Kinds Of Membranes Research Articles

Novel Polyheteroarylene Membranes for Separation of Methanol\u2012Hexane Mixture by Pervaporation

Polymer membranes with improved transport properties are required for effective separation of organic mixtures (such as methanol‒hexane system) by combination of pervaporation and azeotropic distillation. The present work is devoted to comparative study of two types of membranes based on poly(amidoimide acid) with 2,2′-biquinoline-6,6′ units in the backbone; the objects were prepared (i) from the initial polymer and (ii) from the polymer-metal complex (with Cu(I)). Thermo-mechanical and mass spectrometric investigations demonstrated good operational properties of the samples. Density measurements and SEM analysis revealed that the structure formed in polymer-metal complex is more compact as compared to that of the pure polymer membrane. Mass transfer processes of methanol and hexane through both kinds of membranes were studied by sorption, desorption and pervaporation tests. The values of equilibrium sorption degree, the Flory–Huggins parameter, and diffusion coefficient were determined for the obtained membranes. The pervaporation data allowed calculating permeability and selectivity of membranes in addition to the flux and the separation factor. The membrane based on polymer-Cu(I) complex allowed separating the methanol‒hexane azeotropic mixture with a separation factor of 980 and pervaporation separation index equal to 66.6; therefore, this process is significantly more effective than separation procedures involving other known membranes.

Superhydrophobic brass and bronze meshes based on electrochemical and chemical self-assembly of stearate

The preparation and characterization of superhydrophobic membranes formed on metal meshes (brass and bronze) by coating from stearic acid is presented. The membranes were prepared by two methods: electrolysis and acid etching. The electrolysis process is a one-step method performed by anodizing the mesh in ethanol solutions of stearic acid. Stearic acid concentration, support electrolyte concentration and electrolysis time were systematically varied. Nanostructures, including nanotubes, are induced on the metallic filaments. Analysis by FTIR, XRD, XPS and SEM of surfaces and precipitated material indicate that formed nanostructures are assemblies of metallic stearates on the surface (copper and/or zinc stearates). Superhydrophobicity (contact angles larger than 150°) was only achieved (in the electrolysis method) in cases where the formation of nanotubes was observed. On the other hand, the acid etching process is a two-step method: immersion of the meshes in acid solution of CuCl2 or FeCl3, oxidizing the surface with formation of inorganic salts nano crystals, followed by immersion in stearic acid solution. Organic nanostructures (nanoribbons and/or nanopetals) were observed after the second step. Superhydrophobic surfaces (contact angles between 150 and 170°) were obtained for all the membranes.Both kind of membranes (electrolysis and etching) resulted effective in oil-water separation.

ANTIDIABETIC EFFECT OF SILVER NANOPARTICLES SYNTHESIZED USING LEMONGRASS (CYMBOPOGON CITRATUS) THROUGH CONVENTIONAL HEATING AND MICROWAVE IRRADIATION APPROACH

Biosynthesis of nanoparticles using plant extract is an eco- friendly approach which eliminates the need for using physical and chemical techniques. Nanoparticle use in medical field specially anti-diabetes and anti-cancer application has remained in recent studies owing to its large surface area to volume ratio, which imparts them the capability to interact with any kind of membrane and enzymes in a better manner. This paper presents the optimized synthesis of silver nanoparticles (Ag NPs) using lemongrass and visualizing its in-vitro anti-diabetic potential. This study involves the comparative analysis of Conventionally heated (CH) and Microwave irradiated (MI) technique for the synthesis of Ag NPs from lemongrass for the first time. The crystalline nature of the nanoparticles was confirmed using X-ray diffraction assay (XRD) with average size range of 75 nm, the size, and shape of the nanoparticles were confirmed as spherical shaped using scanning electron microscope (SEM), atomic force microscopy (AFM) demonstrated aggregate formation of size range 138 nm with mean average size of individual nanoparticle as 80 nm, elements present in the nanoparticles confirmed using elemental dispersive analysis of X-ray (EDAX) and the functional groups of plant extract responsible for nanoparticles synthesis have been confirmed using Fourier transform infrared spectroscopy (FT-IR). Surface morphology and the dispersity were observed by Transmission electron microscopy (TEM) analysis. The anti-diabetic potential of nanoparticle synthesized was studied using amylase activity inhibition Assay and glucose diffusion-inhibitory Assay.

Rigorous modeling of gas permeation behavior in facilitated transport membranes (FTMs); evaluation of carrier saturation effects and double‐reaction mechanism

AbstractIn this work, a general model for the gas permeation behavior of facilitated transport membranes (FTMs) has been developed. The importance of developing a clearer understanding of FTM permeation behavior by introducing a detailed two‐dimensional FTM model was demonstrated. This model accounts for the effects of partial pressure on permeance by considering the carrier saturation‐state phenomenon and reaction‐diffusion portions in FTMs. The model is based on a first order double‐step reaction mechanism with respect to the role of the concentration of zwitterion ions in the facilitated transport of CO2. It is shown here that the individual values of reaction constant rates and diffusion coefficients of components in the chemical reaction, which belong to the FTM condition, have been determined by the FTMs’ permeability and were not guessed or calculated. Overall, this work provides a method for the more reliable use of models to understand and design of FTMs, and to better comprehend the large and growing body of experimental data on these kinds of membranes. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd.

A Novel Nanofiltration Membrane Prepared with PAMAM and Graphene oxide for Desalination

Nanofiltration is increasingly gaining attention in many separation and treatment processes such as water softening, color removal and separation of medicines. Nanofiltration membranes are often negatively charged, displaying separation characteristics in the intermediate range between reverse osmosis and ultrafiltration. In this research, a novel nanofiltration membrane prepared with poly(amidoamine) (PAMAM) dendrimer and graphene oxide (GO) on amidoximated acrylic ultrafiltration membrane was investigated. Scanning Electron Microscopy (SEM) and contact angle of the water were employed to characterize the chemical and physical changes of resulting membranes. The flux and rejection of resulting membranes increased with increasing generation numbers of PAMAM for NaCl concentration. The salts rejections order of resulting membrane is CaCl2>MgSO4>NaCl>Na2SO4, which shows that resulting membranes were all positively charged NF membrane. The PAMAM/GO NF membrane is especially suitable for separating cationic solutes from others. This kind of membrane is also particularly suitable for treating acidic feed. The studied membrane possesses maximum operating pressure lower than 4 bar and excellent stability during continuous filtration at 27±2°C.

Proton exchange membranes prepared via atom transfer radical polymerization for proton exchange membrane fuel cell: Recent advances and perspectives

Proton exchange membranes (PEMs) with well-defined microphase separation hold great promise for satisfying the demands of operation under high temperature and low humidity. Atom transfer radical polymerization (ATRP), as one of the most popular methods of controllable polymerization, has already been one of the most convenient tools for the synthesis of copolymers with well-defined microphase separated structures. This article tersely and concisely reviews the recent development of the PEMs prepared by ATRP for proton exchange membrane fuel cells. According to the different functional monomers in the polymerization, three kinds of membranes are systematically discussed in this feature article. The first membrane is made of copolymer grafted styrene by ATRP followed by post-sulfonation; the second membrane is prepared by directly grafting a sulfonated monomer to polymer using single-step ATRP; and the membranes grafted other types of monomers are divided into the third membranes. For each category of membrane, structures, properties, and their relationships are conducted targeted analysis. Finally, the perspectives of future trends on PEMs prepared via ATRP are presented.

Enhancement of Thermal Conductivity of Polyvinyl Alcohol Membrane Using Nano-fiber

ABSTRACTThe thermal properties of organic membranes attract much attention due to the fact that heat dissipation in electronic devices limits their functionality and reliability. Here, we enhance the thermal conductivity of polyvinyl alcohol (PVA) membrane using nano-fibers fabricated by electrospinning. Measured by the 3-Omega method, the results show that the effective thermal conductivity of the electrospinning membranes (with/without Cu nanoparticles) are as high as 0.7 W/m-K at room temperature which is as twice as the value of thermal conductivity of amorphous spin-coated PVA membrane (0.35 W/m-K). The mechanism of enhancement are that, compared with amorphous membrane, the phonon scattering is attenuated and the crystallinity is improved in the electrospinning process. Our studies bring new insights in designing new kind of membrane with high thermal conductivity.

An Addressable 2D Heterogeneous Nanoreactor to Study the Enzyme-Catalyzed Reaction at the Interface.

Membrane plays significant role in cellular enzymatic reactions. To better understand its function on membrane integral or bound enzymes, DNA origami and frame-guided assembly strategy are combined to construct a given-size, addressable enzyme-containing nanomembrane as a heterogeneous reactor to explore the enzymatic catalyst reaction on the membrane. The enzymes in the membrane are located precisely. This new kind of membrane can enrich hydrophobic substrate molecules in aqueous solution to the embedded enzymes. Otherwise, this nanomembrane shows the capability of substrate selectivity, which plays important role in the highly efficient and specific properties of enzymes in vivo.

Elastic Evaluation of Poly(Lactic Acid) Electrospun Membranes Using the Pulsed Photoacoustic Technique

Fibrous membranes manufactured by electrospinning possess unique features such as a high porosity and large specific surface area, making them suitable for applications in tissue engineering. However, the determination of their mechanical behavior under different loading conditions remains one of the most difficult technical problems for researchers to overcome. While the tensile properties of this kind of membrane are commonly reported in the literature, few explorations of their properties in other directions have been reported. In this paper, the pulsed photoacoustic technique is employed to obtain the elastic constants of electrospun non-woven membranes, specifically in two directions (L, T). The electrospun samples are hybrid fiber membranes of poly(lactic acid) and hydroxyapatite (HA) nanoparticles at different concentrations. It is found that the concentration of HA nanoparticles determines the mechanical response of the membrane, where the nanoparticles act either as a reinforcement or as a mesh defect. The elastic constants ( $$E_{L}, E_{T}, G_{L}, G_{T}, v_{L}$$ , $$\nu _{T}$$ ) are obtained through velocity waves related to the stress–strain equations, using samples with two different geometries and considering the electrospinning mats as a transversely isotropic material. These values are compared to those acquired using macro-tensile testing equipment according to the ASTM D1708 standard.

High-Flux Graphene Oxide Membranes Intercalated by Metal-Organic Framework with Highly Selective Separation of Aqueous Organic Solution.

Graphene oxide (GO) membranes assembled by single-atom thick GO nanosheets have displayed huge potential application both in gas and liquid separation processes due to its facile and large-scale preparation resulting from various functional groups, such as hydroxyl, carboxyl, and epoxide groups. Taking advantage of these characters, GO membranes intercalated by superhydrophilic metal-organic frameworks (MOFs) as strengthening separation fillers were prepared on modified polyacrylonitrile (PAN) support by a novel pressure-assisted self-assembly (PASA) filtration technique instead of traditional vacuum filtration method for the first time. The synthesized MOF@GO membranes were characterized with several spectroscopic techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS), as well as scanning electron microscopy (SEM). Compared with GO membrane, these MOF@GO membranes combine the unique properties of MOF and GO and thus have significant enhancements of pervaporation (PV) permeation flux and separation factor simultaneously for ethyl acetate/water mixtures (98/2, w/w) through the PV process, which are also superior to the reported other kinds of membranes. Especially, for MOF@GO-0.3 membrane (corresponding MOF loading: 23.08 wt %), the increments are 159% and 244%, respectively, at 303 K, and the permeate water content can reach as high as 99.5 wt % (corresponding separation factor, 9751) with a high permeation flux of 2423 g m-2 h-1. Moreover, the procedures of both the synthesis of MOF and membranes preparation are environmentally friendly that only water was used as solvent. Such a nanosized MOF-intercalating approach may be also extended to other laminated membranes, providing valuable insights in designing and developing of advanced membranes for effective separation of aqueous organic solution through nanostructure manipulation of the nanomaterials.

Mixed matrix membranes incorporated with polydopamine-coated metal-organic framework for dehydration of ethylene glycol by pervaporation

In order to solve the issue of incompatibility between metal-organic frameworks (MOFs) and polymer matrix, mixed-matrix membranes (MMMs) on the basis of a hydrophilic polymer poly(vinyl alcohol) (PVA) and a MOF with hydrophilic sulfonic acid group (SO3H-MIL-101-Cr) coated by a thin and uniform polydopamine (PD) layer were prepared for separation of organic solvent from aqueous solutions by taking ethylene glycol (EG) as an example. The PD layer can control the thickness effectively on the surface of SO3H-MIL-101-Cr through a self-polymerization of dopamine and enhance the compatibility between MOF and PVA due to the formation of hydrogen bond between the abundant amine groups in PD and the hydroxyl in PVA matrix. As a result, the prepared SO3H-MIL-101-Cr@PD-PVA MMM exhibits a largely improved water permeability of 7.05×10−5gm−1h−1kPa−1 (the water flux is 540gm−2h−1) and the selectivity is as high as 68.1 (the separation factor is 2864) for EG aqueous solution (water content: 10wt%) separation at 343K. Compared with those in pure PVA membrane, the water permeability and selectivity were increased by 483% and 567% respectively. To the best of our knowledge, this separation performance is superior to those in all of the reported membranes so far. Therefore, this interfacial modification of MOF fillers may be an effective way to enhance the PV separation performance of MMMs, which can be conveniently extended to prepare other kinds of membranes with advanced properties.

Recent Advances in Pd-Based Membranes for Membrane Reactors.

Palladium-based membranes for hydrogen separation have been studied by several research groups during the last 40 years. Much effort has been dedicated to improving the hydrogen flux of these membranes employing different alloys, supports, deposition/production techniques, etc. High flux and cheap membranes, yet stable at different operating conditions are required for their exploitation at industrial scale. The integration of membranes in multifunctional reactors (membrane reactors) poses additional demands on the membranes as interactions at different levels between the catalyst and the membrane surface can occur. Particularly, when employing the membranes in fluidized bed reactors, the selective layer should be resistant to or protected against erosion. In this review we will also describe a novel kind of membranes, the pore-filled type membranes prepared by Pacheco Tanaka and coworkers that represent a possible solution to integrate thin selective membranes into membrane reactors while protecting the selective layer. This work is focused on recent advances on metallic supports, materials used as an intermetallic diffusion layer when metallic supports are used and the most recent advances on Pd-based composite membranes. Particular attention is paid to improvements on sulfur resistance of Pd based membranes, resistance to hydrogen embrittlement and stability at high temperature.

(Invited) Electrically Conductive Diamond Membrane for Electrochemical Separation Processes

Boron-doped diamond has been applied as an outstanding electrode material for electrochemical applications. Using templated growth techniques, a variety of diamond nanostructures like diamond wires and diamond foams can be fabricated [1, 2]. Using quartz or glass fiber paper as growth templates, porous diamond membranes are fabricated [3]. Compared to polymer membranes or membranes based on sp2 carbons, diamond membranes can survive in aggressive media and high temperature conditions. Also, the ion selectivity can be controlled by surface terminations as well as the bias potential of the membrane. Therefore, this kind of membranes is very promising for the electrochemical separation processes such as desalination, pollutants concentration and protein separation. However, both the fabrication and application of diamond membranes are so far reported only in very limited cases. In this paper, we report our recent progress with respect to the templated diamond growth using quartz fiber paper as the growth template [3]. With optimized microwave CVD growth, nanocrystalline diamond film is fully coated onto the quartz fiber as has been confirmed via SEM. The growth conditions in terms of temperature, methane concentration and boron/carbon ratio are investigated in detail. The diamond quality is evaluated via Raman spectroscopy. The potential window of the diamond membrane is determined via cyclic voltammetry in an aqueous NaClO4 solution to be over 3 V. By applying potential to the membrane, reactive ions will accumulate inside the membrane and change its porosity. As a result, the ion flux through the membrane can be well tuned. This ion selectivity can be used to separate charged molecules. As a proof of concept, Rhodamine B, Ni2+ and Cu2+ are separated by the diamond membrane under different biases. Finally, due to the robustness of diamond, the membrane can be cleaned via a high potential (+2 V vs Ag/AgCl) oxidation process in situ. Metal deposits and organic contaminants are proved to be removable by this method. Therefore, this membrane is also suitable for applications where only simple in-situ maintenances are possible. This project has received funding from the European Union's Horizon 2020 Programme under Grant Agreement no. 665085 (DIACAT). [1] Gao F, Wolfer MT, Nebel CE. Highly porous diamond foam as a thin-film micro-supercapacitor material. Carbon. 2014;80(0):833-40. [2] Gao F, Lewes-Malandrakis G, Wolfer MT, Muller-Sebert W, Gentile P, Aradilla D, et al. Diamond-coated silicon wires for supercapacitor applications in ionic liquids. Diamond Relat Mater. 2015;51:1-6. [3] Gao F, Nebel CE. Diamond-Based Supercapacitors: Realization and Properties. ACS Appl Mater Interfaces. 2015.

Integration of Different Sintering Temperature of Hydroxyapatite and Polyethersulfone Membrane for Fouling Mitigation

This study aimed to investigate the effects of hydroxyapatite integration with polyethersulfone (PES) membrane towards fouling mitigation. PES membrane were modified through self- assembly technique with hydroxyapatite (form fish sclaes) which prepared at different sintering temperatures. This composite membrane were characterized concerning on permeability coefficient, membrane porosity, ATR-FTIR analysis fouling quantification. Overall results showed that PES membrane incorporated with hydroxyapatite sintered at 300°C (PES/FSHAp-300) promoted an excellent characteristics and performance. The membrane demonstrated high permeability coefficient and membrane porosity for about 93.52 L/m2.h and 89.78%, respectively. This kind of membrane was also presented the highest flux recovery ratio around 83.3% and this findings can be a good pathway for the design of low fouling membrane for enzyme separation.

Separation of Peptides and Interaction with Forward Osmosis Biomimetic Membranes: A Solution Diffusion Model

Recently, a membrane based technique, forward osmosis (FO), has gained interest with respect to the separation and purification of biomolecules. Forward osmosis relies on concentration gradients to draw water across the membrane and is as such a gentle technique compared to the traditional pressure driven membrane processes. The challenge within FO is to operate at a high water flux while maintaining a high rejection and low reverse flux of salt that may otherwise interfere with the biomolecules. By adding water-transporting aquaporin protein channels to the membrane matrix to create biomimetic membranes, selective transport of water is possible. These kinds of membranes could as such be ideal for separation of biomolecules.In this study, a biomimetic forward osmosis membrane was tested for the separation of two peptides (416.48 Da and 691.71 Da). The membrane was found to exhibit high, but not complete, rejection rates of both peptides (>98%). It is interesting that even relatively large molecules are able to pass the otherwise dense active layer of the forward osmosis membrane. Therefore, to further understand the transport mechanisms underlying the filtration process, a custom made cell was constructed and used to model the process with filtration models. It was found that the filtration process could be modeled using the solution diffusion approach, with the diffusion coefficient being related to the radius of gyration of the peptides.

Comparison of facilitated transport behavior and separation properties of membranes with imidazole groups and zinc ions as CO2 carriers

Two kinds of membranes using imidazole groups and Zn ions respectively as CO2 carriers are designed to investigate different facilitated transport behaviors and the concomitant separation properties. Poly(N-vinylimidazole)@CNT (PVI@CNT) and Zn-poly(N-vinylimidazole)@CNT (Zn-PVI@CNT) nanoparticles are synthesized via precipitation polymerization then incorporated into polyimide to prepare hybrid membranes. PVI@CNT filled membrane shows CO2 facilitated transport behavior and distinctly enhanced CO2 separation property with a maximum CO2 permeability increment of 90% at humidified state, which is attributed to the nucleophilic addition reaction between imidazole group and CO2. Zn-PVI@CNT filled membrane shows CO2 facilitated transport behavior and distinctly enhanced CO2 separation property with a maximum CO2 permeability increment of 93% at dry state, which is attributed to the π complexation reaction between Zn ion and CO2. The different facilitated transport behaviors of these two membranes are further analyzed for the rational design and intensified separation properties of membrane materials.

Hemodialysis-associated Oxidative Stress: Comparison of Helixone® and Polysulfone® Dialyzer

Background: Patients at end stage renal failure require hemodialysis, a process that contributes to oxidative stress, where the quality of hemodialysis membrane plays a key role. Aim of the Study: We sought to investigate the effect of two different hemodialysis membranes (Helixone® vs Polysulfone®) on several blood biologic and oxidative stress parameters. Patients and Methods: Among 86 patients of our hemodialysis facility at the University Hospital, 12 patients were included in the study according to inclusion and exclusion criteria. Patients used Polysulfone® membrane in a first step of the study, then they switched to Helixone® membrane. Original Research Article Errasfa et al.; JAMPS, 7(1): 1-7, 2016; Article no.JAMPS.24141 2 Under the two kinds of membranes, we measured routine biologic parameters, and preand postdialysis plasma oxidative stress parameters (malondialdehyde and Total Anti-Oxidant Activity, as assessed respectively, by the method of thiobarbituric acid, and an anti-oxidant activity commercial kit). Results: With both Polysulfone® and Helixone® dialyzers, there was an important and significant increase of malondialdehyde upon a single hemodialysis session, however, the increase of malondialdehyde concentration was significantly reduced with Helixone® dialyzer as compared to Polysulfone® one. Plasma total anti-oxidant activity was reduced significantly upon a single hemodialysis session with both dialyzers, however, such a reduction was significantly higher with Polysulfone® (28% reduction) than with Helixone® (11.7% reduction) dialyzer. The levels of other routine blood parameters related to the performance of dialysis process (urea, uric acid, creatinine) under both dialyzers were similar. Conclusion: Hemodialysis-associated oxidative stress, as assessed by MDA concentration and plasma total anti-oxidant activity, seems to be significantly reduced with Helixone® dialyzer when compared to Polysulfone® dialyzer. This difference may bring positive impact on hemodialysisassociated side effects on cardiovascular and cerebrovascular systems.

Stimuli responsive membranes in separation processes- short review

The paper discusses some basic issues related to synthesis and properties of stimuli responsive membranes. Two commonly studied forms of these membranes are presented, namely pore surface grafted and pore volume functionalized membranes. The critical feature allowing to classify membrane to one of the above category is their grafting yield. The first kind of membranes, known under the name of ‘membrane valves’, can be used in stimuli controlled filtration when membrane cut-off is controlled by means of external stimuli. The second category, called sometimes ‘gating membranes’, can be used for transport facilitation of some species. The paper is illustrated by description of our attempts in syntheses of both membrane forms and evaluation of their separation properties.

Use of Novel Reinforced Cation Exchange Membranes for Microbial Fuel Cells

This work has been focused on the synthesis and characterization of different blended membranes SPEEK-35PVA (Water), SPEEK-35PVA (DMAc) prepared by casting and nanofiber-reinforced proton exchange membranes Nafion-PVA-15, Nafion-PVA-23 and SPEEK/PVA-PVB. The two first reinforced membranes were made up of Nafion® polymer deposited between polyvinyl alcohol (PVA) nanofibers. The last composite membrane is considered because the PVA is a hydrophilic polymer which forms homogeneous blends with SPEEK suitable to obtain high proton conductivity, while the hydrophobic PVB can produce blends in a phase separation morphology in which very low water uptake can be found. The synthesized membranes showed an outstanding stability, high proton conductivity, and enhanced mechanical and barrier properties. The membranes were characterized in single chamber microbial fuel cells (SCMFCs) using electrochemically enriched high sodic saline hybrid H-inocula (Geobacter metallireducen, Desulfurivibrio alkaliphilus, and Marinobacter adhaerens) as biocatalyst. The best performance was obtained with Nafion-PVA-15 membrane, which achieved a maximum power density of 1053 mW/m3 at a cell voltage of 340mV and displayed the lowest total internal resistance (Rint≈522Ω). This result is in agreement with the low oxygen permeability and the moderate conductivity found in this kind of membranes. These results are encouraging towards obtaining high concentrated sodic saline model wastewater exploiting MFCs.

Porous Diamond Membrane Fabricated By Templated Growth for Electrochemical Separation Processes

Boron-doped diamond has been applied as an outstanding electrode material for electrochemical applications. Using templated growth techniques, a variety of diamond nanostructures like diamond wires and diamond foams can be fabricated [1, 2]. Using quartz or glass fiber paper as growth templates, porous diamond membranes are fabricated [3]. Compared to polymer membranes or membranes based on sp2 carbons, diamond membranes can survive in aggressive media and high temperature conditions. Also, the ion selectivity can be controlled by surface terminations as well as the bias potential of the membrane. Therefore, this kind of membranes is very promising for the electrochemical separation processes such as desalination, pollutants concentration and protein separation. However, both the fabrication and application of diamond membranes are so far reported only in very limited cases. In this paper, we report our recent progress with respect to the templated diamond growth using quartz fiber paper as the growth template. With optimized microwave CVD growth, nanocrystalline diamond film is fully coated onto the quartz fiber as has been confirmed via SEM. The growth conditions in terms of temperature, methane concentration and boron/carbon ratio are investigated in detail. The diamond quality is evaluated via Raman spectroscopy, and the boron concentration is determined via SIMS. The potential window of the diamond membrane is determined via cyclic voltammetry in an aqueous NaClO4 solution to be ~2.5 V. By applying potential to the membrane, ions will accumulate inside the membrane and change its porosity. As a result, the ion flux through the membrane can be well tuned. This ion selectivity can be used to separate charged molecules. As an example, 5-Carboxyfluorescein and substance P are separated by the diamond membrane under different biases. In a neutral solution, for example, negatively charged 5-caboxyfluorescein can penetrate a positively charged membrane, while the positively charged substance P cannot. Therefore, this membrane can potentially be used for separation processes in biochemical and biomedical applications. Finally, due to the robustness of diamond, the membrane can be cleaned via a high potential (+3 V vs Ag/AgCl) oxidation process in 2 M H2SO4. Metal deposits and organic contaminants are proved to be removable by this method. Therefore, this membrane is also suitable for applications like undersea activities where only simple in-situ maintenances are possible. [1] F. Gao, M.T. Wolfer, C.E. Nebel, Carbon, 80 (2014) 833-840. [2] F. Gao, G. Lewes-Malandrakis, M.T. Wolfer, W. Müller-Sebert, P. Gentile, D. Aradilla, T. Schubert, C.E. Nebel, Diamond Relat. Mater., 51 (2015) 1-6. [3] S. Ruffinatto, H.A. Girard, F. Becher, J.C. Arnault, D. Tromson, P. Bergonzo, Diamond Relat. Mater., 55 (2015) 123-130.