Nanofiltration Membrane Technology Research Articles

Enhanced properties of a positive-charged nanofiltration membrane containing quaternarized chitosan through second interfacial polymerization for the removal of salts and pharmaceuticals.

Nanofiltration (NF) membrane technology has been widely used in the removal of salts and trace organic pollutants, such as pharmaceuticals and personal care products (PPCPs), due to its superiority. A positive-charged composite NF membrane with an active skin layer was prepared by polyethyleneimine (PEI), trimethyl benzene chloride, and quaternate chitosan (HTCC) through second interfacial polymerization on the polyethersulfone ultrafiltration membrane. The physicochemical properties of the nanocomposite membrane were investigated using surface morphology, hydrophilicity, surface charge, and molecular weight cut-off (MWCO). The influence of the concentration and reaction time of PEI and HTCC was documented. The optimized membrane had a MWCO of about 481 Da and possessed a pure water permeability of 25.37 L·m-2·h-1·MPa-1. The results also exhibited salt rejection ability as MgCl2 > CaCl2 > MgSO4 > Na2SO4 > NaCl > KCl, showing a positive charge on the fabricated membrane. In addition, the membrane had higher rejection to atenolol, carbamazepine, amlodipine, and ibuprofen at 89.46, 86.02, 90.12, and 77.21%, respectively. Moreover, the anti-fouling performance and stability of the NF membrane were also improved.

Intercalation of small molecules in the selective layer of polyamide nanofiltration membranes facilitates the separation of Mg2+/Li+

In addressing lithium supply shortages driven by increased energy demand, nanofiltration membrane technology is crucial for recovering lithium from salt lake brines. Overcoming the challenge of achieving high selectivity for Li+ and water permeability in polymer nanofiltration membranes, this study proposes a simple approach using Aminomalononitrile (AMN) intercalation to modify polyamide layers. Density functional theory simulations predict AMN's superior selectivity and enhanced hydrophilicity. Stable intercalation of AMN between polyethyleneimine (PEI) molecules is demonstrated, synergistically enhancing water permeability and Li+ selectivity. The resulting PEI/AMN-TMC membrane exhibits exceptional Li+ selectivity and improved water permeability (13.1 L·m−2·h−1·bar−1), 2.9 times higher than traditional PEI-TMC membranes. Stable performance for over seven days, along with anti-scaling and anti-bacterial properties, underscores its practicality. This investigation sheds light on membrane structure regulation through small-molecule intercalation, offering insights into precise adjustments for enhanced water permeability and ion selectivity.

Study of the removal of nitrate and dissolved iron pollutants from industrial wastewater to become raw water using nanofiltration

Nowadays, industrial nanofiltration membrane technology is widely used, particularly when it comes to recovering and recycling water for preservation. This research is related to the processing of wastewater from one of the industrial areas in Indonesia into raw water using nanofiltration on a pilot scale. This research aims to identify the removal of nitrate and dissolved iron from industrial area wastewater through flow recirculation in nanofiltration and identify the effect of variations in wastewater concentration and variations in product recovery. The wastewater being treated is wastewater from an industrial area owned by PT. Jababeka Infrastruktur is composed of a ratio of 100% WWTP effluent, 9:1, 8:2, 7:3, and 6:4 between WWTP influent and effluent ratio. This study’s membrane module employs a two-stage membrane system and a spiral wound with model specifications NF2-4040. Recirculation is used in the reactor to process the material and provide cross flow. The results of the study stated that variations in concentration made a significant difference to the removal of nitrate and dissolved iron (p value < 0.05), but variations in product recovery the opposite response. The processed water meets the raw water quality standards for nitrate parameters, but not for dissolved iron parameters at processed water concentrations of 7:3 and 6:4.

Removal of total phosphate and sulfate from industrial wastewater by recirculating flow in nanofiltration

This study is related to industrial wastewater treatment in Indonesia using nanofiltration membrane technology and was carried out on a pilot scale. This research aims to study the total removal of phosphate and sulfate from industrial wastewater through flow recirculation in nanofiltration and the membrane pressure factors that influence the removal of these pollutants. The treated wastewater is industrial wastewater belonging to Jababeka Infrastruktur Corp. and is arranged in various concentrations. The membrane module in this study uses a spiral wound with model specifications NF2-4040 and a two-stage membrane system. The reactor used provides crossflow velocity and is processed by recirculation. The research results stated that variations in concentration and recovery rate provided total removal of phosphate and sulfate in the range of 70-90% and pressure reached 11 bar as both increased. This research has proven that nanofiltration membrane technology can remove total phosphate and sulfate, with the consequence that the more concentrated the wastewater being treated, the greater the pressure required.

Modulating interfacial polymerization via 1-methylimidazole as reactive additive for nanofiltration membrane with high-performance

Nanofiltration (NF) membrane technology has become the most critical alternative to resolve fresh water resources shortage and water pollution. Preparing polyamide (PA) NF membrane with excellent water permeance and mono/multivalent salts selectivity is highly desired. Herein, we introduced 1-methylimidazole (1-MI) as a reactive additive into interfacial polymerization (IP) to prepare NF membrane and attempted to improve the NF membrane performance. 1-MI modified NF membranes exhibited enlarged pore size and thickness of PA layer, as well as a smooth and hydrophilic membrane surface, the water permeance improved from 7.7 L/(m2·h·bar) of Virgin-NF to 13.1 L/(m2·h·bar) of 1-MI-0.05-NF. The Na2SO4 rejection was maintained at 95.01% while NaCl rejection dramatically reduced from 25.79% to 13.29%, and the Cl−/SO42− selectivity slightly increased from 21.47 to 23 under the mixed salts solution as feed. The enhancement of water permeance was ascribed to the looser PA layer and enhanced hydrophilicity. The retaining Na2SO4 rejection was attributed to electrostatic repulsion caused by more carboxylic acid groups, and the decreased NaCl rejection was ascribed to the looser PA layer. Besides, the modified membrane had an acceptable pH stability. In summary, 1-MI modified NF membrane was suitable for the separation of monovalent/divalent anionic salts.

Nanofiltration Membranes for the Removal of Heavy Metals from Aqueous Solutions: Preparations and Applications.

Water shortages are one of the problems caused by global industrialization, with most wastewater discharged without proper treatment, leading to contamination and limited clean water supply. Therefore, it is important to identify alternative water sources because many concerns are directed toward sustainable water treatment processes. Nanofiltration membrane technology is a membrane integrated with nanoscale particle size and is a superior technique for heavy metal removal in the treatment of polluted water. The fabrication of nanofiltration membranes involves phase inversion and interfacial polymerization. This review provides a comprehensive outline of how nanoparticles can effectively enhance the fabrication, separation potential, and efficiency of NF membranes. Nanoparticles take the form of nanofillers, nanoembedded membranes, and nanocomposites to give multiple approaches to the enhancement of the NF membrane's performance. This could significantly improve selectivity, fouling resistance, water flux, porosity, roughness, and rejection. Nanofillers can form nanoembedded membranes and thin films through various processes such as in situ polymerization, layer-by-layer assembly, blending, coating, and embedding. We discussed the operational conditions, such as pH, temperature, concentration of the feed solution, and pressure. The mitigation strategies for fouling resistance are also highlighted. Recent developments in commercial nanofiltration membranes have also been highlighted.

Bifunctional polyhedral oligomeric silsesquioxane engineered polyamide membrane for efficient Li+/Mg2+ separation

Nanofiltration membrane technology holds great promise in extracting lithium (Li) from salt-lake brines. However, designing nanofiltration membranes with both high water permeance and ion selectivity remains a grand challenge. Here, amino-functionalized polyhedral oligomeric silsesquioxane (8NH2-POSS) nanocage is designed as a bifunctional molecular filler into polyamide (PA) layer during the interfacial polymerization of polyethyleneimine (PEI) and trimesoyl chloride (TMC). The 8NH2-POSS not only provides abundant amino groups to increase the membrane electropositivity from +4.5 mV to +33.2 mV (pH = 6.0), but also enlarges the pore size of PA matrix and constructs additional water channels to facilitate water transport. The optimal POSS-PA membrane has a rejection rate of 98.1 % to 1 g/L MgCl2, a pure water permeance of 12.0 L m-2h−1 bar−1 and an exceptional separation factor (SLi,Mg) of 13.9 at an ultralow Li+/Mg2+ mass ratio of 1:150, surpassing the benchmark PA membranes.

Nitrate rejection of sulfonic acid group incorporated polyethersulfone‐type nanofiltration membrane and reutilization of the concentrated solution

AbstractThe nanofiltration (NF) membrane technology has attracted considerable attention for the rejection removal of various salts. However, the practical application of this membrane separation process has been severely retarded due to the ineffective rejection of monovalent ions (such as nitrate and chloride), undesirable filtration flux, and insufficient disposal of the concentrated solution. In this work, three polyethersulfone‐type NF membranes were fabricated and their morphologies, functional groups, chemical components, wettabilities, chargeabilities, and rejection molecular weights were characterized. Among them, the membrane of NF_M3 bearing sulfonic acid group (SO3H) shows the desirable rejection efficiency of nitrate (90.32%), acceptable solution filtration flux (10.15 L m−2 h−1 at 0.6 MPa), and the decent pure water permeation flux (50.8 L m−2 h−1 at 0.6 MPa). The introduction of SO3H can significantly enhance the performances of NF_M3 membrane in hydrophilicity, chargeability, anti‐fouling, and the oxidation resistance. Promisingly, the concentrated nitrate was ingeniously recycled for the electrochemical intercalation of flake graphite to prepare expandable graphite, and the obtained expanded graphite has an acceptable expanded volume (243 mL g−1 via the microwave expansion process), thereby achieving the resource utilization of NF concentrated solution.

Ethylenediamine-graphene oxide impregnated thin film nanocomposite membrane for the enhanced boron separation from seawater

The separation of toxic boron from seawater using nanofiltration (NF) membrane technology is challenging due to the neutral charge associated with boric acid at seawater pH. In this study, the ethylenediamine functionalized Graphene oxide (EDA-GO) derivative is utilized as a nanofiller to coat the active top layer of the NF membrane over the polyethersulfone ultrafiltration support. The coating involved a self-assembly reaction of hydrolyzed trimesic acid (TMA) molecules facilitated by a triethylamine base. The unique hypothesis for coating enabled the –NH2 of EDA-GO to interact with the –COOH of TMA via hydrogen bonding interactions. The rejection shown by the M-0.05 membrane with 0.05wt% loading of EDA-GO towards MgSO4, Na2SO4, and NaCl was &gt;98%, &gt;97%, and 63%, respectively. The same membrane produced water flux in the range of 35-37 L/m2h with the modest significance of the salts on the membrane flux. The M-0.05 membrane showed significantly higher rejection towards boron (&gt;47%) with a flux of 16.7 L/m2h for the beachwell seawater feed owing to the repulsive interaction between the borate ions and -NH2 and -OH groups. The rejection and flux offered by the M-0.05 membrane towards seawater's monovalent and divalent constituents were much higher than the commercial NF-90 and NF-270.

Toray Industries’ membranes play an important role in the battery industry

Recently, our coverage of Toray Industries Inc's technology has focused on membranes that the company has developed for reducing carbon dioxide emissions in hydrogen purification processes, reverse osmosis in the desalination sector and ultrafiltration for water treatment. However, the Japanese firm's material science is also applied widely in the battery industry. This focus article briefly looks at nanofiltration membrane technology it has developed to recover lithium from used car batteries. It also discusses an ion-conductive polymer membrane it has created to enhance the safety and longevity of lightweight air batteries used to power industrial drones and required to make urban air mobility systems a reality.

Theoretical design of porous dodecagonal germanium carbide (d-GeC) monolayer.

Porous nanosheet materials have recently emerged as attractive candidates to serve as nanofiltration membranes. Through first-principles calculations based on density functional theory (DFT) calculations, we propose a new porous dodecagonal GeC (d-GeC) monolayer. We show that the d-GeC monolayer exhibits excellent energetic, mechanical, dynamic, and thermal stabilities. The d-GeC monolayer shows semiconducting properties with an indirect band gap of 1.73 eV (2.53 eV) PBE(HSE06). We also show that the d-GeC monolayer can serve as a good membrane for molecular and atomic permeation due to its low value of estimated diffusion energy barriers. Our results demonstrate the potential of the d-GeC monolayer for the design of nanofiltration membrane technology.

Extra A Review of Nanofiltration Membrane Technology To Treat Water Problems

One of the most widely used membranes is the nanofiltration membrane, this membrane is formed from various nanomaterials, such as metal nanoparticles and metal oxides, carbon-based nanoparticles, metal organic frameworks, and micro or organic nanoparticles. Membrane separation processes are used to concentrate or fractionate liquids to produce two liquids with different compositions. This makes the nanofiltration process an alternative compared to conventional processes. The potential of nanofiltration membranes can be used in textile industry wastewater treatment, tofu liquid waste, tofu liquid waste treatment, batik wastewater testing, and groundwater management as drinking water. In addition, nanofiltration membrane technology can be used as a separator for a substance in the air, such as removal of cypermethrin, arsenic cream, concentration of lactic acid bacteria as a tasty probiotic, removal of carbosulfan, Zr-Hf separation, and can see the characterization and performance evaluation of the antifouling properties of membranes. . Based on the process, the performance of a membrane is determined by two simple factors, namely flux (permeate flow rate) and membrane selectivity.

3D printed nanofiltration membrane technology for waste water distillation

Surface water supply provides the vast majority of the world's drinkable water, however, surface water may contain a broad variety of pollutants originated from various sources, such as households, industry, and agriculture. As a result, it is critical to achieve acceptable water quality while also reducing the organic and inorganic impurities. Potable water production methods have been developed and tested in various ways. It is possible to manufacture high-quality drinking water using nanofiltration (NF) membranes. In contrast, fouling has remained the most significant barrier to membrane technology advancement. Renewable energy sources may decrease the extra energy needed by a membrane with tiny holes. Recent years have seen a significant increase in interest in three-dimensional printing (3D printing [3D-P]). Surface imprinting technologies, in general, have not yet reached the maturity stage of development, notably in membrane design and production. It is discussed in this review article how different 3D printing technologies are now accessible, how they relate to current breakthroughs in the area, and how they may be used to fabricate nanosheets, module spacers, or thin layers design for water purification as well as potential applications of surface imprinting in the near future. It is anticipated that the revolutionary synthesis of novel membrane module components will occur in the near future due to recent breakthroughs in 3D-P technology. It is predicted that 3D-P technologies would create a broader range of membrane module components with improved efficacy and efficiency due to speed, materials, and resolution improvements. Water purification methods comprising membrane separation are potential applications that might benefit from surface imprinting patterns with complicated topography in the future for water purification among them.

A PEI/TMC membrane modified with an ionic liquid with enhanced permeability and antibacterial properties for the removal of heavy metal ions

Heavy metal ions in drinking water severely threaten public health in various places worldwide. Nanofiltration (NF) membrane technology is an attractive option for heavy metal ions removal; however, improving NF membrane filtration performance is required to make their industrial application viable. In this study, a positively charged THPC/PEI-TMC NF membrane was designed via simple one-step incorporation of Tetrakis (hydroxymethyl) phosphonium chloride (THPC) biocide on the surface of PEI-TMC membranes, significantly optimizing surface morphology, roughness, hydrophilicity, and zeta potential of PEI-TMC membranes. It was found that the pure water permeability (11.6 Lm−2h−1bar−1) of the THPC modified membrane was three times larger than that of the original PEI-TMC membrane (3.4 Lm−2h−1bar−1) while maintaining a high level of ion rejections (around 95% for Zn2+, Cd2+, Ni2+, Cu2+ and about 90% for Pb2+). Additionally, the incorporation of the THPC on the original PEI-TMC membrane surface also conferred good antibacterial properties, which protect the organic membrane from bacterial growth and prolong the lifespan of the membrane.

Nanofiltration membranes fabricated through ultra-thin α-Co(OH)2 nanosheets with high chlorine resistance and long-term stability for efficient dye removal

At present, freshwater resources are scarce, and printing and dyeing wastewater are the main freshwater pollution sources. To purify dye wastewater, nanofiltration membrane technology was developed. This study developed a new nanofiltration membrane by mixing an ultra-thin α-Co(OH)2 nanosheets with sodium alginate (SA) and papermaking by-products calcium lignosulfonate (CaLS). X-ray diffraction (XRD), Fourier Infrared Spectroscopy (FITR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Contact angle (CA) were used to analyze ultra-thin α-Co(OH)2 nanosheets and α-Co(OH)2@CaLS/SA membrane, confirming the successful synthesis and sheet morphology of the α-Co(OH)2 nanosheets, and finding the hydrophilicity increases of the α-Co(OH)2@CaLS/SA membrane and its morphology change. Dye separation experiments showed that the α-Co(OH)2@CaLS/SA membrane has a good separation effect on Rose Bengal sodium salt, Coomassie brilliant blue and Congo red dyes, with a retention rate is above 99%. Moreover, the membrane showed high flux for Rose Bengal sodium salt 48.5 L m−2 h−1, Coomassie Brilliant Blue 60.4 L m−2 h−1, Congo Red 74.8 L m−2 h−1. In addition, the α-Co(OH)2@CaLS/SA membrane has superior chlorine resistance and long-term operation stability, which provides advantages in industrial applications.

Thin-film composite polyester nanofiltration membrane with high flux and efficient dye/salts separation fabricated from precise molecular sieving structure of β-cyclodextrin

The prepared β -CD/TMC-MWCNTs polyester membranes exhibited effective selectively separation performance for dye/salt mixture solution filtration. • The high-flux β -CD/TMC polyester membrane supported by MWCNTs network was prepared. • The membrane showed selective separation for dye/salt mixture based on β -CD cavity. • The main mechanism was size exclusion, electrostatic interaction, Donnan effect. • Reusability, chlorine resistance, and antifouling ability of the membrane was good. The treatment of dye pollutant and salts by nanofiltration membrane technology usually has the difficulty of low permeability and higher pressure in the case of maintaining a high rejection. In this study, high flux polyester membranes of β -cyclodextrin/trimesoyl chloride - multiwalled carbon nanotubes ( β -CD/TMC-MWCNTs) were fabricated on a modified multiwalled carbon nanotubes (MWCNTs) substrate via interfacial polymerization (IP) process. The modified MWCNTs substrate was not only beneficial to modulating the permeation and distribution of aqueous phase monomer ( β -cyclodextrin, β -CD), but also in favor of the formation of an ultrathin loose selective polyester active layer due to the porous network structure. The optimization experiments about the reaction time and monomer concentrations were conducted. The experimental results showed that the pure water flux of the as-prepared β -CD/TMC-MWCNTs membrane was 179.93 L m -2 h - 1 bar - 1 (at the pressure of 0.1 MPa) when the reaction time of IP process was 5 min. The single dye removal efficiency of β -CD/TMC-MWCNTs membrane was 97.41% for Brilliant Green (BG) and 96.39% for Congo red (CR), respectively. The removal efficiency of dye/salt mixture by the membrane was above 84% for BG and over 98% for CR, respectively. The results indicated that the membrane had the efficient selective separation performance for the dye/salt mixture benefiting from the special molecular sieving architectures with the precisely intrinsic inner cavity of β -CD/TMC-MWCNTs membrane. Furthermore, the reusability, chlorine resistance, and antifouling ability of the β -CD/TMC-MWCNTs membrane was relatively excellent, and the membrane could effectively remove BG (>93%) and CR (>98%) simultaneously for mixed BG/CR dyes in real water body. These results suggested that the as-prepared β -CD/TMC-MWCNTs membrane had the potential of practical application in dye wastewater treatment.

Study of Turbulence Promoters in Prolonging Membrane Life.

Nanofiltration membrane technology is an effective method for secondary treated sewage purification. However, membrane fouling, which is inevitable in the membrane-separation process, can reduce membrane performance and shorten membrane life. Installing a turbulence promoter is a promising means of improving the hydraulic conditions inside the membrane chamber. In this study, the effect of turbulence promoter on prolonging membrane life was studied for the first time. Flat-sheet polyethersulfone nanofiltration membrane was used to filter humic acid solution, used for simulating secondary treated sewage. By comparing photographs and SEM images of the membrane before and after the simulated secondary treated sewage filtration, it was found that humic acid tended to be deposited on the low-velocity region, which was reflected by COMSOL simulation. After incorporating a turbulence promoter, the reduction of the humic acid deposition area and membrane fouling resistance indicated that the turbulence promoter could reduce membrane fouling due to the improved hydraulic conditions. Additionally, the turbulence promoter also increased the flux and reduced the flux decay rate. The turbulence promoter was then place in the crossflow flat-sheet membrane filtration module, and the variation of flux with time was tested in simulated secondary treated sewage with different concentrations. The results showed that the membrane life for the filtration of simulated secondary treated sewage comprising 50, 250, and 500 ppm humic acid increased by 23.1%, 80.4%, and 85.7%, respectively. The results of this article can serve as a reference for the prediction of membrane life and the performance enhancement mechanism of membranes containing a turbulence promoter.

Treatment of complex multi-sourced industrial wastewater — New opportunities for nanofiltration membranes

Restrictions on the volume of organics discharged from industrial wastewater (IWW) treatment plants has created an impetus to implement nanofiltration (NF) membrane technology at these facilities. However, NF membranes are rated based on simple performance metrics (i.e. permeability and salt rejection), not their capacity to reject organic content. In this study, three IWW samples with varying concentrations (measured via COD) and compositions (analyzed via gas chromatography-mass spectrometry) were filtered using four commercial NF membranes (NF90, TS80, NFS and NFX). The NF90 membrane demonstrated the best COD removal, however compositional differences between samples significantly influenced the magnitude of COD reduction, the permeate flux performance during filtration, and the change in the measured hydraulic permeability and salt rejection after wastewater filtration. To investigate this further, separate solutions of commonly occurring chemical compounds (benzyl alcohol, 2-phenyl ethanol, pentanoic acid) were made with equivalent COD concentrations and filtered using the NF90 and NFX membranes. The NF90 membrane demonstrated significantly better COD removal for all three solutions. It was found that the NFX membrane achieved an increase in permeate flux during constant pressure filtration which was attributed to a “solvent activation” phenomena. These results serve as “proof-of-concept” that commercial NF membranes can significantly reduce the COD concentration of IWW, however, performance metrics that encompass both bulk and compositional properties must be adopted and standardized.

Cerahelix moves HQ to Bangor facility

Ceramic nanofiltration membrane technology specialist Cerahelix Inc has relocated its corporate headquarters to and consolidated its operations at its manufacturing facility at the Bangor Innovation Center in Bangor, Maine, USA.

Boron-doped diamond (BDD) electro-oxidation coupled with nanofiltration for secondary wastewater treatment: Antibiotics degradation and biofouling

In this study, a boron-doped diamond (BDD) electro-oxidation technology coupled with nanofiltration membrane (EO-NF) technology was investigated for its effectiveness in removing antibiotics (i.e., sulfamethazine:SMZ) and mitigating biofouling during secondary wastewater treatment. The result showed that EO obtained an effective SMZ removal, owing to the ·OH generation observed by Electron paramagnetic resonance (EPR) analysis; complete elimination of SMZ was found under the high current density (30 mA/cm2) and long Electrolysis Time (ET = 60 min). Meanwhile, EO-NF process enabled to reduce COD content from 60 mg/L to nearly 5 mg/L. Furthermore, regardless of the effect of EO process, NF could retain most NH3-N because of the excellent performance of NF for ions rejection, and its permeate concentration was below 0.5 mg/L. EO was able to reduce membrane fouling notably, increasing the final flux (15 L/(m2·h)) of NF by 25.1% during long-term operation (240 h). Scanning electron microscopy-Energy dispersive spectrometry (SEM-EDS) showed that a porous layer formed on the vicinity of NF membrane in the case of filtrating EO effluent, in contrast to a uniform and dense biofouling layer generated during the direct NF. Besides, the content of adenosine triphosphate (ATP) and the number of bacterial colonies in the retentate of the EO-NF process were greater than those of the direct NF process. This resulted in a smaller amount of extracellular polymeric substances (EPS) attaching to the membrane surface, decreasing the tightness and hardness of the fouling layer in the case of EO, as indicated by CLSM analysis. Overall, considering its ability to effectively eliminate persistent contaminants and reduce membrane fouling, BDD-based EO is considered a promising pre-treatment option for future NF applications.