Separation Performance Of Membranes Research Articles

Rapid fabrication of composite membranes based on conjugated microporous polymers: Microstructural design for performance optimization

Composite membranes based on conjugated microporous polymer (CMPs) with permanent porosity and high tolerance to harsh environments have been considered as one of the most promising separation methods to treat wastewater. Nevertheless, using simple and low-cost methods to accomplish the rapid fabrication of CMPs-based membranes with excellent performance is challenging. Herein, unidirectional diffusion synthesis in diffusion cells of different inner diameters achieved the rapid fabrication and adjustable size of three CMPs-based composite membranes (i.e., TpMa-H, TpMa-CH3 and TpMa-Cl). Among them, TpMa-CH3 or TpMa-Cl was obtained by replacing -H of Carbon 4 in the amine moieties of TpMa-H with -CH3 or -Cl groups. This microstructural design enhanced the rejection rates of TpMa-CH3 and TpMa-Cl to model waste molecules compared with TpMa-H. In addition, the composite membranes had strong hydrolytic resistance, thermal stability and acid-base resistance. Interestingly, TpMa-CH3 showed better rejection to positively charged methyl violet (Mw.358) than that to negatively charged sodium cresol (Mw.404), probably due to the electrostatic adsorption of bigger positive portion of methyl violet on the membrane surface and resultant bridging effect. Such electrostatic adsorption and the adjustable microstructures significantly varied the repellence of CMPs-based membranes to different charged molecules. This work provides a beneficial idea to optimize the separation performance of the CMPs-based membrane.

Efficient purification of high-salt rural groundwater in the areas along the Yellow River in Henan Province, China, by hollow fiber membrane distillation process

The vast rural drinking water sources along the Yellow River basin in Henan Province mainly come from the local high-salinity groundwater, which cannot be directly drunk. Zeolitic imidazolate framework-71/polyvinylidene fluoride hollow fiber composite membrane was applied to treat rural groundwater through membrane distillation technology. The variations of water quality parameters from 12 different rural regions after membrane distillation treatment were well analyzed and compared. Membrane separation performance for water samples from different regions during the membrane distillation process was investigated, including water flux and salt rejection. During a continuous 24-h membrane distillation process for the treatment of these water samples, hollow fiber membrane exhibits high solute retention rates (>99%) for salt ions, suspended solids and total dissolved solids, which are within the limits of national standards (GB 5749-2006), meanwhile membrane permeation water flux can remain stable. After the acid-cleaning for 180 min, all hollow fiber membranes can recover water flux well with a flux recovery rate above 98%. Even if the concentration ratio continued to increase, the water production rate of membrane distillation was basically maintained between 50% and 60%, which was obviously higher than the 30% of the reverse osmosis process. The economic analysis confirmed that the water production cost varied between US$0.45 and US$0.29/m3. With the extension of membrane service life, the specific membrane cost decreased rapidly in the first 6 years and then leveled off. The proposed vacuum membrane distillation process proved to be a promising water purification method for treating rural high-salinity groundwater.

Effective and low-toxicity: A membrane cleaning method using peroxymonosulfate catalytic chlorination

In chemical membrane cleaning, the challenge is to efficiently remove irreversible fouling while minimizing the impact on membrane materials. Particularly, traditional hypochlorite cleaning will further lead to the generation of toxic halogenated by-products. To address these issues, a combined system composed of peroxymonosulfate and chloride (PMS/Cl−) was applied to clean irreversible-humic-acid-fouled polyethersulfone (PES) membranes. After fouled membranes were soaked for 1 h in a PMS/Cl− solution (10 mM/15 mM) at 25 °C under neutral conditions, 94% flux recovery and 96% resistance removal were realized. Surface properties of virgin and cleaned membranes were very similar, confirming the effectiveness of the PMS/Cl− solution in removing irreversible foulants. The stability of membrane separation performance during multiple fouling and cleaning cycles further confirmed the minimal impact on membrane materials. Rapid diminution of the peaks centered in the region of fulvic-like and humic-like components, monitored under 3D-fluorescence for the cleaning solution, was attributed to PMS-catalyzed chlorination, thereby revealing the primary foulant detachment mechanism. Crucially, the approach exhibited lower toxicity than hypochlorite, as evidenced by reduced halogenated by-products and lower acute toxicity to Photobacterium phosphoreum T3. Overall, this novel cleaning system is promising for the efficient and environmentally friendly removal of irreversible organic foulants in practical water-treatment.

Thin‐Film Composite Membranes for Organic Solvent Nanofiltration

AbstractOrganic solvent nanofiltration (OSN) is an emerging separation technology. Significant efforts have been dedicated to designing and fabricating thin film composite (TFC) membranes for OSN in recent years. The development and utilization of TFC membranes in OSN are paramount in ensuring the permeability of organic solvent and rejection of solute. Additionally, researchers have delved into optimizing preprocessing and post‐treatment procedures during preparation. The preparation process has emerged as another avenue for improving the separation performance of TFC membranes. Simultaneously, various supports have been explored to enhance the TFC membranes′ performance, including polymer substrates and inorganic substrates, as well as the interlayers between the substrate and the TFC membrane, each with unique advantages and disadvantages, and the choices of support depend on the specific requirements of the intended application. The limitations of conventional membranes could be overcome and thus achieve superior performance via an improved preparation strategy of the TFC membranes. This review presents a comprehensive overview of the preparation process for TFC membranes, including a detailed discussion of the preparation methods, the optimizing processes, and the substrates.

High CO2 adsorption of ultra-small Zr-MOF nanocrystals synthesized by modulation method boosts the CO2/CH4 separation performance of mixed-matrix membranes

The separation performance of mixed matrix membranes (MMMs) is greatly impacted by both the inherent structure of porous fillers and the interfacial compatibility between the filler and matrix. Here, ultra-small Zr-MOFs (UiO-66-mod and NH2-UiO-66-mod) with more defect sites were synthesized through a simple sodium formate modulation strategy. Then, these modulated Zr-MOFs were used as porous fillers in combination with polyetherimide (PEI) to construct a high-quality mixed matrix membrane for efficient CO2 separation. The modulated Zr-MOF not only exposed more defect sites, which significantly enhanced the CO2 adsorption capacity but also exhibited high dispersion in the PEI matrix due to strong interfacial forces, avoiding non-selective voids. The 10-UiO-66-mod-PEI and 10-NH2-UiO-66-mod-PEI membranes developed here showed admirable CO2/CH4 separation performance (CO2 permeability of around 400 and 440 Barrer, CO2/CH4 selectivity of ∼33 and ∼47, respectively) much higher than that of non-modulated UiO-66-PEI membranes, surpassing the 2008 upper bound of MMMs. This work demonstrated that the proposed UiO-66-mod-PEI and NH2-UiO-66-mod-PEI MMMs could be potential candidates for an efficient CO2 capture process.

Mixed matrix membrane with amorphous metal-based complexes displays high CO2 separation performance

Design and exploration of advanced nanofillers that can be highly compatible with the existing polymeric membrane materials remain a subject of future study for mixed matrix membranes for gas separation. In this study, we propose the use of the newly synthesized metal-based complex (Zn-SiF6-py) as a promising filler to prepare high-performance PIM-1 based mixed matrix membranes for efficient CO2 separation. Results demonstrated that the as-synthesized Zn-SiF6-py features an amorphous mesoporous structure, and the inclusion of Zn-SiF6-py in the PIM-1 matrix can concurrently elevate the CO2 permeability and CO2/N2 selectivity. The significant improvements in membrane separation performance can be ascribed to the combined effects of additional gas transport channels and abundant active sites to CO2 molecules provided by Zn-SiF6-py fillers as well as a rigidified polymer region at the filler/matrix interface. Consequently, the optimized mixed matrix membrane at only 5 wt% filler loading achieves a CO2 permeability of 6268 Barrer and a CO2/N2 selectivity of 26.3, surpassing the 2008 Robeson upper bound.

Tailoring filler/gas vs. filler/polymer interactions via optimizing Co/Zn ratio in bimetallic ZIFs and decorating on GO nanosheets for enhanced CO2 separation

Despite numerous efforts devoted to enhancing the gas separation performance of mixed matrix membranes (MMMs), there still remain challenges in effectively embedding nanofillers into the polymer matrix due to the improper interactions between filler and polymer/gas molecules. Concerning that, synthesizing filler with well-structured physical and chemical properties and endowing its synergistic effects with a 2D filler has been considered a promising idea. Herein, five series of bimetallic ZIFs with various Co/Zn ratios were synthesized and embedded within the Pebax-1657 matrix to investigate the exact influence of metal ratio on the separation performance of MMMs. The results revealed that the Co60Zn40ZIF has the highest Co content that does not induce early chain rigidification, and enhances permeability and selectivity by 41.93 % and 93.65 % at 7.5 wt% loading, respectively. Furthermore, by hybridizing the optimized bimetal ZIF with GO, a substantial enhancement in selectivity was achieved, elevated by 250.37 % (compared to neat Pebax-1657) at the 7.5 % loading of GO@ZIF. The integration of the strategies applied to synthesizing bimetal ZIF with fine-tuned pores on the GO nanosheets exceeded the Robeson upper bond and yielded an exemplary separation index, which may offer enormous prospects for future research on multi-metallic composited MOF fillers.

Enhancing membrane separation performance in the conditions of different water electrical conductivity and fouling types via surface grafting modification of a nanofiltration membrane, NF90

A commercialized and widely applied nanofiltration membrane, NF90, was in-situ modified through a surface grafting modification method by using 3-sulfopropyl methacrylate potassium salt and initiators. The effects of water electrical conductivity (EC) and fouling types on membrane separation efficiency were examined before and after membrane modification. Results reveal that both the pristine membrane (PTM) and surface grafting modification membrane (SGMM) had a declining permeate flux and salt (NaCl) removal efficiency but an increasing trend of pharmaceuticals and personal care products (PPCPs) removal with increasing water EC from 250 to 10,000 μs cm−1. However, SGMM exhibited a slightly declining permeate flux but 13%–17% and 1%–42% higher rejection of salt and PPCPs, respectively, compared with PTM, due to electrostatic repulsion and size exclusion provided by the grafted polymer. After sodium alginate (SA) and humic acid (HA) fouling, SGMM had 17%–26% and 16%–32% higher salt rejection and 1%–12% and 1%–51% greater PPCP removal, respectively, compared with PTM due to the additional steric barrier layer contributed by the foulants. The successful grafting and increasing hydrophilicity of the SGMM were confirmed by contact angle analysis, which was beneficial for mitigating membrane fouling. Overall, the proposed in-situ surface grafting modification of NF90 can considerably mitigate organic and biological fouling while raising the rejection of salt and PPCPs at different background water EC, which is beneficial for practical applications in producing clean and high quality water for consumers.

‘Green’ fabrication of PVC UF membranes with robust hydrophilicity and improved pore uniformity

Hydrophilicity and pore uniformity are the key parameters for ultrafiltration (UF) membranes to avoid fouling and ensure separation effectiveness. In this paper, a simple ‘green’ in-situ chemical reaction assisted phase separation method was studied, in which amine molecules bearing hydrophilic hydroxyl groups were grafted onto polyvinyl chloride (PVC) chains in dissolution process without initiator. The influence of modifier concentration on the structure, separation and anti-fouling performance of the PVC membranes was studied. The results indicated that the robust hydrophilicity, and high pore size uniformity and porosity of were achieved by properly anchoring preferable amine molecules. The pure water flux of the modified membrane was 261.5 L·m−2·h−1, BSA rejection was 99.1 % when 10 wt% SRN was added. Approximately 27 % increase of rejection to BSA, and 10-fold pure water flux that of the pristine PVC membrane. Due to the stable existence of modifiers in the membrane, the improved membrane hydrophilicity was maintained through 320 h filtration and acid/alkali soaking tests. This study provides a simple modification approach to enhance PVC UF membrane hydrophilicity and pore uniformity.

Ammonia-assisted ZnO support-induced conversion approach to prepare oriented Zn2(bIm)4 membrane for hydrogen separation

The construction of oriented two-dimensional MOF membrane is highly desirable for gas separation. At present, the most commonly used method is top-down exfoliation-deposition, but this method is complex, time-consuming, arduous, and difficult to prepare on a large-scale. The relatively simple and scalable direct growth approach is more attractive but still a major challenge. In this contribution, an ammonia-assisted ZnO support-induced strategy was developed to prepare highly oriented Zn2(bIm)4 membranes via in-situ solvothermal growth just in one cycle. This proposed approach is on the basis of the self-conversion of ZnO-support in ligand solutions containing ammonia modulators. The effects of ZnO-support calcination temperature, ammonia concentration, growth time and temperature on the formation of Zn2(bIm)4 membrane and gas separation performance were studied in detail. The prepared Zn2(bIm)4 membrane exhibited good stability in the mixed-gas test with H2/CO2 selectivity of 15.3 and hydrogen permeance of 1.25 × 10−8 mol· m−2·s−1·Pa−1, which is better than the upper-bound in 2008. The excellent membrane stability was due to the fact that ZnO support as the nucleation and anchoring sites to make the Zn2(bIm)4 membrane and support integrate. The preparation of Zn2(bIm)4 membrane by support-induced technology has the advantages of relatively simple preparation process, outstanding membrane stability and high gas separation property, which provides a very promising H2/CO2 separation membrane material. This method also provides a new way for the scaling-up 2D MOF membranes and their industrial applications.

Tuning the Stacking Modes of Ultrathin Two‐Dimensional Metal–Organic Framework Nanosheet Membranes for Highly Efficient Hydrogen Separation

AbstractTwo‐dimensional (2D) metal–organic framework (MOF) membranes are considered potential gas separation membranes of the next generation due to their structural diversity and geometrical functionality. However, achieving a rational structure design for a 2D MOF membrane and understanding the impact of MOF nanosheet stacking modes on membrane separation performance remain challenging tasks. Here, we report a novel kind of 2D MOF membrane based on [Cu2Br(IN)2]n (IN=isonicotinato) nanosheets and propose that synergetic stacking modes of nanosheets have a significant influence on gas separation performance. The stacking of the 2D MOF nanosheets is controlled by solvent droplet dynamic behaviors at different temperatures of drop coating. Our 2D MOF nanosheet membranes exhibit high gas separation performances for H2/CH4 (selectivity >290 with H2 permeance >520 GPU) and H2/CO2 (selectivity >190 with H2 permeance >590 GPU) surpassing the Robeson upper bounds, paving a potential way for eco‐friendly H2 separation.

Tuning the Stacking Modes of Ultrathin Two-Dimensional Metal-Organic Framework Nanosheet Membranes for Highly Efficient Hydrogen Separation.

Two-dimensional (2D) metal-organic framework (MOF) membranes are considered potential gas separation membranes of the next generation due to their structural diversity and geometrical functionality. However, achieving a rational structure design for a 2D MOF membrane and understanding the impact of MOF nanosheet stacking modes on membrane separation performance remain challenging tasks. Here, we report a novel kind of 2D MOF membrane based on [Cu2 Br(IN)2 ]n (IN=isonicotinato) nanosheets and propose that synergetic stacking modes of nanosheets have a significant influence on gas separation performance. The stacking of the 2D MOF nanosheets is controlled by solvent droplet dynamic behaviors at different temperatures of drop coating. Our 2D MOF nanosheet membranes exhibit high gas separation performances for H2 /CH4 (selectivity >290 with H2 permeance >520 GPU) and H2 /CO2 (selectivity >190 with H2 permeance >590 GPU) surpassing the Robeson upper bounds, paving a potential way for eco-friendly H2 separation.

PAN/TiO2 Ultrafiltration Membrane for Enhanced BSA Removal and Antifouling Performance

Membrane separation has been widely utilized to eliminate pollutants from wastewater. Among them, a polyacrylonitrile (PAN) ultrafiltration (UF) membrane has presented outstanding stability, and distinguished chemical and thermal properties. However, UF membranes inevitably incur fouling issues during their operation procedure caused by contaminant adhesion on the membrane surface, which would restrict the operational efficiency and increase the maintenance cost. The conventional physical and chemical cleaning is not an effective technique to reduce the fouling due to the additional chemical addition and inevitable structure damage. Recently, UF membranes combined with photocatalytic materials are suggested to be a useful approach to conquer the membrane fouling issues. Herein, TiO2 nanoparticles were utilized to blend with a PAN casting solution for fabricating a composite UF membrane via a phase inversion method. With a certain TiO2 addition, the obtained membranes presented an enhancement of hydrophilicity, which could promote the water permeability and antifouling performance. The optimized M3 membrane prepared with 15.0 wt% PAN and 0.6 wt% TiO2 exhibited an excellent water permeability up to 207.0 L m−2 h−1 bar−1 with an outstanding 99.0% BSA rejection and superior antifouling property. In addition, the photocatalytic TiO2 nanoparticles endowed the M3 membrane with a remarkable self-cleaning ability under the UV irradiation. This facile construction method offered new insight to enhance the UF membrane separation performance with an enhanced antifouling ability.

Functionalized graphene-based ultrafiltration and thin-film composite nanofiltration membranes for arsenic, chromium, and fluoride removal from simulated groundwater: Mechanism and effect of pH

Groundwater contaminant removal using ultrafiltration (UF) and nanofiltration (NF) membranes is complex due to limitations such as low selectivity-permeability and membrane fouling tendency. In this study, we fabricated a thin film composite (TFC) membrane over a highly permeable mixed matrix support UF membrane using sulfonic acid functionalized graphene oxide (SGO) and polyethersulfone (PES) for groundwater remediation application. The pure water permeability of the PES-SGO-TFC membrane was threefold (3.09 LMH bar−1) compared to the pristine PES-TFC membrane. The membrane showed excellent organic fouling resistance with more than 95% flux recovery. The salts and contaminant removal were checked in a cross-flow mode to understand a more practical approach to the applicability of the developed PES-SGO-TFC membrane. The membrane rejected Cr(VI), As(V), and fluoride to the extent of ∼89%, ⁓99%, and ∼77%, respectively, at pH ⁓7. The membrane separation performance varied as a function of pH, with more than 90% removal for monovalent fluoride at higher pH values. In a simulated groundwater matrix, the membrane demonstrated promising results for rejecting these ions. However, the simultaneous rejection of As(V) and fluoride may be impacted by interfering co-ions. This study offers a novel approach for developing highly permeable support UF-modified TFC membranes for better separation for groundwater remediation.

Oriented Ultrathin π‐complexation MOF Membrane for Ethylene/Ethane and Flue Gas Separations

AbstractRational design and engineering of high‐performance molecular sieve membranes towards C2H4/C2H6 and flue gas separations remain a grand challenge to date. In this study, through combining pore micro‐environment engineering with meso‐structure manipulation, highly c‐oriented sub‐100 nm‐thick Cu@NH2‐MIL‐125 membrane was successfully prepared. Coordinatively unsaturated Cu ions immobilized in the NH2‐MIL‐125 framework enabled high‐affinity π‐complexation interactions with C2H4, resulting in an C2H4/C2H6 selectivity approaching 13.6, which was 9.4 times higher than that of pristine NH2‐MIL‐125 membrane; moreover, benefiting from π‐complexation interactions between CO2 and Cu(I) sites, our membrane displayed superior CO2/N2 selectivity of 43.2 with CO2 permeance of 696 GPU, which far surpassed the benchmark of other pure MOF membranes. The above multi‐scale structure optimization strategy is anticipated to present opportunities for significantly enhancing the separation performance of diverse molecular sieve membranes.

Oriented Ultrathin π-complexation MOF Membrane for Ethylene/Ethane and Flue Gas Separations.

Rational design and engineering of high-performance molecular sieve membranes towards C2 H4 /C2 H6 and flue gas separations remain a grand challenge to date. In this study, through combining pore micro-environment engineering with meso-structure manipulation, highly c-oriented sub-100 nm-thick Cu@NH2 -MIL-125 membrane was successfully prepared. Coordinatively unsaturated Cu ions immobilized in the NH2 -MIL-125 framework enabled high-affinity π-complexation interactions with C2 H4 , resulting in an C2 H4 /C2 H6 selectivity approaching 13.6, which was 9.4 times higher than that of pristine NH2 -MIL-125 membrane; moreover, benefiting from π-complexation interactions between CO2 and Cu(I) sites, our membrane displayed superior CO2 /N2 selectivity of 43.2 with CO2 permeance of 696 GPU, which far surpassed the benchmark of other pure MOF membranes. The above multi-scale structure optimization strategy is anticipated to present opportunities for significantly enhancing the separation performance of diverse molecular sieve membranes.

Effect of aluminum and manganese ions on the chlorination of polyamide membranes

The deterioration of separation performance of polyamide membranes after chlorine exposure is a core issue in the application process of membrane technology. The co-existence of metal ions (i.e., Al3+ and Mn2+), which are ubiquitous in different types of water bodies, may complicate the chlorination process. This study systematically evaluated membrane degradation under the simultaneous presence of free chlorine and Al3+ or Mn2+. The membrane water flux after chlorine exposure of 2400 mg/L·h was decreased by 70 %, of which 49 % was resulted from chlorine exposure, attributing to competing effects of the decreased hydrophilicity (contact angle increased from 56° to 68°) and cross-linking degree (Onet/N ratio increased from 1.1 to 2.3). The changes in the physiochemical properties of membranes were due to chlorination and hydrolysis induced by chlorination. The addition of Al3+ or Mn2+ to chlorine resulted in a further reduction of 8 %–13 % for water flux, and a variation as high as 21 % (increase) and 15 % (decrease) for salt rejection compared to virgin membrane at different exposure periods. These cations similarly resulted in a more hydrophobic membrane surface with varied surface charge and the formation of deposition layers. In addition, Al3+ and Mn2+ did not affect chlorination degree (chlorine incorporation). However, Al3+ promoted chlorination-promoted hydrolysis, while Mn2+ inhibited, reflected by the opposite trends of Onet/N.

PEI@MOFs thin film nanocomposite (TFN) membrane for efficient CO2 separation

Polyetherimide (PEI) membrane exhibits high CO2 selectivity while suffer from low permeance thus limiting the further application in CO2 separation. Thin film nanocomposite (TFN) membrane which contains a thin selective functional layer with nanomaterials porous fillers is a new class of high-performance membranes. In this work, a series of novel PEI@MOFs TFN membranes were prepared for efficient CO2 separation. The sub-micro scale PEI layers (about 400 nm) with four kinds of MOFs fillers including 3-dimensional MOFs nanoparticles (UiO-66 and MIL-101 (Cr)) and MOFs nanosheets (2-D CuBDC and Zn2(bim)4) were prepared by a simple spin-coating strategy. The properties and CO2 separation performance of the TFN membranes were further studied. The MOFs in PEI increased the diffusion coefficient and selectivity for CO2, at the same time, the ultra-thin functional layer maximized reducing the CO2 transport resistance. As a result, the PEI@MOFs TFN membranes exhibited high CO2 permeance as well as enhanced CO2 separation performance which close to the Robeson upper bound. The PEI@CuBDC TFN membrane exhibited CO2 permeance of 15.6 GPU (3.3 times higher than the neat PEI membrane), and the selectivity of CO2/CH4 reached 39.8 (2.2 times higher than the neat PEI membrane). In addition, the PEI@MOFs TFN membranes showed good thermal and operation stability.

Effect of uniaxial stretching on gas separation performance of polyimide membranes

Fine-tuning of the physical stacking structure for microporous polyimide (PI) membranes via the stretching processing is a practical way of achieving advanced membrane materials with improved aging resistance as well as high gas separation performance. Here, a fluorinated polyimide 6FDA:BPDA-TFDB(1:1:2) is used as a prototype and a series of stretched membranes X%-PI are fabricated by uniaxially stretching the membrane to different elongation ratio and then annealing. Based on birefringence and wide-angle X-ray diffraction measurements, it's found that regular orientation of polymer chains along the stretching direction and fine-tuning of d-spaces from interchain packing and π-π stacking happen during the uniaxial stretching process. As such, compared to pristine PI membrane, the stretched membranes show better mechanical and thermal stability, especially for the one with higher stretching ratio. In addition, owing to the increased packing density of polymer chains, the highly stretched membrane of 40%-PI shows significantly improved gas perm-selectivity by 32.8%, 24.3%, and 12.6% for He/CH4, H2/CH4, and CO2/CH4 gas pairs, respectively, in comparison to pristine membrane. Furthermore, 40%-PI exhibits much higher gas permeability retention rate than that of other membranes after three months' aging. We expect that this work can offer polymer materials processing guidance for the preparation of high-performance gas separation membrane in future.

Rationally designed fluorinated aromatic polyamide membrane for stable air dehumidification

Membrane based dehumidification technology has attracted wide attention. The anti-hydrolytic property of the membrane holds a significant role in its long-term operation in a wet environment. Herein, a series of fluorinated aromatic polyamides (FPA) are first proposed for stable air-dehumidification. Amide bond offers superior hydrolytic stability over chemical bond in the present dehumidification membrane. The deliberately introduced bulky fluorinated group (-CF3) increases the water permeability and enhances the anti-hydrolytic property of the FPA membranes. The membrane separation performance and membrane stability are further tuned by adjusting the molar ratio of para- and meta-amide groups to optimize the intermolecular forces and polymer chain arrangement, which is verified by the refractive index data and wide-angle X-ray diffraction results. The obtained co-FPA membranes exhibit tunable gas and water vapor permeation properties. With increasing para-amide group content, the gas and water vapor permeability of copolyamides gradually decreases and the selectivity of H2O/N2 increases. Meanwhile, the hydrolytic stability of the co-FPA membranes increases with the increase of TPC content as verified by 1H NMR, GPC, and mechanical property tests. Among these co-FPA membranes, the co-FPA-70 membrane exhibits the most excellent hydrolytic stability. The membrane shows almost no change in 1H NMR spectra and 97% retention of tensile strength after 5000 h of hydrolysis reaction. In the meanwhile, it shows excellent separation stability with a water vapor permeability retention of 74% during long-term hydrolysis aging operation. This study demonstrates the great potential of polyamide for the fabrication of dehumidification membranes with high hydrolysis resistance.