalized multiwalled carbon nanotubes (MWCNT). Two types of MWCNT were used; oxidized MWCNT (OMWCNT) and polyethyleneimine (PEI) functionalized MWCNT (PEI‐MWCNT). Z potential measurements indicate that OMWCNT and PEI‐MWCNT were negatively charged, being OMWCNT most negative. Na2SO4, MgSO4, and methylene blue (MB) rejection was enhanced due to OMWCNT and PEI‐MWCNT incorporation in DLHFM outer layer. Enhanced hydrophilicity and negatively charge mixed matrix DLHFM layer was the key factor for a better mixed matrix DLHFM performance. The best salt and MB rejection was found in those membranes prepared with (OMWCNT) followed by (PEI‐MWCNT) compared with neat PPSU membranes. An increase of 113% and 100% in Na2SO4 and MB rejection respectively was attained in DLHFM with 0.04 wt%, OMWCNT (relative to dope's weight) in comparison with the neat PPSU membrane. Antifouling test for bovine serum albumin (BSA) and MB showed better performance also for the mixed matrix DLHFM containing OMWCNT's. In antifouling tests, a 4.4% and 25% flux recovery increase for MB and BSA respectively was obtained in DLHFM with 0.04 wt% OMWCNT compared with the neat PPSU DLHFM.

Visible-light-driven photocatalytic dual-layer hollow fibre membrane ameliorates the changes of bisphenol A exposure in gastrointestinal tract.

Various treatments of choice are available to overcome contamination of bisphenol A (BPA) in the environment including membrane technologies; however, the treatment still releases contaminants that threaten the human being. Therefore, the present study is conducted to investigate the degradation of BPA by recently developed visible-light-driven photocatalytic nitrogen-doping titanium dioxide (N-doped TiO2) dual-layer hollow fibre (DLHF) membrane and its efficiency in reducing the level of BPA in contaminated water. Fabricated with suitable polymer/photocatalyst (15/7.5 wt.%) via co-extrusion spinning method, the DLHF was characterized morphologically, evaluated for BPA degradation by using submerged photocatalytic membrane reactor under visible light irradiations followed by the investigation of intermediates formed. BPA exposure effects were accessed by immunohistochemistry staining of gastrointestinal sample obtained from animal model. BPA has been successfully degraded up to 72.5% with 2 intermediate products, B1 and B2, being identified followed by total degradation of BPA. BPA exposure leads to the high-intensity IHC staining of Claudin family which indicated the disruption of small intestinal barrier (SIB) integrity. Low IHC staining intensity of Claudin family in treated BPA group demonstrated that reducing the level of BPA by N-doped TiO2 DLHF is capable of protecting the important component of SIB. Altogether, the fabricated photocatalytic DLHF membrane is expected to have an outstanding potential in removing BPA and its health effect for household water treatment to fulfil the public focus on the safety of their household water and their need to consume clean water.

Dual-layer hollow fibre haemodialysis membrane for effective uremic toxins removal with minimal blood-bacteria contamination

Bacterial endotoxin contamination in dialysate may pass through haemodialysis membrane and cause a silent chronic microinflammation to kidney patients. Dual-layer hollow fibre (DLHF) membranes with dual function, biocompatible adsorptive and antibacterial effects were developed to solve the problem of incompatible membrane and endotoxin contamination. All membranes were fabricated via the co-extrusion dry-wet phase inversion technique. In this study, silica/α-mangostin nanoparticle was incorporated into the inner layer of membrane to enhance the biocompatibility of the membrane while maintaining its adsorption capacity. Activated carbon (AC) was incorporated in the outer layer of membrane for improved antibacterial property. The DLHF membranes were characterised based on its morphology and surface hydrophilicity. The performance of the DLHF membranes was evaluated in terms of permeability, urea, and creatinine removal capabilities, bovine serum albumin (BSA) rejection and antibacterial properties. The dense and small pore size on the outer layer of AC created a smoother surface for the DLHF membrane. The BSA rejection of the DLHF membranes was enhanced by 6–8% compared to that of unmodified single layer hollow fibre membrane. Silica/α-mangostin nanoparticle in the inner layer of membrane enhanced the removal of urea and creatinine by chemisorption. Result also showed that the incorporation of AC in the outer layer of DLHF membrane successfully filtered bacteria by bacteria entrapment. DLHF membrane with the combination of silica/α-mangostin nanoparticle in the inner layer and AC in the outer layer possessed the higher bacteria inhibition into blood compartment against Escherichia coli and Staphylococcus aureus, with removal rate of 68% and 75%, respectively, and better urea and creatinine removal by 60.57% and 75.18%, respectively, compared to single-layer PSf based membrane. The development of co-adsorptive biocompatible DLHF membrane can play an important role in improvement of kidney patient life.

Bisphenol A Removal Using Visible Light Driven Cu2O/PVDF Photocatalytic Dual Layer Hollow Fiber Membrane.

Bisphenol A (BPA) is amongst the endocrine disrupting compounds (EDCs) that cause illness to humans and in this work was removed using copper (I) oxide (Cu2O) visible light photocatalyst which has a narrow bandgap of 2.2 eV. This was done by embedding Cu2O into polyvinylidene fluoride (PVDF) membranes to generate a Cu2O/PVDF dual layer hollow fiber (DLHF) membrane using a co-extrusion technique. The initial ratio of 0.25 Cu2O/PVDF was used to study variation of the outer dope extrusion flowrate for 3 mL/min, 6 mL/min and 9 mL/min. Subsequently, the best flowrate was used to vary Cu2O/PVDF for 0.25, 0.50 and 0.75 with fixed outer dope extrusion flowrate. Under visible light irradiation, 10 mg/L of BPA was used to assess the membranes performance. The results show that the outer and inner layers of the membrane have finger-like structures, whereas the intermediate section of the membrane has a sponge-like structure. With high porosity up to 63.13%, the membrane is hydrophilic and exhibited high flux up to 13,891 L/m2h. The optimum photocatalytic membrane configuration is 0.50 Cu2O/PVDF DLHF membrane with 6 mL/min outer dope flowrate, which was able to remove 75% of 10 ppm BPA under visible light irradiation without copper leaching into the water sample.

Highly efficient recovery of hydrogen from dilute H2-streams using BaCe0.7Zr0.1Y0.2O3-δ/Ni-BaCe0.7Zr0.1Y0.2O3-δ dual-layer hollow fiber membrane

BaCe0.7Zr0.1Y0.2O3-δ/Ni-BaCe0.7Zr0.1Y0.2O3-δ dual-layer hollow fiber membranes are prepared by a co-spinning/co-sintering method, which is a simple and practical technique to integrate the electrolyte (BaCe0.7Zr0.1Y0.2O3-δ) and the electrode (Ni-BaCe0.7Zr0.1Y0.2O3-δ). A galvanic hydrogen pump is assembled by using this dual-layer hollow fiber membrane for hydrogen separation from dilute H2 streams, in which the hydrogen permeation can be moderately controlled by the applied voltage. At 550℃ and 2 V voltage, a hydrogen flux of 2.15 mL·min−1·cm−2 and a hydrogen recovery rate of 81% are obtained when the feed is low concentration (13 vol%) H2 stream. The one-step manufacturing method of integrating electrolytes and electrodes can be regarded as a more efficient method for the mass production of micro-tubular galvanic hydrogen pumps.

Grand Challenges of Perovskite and Metal Oxide-based Membrane: A Form of Dual-layer Hollow Fibre

Perovskite and metal oxides-based dual-layer hollow fibre membrane (DHF) has a high appeal as separator and catalyst for methane conversion application which operated at intermediate and high temperature. The membrane mostly fabricated via the co-extrusion followed by co-sintering method, which is quite challenging, due to the complexity to handle the barrier between layers from delamination, membrane cracking and crystal structure distortion which affects the material performance in a DHF form. This recent review clarifies the challenges in the DHF fabrication process to regulate physical and chemical properties in terms of mechanical strength, tightness, elemental distribution, and crystal structure stability. The based material of the membrane focuses on NiO-YSZ in the inner layer directly interconnected with LSCF-YSZ in the outer layer. The understanding of the challenges in DHF fabrication, will further reduce crucial errors in the fabrication process and accelerate performance improvement for application such as syngas, methanol and long-chain hydrocarbons production, and solid oxide fuel cell.

Novel ceramic hollow fibre membranes contactor derived from kaolin and zirconia for ammonia removal and recovery from synthetic ammonia

The adverse effects of ammonia found in wastewater streams lead to the development of advanced water treatment technology, i.e. membrane contactor (MC). In this study, single layer hollow fibre membrane (SLZK) and dual layer hollow fibre membrane (DLZK) were prepared from zirconia and kaolin and modified into hydrophobic membrane through simple grafting process via fluoroalkylsilane (FAS) agent. The properties of membranes such as morphology, surface roughness, mechanical strength, wettability and liquid entry pressure were analysed through scanning electron microscopy (SEM), atomic force microscopy (AFM), 3-point bending strength, contact angle and LEPw setup. Finally, the performance of the membranes was also investigated towards ammonia removal via membrane contactor system. Our findings showed that hydrophobicity properties significantly improved for both SLZK and DLZK membranes after grafting modification process as indicated by the increase of contact angle value from 5° and 1° to 132.7° and ~180.0° respectively. Based on the morphological analysis, the surface of DLZK showed more porous structure as compared to the SLZK. In addition, DLZK also displayed the highest mechanical strength and contact angle reading of 125 MPa and ~180° respectively. This suggests that the DLZK showed an excellent membrane contactor performance with highest value of mass transfer coefficient (3.77 x 10-5 ms-1) and almost complete removal of ammonia removal (91%). Overall, these results implied that dual layer ceramic membrane developed from kaolin and zirconia could provide the basis for the development of alternative ceramic membrane with excellent properties for membrane contactor system.

Silver doped titania nanotubes incorporated photocatalytic dual layer antibiofouling hollow fiber membrane for palm oil wastewater treatment

Photocatalytic dual layer hollow fiber membrane (DLHFM) is advantageous over its single layer counterpart due to a better photocatalyst dispersion on the outer layer to maximize the potential of the photocatalyst in improving the overall membrane performance. In this study, a polyvinylidene fluoride (PVDF) dual-layer hollow fiber membrane with antibiofouling properties was successfully synthesized via dry-wet spinning phase inversion method, where the Ag-TNT was incorporated onto the outer layer membrane for photocatalytic degradation of AT-POME pigments in a submerged membrane photoreactor (SMPR). The results revealed that the incorporation of Ag-TNT into the PVDF matrix increased pure water flux from 16.20 L/m2 h for pristine PVDF membrane to 37.12 L/m2 h. The synergistic advantages of photocatalysis and membrane filtration was exhibited by the photocatalytic Ag-TNT membrane which showed the highest AT-POME color removal efficiency of 84.0% compared to the other membranes prepared in this work. With the presence of silver nanoparticles, the modified membrane exhibited antibacterial efficiency of 95.8% with a 1.73 mm inhibition zone around the membrane against P. aeruginosa. Based on the results obtained, the photocatalytic PVDF Ag-TNT membrane showed immense potential as an innovative technology for water reclamation in the palm oil industry.

Dual Layer Hollow Fiber Membranes with Functionalized Separation Layer for Improved Hydrophilicity

AbstractPolyethersulfonbasierte Hohlfasermembranen mit einer hydrophil funktionalisierten Trennschicht wurden hergestellt und untersucht. In die Trennschicht wurde ein amphiphiles Triblockcopolymer mit verschiedenen Konzentrationen integriert. Um eine gesteigerte Hydrophilie und damit assoziiertes verringertes Fouling zu erreichen, bestehen die Blockcopolymere aus zwei äußeren Poly(ethylenoxid)‐Blöcken. Diese flankieren den inneren Polyethersulfonblock, welcher der Verankerung des Additivs in die Membran dient. Gesteigerte Hydrophilie, gepaart mit Permeanzen von 2000 L m−2h−1bar−1 und einem Rückhalt von 100 kDa, kennzeichnete die vielversprechendste Membran dieser Studie.