Mixed matrix PES-based nanofiltration membrane decorated by (Fe3O4–polyvinylpyrrolidone) composite nanoparticles with intensified antifouling and separation characteristics

Polydopamine-modified carboxylated cellulose nanocrystrals as functional fillers for polyethersulfone (PES) membranes to achieve superior dye/salt separation

This study presents the development of advanced tight polyethersulfone (PES) ultrafiltration membranes enhanced with polydopamine-coated carboxylated cellulose nanocrystrals (PDA@C-CNC) as functional fillers. The PDA@C-CNC fillers were synthesized via an in situ self-polymerization approach and employed as surface segregation agents during membrane preparation. Utilizing the non-solvent-induced phase separation (NIPS) technique, the highly hydrophilic PDA@C-CNC particles migrated to the interface between the polymer solution and the coagulation bath and tightly adhered to the polyethersulfone (PES) matrix through strong hydrogen bonding and π-π interactions, forming a dense, hydrophilic selective surface layer rich in polar functional groups (amino group (-NH2) and hydroxyl group(-OH)). Concurrently, the support layer developed a porous structure characterized by extended and widened cavities, facilitating enhanced mass transfer. The synergistic combination of a selective dense surface layer and an optimally structured support layer endowed the modified membranes with remarkable permeability and selectivity. Surprisingly, the water flux of the modified membrane with 0.2 % PDA@C-CNC (MPC0.2) achieved a remarkable 332 L·m-2·h-1·bar-1, which is 2.29 times higher than that of the unmodified membrane (M0). Additionally, MPC0.2 demonstrated exceptional dyes rejection rates (Congo red (CR) > 99.7 %, Eriochrome Black T (EBT) > 97.7 %) alongside minimal salt rejection (sodium chloride (NaCl): 0.2 %, sodium sulfate (Na2SO4): 1.7 %). These findings highlight the potential of PDA@C-CNC/PES composite membranes for efficient and selective removal of dyes and salts from textile wastewater.

Nanostructure-manipulated filtration performance in nanocomposite membranes: A comprehensive investigation for water and wastewater treatment

The main objective of this article is to examine one of the most important challenges facing researchers in the field of nanocomposite membranes: what is the most suitable arrangement (unmodified, functionalized, coated, or composite) and the most suitable loading site for the nanostructure? In the review articles published on nanocomposite membranes in recent years, the focus has been either on a specific application area (such as nanofiltration or desalination), or on a specific type of polymeric materials (such as polyamide), or on a specific feature of the membrane (such as antibacterial, antimicrobial, or antifouling). However, none of them have targeted the aforementioned objectives on the efficacy of improving filtration performance (IFP). Through IFP calculation, the results will be repeatable and generalizable in this field. The novelty of the current research lies in examining and assessing the impact of the loading site and the type of nanostructure modification on enhancing IFP. Based on the performed review results, for the researchers who tend to use nanocomposite membranes for treatment of organic, textile, brine and pharmaceutical wastewaters as well as membrane bioreactors, thePES NH 2 - PDA - Fe 3 O 4 M ,PAN Fe 3 O 4 / ZrO 2 M ,PVDF CMC - ZnO M ,AA AA - CuS PSf M andPVDF OCMCS / Fe 3 O 4 M with IFP equal to 132.27, 15, 423.6, 16.025 and 5, were proposed, respectively.

Recovery of Oleuropein from Olive Leaf Extract Using Zinc Oxide Coated by Polyaniline Nanoparticle Mixed Matrix Membranes

This study explores the integration of zinc oxide coated with polyaniline (ZnO-PANI) nanoparticles into a poly(ether sulfone) (PES) matrix to concurrently enhance permeate flux and oleuropein (OLP) rejection during the filtration of olive leaf extract (OLE). The effect of ZnO-PANI content on porosity, pore size, surface hydrophilicity, and pure water flux (PWF) was studied. The results indicate that an increase in ZnO-PANI content (0-0.2%) leads to a 3-fold increase in mean pore size, permeability (1.29-7.18 L/m2 h bar), porosity (72.2-77.8%), and improved surface hydrophilicity of the prepared membranes. Membrane performance was tested for OLE permeate flux of the OLE and total phenolic compounds (TPC) rejection at various pressures (10-30 bar), the performance of the OLP rejection at 30 bar, and fouling resistance. The 0.2 wt % ZnO-PANI membrane exhibits the highest permeate flux, while the 0.4 wt % ZnO-PANI membrane offers the highest rejection values (90-97% for TPC and 100% for OLP). Bare PES demonstrated the best fouling resistance. Strategic ZnO-PANI incorporation achieves a balance, enhancing both the flux and rejection efficiency. The 0.2 wt % ZnO-PANI membrane emerges as particularly favorable, striking a beneficial equilibrium between permeate flux and OLP rejection. Intriguingly, the use of these membranes for OLE filtration, postpretreatment with ultrafiltration (UF), results in a remarkable 100% rejection of OLP. This discovery underscores the significant and specific separation of OLP from OLE facilitated by a ZnO-PANI-based mixed matrix membrane (MMM). The study contributes valuable insights into the development of advanced membranes with enhanced filtration capabilities for high-added value phenolic compound separation.

Preparation of pH-sensitive composite polyethersulfone membranes embedded by Ag(I) coordination polymer for the removal of cationic and anionic dyes

A pH-sensitive polyethersulfone (PES) membrane was prepared with the aid of newly synthesized Ag(I) coordination polymer (Ag(I)-CP) particles. Indicating obvious adsorptive property toward dyes, the Ag(I)-based metalorganic framework (MOF) was selected to be used as an additive to improve the dye selectivity of PES membranes for both cationic and anionic dyes. The performance examination and characterization of prepared membranes indicated the influence of Ag(I)-CP in PES membrane improvement. The effect of feed pH approved the membrane response to pH changes in dye removal results. By adjusting feed pH based on pHpzc of Ag(I)-CP, it is possible to remove both anionic and cationic dyes (97% of acid orange 7 (AO) & and 100% of methylene blue (MB)) from the effluent along with an enhanced permeated flux. The results offered a synergism in embedding Ag(I)-CP in PES membrane in dye removal efficiency. The additive particles can be applied with their natural size (200-300 nm) without severe influence on the uniformity of the membrane morphology if the optimum Ag(I)-CP content is considered.

Recent Advances on the Fabrication of Antifouling Phase-Inversion Membranes by Physical Blending Modification Method

Membrane technology is an essential tool for water treatment and biomedical applications. Despite their extensive use in these fields, polymeric-based membranes still face several challenges, including instability, low mechanical strength, and propensity to fouling. The latter point has attracted the attention of numerous teams worldwide developing antifouling materials for membranes and interfaces. A convenient method to prepare antifouling membranes is via physical blending (or simply blending), which is a one-step method that consists of mixing the main matrix polymer and the antifouling material prior to casting and film formation by a phase inversion process. This review focuses on the recent development (past 10 years) of antifouling membranes via this method and uses different phase-inversion processes including liquid-induced phase separation, vapor induced phase separation, and thermally induced phase separation. Antifouling materials used in these recent studies including polymers, metals, ceramics, and carbon-based and porous nanomaterials are also surveyed. Furthermore, the assessment of antifouling properties and performances are extensively summarized. Finally, we conclude this review with a list of technical and scientific challenges that still need to be overcome to improve the functional properties and widen the range of applications of antifouling membranes prepared by blending modification.

New Hybrid Nanofiltration Membranes with Enhanced Flux and Separation Performances Based on Polyphenylene Ether-Ether-Sulfone/Polyacrylonitrile/SBA-15

This study presents the preparation of hybrid nanofiltration membranes based on poly(1,4-phenylene ether ether sulfone), polyacrylonitrile, poly(vinyl pyrrolidone), and SBA-15 mesoporous silica. Laser treatment of polymeric solutions to enhance the hydrophilicity and performance of membranes was investigated. The membranes’ structure was characterized using scanning electron (SEM) and atomic force (AFM) microscopy and contact angle measurements. The addition of PAN in the casting solution produced significant changes in the membrane structure, from finger-like porous structures to sponge-like porous structures. Increased PAN concentration in the membrane composition enhanced the hydrophilicity of the membrane surface, which also accounted for the improvement in the antifouling capabilities. The permeation of apple pomace extract and the content of polyphenols and flavonoids were used to evaluate the efficacy of the hybrid membranes created. The results showed that the hybrid nanofiltration membranes based on PPEES/PAN/PVP/SBA-15: 15/5/1/1 and 17/3/1/1 exposed to laser for 5 min present a higher rejection coefficient to total polyphenols (78.6 ± 0.7% and 97.8 ± 0.9%, respectively) and flavonoids (28.7 ± 0.2% and 50.3 ± 0.4%, respectively) and are substantially better than a commercial membrane with MWCO 1000 Da or PPEES-PVP-based membrane.

Performance improvement of PES membrane decorated by Mil-125(Ti)/chitosan nanocomposite for removal of organic pollutants and heavy metal

The Mil-125(Ti)-CS nanocomposite was successfully synthesized and characterized by using scanning electron microscopy (SEM) images, Fourier-transform infrared (FTIR) analysis and X-ray diffraction (XRD). Then, to improve the membrane performance, the synthesized Mil-125(Ti)-CS nanocomposite was embedded into the polyethersulfone (PES) membrane matrix. The nanofiltration membranes were fabricated via phase inversion method. Presence of chitosan in the structure of Mil-125(Ti) has increased the compatibility of nanoparticles with the polymer and also improved the hydrophilicity of the resulted membranes. The water contact angle of bare membrane (58°) was reduced to 40° by blending of 1 wt% nanocomposite led to increasing the pure water flux. However, the incorporation of more than 1 wt% of the nanocomposite caused the accumulation of nanocomposites and this was reduced the pore radius and permeability. The membrane containing 1 wt% nanocomposite was displayed the highest flux recovery ratio (FRR) ∼ 98% in bovine serum albumin (BSA) filtration. The membranes containing Mil-125(Ti)-CS also showed good performance against fouling. The performance of membranes was evaluated by treatment of six reactive dyes, antibiotic (cefixime), heavy metal, NaCl and Na₂SO₄ solutions. Addition of Mil-125(Ti)-CS NPs at low concentrations resulted in membranes with high pure water flux, higher separation efficiency, and remarkable anti-fouling behavior.

Surface-engineered polyethersulfone membranes with inherent Fe-Mn bimetallic oxides for improved permeability and antifouling capability

In recent years, bimetallic oxide nanoparticles have garnered significant attention owing to their salient advantages over monometallic nanoparticles. In this study, Fe₂O₃-Mn₂O₃ nanoparticles were synthesized and used as nanomodifiers for polyethersulfone (PES) ultrafiltration membranes. A NIPS was used to fabricate asymmetric membranes. The effect of nanoparticle concentration (0-1 wt.%) on the morphology, roughness, wettability, porosity, permeability, and protein filtration performance of the membranes was investigated. The membrane containing 0.25 wt% nanoparticles exhibited the lowest water contact angle (67°) and surface roughness (10.4 ± 2.8 nm) compared to the other membranes. Moreover, this membrane exhibited the highest porosity (74%) and the highest pure water flux (398 L/m² h), which was 16% and 1.9 times higher than that of the pristine PES membrane. The modified PES membranes showed an improved antifouling ability, especially against irreversible fouling. Bovine serum albumin protein-based dynamic five-cycle filtration tests showed a maximum flux recovery ratio of 77% (cycle-1), 67% (cycle-2), and 65.8% (cycle-5) for the PES membrane containing 0.25 wt% nanoparticles. Overall, the biphasic Fe₂O₃-Mn₂O₃ nanoparticles were found to be an effective nanomodifier for improving the permeability and antifouling ability of PES membranes in protein separation and water treatment applications.

High Flux and Antifouling Nanofiltration Membrane Modified by Ag@UiO-66-NH2 and Its Application for Biphenol A Removal

Owing to the specific porous structure which could provide additional passage channel for some molecules, metal organic frameworks are attractive candidates for enhancing permeability and selectivity of membranes in pervaporation, reverse osmosis, and gas separation. In this experiment, Ag@UiO-66-NH2 was introduced into polyamide separation layer by interfacial polymerization of triethylenetetramine and 1,3,5-benzenetricarboxylic acid chloride for nanofiltration. The results indicated that Ag@UiO-66-NH2 nanoparticles did endow the membranes with rapid diffusion pathways for water molecules. When the content of Ag@UiO-66-NH2 was 0.03 g, the prepared membrane (NF-Ag-3) showed high flux about 47.3 L·m-2·h-1 at 0.6 MPa, which is about 2-fold higher than that of polyamide membrane without Ag@UiO-66-NH2, while the MgSO4 rejection rate remained about 87.4%. The membrane also showed excellent antifouling properties, and the water flux recovery ratio was 95.6% after filtration BSA solution. When it was applied for 50 mg/L bisphenol A removal, the rejection rate reached 94.6%, and the flux is about 49.1 L·m-2·h-1. Moreover, Ag particles on UiO-66-NH2 rendered the membrane with good inhibition for Escherichia coli. The antibacterial rate of the membranes is above 95% when the loading of Ag@UiO-66-NH2 is more than 0.03 g.

Planning of smart gating membranes for water treatment

The use of membranes in desalination and water treatment has been intensively studied in recent years. The conventional membranes however have various problems such as uncontrollable pore size and membrane properties, which prevents membranes from quickly responding to alteration of operating and environmental conditions. As a result the membranes are fouled, and their separation performance is lowered. The preparation of smart gating membranes inspired by cell membranes is a new method to face these challenges. Introducing stimuli-responsive functional materials into traditional porous membranes and use of hydrogels and microgels can change surface properties and membrane pore sizes under different conditions. This review shows potential of smart gating membranes in water treatment. Various types of stimuli-response such as those of thermo-, pH-, ion-, molecule-, UV light-, magnetic-, redox- and electro-responsive gating membranes along with various gel types such as those of polyelectrolyte, PNIPAM-based, self-healing hydrogels and microgel based-smart gating membranes are discussed. Design strategies, separation mechanisms and challenges in fabrication of smart gating membranes in water treatment are also presented. It is demonstrated that experimental and modeling and simulation results have to be utilized effectively to produce smart gating membranes.

Nanofiltration Composite Membranes Based on KIT-6 and Functionalized KIT-6 Nanoparticles in a Polymeric Matrix with Enhanced Performances

The nanofiltration composite membranes were obtained by incorporation of KIT-6 ordered mesoporous silica, before and after its functionalization with amine groups, into polyphenylene-ether-ether-sulfone (PPEES) matrix. The incorporation of silica nanoparticles into PPEES polymer matrix was evidenced by FTIR and UV–VIS spectroscopy. SEM images of the membranes cross-section and their surface topology, evidenced by AFM, showed a low effect of KIT-6 silica nanoparticles loading and functionalization. The performances of the obtained membranes were appraised in permeation of Chaenomeles japonica fruit extracts and the selective separation of phenolic acids and flavonoids. The obtained results proved that the PPEES with functionalized KIT-6 nanofiltration membrane, we have prepared, is suitable for the polyphenolic compound’s concentration from the natural extracts.

Metal- and metal/oxide-based engineered nanoparticles and nanostructures: a review on the applications, nanotoxicological effects, and risk control strategies

The production and demand of nanoparticles in the manufacturing sector and personal care products, release a large number of engineered nanoparticles (ENPs) into the atmosphere, aquatic ecosystems, and terrestrial environments. The intentional or involuntary incorporation of ENPs into the environment is carried out through different processes. The ENPs are combined with other compounds and release into the atmosphere, settling on the ground due to the water cycle or other atmospheric phenomena. In the case of aquatic ecosystems, the ENPs undergo hetero-aggregation and sedimentation, reaching different living organisms and flora, as well as groundwater. Accordingly, the high mobility of ENPs in diverse ecosystems is strongly related to physical, chemical, and biological processes. Recent studies have been focused on the toxicological effects of a wide variety of ENPs using different validated biological models. This literature review emphasizes the study of toxicological effects related to using the most common ENPs, specifically metal and metal/oxides-based nanoparticles, addressing different synthesis methodologies, applications, and toxicological evaluations. The results suggest negative impacts on biological models, such as oxidative stress, metabolic and locomotive toxicity, DNA replication dysfunction, and bioaccumulation. Finally, it was consulted the protocols for the control of risks, following the assessment and management process, as well as the classification system for technological alternatives and risk management measures of ENPs, which are useful for the transfer of technology and nanoparticles commercialization.

Infusion of Silver-Polydopamine Particles into Polyethersulfone Matrix to Improve the Membrane's Dye Desalination Performance and Antibacterial Property

The advancement in membrane science and technology, particularly in nanofiltration applications, involves the blending of functional nanocomposites into the membranes to improve the membrane property. In this study, Ag-polydopamine (Ag-PDA) particles were synthesized through in situ PDA-mediated reduction of AgNO₃ to silver. Infusing Ag-PDA particles into polyethersulfone (PES) matrix affects the membrane property and performance. X-ray photoelectron spectroscopy (XPS) analyses confirmed the presence of Ag-PDA particles on the membrane surface. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) describe the morphology of the membranes. At an optimum concentration of Ag-PDA particles (0.3 wt % based on the concentration of PES), the modified membrane exhibited high water flux 13.33 L∙m⁻²∙h⁻¹ at 4 bar with high rejection for various dyes of >99%. The PES_Ag-PDA0.3 membrane had a pure water flux more than 5.4 times higher than that of a pristine membrane. Furthermore, in bacterial attachment using Escherichia coli, the modified membrane displayed less bacterial attachment compared with the pristine membrane. Therefore, immobilizing Ag-PDA particles into the PES matrix enhanced the membrane performance and antibacterial property.

Synthesis, characterization, and performance analysis of carbon molecular sieve-embedded polyethersulfone mixed-matrix membranes for the removal of dissolved ions

The asymmetric polyethersulfone (PES-15 wt.%) mixed-matrix membranes were prepared by incorporation of carbon molecular sieve (CMS) with varying concentrations (1, 3, and 5 wt.%). Physicochemical characterization of synthesized membranes was carried out using field emission scanning electron microscope, atomic force microscopy, contact angle, thermogravimetric analysis, zeta potential analyzer, porosity, and mean pore sizes. Performance analysis of synthesized mixed-matrix membranes was carried out by varying the operating parameters such as pressure (2-10 bar), feed concentration (100-1,000 mg/L), and cations type (Na⁺ , Ca²⁺ , Mg²⁺ , and Sn²⁺ ). Effect of operating parameters and CMS concentration was investigated on pure water flux (PWF), permeate flux, and rejection of membranes. It was found that mixed-matrix membrane containing 15 wt.% PES with 1 wt.% CMS displayed the superior physicochemical characteristics in terms of hydrophilicity (37.9°), surface charge (-13.8 mV), mean pore diameter (6.04 nm), and thermal properties (T_g  = 218.5°C), and overall performance. E5C1 membrane showed 1.5 times higher PWF (75.5 L m^-2  hr^-1 ) and incremented in rejection for all salts than the nascent membrane. PRACTITIONER POINTS: Carbon molecular sieve-embedded mixed-matrix membranes were synthesized by phase inversion method. The resultant membranes experienced improved hydrophilicity, roughness, surface charge, porosity, and mean pore diameter with 1 wt.% CMS loading. The pure water flux was improved from 55.77 to 75.05 L m^-2  hr^-1 when 1 wt.% CMS was added in pure PES. The observed rejection of a mixed-matrix membrane with 1 wt.% CMS was the maximum for all salts.