M2 Membrane Research Articles

Hyperbranched polyester amide/polyethersulphone mixed matrix nanofiltration membranes for contaminant rejection.

Nanofiltration (NF) separation technology is a low-pressure filtration process, which is highly efficient and environmentally friendly. As a result, it has found wide application in water treatment. This work describes the preparation of flat sheet membranes via the phase inversion method using blends of hyperbranched polyester amide (PEA) and polyether sulphone (PES) in definite ratios. The obtained mixed matrix membranes were characterized using FTIR, TGA and contact angle analysis, and their morphologies were investigated using SEM. SEM images showed a porous membrane with micro-voids found underneath, confirming the suitability of the membranes for nanofiltration. Adding PEA to PES changed the porosity, which changed the membrane performance. Examining the removal of heavy metals [Pb(NO3) and CuSO4] using the prepared membranes revealed that the NF membranes had a higher salt rejection efficiency than pure PES with a good permeate flux. M3 membrane showed 81% rejection of Pb (NO3)2, while M2, the membrane with a low PEA ratio, rejected 85%, with high water flux for both membranes. Moreover, the presence of PEA in the membrane tissue led to protein rejection up to 99.5%. Thus, these novel blend membranes proved themselves as NF-type membranes with better performance in water treatment.

Sustainable Pb(II) Removal and Recovery from Wastewater Using a Bioinspired Metal-Phenolic Hybrid Membrane with Efficient Regeneration.

High-performance adsorbents often require efficient selectivity in wastewater, recoverability, and ease of multiple regeneration cycles, but achieving this remains a significant challenge. We report a new strategy for the efficient removal of lead (Pb(II)) from contaminated water streams using an innovative tannic acid (TA)-Fe(III)-based metal-phenolic network (MPN) hybrid membrane (MPN-PAM). This novel membrane exploits the tunable pH-sensitive coordination structure of the MPN to achieve selective removal and recovery of Pb(II) while enabling efficient membrane regeneration by filtration. This membrane demonstrates superior selectivity for Pb(II) with a removal efficiency of up to 98 % and an adsorption capacity of approximately 117.58 mg/g, even in the presence of high salinity, as well as coexisting heavy metals. The membrane maintains high Pb(II) removal efficiency over 20 consecutive cycles and 95 % efficiency over 10 regeneration cycles. Under continuous operation, it treats approximately 85 L per m2 of membrane, reducing Pb(II) concentrations to trace levels (~40 μg/L), meeting electroplating wastewater standard (GB21900-2008). Additionally, even low concentrations of Pb(II) (<5 mg/L) are efficiently purified to below WHO drinking water standard (10 μg/L). The operational cost for treating Pb(II)-contaminated wastewater is about $0.13 per ton, highlighting the cost-effectiveness and potential for large-scale application in wastewater treatment.

Macrophage membrane-encapsulated miRNA nanodelivery system for the treatment of hemophilic arthritis

Hemophilic arthritis (HA) is one of the most pathologically altered joint diseases. Specifically, periodic spontaneous hemorrhage-induced hyperinflammation of the synovium and irreversible destruction of the cartilage are the main mechanisms that profoundly affect the behavioral functioning and quality of life of patients. In this study, we isolated and characterized platelet-rich plasma-derived exosomes (PRP-exo). We performed microRNA (miRNA) sequencing and bioinformatics analysis on these exosomes to identify the most abundant miRNA, miR-451a. Following this, we developed an M@ZIF-8@miR nanotherapeutic system that utilizes nanoscale zeolitic imidazolate framework (ZIF) as a carrier for miRNA delivery, encapsulated within M2 membranes to enhance its anti-inflammatory effects. In vitro and in vivo studies demonstrated that M@ZIF-8@miR significantly reduced pro-inflammatory cytokines, controlled synovial inflammation, and achieved potent therapeutic efficacy by reducing joint damage. We suggest that the ability of M@ZIF-8@miR nanocomposites to inhibit pro-inflammatory cytokines, enhance cellular uptake, and exhibit good endosomal escape properties makes them promising carriers for the efficient delivery of therapeutic nucleic acid drugs. This approach delays joint degeneration and provides a promising combinatorial strategy for HA treatment.

Refinery oily wastewater treatment using PVC/SiO2 ultrafiltration membranes

AbstractPolyvinyl chloride (PVC)/SiO2 membranes were prepared and characterized for ultrafiltration of oily wastewater from Tabriz Oil Refinery. The results showed that the addition of SiO2 into the membranes increased the density of surface pores. The contact angle decreased from 78.89° for the PVC membrane to 63.16° for the 0.75% PVC/SiO2 membrane, indicating that the presence of SiO2 resulted in enhancement of hydrophilicity. In addition, the pure water flux of the membranes witnessed an increasing trend with increasing SiO2 content. The mechanical tensile strength of the membranes was enhanced as a result of the reinforcement effect of nanoparticles. The results of filtration revealed that the antifouling properties and rejection of the composite membranes were higher than those of the PVC membrane because of the presence of SiO2. Membrane M3 containing 0.75 wt.% SiO2 nanoparticles exhibited a rejection of 84.19%, a total fouling ratio (TFR) value of 31.7% and an irreversible fouling ratio (IFR) value of 6.4%. In general, PVC/SiO2 membranes exhibited acceptable performance and can be tested for separation applications.

Innovation of poly(ionic liquid)-stabilized TiO2 for membrane-based dye waste remediation

Organic–inorganic nanohybrids based membrane materials are reported for separation applications. In the present study, poly(ionic liquid)-stabilized TiO2/polysulfone-based mixed matrix membranes are produced using a phase separation technique induced by a nonsolvent. The presence of PIL-stabilized TiO2 nanohybrids and the hydrophilic nature of PIL enhance the overall hydrophilicity of the PSf membrane, reaching an impressive water flux of 158 LMH at an operating pressure of 6 bar. Further, membranes were characterized through, Field emission scanning electron microscopy, X-ray diffraction, Atomic force microscopy, Thermogravimetry, and Zeta potential. The synergistic effect of positively charged PIL and TiO2 nanohybrids enhances the membrane's anionic dye retention capability, achieving retention rates of nearly 90.83% for Methyl Blue, 94.28% for Congo red, 65.89% for Evan's blue, and 30.98% for Methyl orange with respect to dye size. However hydrophilic membrane showed outstanding antifouling property of the M2 membrane achieved ∼77% of flux recovery ratio with minimal of ∼37% total fouling for 1000 ppm of Bovine Serum Albumin as a foulant. Highly efficient nanocomposite membranes exhibit significant potential for dye removal and addressing water contamination issues, making them attractive solutions for sustainable fouling resilient water treatment processes.

Bioinspired black phosphorus delivers histone deacetylase inhibitor-induced synergistic therapy for lung cancer

Lung cancer remains one of the most fatal cancers worldwide, with a high incidence of metastasis and a low 5-year survival rate. Histone deacetylase inhibitors (HDACis) have shown significant potential in lung cancer treatment, but their clinical use is often hindered by poor water solubility, rapid clearance, and systemic toxicity. In this study, we developed a novel therapeutic strategy by camouflaging black phosphorus (BP) with M1 macrophage membranes (MB) and loaded HDACi suberoylanilide hydroxamic acid (SAHA) onto the camouflaged black phosphorus (MB) for targeted lung cancer therapy. The M1 membrane coating enhanced the specificity of the SAHA-loaded black phosphorus toward lung cancer cells. Black phosphorus not only served as a carrier for HDACis but also facilitated photothermal therapy (PTT) through its photothermal conversion capabilities, establishing a highly efficient therapeutic platform. MBS demonstrated strong antitumor activity with minimal systemic toxicity. This multifunctional platform, inspired by biological systems, shows great promise for delivering a wide range of HDACis and offers synergistic therapeutic potential through the combination of photothermal therapy and chemotherapy.

Investigating novel thin-film nanocomposite membranes for sustainable water recovery using fertilizer-driven forward osmosis – Experimental and machine learning approaches

Water recovery from municipal wastewater can augment freshwater resources to meet increasing demand. An osmotic-driven membrane separation process- forward osmosis (FO) is currently being explored as a sustainable technology. This work proposes to address the challenges associated with FO namely (i) robust membrane and (ii) draw solute (DS) recovery. Robust thin-film nanocomposite membranes incorporating a) nickel ferrite or b) nitrogen-enriched nanoporous polytriazine (NENP-1) covalent organic framework were fabricated with enhanced hydrophilicity, surface roughness and anti-fouling properties. The optimum membranes M2 and C2 displayed a pure water flux of 4.86 ± 0.11 and 5.4 ± 0.2 L/m2h respectively and a specific reverse solute flux (SRSF) <<1 when using 1 M NaCl solution as the DS (feed solution – DI water). Fertilizer-driven FO (FDFO) was proposed as the diluted DS need not be recovered but could be used directly for irrigation. The pure water flux for both M2 and C2 membranes were in the following order for the fertilizers used as DS (1 M) - (NH4)2SO4 + (NH₄)₂HPO₄ > (NH4)2SO4 > (NH₄)₂HPO₄ which indicates that the mixed ions in the DS enhanced the water permeance. In all cases, the SRSF was < 1 g/L indicating the feasibility of the process. The membranes exhibited a TOC removal of > 90 % from synthetic municipal wastewater containing persistent organic pollutants and personal & pharmaceutical care products and the membranes could be regenerated after washing with a 10 mM solution of SDS for 5 cycles of operation. Further, ANN was used to develop a predictive model for water flux in FO membranes and the optimized architecture of 7–5–50–40–1 displayed a remarkable overall R2 value of 0.98 (MSE= 0.027). The FDFO process using the fabricated thin-film nanocomposite membranes holds enormous potential to be investigated in larger-scale studies.

Preparation of TA-O-MoS2/PES mixed matrix ultrafiltration membrane for rare earth wastewater treatment

The trade-off between permeability and selectivity, along with the issue of membrane fouling, has constrained the widespread application of ultrafiltration (UF) membranes in recycling rare earth wastewater. Here, we present the incorporation of tannic acid (TA) modified molybdenum disulfide oxide (O-MoS2) as a functional enhancer to fabricate polyethersulfone (PES) based mixed matrix membranes through a nonsolvent induced phase separation (NIPS) approach. Compared to the unmodified PES membrane, the integration of TA-O-MoS2 significantly improves the hydrophilicity, porosity in the mixed matrix membrane. By altering the concentration of TA-O-MoS2, the TA-O-MoS2/PES UF membrane achieves enhanced hydrophilicity and charge properties, resulting in a remarkable improvement in separation performance. Specifically, the optimized membrane M2 (TA-O-MoS2 addition of 0.1 wt%) exhibits a water flux of 140.98 Lm−2h−1bar−1 and a PEG 20000 rejection rate of 91.00 %, representing increases of 180 % and 120 % over the control PES membrane, respectively. Notably, membrane M2 effectively retains 91.31 % of macromolecular organic compounds in rare earth wastewater, while permitting nearly complete passage of inorganic salts, for instance CaCl2 (3.26 %) and MgSO4 (4.84 %). Moreover, the TA-O-MoS2/PES membrane demonstrates robust antifouling properties and exceptional durability, indicating its significant potential for efficient treatment and resource recovery in rare earth wastewater.

Desalination Performance Evaluation of hBN@UiO‐66 MOF Incorporated Hollow Fiber Membrane using Membrane Distillation

AbstractIn the present study, the polyvinylidene fluoride (PVDF) modified hollow fiber (HF) membranes have been synthesized by dry‐jet wet phase inversion technique for desalination via direct contact membrane distillation (DCMD). UiO‐66 metal‐Organic framework (MOF) and surface‐modified UiO‐66 with h‐BN nanomaterial have been incorporated with PVDF‐HF membrane. The various analytical methods like FE‐SEM, FTIR, PXRD, TGA, tensile strength, were used to characterize prepared MOF and HF membranes. It was observed from DCMD results that the h‐BN@UiO‐66/PVDF (M3) HF membrane gives higher flux than UiO‐66/PVDF (M2) and pure PVDF (M1) membrane. In the present investigation, response surface methodology (RSM) by box‐behnken design (BBD) was used to optimize the DCMD system and evaluate the behavior of operating parameters such as feed temperature, feed concentration, and feed flow rate. The optimum operating values of feed temperature, feed flow rate, and feed concentration were found as 65 °C, 1 LPM, and 1.5 wt.%, respectively. Under optimum conditions, the M3 HF membrane gives the highest flux of 26.78 L/m2 ⋅ h compared to M2 and M1 membranes. During DCMD, salt rejection is almost greater than 99.8 % for all prepared membranes. Other salts like potassium chloride (KCl), Magnisium Sulphate (MgSO4), and calcium sulphate (CaSO4) are also used to check salt rejection of all membranes at optimum operating conditions. Moreover, the M3 membrane exhibits stable permeate flux and high salt rejection (&gt;99.9 %) at optimized process parameters over 80 h running. Overall, the present study provides the positive effects of h‐BN nanoparticles and UiO‐66 MOF on HF membrane to improve performance in DCMD.

Exercise Intolerance in McArdle Disease: A Role for Cardiac Impairment? A Preliminary Study in Humans and Mice.

Whether cardiac impairment can be fully discarded in McArdle disease-the paradigm of 'exercise intolerance', caused by inherited deficiency of the skeletal muscle-specific glycogen phosphorylase isoform ('myophosphorylase')-remains to be determined. Eight patients with McArdle disease and seven age/sex-matched controls performed a 15-minute moderate, constant-load cycle-ergometer exercise bout followed by a maximal ramp test. Electrocardiographic and two-dimensional transthoracic (for cardiac dimension's assessment) and speckle tracking [for left-ventricle global longitudinal (GLS) assessments] echocardiographic evaluations were performed at baseline. Electrocardiographic and GLS assessments were also performed during constant-load exercise and immediately upon maximal exertion. Four human heart biopsies were obtained in individuals without McArdle disease, and in-depth histological/molecular analyses were performed in McArdle and wild-type mouse hearts. Exercise intolerance was confirmed in patients ('second wind' during constant-load exercise, -55% peak power output vs controls). As opposed to controls, patients showed a decrease in GLS during constant-load exercise, especially upon second wind occurrence, but with no other between-group difference in cardiac structure/function. Human cardiac biopsies showed that all three glycogen phosphorylase-myophosphorylase, but also liver and especially brain-isoforms are expressed in the normal adult heart, thereby theoretically compensating for eventual myophosphorylase deficiency. No overall histological (including glycogen depots), cytoskeleton, metabolic or mitochondrial (morphology/network/distribution) differences were found between McArdle and wild-type mouse hearts, except for lower levels of pyruvate kinase M2 and translocase of outer membrane 20 kDa subunit in the former. This study provides preliminary evidence that cardiac structure and function seem to be preserved in patients with McArdle disease. However, the role for an impaired cardiac contractility associated with the second wind phenomenon should be further explored.

Effect of surfactants on the permeation rate and selectivity of polyamide composite membranes for organic solvent nanofiltration

Solvent-resistant membranes are pivotal in industrial separations. This study aims to develop thin-film composite polyamide (TFC-PA) membranes with enhanced organic solvent nanofiltration (OSN) capabilities. Polyallylamine hydrochloride (PAAH) was used as the aqueous amine and isophthaloyl chloride (IPC) as the crosslinker to form the polyamide active layer by interfacial polymerization (IP) on a polyacrylonitrile (PAN) support. The impact of using anionic sodium dodecyl sulfate (SDS) and cationic cetyltrimethylammonium bromide (CTAB) to act as phase transfer agents during IP was investigated to understand their potential for facilitating the transfer of PAAH to the organic phase for reaction with IPC. The SDS and CTAB were separately dissolved into the PAAH solutions before IP to evaluate their effects on membrane properties. Extensive characterization including SEM, EDX, AFM, Water Contact Angle, ATR-FTIR, and Solid (CP-MAS) 13C NMR revealed various chemical and structural features of the membrane. The membrane M2 (PAAH-IPC) (exhibited >98% rejection for various anionic and cationic dyes. The inclusion of SDS during interfacial polymerization led to a substantial 3-fold increase in methanol permeate flux from 31 L m−2 h−1 to 119 L m−2 h−1, at a pressure of 15 bar. Conversely, the addition of CTAB resulted in membranes with higher permeate flux but insufficient dye rejection. Moreover, after three weeks of static aging of the membranes no significant changes were detected in either permeability or solute rejection, substantiating the stability of membranes.

Surface functionalization of polytetrafluoroethylene membrane by polydopamine and quaternary ammonium compound for fouling mitigation in membrane distillation of secondary effluent

Considering the worldwide water scarcity issue, membrane distillation (MD) offers a promising solution for producing reclaimed water from secondary effluent generated by municipal wastewater treatment plants. However, prolonged operation of MD systems can result in membrane fouling, which impairs separation efficiency and shortens the membrane's lifespan. To overcome these challenges, novel surface-modified polytetrafluoroethylene (PTFE) membranes have been developed through a combination of polydopamine deposition and quaternary ammonium compound (QAC) grafting (named as PDQ membranes). The objectives of this preparation are to reduce the membrane hydrophobicity, impart anti-adhesive and bactericidal properties, and improve water permeability and antifouling performance in the MD system. In particular, the membrane coated by a QAC solution with the concentration of 40 mM (named as M3 membrane), achieved a flux of 47.0 LMH, surpassing the original PTFE membrane by 11.4%. During the long-term direct contact membrane distillation operation with the secondary effluent, the M3 membrane exhibited significantly superior antifouling capability than the PTFE membrane. Undergoing three runs of the MD process, the flux reduction of M3 was only 38.1%, whereas the flux of original PTFE membrane experienced a 71.4% decline. The PDQ membranes were also capable of providing stable distillate quality (over 40 h). Notably, the M3 demonstrated a high rejection capability, with an impressive removal efficiency of 96.9% for low molecular weight organics and 92.5% for humus-like substances. Additionally, the PDQ membrane exhibited good anti-bioadhesion and bactericidal properties. This study highlights the promising application potential of the PDQ membrane for fouling mitigation in water and wastewater treatment.

Green polycaprolactone/sulfonated kraft lignin phase inversion membrane for dye/salt separation

Exploring environmentally friendly, renewable, and cost-effective raw materials is essential in sustainable membrane fabrication. This study presents a facile and scalable method for fabricating a green and biodegradable tight ultrafiltration membrane for dye/salt separation. This involves simply blending biodegradable polycaprolactone (PCL) with the low-cost biobased sulfonated kraft lignin (SKL) additive. Additionally, we employed acetic acid as a green alternative solvent to enhance the sustainability of the membrane fabrication process. The incorporation of hydrophilic SKL into the PCL matrix resulted in increased hydrophilicity (water contact angle changed from 72° to 56°), surface roughness (increased from 29 nm to 43.5 nm), and enhanced negative electrostatic charge of the membrane (−40 mV to −45 mV). The optimized PCL/SKL membrane (M3) exhibited excellent water flux (∼45 LMH) under 40 psi hydraulic pressure coupled with ∼98 % and ∼10 % rejection rates for reactive red (RR) dye and NaCl, respectively. Moreover, the M3 membrane maintained its exceptional dye/salt fractionation performance while separating the mixtures at low salt concentrations. However, with increasing salt concentration (1–50 g/L), the membrane's RR dye rejection declined from ∼90 % to ∼50 %, with a significant reduction in NaCl and Na2SO4 salts rejection (from ∼14 % to ∼1 % and ∼22 % to –∼1 %, respectively). The M3 membrane exhibited remarkable antifouling properties during dye and humic acid filtration with a high flux recovery ratio (>98 %) and low flux decline rate (<7 %). The PCL/SKL membrane also showed excellent stability and maintained consistent separation performance over a long period. Overall, the novel biodegradable PCL/SKL membrane prepared in this study presents a promising avenue toward sustainable membrane fabrication for wastewater treatment applications.

Efficient decolorization performance of graphene quantum dots modulated nanofiltration membranes with tunable pore size for precise molecular sieving

The discharge of wastewater containing dyes not only causes serious environmental pollution but also poses a severe threat to human health. The selective separation of dyes and reuse of inorganic salts are vital in the textile industry. In this work, nitrogen-doped graphene quantum dots (N-GQDs) was successfully synthesized via the “one-step solvothermal method”, and the N-GQDs composite membranes were innovatively fabricated by constructing a thin selective layer top the modified multi-walled carbon nanotubes (MWCNTs) matrix membrane via interfacial polymerization process. The pore size of the N-GQDs membranes could be flexibly modulated by regulating the contents of the N-GQDs. The suitable N-GQDs membrane (M4, 0.35 wt% of N-GQDs) possessed over 96 % rejection rate for diverse charged dyes, which was higher than that of the piperazine polyamide (PA3) membrane. Notably, the rejection of the smaller molecular weight of Methylene Blue by the M4 membrane reached ∼98.93 %, which was higher than that reported in most literature, mainly owing to the relatively smaller average pore size and stronger electronegativity of the membrane. Especially compared with our previous work, the prepared M3 and M4 membranes exhibited an enhancement of ∼37.79 % and 39.48 % in rejection of Methylene Blue, ∼ 78 % and 19 % in pure water permeability, respectively. On account of the size sieving and charge effect, the N-GQDs membrane (M4) could maintain high rejection for dyes and exhibited efficient separation for dye/salt with a separation factor of 115 for the Congo Red/sodium chloride mixture after continuous cross-flow filtration for 24 h in the simulated wastewater condition. Furthermore, the N-GQDs membrane also exhibited favorable acid-base resistance and satisfactory anti-fouling performance. Importantly, the N-GQDs membranes presented excellent decolorization efficiency for the practical textile wastewater. These results revealed that the as-prepared N-GQDs membrane possessed great potential for actual textile wastewater advanced treatment and purification. This study also offers a new candidate to rationally manipulate the separation properties of nanofiltration membranes adopting new aqueous monomers.

The engineering legacy of the FIFA World Cup Qatar 2022TM: Al Bayt Stadium

In contemporary architecture, textile membranes offer a wide range of possible structural applications, especially for facades and roofs with large spans and where the reduction of self-weight plays an important role for an efficient and sustainable structural design. On 30 November 2021, the Al Bayt Stadium was inaugurated in Qatar; with its 190 000 m2 of textile membrane it is one of the biggest architectural membrane projects in the world. An innovative new membrane material with a natural textile appearance was developed from scratch to meet the specific requirements of the project. This makes the construction of Al Bayt Stadium, shaped like the local Bedouin tents, a milestone in modern membrane architecture; this is attributable not only due to the pure size of the membrane, but also to the significant advances made in textile membrane material design and development as part of the project. Other design aspects include the large, retractable roof above the pitch, which transforms the open-air stadium into a fully enclosed and temperature-controlled multi-purpose arena within minutes. This paper presents details of the design and construction aspects of the stadium, as well as the material development conducted for the inner membrane.

High hydrogen permeability of Pd-Ru-In membranes prepared by electroless co-deposition

In this work, Pd-Ru-In membranes were prepared by electroless co-deposition and characterized by SEM, XRD, XPS, AES and hydrogen permeation test. The results show that defect-free 5–6 μm thick Pd-Ru-In membrane with homogeneous element distribution was successfully prepared. The composition of the membrane is Pd-Ru0.5at%-In1at% (M1) and Pd-Ru0.5at%-In2at% (M2), respectively. The hydrogen permeability of the membrane M2 reaches 1.32 × 10-8 mol·m−1·s−1·Pa−0.5 at 773 K, which is 1.6 times higher than that of a Pd-Ru0.5at% membrane prepared under the same conditions. The addition of the element In leads to a structural evolution of the membrane: the lattice parameters of the Pd-Ru-In membranes increase. This lattice expansion results in an improvement in the hydrogen permeability. Our study provides a useful reference for the fabrication of Pd-Ru-In ternary membranes with high hydrogen permeability.

Removal of organochlorine pesticides by nanofiltration membranes modified with NH2-MWCNTs

Excessive use of pesticides and therefore the spread of pesticides in the environment with destructive effects on human and animal health is a very great problem in the world. In this study, the removal of three samples of organochlorine pesticides including aldrin, lindane, and endosulfan was investigated using nanofiltration membranes modified with NH2-MWCNTs. The properties of the prepared membranes were investigated by scanning electron microscopy (SEM), contact angle, water content, porosity, and mechanical strength. The performance of the membranes was evaluated by analysis of the rejection and flux of pesticide solutions at different pH. The addition of NH2-MWCNTs to the polymer matrix significantly improved the hydrophilic properties of the membranes and reduced the contact angle. Membrane flux was also improved by increasing the concentration of carbon nanotubes to 0.2 wt%. The highest flux at pH 10 is related to lindane pesticide. The modified membrane with 0.5 wt% functionalized carbon nanotubes showed a 98% rejection for endosulfan at neutral pH compared to the pure membrane. In the pH range experiment, lindane rejection was lower than of other pesticides. The steric hindrance due to the structure and molecular size of pesticides and interaction with membrane surface was very important in membrane efficiency. The M3 membrane with 0.3 wt% NH2-MWCNTs revealed high antifouling performance.

Photodegradation of imidacloprid insecticide using polyethersulfone membranes modified with iron doped cerium oxide

AbstractThe widespread accumulation of insecticides in water systems is a growing concern. This study reports efficient photodegradation of imidacloprid (IMD) insecticide using polyethersulfone (PES) membranes modified with iron‐doped cerium oxide (Fe‐CeO2). The work focuses on the modification of ultrafiltration polyethersulfone membranes with incremental amounts of Fe‐CeO2 photocatalysts (0.5–2.0 wt.%) using phase inversion method. An increase in Fe‐CeO2 content showed an improvement in surface roughness and porosity of membranes. Pure water flux (PWF) increased from 55.9 L m2 h−1 in M0 (PES) to 77.2 (M1, 0.5% Fe‐CeO2‐PES), 118.0 (M2, 1% Fe‐CeO2‐PES), 128.0 in M3 (1.5 wt.% Fe‐CeO2‐PES) and then decreased to 98.5 L m2 h−1 in M4 (2 wt.% Fe‐CeO2‐PES). This decrease is brought about by the high Fe‐CeO2 content, which minimizes the membranes' surface pores. Fe‐CeO2 photocatalysts are thought to give the membrane both hydrophilic and photocatalytic qualities because of their capacity to absorb light and create radical species that cause the photodegradation of IMD molecules. Consequently, under visible light irradiation, modified membranes demonstrated photocatalytic ability over IMD. Photocatalytic efficiencies of the membranes were found to be 5.2% (M0), 68.9 (M1), 75.8 (M2), 81.8 (M3), and 56.0% (M4), respectively, with M3 membranes showing the highest photocatalytic degradation efficiency and low leaching of metals. The remarkable performance observed by M3 membranes during both water filtration and photocatalytic performance may be an illustration of well dispersed photocatalyst which receives high absorption of light irradiation. Membranes with photocatalytic functionalities are tailored to exploit dual benefits of the membrane filtration and photocatalysis without compromising their original functions. However, maintaining the delicate balance of this phenomenon is still very challenging.

Preparation and characterization of ultrafiltration membranes derived from recycled Polyethylene terephthalate (PET) bottles

The pressing need for sustainable practices and eco-friendly materials in the face of escalating environmental concerns has led to exploring the transformation of discarded polyethylene terephthalate (PET) bottles into functional ultrafiltration membranes. This research prepares and characterizes ultrafiltration membranes derived from PET bottle waste. The study involves collecting PET waste material and fabrication processes to develop asymmetric flat sheet membranes blended with varying proportions of hydrophilic polyethylene glycol (PEG) using phase inversion techniques. Rigorous characterization employing SEM, EDS analysis, and water vapor permeability (WVP) assessments examine these membranes' structural, morphological, and performance attributes. The surface analysis elucidates a notable correlation between increased PEG content and larger pore sizes, consistent with prior studies involving PEG in membrane modifications. Additionally, incorporating PEG in the casting solution elevates water vapor permeability. Ultrafiltration experiments reveal differing rejection rates, with membrane M2 exhibiting enhanced anti-fouling properties despite reduced flux compared to M3 and M4. This research lays the groundwork for repurposing PET waste into selective membrane materials, emphasizing optimization strategies to enhance membrane quality and performance for diverse operational settings.

Comparison of Six Aptamer-Aptamer Pairs on Rapid Detection of SARS-CoV-2 by Lateral Flow Assay.

SARS-CoV-2 is a threat to humanity. Both the spike (S) protein and its receptor binding domain (sRBD) are extensively used for rapid detection. Although real-time reverse transcription polymerase chain reaction (rRT-PCR) is mostly used method for the molecular detection of SARS-CoV-2, rapid assays for antigenic detection are always needed. Lateral flow assays (LFAs) are the most commonly used tests for this purpose, and aptamers having stability and long shelf life are used as capture reagents. This study aimed to develop the LFAs based on the aptamer pairs for the antigenic detection of SARS-CoV-2 with the naked eye. Gold nanoparticles (AuNPs) were used as labels, and six sandwich models by three different aptamers were prepared using 4 μM and 8 μM probes and two kinds of membranes for developing the LFAs. The 8 μM probe concentration and M2 membrane showed the best recognition of both the synthetic sRBD and SARS-CoV-2 coming from the naso/oropharingeal swabs by designed LFAs as 100% sensitivity and 93.3% specificity compared to the antibody-detecting LFAs. Our developed strip assays based on aptamer pairs recognized the target directly in 5-6 min with the naked eye. It was also concluded that aptamer pairs, membrane types, assay buffers, and probe concentrations have a significant role in the detection of SARS-CoV-2 by LFAs. The detection of SARS-CoV-2 in clinical samples was demonstrated with the best aptamer pairs, sensitively and selectively among the designed six aptamer pairs for LFAs. Developed LFAs can be an alternative method to the conventional antibody-based LFAs for SARS-CoV-2 detection.