Filter Membrane Research Articles

A novel magnetoelastic biosensor consisting of carbon quantum dots/nitrocellulose membranes and NiFe2O4/ polylactic acid based on 3D printing for α2-macroglobulin detection

α2-macroglobulin (α2-M) have crucial clinical significance as a potent biomarker for diabetes nephropathy (DN). There is an increasing demand for rapid detection of α2-M. Herein, a magnetoelastic (ME) biosensor with a layered composite structure is developed for α2-M detection. Based on 3D printing, the basal layer of the biosensor is prepared as a grid structure fabricated by polylactic acid (PLA) doped with NiFe2O4. The conductivity of the biosensor was improved significantly due to the addition of multi-walled carbon nanotubes (MWCNTs). The biological site for capturing α2-M antigen was provided by the carbon quantum dots (CDs) coupled with anti-α-2M (anti-α2-M@CDs) in the nitrocellulose filter (NC) membrane. Meanwhile, the distribution of antibodies on the biosensor surface can be observed more directly due to the fluorescence characteristics of CDs. The biosensor in this work can realize multi-pattern recognition of fluorescent signal and electromagnetic signal. The results show that the limit of detection (LOD) was 0.506 ng/mL in the linear range from 10 ng/mL to 100 µg/mL and the linear equation of fitting curve is: y = 0.21 x - 0.15. The ME biosensors with a simple preparation method have advantages of high sensitivity, good stability and low LOD, showing the great potential for α2-M detection.

Tannic acid non-covalent functionalized two-dimensional h-BN membrane for efficient water filtration

Tannic acid (TA) non-covalent functionalized hexagonal boron nitride (h-BN) two-dimensional (2D) membrane (TA/h-BN) was developed by π-π interaction between h-BN and TA. The π-π interaction between h-BN and TA eliminated the agglomeration of h-BN nanosheets because of strong Van der Waals' force, and TA/h-BN nanosheets showed improved membrane forming ability. Separation performance of h-BN membrane was improved significantly after the TA non-covalent functionalization on h-BN nanosheets. TA/h-BN membrane with a thickness of 650 nm presented a water permeance of 600 L m−2 h−1 bar−1 and a rejection rate of 91 % for Congo red (CR). Moreover, prepressed TA/h-BN membrane with a thickness of 1150 nm under 3 bar for 7 h could remove 90 % of [Fe(CN)6]3-, and this prepressed membrane exhibited excellent stability during a 72 h of cross-flow filtration, suggesting its broad application prospects in water filtration.

Comparative Analysis of the Impact of Protein on Virus Retention for Different Virus Removal Filters.

The performance of virus filters is often determined by the extent of protein fouling, which can affect both filtrate flux and virus retention. However, the mechanisms governing changes in virus retention in the presence of proteins are still not well understood. The objective of this work was to examine the effect of proteins on virus retention by both asymmetric (Viresolve® NFP and Viresolve® Pro) and relatively homogeneous (Ultipor® DV20 and PegasusTM SV4) virus filtration membranes. Experiments were performed with bacteriophage ϕX174 as a model parvovirus and human serum immunoglobulin G (hIgG) as a model protein. The virus retention in 1 g/L hIgG solutions was consistently less than that in a protein-free buffer solution by between 1 to 3 logs for the different virus filters. The virus retention profiles for the two homogeneous membranes were very similar, with the virus retention being highly correlated with the extent of flux decline. Membranes prefouled with hIgG and then challenged with phages also showed much lower virus retention, demonstrating the importance of membrane fouling; the one exception was the Viresolve® Pro membrane, which showed a similar virus retention for the prefouled and pristine membranes. Experiments in which the protein was filtered after the virus challenge demonstrated that hIgG can displace previously captured viruses from within a filter. The magnitude of these effects significantly varied for the different virus filters, likely due to differences in membrane morphology, pore size distribution, and chemistry, providing important insights into the development/application of virus filtration in bioprocessing.

Fabrication of Flat Tubular Clay-Based Porous Support Filters

Objective: Mongolia has few freshwater resources. It is therefore important to conserve water resources. An efficient possibility is to purify water and reuse it. Therefore, the scientists from the Material Science Center of the Mongolian University of Science and Technology collaborated with the researcher from the Korea Institute of Material Science and carried out a project between 2017-2020. Theoretical Framework: In this study, Mongolian zeolites and prepared kaolin were used and flat tubular porous support was extruded by a double screw vacuum extruder at KIMS. Method: The supports were burned at 800 and 1000°C and the properties such as pore distribution were determined by mercury porosimetry Results and Discussion: The zeolite-kaolin support had a bulk density of 1.46 g/cm3, a porosity of 41.52% and, an average pore size of 218 nm. With its water permeability of 115 L/m2·h at 0.01 MPa and 970 L/m2·h at 0.08 MPa, the support achieved good results. Research Implications: The wastewater treatment tests show that these membranes also have good compressive strengths. We have cleaned the sewage from a leather factory, which was very highly contaminated and has high viscosity. Originality/Value: Since there is no chemical industry in Mongolia, raw materials for synthetic materials are imported. The main significance of this research work lies in determining the possibility of producing ceramic membranes for water filtration using the mineral resources of our country, and it will serve as the basis for future research.

Boronate-modified electro-spun Fe doped carbon nanofibrous membrane for selective dye adsorption, catalytic degradation, and bacterial inhibition in treatment of water

Recently, dye and microorganism have become the main sources of water pollution due to the rapid development of modern industries and wantonly draining of living sewage. Therefore, the efficient removal of dye and microorganism from the wastewater have attracted considerable attentions of the scientists and engineers around the world. In this regard, a novel phenyl boronic acid (PBA) modified electro-spun Fe doped carbon nanofibrous membrane, C/Fe@PBA, was fabricated in this study for simultaneously selective removal of dye and efficient inhibition of bacteria in water. Firstly, the C/Fe@PBA displayed selective adsorption towards Congo Red (CR) among other dyes by the adsorption order of CR>Methyl Orange (MO) > Neutral Red (NR) > Methylene Blue (MB) > Malachite Green (MG) > Rhodamine B (RhB) with adsorption ability at 25.75, 8.41, 7.11, 7.02, 5.41, and 3.13 mg·g−1. The pseudo first order kinetics and Langmuir isotherm model is calculated to better match the adsorption process of the as prepared membrane towards CR. After 7 rounds of adsorption desorption or 5 degradation cycles, the carbon membrane showed a removal efficiency of 62.2 % or 57.4 %, respectively. Furthermore, the C/Fe@PBA can be employed as effective catalyst to degrade CR in presence of H2O2 under 808 nm near-infrared (NIR) irradiation by the photothermal effect, and the possible catalytic mechanisms and degradation pathway were proposed. Moreover, the as prepared membrane exhibited high bactericidal rate of 99.94 % and 97.44 % against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), respectively. In conclusion, the as prepared carbon membrane with ability of selective adsorption, catalytic degradation, and bacterial inhiation is a promising candidate of filtration membrane in practical sewage management.

Impact of feeding regimes on the performance of anaerobic sequencing batch membrane bioreactor treating wastewater from an urban drain

ABSTRACT This work evaluated an anaerobic sequencing batch membrane bioreactor (AnSBR-MBR) equipped with waste-based ceramic membranes for treating low-strength real drain wastewater. Two feeding regimes, viz. settled feed (Phase 1) and mixed feed (Phase 2) were compared. The biological performance (chemical oxygen demand (COD) and phosphate (PO43-) removal) and filtration performance (total suspended solids (TSS) removal and membrane fouling) were investigated. The reactor characteristics in terms of solids content, sludge settling behaviour, and extracellular polymeric substances (EPS) were also assessed. In Phase 1, the settled feed (with the absence of particulate organic matter) resulted in low volatile suspended solids (VSS; 0.23 ± 0.15 g/L), causing low COD removal (28.38 ± 8.14%). In the mixed feed regime in Phase 2, VSS increased (1.82 ± 0.60 g/L) due to the organic content in the particulate matter, which gave microorganisms additional food, resulting in increased COD removal (47.42 ± 2.81%); this phase was also characterised by lower membrane fouling because of the lower EPS content. Marginally higher TSS removal was obtained as well in Phase 2 (96.72 ± 3.26%) than in Phase 1 (90.48 ± 8.14%). This work demonstrates that AnSBR-MBR performance is superior with mixed drain wastewater containing suspended solids and thus pre-settling is not recommended.

Effectiveness of cloth media filters on mitigating membrane fouling in anaerobic filter membrane bioreactors

Membrane fouling is a persistent challenge that has impeded the broader application of anaerobic membrane bioreactors (AnMBRs). To mitigate membrane fouling, between the outlet of the UASB anaerobic bioreactor and the PVDF membrane to form the anaerobic filter membrane bioreactor (AnFMBR) system. Through comprehensive experiments, the optimal pore size for cloth filters was determined to be 50 μm. A comprehensive assessment over 140 days of operation shows that the novel AnFMBR had significantly greater resistance to membrane pollution than the traditional AnMBR. The AnFMBR system membrane tank exhibited lower mixed liquor suspended solid and mixed liquor volatile suspended solid concentrations, smaller sludge particle sizes, increased hydrophilicity of sludge flocs, and optimized microbial community distribution compared to those of conventional AnMBRs. The total solids foulant accumulation rate in the AnMBR was 5.1 g/m2/day, while in the AnFMBR, the rate was 2.4 g/m2/day, marking a 53.7 % decrease in fouling rate for the AnFMBR compared with the AnMBR. This decrease indicates that integrating the filtration assembly significantly lowered the rate of solid foulant accumulation on the membrane surface, primarily by controlling the buildup of solid foulants in the cake layer, thereby alleviating membrane fouling. AnFMBR compared to AnMBR, the membrane fouling rate halved, effectively doubled the interval between membrane cleaning from seven days, as observed in the AnMBR system, to fourteen days. These findings underscore the potential of integrating cloth media filters into AnMBRs to improve operational efficiency, economic viability, and sustainability.

A novel Pumice@PVA membrane with high separation efficiency for oil-water emulsion application

Oil pollution poses a major threat to both human health and economic development, and therefore the development and improvement of oil-water separation technology is urgent. Traditional methods have problems such as complicated preparation, high cost and the vulnerability of lipophilic materials to oil contamination. Therefore, finding an inorganic material that meets the requirements of underwater superoleophobic performance and reduces surface modification has become a new demand. In this study, natural pumice was found for the first time to have excellent underwater superoleophobic performance and chemical stability, and the underwater superoleophobic filter membrane was prepared by vacuum adsorption using hydrogen bond cross-linking between natural pumice and PVA. The experimental data show that the prepared PVA/natural pumice ultrafiltration membrane has superhydrophilic and superoleophobic properties, and exhibits excellent stability (OWA>150°) under the harsh environment of strong acid and strong alkali. In addition, the composite membrane has good emulsion separation efficiency (>97 %) and a separation flux of 39.91 Lm-2h-1. It is demonstrated that the composite membrane has oleophobic and wettable properties, and is capable of separating both oil-water mixtures without phase mixing and oil-in-water emulsions without oil contamination. This study provides a new idea for the preparation of superoleophobic materials for oil-water separation, which has the potential for large-scale application.

Enhanced filtration membranes with graphene oxide and tannic acid for textile industry wastewater dye removal

ABSTRACT A novel modification technique employing a layer-by-layer (LbL) self-assembly method, integrated with a pressure-assisted filtration system, was developed for enhancing a commercial polyethersulfone (PES) microfiltration (MF) membrane. This modification involved the incorporation of tannic acid (TA) in conjunction with graphene oxide (GO) nanosheets. The effectiveness of the LbL method was confirmed through comprehensive characterization analyses, including ATR-FTIR, SEM, water contact angle (WCA), and mean pore size measurements, comparing the modified membrane with the original commercial one. Sixteen variations of PES MF membranes were superficially modified using a three-factorial design, with the deposited amount of TA and GO as key factors. The influence of these factors on the morphology and performance of the membranes was systematically investigated, focusing on parameters such as pure water permeability (PWP), blue corazol (BC) dye removal efficiency, and flux recovery rate (FRR). The membranes produced with the maximum amount of GO (0.1 mg, 0.55 wt%) and TA as the inner and outer layers demonstrated remarkable FRR and significant BC removal, exceeding 80%. Notably, there was no significant difference observed when using either 0.2 (1.11 wt%) or 0.4 mg (2.22 wt%) in the first layer, as indicated by the Tukey mean test. Furthermore, the modified membrane designated as MF/TA0.4GO0.1TA0.4 was evaluated in the filtration of a simulated dye bath wastewater, exhibiting a BC removal efficiency of 49.20% and a salt removal efficiency of 27.74%. In conclusion, the novel PES MF membrane modification proposed in this study effectively enhances the key properties of pressure-driven separation processes.

A Dual-Function AgNW@COF SERS Membrane for Organic Pollutant Removal and Simultaneous Concentration Determination.

Surface enhanced Raman spectroscopy (SERS) is a highly sensitive analytical detection method commonly employed in biochemical and environmental analysis. Nevertheless, the rapid movement of analytes and interfering components in flow systems can impact the real-time, online detection capability of Raman spectroscopy. To address this issue, we developed an innovative approach utilizing covalent organic framework (COF), a robust porous material with excellent water stability, to coat the surface of Ag nanowire (AgNW) for synthesizing AgNW@COF hybrid. The regular pores of the COF serve to effectively eliminate large interfering molecules while facilitating the efficient transport of specific analytes to SERS hot spots. Additionally, the fluid flow-induced scouring effect aids in excluding interfering molecules from the surface of AgNW. By incorporating AgNW@COF into a bifunctional filter membrane with simultaneous filtration and sensing capabilities, we had achieved efficient purification of organic pollutants as well as real-time identification of pollutant species and concentration.

Exploring the diversity of clays: Impacts of temperature on physicochemical changes, mechanical characteristics, and permeability, and their relevance to membrane applications

This study investigates the characterization of two clays obtained from the Safi and Fez regions, focusing on their analysis for filtration membrane applications. Various analytical techniques were employed, including chemical composition analysis, elemental analysis, mineralogical characterization, carbonate content determination, color assessment, plasticity evaluation, thermal treatment analysis (DTA-TG), mineralogical transformation study, fusion tests, membrane tests, and scanning electron microscopy (SEM).The results reveal significant differences between the two clays regarding their chemical composition. The red clay exhibits a mineralogical composition comprising quartz, calcite, dolomite, hematite, illite, and kaolinite, whereas the gray clay contains quartz, calcite, dolomite, illite, talc, and montmorillonite. Furthermore, upon thermal treatment, both clays exhibit changes in their physical properties.Despite the decrease in porosity and water absorption, as well as the increase in compression strength for both clays, the permeability of the grey clay increases, unlike the red clay, which exhibits a constant permeability beyond 1000°C.These findings highlight the diversity and industrial significance of clays from the Safi and Fez regions for filtration membrane applications. The contrasting properties of red and gray clays provide insights into their potential utilization in different industries. Exploring these clays’ behavior can lead to better filtration membranes and new industrial applications.

Electrospun porous polyacrylonitrile/polyvinylpyrrolidone nanofiber membrane with ultra-hydrophilic and high moisture-permeability for dust personal protection

The serious dust pollution in coal mine working environment can cause occupational lung diseases and other diseases, affecting the life and health of miners. Therefore, the prospect of developing an air filtration membrane with high filtration performance is of remarkable significance. This study prepared a porous Polyacrylonitrile (PAN) /Polyvinylpyrrolidone (PVP) nanofiber membrane based on Electrospinning and post-treatment technology used for downhole personal protection. The prepared porous nanofiber membrane increased the specific surface area by 133.63 % and the porosity by 391.02 % (compared with the pure PAN nanofiber membrane), and was able to achieve a high filtration efficiency of 98.76 % and a low pressure drop of 165 Pa at an air flow rate of 85 L/min. Meanwhile, this study conducted contact angle and moisture permeability tests on the prepared composite fiber membrane. After 1 second of water droplets falling on the fiber membrane, it had a 14° contact angle (strong hydrophilicity), and the moisture permeability reached 4256.677 cm3/m2·d·Pa, which could discharge the water vapor generated by respiration in time. In addition, given the complex and irregular pore distribution of electrospun nanofibers, the fractal correlation dimension of nanofiber membrane pores was studied through fractal theory, and the relationship between the fractal dimension of fiber pores and respiratory resistance was discussed. Based on this, the nanofiber membrane prepared in this study can be widely used in individual protection in mines.

Preparation of ethyl cellulose bimodal nanofibrous membrane by green electrospinning based on molecular weight regulation for high-performance air filtration

Preparing bio-based air filtration membrane through green electrospinning strategy is a vital approach to alleviating environmental and energy crises. However, the development of related biomaterials and method for regulating membrane structure are still lacking. In this study, ethyl cellulose (EC) bimodal nanofibrous membrane was prepared by electrospinning using ethanol and water as solvents to achieve high-performance air filtration. A new strategy for bimodal fiber molding based on molecular weight modulation was proposed. The EC polymer chains with medium molecular weights were subject to the highest degree of inhomogeneity of solvent intrusion, and there were significant differences in viscous forces “microscopically”, leading to the formation of bimodal structure by inhomogeneous stretching of the jet. The well-defined bimodal structure endowed EC membrane with excellent air filtration performance. The filtration efficiency for PM0.3, pressure drop, quality factor were 99.11 %, 42.2 Pa, and 0.112 Pa−1, respectively. Compared to the commonly used zein, EC cost just 12.77 %, and its solution had a 50 % longer shelf life, making it a more desirable biomaterial. This work will facilitate the application of more biomaterials in air filtration, promote the green fabrication of high-performance air filtration membranes, and realize sustainable development.

A New Method for Growth Factor Enrichment from Dairy Products by Electrodialysis with Filtration Membranes: The Major Impact of Raw Product Pretreatment.

This study is focused on fractionation of insulin-like growth factor I (IGF-I) and transforming growth factor-β2 (TGF-β2) using a new electro-based membrane process calledelectrodialysis with filtration membranes (EDFM). Before EDFM, different pretreatments were tested, and four pH conditions (4.25, 3.85, 3.45, and 3.05) were used during EDFM. It was demonstrated that a 1:1 dilution of defatted colostrum with deionized water to decrease mineral content followed by the preconcentration of GFs by UF is necessary and allow for these compounds to migrate to the recovery compartment during EDFM. MS analyses confirmed the migration, in low quantity, of only α-lactalbumin (α-la) and β-lactoglobulin (β-lg) from serocolostrum to the recovery compartment during EDFM. Consequently, the ratio of GFs to total protein in recovery compartment compared to that of feed serocolostrum solution was 60× higher at pH value 3.05, the optimal pH favoring the migration of IGF-I and TGF-β2. Finally, these optimal conditions were tested on acid whey to also demonstrate the feasibility of the proposed process on one of the main by-products of the cheese industry; the ratio of GFs to total protein was 2.7× higher in recovery compartment than in feed acid whey solution, and only α-la migrated. The technology of GF enrichment for different dairy solutions by combining ultrafiltration and electrodialysis technologies was proposed for the first time.

Hierarchical three-layered fibers for bioaerosol and CO2 capture, and antimicrobial performance

As the duration of indoor activities has increased owing to environmental issues and the prevalence of respiratory diseases, it has become important to reduce indoor air pollutants. In this study, air filters with structurally modified surfaces are fabricated to effectively capture and remove indoor air pollutants. High-temperature alkali treatment is applied to a smooth fiber filter to convert it into porous calcium silicate hydrate and create a hierarchical three-layered (H3L) fibrous structure. The outer, middle, and inner layers of the H3L fiber are designed for bioaerosol capture and disinfection, CO2 capture, and maintenance of mechanical strength, respectively. An antimicrobial agent ((3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride, TPMMC) is covalently grafted onto the surface of H3L fibers to impart antimicrobial performance. The H3L-TPMMC filter outperforms the bare filter in capturing E. coli and S. aureus aerosols, displaying improved quality factors of 31.9 % and 63.9 %, respectively. It achieves a 99.999 % reduction and 99.790 % for the collected E. coli and S. aureus aerosols, respectively. The H3L-TPMMC filter demonstrates selective CO2 capture and maintains consistent performance and antimicrobial efficacy even in environments with bioaerosols and CO2. This hierarchical filter membrane provides an efficient approach for reducing various indoor air pollutants using a single filter system.

Influence of Particle Surface Energy and Sphericity on Filtration Performance Based on FLUENT-EDEM Coupling Simulation

The adhesion of dust particles on the surface of the dust collector tends to cause great resistance to the dust collector and affects the operating efficiency. In order to visualize particles in the filtration process and to grasp the mechanism of particle viscosity and sphericity on filtration performance, a numerical simulation study was conducted to investigate the deposition behavior of particles during filtration, employing FLUENT-EDEM coupling technology. By examining the deposition process, the role of particle characteristics on dust behavior within the entire filtration system was elucidated. The effects of varying particle surface energy and particle sphericity on filtration pressure drop and cake porosity were analyzed. The findings reveal that under the force of the air, particles on the surface of the filter membrane experience compaction, leading to a reduction in the porosity of the formed cake layer. The diminution of porosity serves to impede the air, consequently augmenting the pressure drop across the filtration system and hindering the operational efficacy of the dust collector. As the surface energy of the particles increases, the adhesive forces between particles are intensified, leading to an elevation in the porosity of the cake layer and a subsequent decrease in the pressure drop. When the surface energy of the particles is increased from 0.01 J/m2 to 0.04 J/m2, the porosity experiences a modest increase of only 9.1%, yet the pressure drop is significantly reduced by half, amounting to a decrease of 1594 Pa. Under high particle surface energy, as filtration air velocity increases, particles are compressed, resulting in a decrease in cake porosity and an increase in pressure drop. Concurrently, our findings indicate that as the sphericity of particles increases, their surfaces become increasingly smooth which in turn results in a decreased porosity of the cake layer and, consequently, an elevation in the filtration pressure drop.

Simultaneous SERS-decoding detection of multiple pathogens in drinking water with home-made portable double-layer filtration and concentration device.

Theengineering of a home-made portable double-layer filtration and concentration device with the common syringe for rapid analysis of water samplesis reported. The core elements of the device were two installed filtration membranes with different pore sizes for respective functions. The upper filtration membrane was used for preliminary intercepting large interfering impurities (interception membrane), while the lower filtration membrane was used for collecting multiple target pathogens (enrichment membrane) for determination. This combination can make the contaminated environmental water, exemplified by surface water, filtrated quickly through the device and just retained the target bacteria of Escherichia coli O157:H7, Staphylococcus aureus, and Listeria monocytogenes on the lower enrichment membrane. Integrating with surface-enhanced Raman spectra (SERS) platform to decode the SERS-Tags (SERS-TagCVa, SERS-TagR6G, and SERS-TagMB) already labeled on each of the enriched bacteria based the antibody-mediated immuno-recognition effect, fast separation, concentration, and detection of multiple pathogenic bacteria from the bulk of contaminated environmental water were realized. Results show that within 30min, all target bacteria in the lake water can be simultaneously and accurately measured in the range from 101 to 106 CFU mL-1 with detection limit of 10.0 CFU mL-1 without any pre-culture procedures. This work highlights the simplicity, rapidness, cheapness, selectivity, and the robustness of the constructed method for simultaneous detecting multiple pathogens in aqueous samples. This protocol opens a new avenue for facilitating the development of versatile analytical tools for drinking water and food safety monitoring in underdeveloped or developing countries.

Reusable MIL-100(Fe)-polyacrylonitrile-TiO2 nanofiber webs for adsorption and decomposition of toluene

Due to rapid industrialization and urbanization, addressing the pressing issue of environmental pollution, particularly indoor air quality, demands innovative solutions. Volatile organic compounds (VOCs), notably toluene, are prevalent indoor pollutants that necessitate effective adsorption and removal strategies due to their adverse health impacts. Here, we propose a novel method for crafting a multifunctional air-filter membrane capable of simultaneous toluene adsorption and photocatalytic degradation across diverse light conditions, thus facilitating the development of a reusable air filtration system. This study outlines the successful synthesis of an air filter membrane by illustrating the in-situ growth of MIL-100(Fe) particles on polyacrylonitrile (PAN) nanofibers loaded with TiO2 nanoparticles, resulting in the formation of a PTF membrane. The PTF membrane exhibits an exceptional toluene adsorption efficiency of 98 % and a high toluene capacity of 383.94 mg g−1 (4.166 mmol/g), with a corresponding partition coefficient (PC) of 38.39 L/g ± 1.41. Notably, its design enables functionality, demonstrating impressive photocatalytic degradation efficiencies of 62.3 %, 71.3 %, and 80.2 % under UV, visible, and combined UV–visible light, respectively. This high efficiency is attributed to the PTF membrane’s reduced bandgap and enhanced light-absorption capabilities. Under the combined light conditions, the PTF membrane achieved the highest space–time yield (STY) of 0.197 mol/g/h and the highest reaction kinetic rate for toluene degradation, determined to be 6.34 × 10-8, surpassing the performance observed under individual UV and visible light sources. Moreover, the regeneration cycle of the PTF membrane demonstrates minimal efficiency loss, ensuring prolonged performance. The developed PTF membranes demonstrate notable stability and resilience even under the most extreme humid conditions, suggesting their strong potential for future applications in air filtration. This innovative approach offers a straightforward and environmentally friendly method for fabricating metal–organic framework (MOF)-based photocatalytic filters tailored to indoor VOC purification systems. This study is expected to significantly advance efforts aimed at improving and managing air quality, thereby fostering a healthier and more sustainable environment.

Application of Membrane Bioreactor (MBR) for Antibiotic Elimination From Wastewater

In this study, a membrane bioreactor – MBR system at laboratory-scale was designed to remove sulfamethoxazole (SMX) in water. The system consists of a 8-liter aerobic tank combined with a hollow fiber micro filtration membrane (MF). Influent flow rate of wastewater was 15,84 L/day. Affecting factors to treatment efficiencies (organic pollutants and antibiotics) such as contact time and initial antibiotic concentration were investigated. Experimental results indicated that wastewater with initial parameters COD, NH4+, NO3-, PO43- were respectively 240, 9,4, 37,5, 6,3 mg/L, the treatment efficiencies achieved were respectively at 63,4, 89,7, 78,1, and 79,8%. The removal efficiencies of the wastewater containing SMX (concentrations range from 0,052 to 0,268 mg/L) for COD and NH4+ decreased by 4,2 and10,9% respectively, and for NO3- and PO43- increased by about 4,5 and 7,9%, correspondingly. Overall SMX elimination performance is about 49,7%.

Multifunctional nanofibrous membranes for highly efficient harsh environmental air filtration and oil–water separation

With the acceleration of the global industrialization process, the treatment of corrosive waste gas and oily wastewater in pharmaceutical, petrochemical and smelting fields still remains tremendous challenges. Herein, a robust polysulfonamide/polyacrylonitril@silica (PSA/PAN@SiO2) nanofibrous membrane with a hierarchical structure was successfully developed to deal with air filtration and oil–water separation under practical complex environments. In the process of air purification, the synergistic effect of multiple components could effectively surmount the conflict between pollution particle removal efficiency and pressure resistance. The air cleaning efficiency (PM0.3) of the PSA/PAN@SiO2 composite membranes could reach 99.05 ± 0.13 % at a low pressure drop of 30 ± 2 Pa. Due to the outstanding stability of PSA and SiO2, the composite membranes still possessed stable filtration performance in complex environments (strong acid, strong alkali and high temperature). Furthermore, PSA/PAN@SiO2 composite membranes with unique wettability (under oil superhydrophobicity and underwater superoleophobicity) could efficiently separate oil–water mixtures and emulsions. This multifunctional filtration membrane provides enormous application potential for the field of individual protection and environmental governance, even in complex environments.