Polyacrylonitrile Hollow Fiber Membranes Research Articles

Energy recovery and clean water remediation using antibiofouling polysaccharide coated PAN hollow fiber membrane obtained via green route synthesis

Biofouling is an important biological constrain in the water treatment process, and the control or management strategies using green principles have gained recent attention. Antibiofouling agents based on the biological source are now extensively studied due to their high efficacy and are environmentally friendly. In this present study, Poly Acrylo Nitrile (PAN)/Ulvan hollow fibre membranes of four different modules were fabricated for water treatment studies by testing against B. subtilis and E. coli along with separation efficiency studies on proteins such as albumin, pepsin, and clay. Ulvan (Ulv), green seaweed sulfated polysaccharide extracted from Ulva fasciata, was coated on PAN hollow fibres, fabricated using a wet-spinning process. Ulvan was dip-coated on membrane surface followed by cross-linking and resultant changes in terms of performance and morphology. PAN/Ulv hollow fibre membranes were examined for the pure water flux and protein separation analysis to analyse the membrane efficiency. SEM was used to analyse the membrane structure and ATR- FTIR for the determination of functional groups. Ulvan coated (310 C) hollow fibre membrane showed better performance than the other three membranes with a flux of 398.1 L m−2 h−1. Higher sample concentration of suspended solids paved simpler route for enhanced COD sequestration efficacy. Pepsin, albumin, and clay particles were rejected by the 310C Ulvan adorned membranes at rates greater than 80%. By incrementing suspended particles beyond 3200 mg/L, the greatest power recovery was reduced that portrays an adverse influence of bio-fouling process on membrane operation. Experimental results demonstrated that synthesised 310 C membrane possessed better separation performance and antifouling characteristics for aquatic water systems.

Using Tannic-Acid-Based Complex to Modify Polyacrylonitrile Hollow Fiber Membrane for Efficient Oil-In-Water Separation

Separating oil from water allows us to reuse both fluids for various applications, leading to a more economical process. Membrane separation has been evidenced as a cost-effective process for wastewater treatment. A hollow fiber membrane made of polyacrylonitrile (PAN) is an excellent choice for separating oil from water because of its superior chemical resistance. Its low antifouling ability, however, reduces the effectiveness of its separation. Hence, in this study, we used tannic acid (TA) and FeIII complex to modify the surface of the PAN hollow fiber membrane. To improve membrane performance, different reaction times were investigated. The results demonstrate that even when the TA-FeIII covered the pores of the PAN membrane, the water flux remained constant. However, when an emulsion was fed to the feed solution, the flux increased from 50 to 66 LMH, indicating low oil adhesion on the surface of the modified membrane. When compared to the pristine membrane, the modified membrane had superior antifouling and reusability. As a result, the hydrophilic TA-FeIII complex on PAN surface improves overall membrane performance.

Preparation and properties of phosphinic acid-functionalized polyacrylonitrile hollow fiber membrane for heavy metal adsorption.

In this study, phosphorylated polyacrylonitrile hollow fiber membrane was synthesized by reacting aminated polyacrylonitrile hollow fiber membrane with phosphinic acid in a Mannich reaction. The batch single-factor measurements revealed that the phosphorylated polyacrylonitrile (PPAN) membrane had an outstanding ability for Hg2+ adsorption. Thermodynamic investigations indicated that the adsorption process was homogenous, and the theoretical maximum adsorption capacity predicted by the Langmuir model was 371.75mg·g-1. The PPAN membrane was able to successfully chelate Hg2+ ions and attain saturation in 4h, demonstrating that the reaction was chemically controlled by the adsorption kinetics. Based on the FT-IR and XPS spectral characterization data, successful phosphinic acid group grafting was proven, and a plausible mechanism for Hg2+ adsorption by PPAN membranes was presented. Furthermore, the five adsorption-desorption cycle experiments revealed that PPAN hollow fiber membranes had outstanding reusability, indicating a possible use for removing heavy metal ions from wastewater.

Preparation and characterization of nanoclay loaded polyacrylonitrile hollow fiber membranes

New Polyacrylonitrile (PAN) nanoclay hollow fiber membranes were successfully fabricated through the dry-jet wet spinning process. The effects of adding the nanoclay on the hollow fiber mechanical properties and permeation performance and dye removal from water were investigated. Direct red 80, Direct orange 26 and Direct brown 2 dyes were used for dye removal experiments. Field emission scanning electron microscopy (FESEM) was used to analyze the cross-sectional and surface morphology and porosity. X-ray diffraction (XRD) has been used to compare crystalline structure of the fabricated hollow fiber membranes. The results showed that permeation is increased by adding nanoclay to the spinning dope. In addition, hollow fibers spun with lower nanoclay content showed lower hydraulic permeability and higher dye removal efficiency. Tensile strength increased from 1.09 to 2.06 with 3 wt% nanoclay loading.

Polyacrylonitrile homogeneous blend hollow fiber membrane with stable structure as a substrate to support Fe/Mn oxide and its enhanced capability to purify dye wastewater

Abstract Blending different molecular weight polyacrylonitrile (PAN) was adopted to solve the shrinkage problem of high molecular weight PAN hollow fiber membrane, to enhance the application performance of low molecular weight PAN membrane, and to adjust the porosity, pore size distribution, and hydrophilicity of the end product. The structurally-optimized membrane was chosen as a substrate to support Fe/Mn oxides and then used as a reactor to remove dyes from their solutions in the presence of H2O2. The results showed that the flux of methylene blue (MB) aqueous solution was 83.7 L/m2 h for the PAN homogeneous blend membrane, much higher than 29.1 L/m2 h of high molecular weight PAN membrane; MB removal efficiency was 97.3%, higher than 62.3% of low molecular weight PAN membrane, and it could be reused 25 times to remove dyes from their solutions without any loss in removal efficiency. The membrane was also found to have the application advantages of decreasing H2O2 dosage, reducing operation pressure, and raising MB removal efficiency compared with other membranes reported in the pieces of literature. Therefore, we were confident that the hollow fiber membrane fabricated by us would exhibit great application potential in the field of decontaminating dye wastewater.

Iron/manganese oxide-decorated GO-regulated highly porous polyacrylonitrile hollow fiber membrane and its excellent methylene blue-removing performance

Polyacrylonitrile (PAN) hollow fiber membrane wet-spun without any porogen usually has a wide pore size distribution, low porosity, and unstable porous structure. In this work, graphene oxide (GO) was selected as a structural optimizer to tune the porous structure of the PAN membrane. The results show that pore size and porosity increase from 156.4 nm and 37.0% to 590.8 nm and 81.4% as GO amount increases from 0 to 0.15%, which also causes a narrower pore size distribution. A simple and viable route of gradient hydrolysis, coordination, and oxidation was then adopted to decorate the PAN membrane with well-grown and well-dispersed iron/manganese oxide to achieve a functional membrane that could remove methylene blue (MB) from water stably and efficiently in the presence of H2O2. Compared with the membrane without GO, the functional membrane has a higher oxide decoration ratio, lower water contact angle, larger pores, higher porosity, and better mechanical property, and its MB solution flux is roughly two times higher than that of the membrane without GO. Additionally, the functional membrane can remove MB from the water after 30 cycles without any obvious efficiency attenuation; by contrast, MB removal efficiency induced by the membrane without GO attenuates remarkably after 25 cycles.

Fe/Mn oxide decorated polyacrylonitrile hollow fiber membrane as heterogeneous Fenton reactor for methylene blue decolorization

ABSTRACTA very distinctive modification route was schemed to fabricate a membrane reactor that could heterogeneously catalyze Fenton reactions to decolorize dye wastewater in the process of filtration. Through this route, porogen‐free polyacrylonitrile (PAN) hollow fiber membrane was decorated with in situ generated well‐distributed Fe/Mn composite oxide, and the so‐called membrane reactor was finally acquired. Its performance of decolorizing dye wastewater was evaluated by feeding methylene blue (MB) aqueous solution into its lumen side and analyzing the permeate gained from its shell side. The results showed that about 97.4% of MB could be removed from its aqueous solution as the solution passed through the shell side of hollow fiber membrane, and this removal efficiency would keep unchanged when operation period was lengthened. The membrane reactor presented excellent capability to decolorize MB aqueous solution and could be used repeatedly without any loss in decolorization efficiency. Finally, the mechanism of causing MB decolorization was proposed by comparing decolorization performance of modified and unmodified membranes, measuring total organic carbon, and analyzing UV–Vis spectra. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48217.

Preparation of polyamide/polyacrylonitrile composite hollow fiber membrane by synchronous procedure of spinning and interfacial polymerization

In this investigation, a new concept for fabrication polyamide (PA)/polyacrylonitrile (PAN) composite hollow fiber membrane by using a triple orifice spinneret was explored. Tetraethylenepentamine (TEPA) and trimesoyl chloride (TMC) were used as the monomers of aqueous solution and acid chloride solution, respectively. The PAN dope, TEPA solution and TMC solution were pumped into the outermost, middle and inner channel of the triple orifice spinneret, respectively, and then co-extruded into water from the outlet of the spinneret simultaneously. The PA layer then was formed on the lumen surface of the synchronous wet-spun PAN hollow fiber membrane. SiO2 was added into the dope to increase the hydrophilicity of the dope. The resultant PA/PAN composite hollow fibers were characterized by using FTIR-ATR, SEM, light transmission, contact angle and positron annihilation spectroscopy (PAS). The effects of SiO2 content, TEPA concentration, as well as the TEPA solution flow rate on the properties and pervaporation performances of resultant PA/PAN composite hollow fibers were investigated. The PA layer was completely attached to the lumen surface of the resulted hollow fibers through the spinning and interfacial polymerization synchronous procedure. The pervaporation performances with 419 g/m2h of permeation flux and 96.6 wt% of water content in permeate of the 90 wt% aqueous isopropanol solution at 25 °C can be obtained through the synchronous fabricated PA/PAN composite hollow fiber membrane which was fabricated by the 18 wt% PAN dope containing 5 wt% SiO2, 1 ml/min of 14 wt% TEPA solution and 2 ml/min of 1 wt% TMC solution.

Aluminium fumarate metal organic framework incorporated polyacrylonitrile hollow fiber membranes: Spinning, characterization and application in fluoride removal from groundwater

Novel mixed matrix hollow fiber membranes (MMM) were prepared by phase inversion technique using polyacrylonitrile (PAN) as base polymer and aluminium fumarate (AlFu) metal organic framework (MOF) as additive. The membranes were characterized in terms of surface morphology, surface charge, permeability, molecular weight cut off, porosity, pore size and contact angle. Permeability of the membrane increased from 3.5 × 10−10 to 4.5 × 10−10 m/Pa.s with increment of MOF concentration from 0 to 10 wt%. The contact angle of the corresponding membranes decreased from 80° to 51° indicating an increase in hydrophilicity. The MH10 (10 wt% concentration) membrane sustained up to 20, 19 and 17.5 h of operation with fluoride concentration of 4, 8 and 12 mg/l, respectively, at 35 kPa transmembrane pressure and 30 l/h cross flow rate with a membrane area of 0.026 m2. Regeneration study and performance of the MMM in real life ground water samples were also investigated. Filter performance was successfully predicted by a modified model available in literature.

From ultrafiltration to nanofiltration: Hydrazine cross-linked polyacrylonitrile hollow fiber membranes for organic solvent nanofiltration

Ultrafiltration-level polyacrylonitrile (PAN) hollow fiber membranes were molecularly engineered via chemical cross-linking to obtain membranes suitable for use in organic solvent nanofiltration (OSN). By adjusting the dope composition and spinning conditions, hollow fibers possessing a desirable sponge-like cross-section with minimal macrovoids were obtained. Hydrazine monohydrate was used as the cross-linker and the effects of cross-linking time on the membrane's separation performance were investigated. X-ray photoelectron spectroscopy was used to elucidate the possible reactions and indicated the successful cross-linking of the PAN hollow fiber membranes. The cross-linked nanofiltration-level hollow fibers were subjected to OSN tests using ethanol and dyes as model feed solutions. With this simple and effective modification, the PAN hollow fiber membranes were able to achieve a pure ethanol permeance of 2.32Lm−2 h−1bar−1 and an impressive Remazol Brilliant Blue R (Mw 626.54gmol−1) rejection of more than 99.9%. Given the ease of fabrication and modification, these PAN hollow fibers represent a significant step forward in the use of hollow fiber membranes for OSN, particularly in larger-scale operations.

Preparation and performance of biofouling resistant PAN/chitosan hollow fiber membranes.

The preparation of polyacrylonitrile (PAN) hollow fiber (HF) membranes has been carried out by dry-jet wet spinning. PAN HF membranes were coated with chitosan biopolymers 2 wt% by dip coating and further crosslinked by chemical reagents (Tri sodium polyphosphate). PAN HF (Virgin) and PAN/chitosan coated membrane were characterized by SEM and tested for water flux. Proteins Pepsin, Albumin, and Clay of 1000ppm concentration were tested for separation efficiency. In addition, bacterial speciesEscherichia coliandBacillus subtiliswere tested for fouling control efficiency and found out that PAN/chitosan membranes were quite superior to virgin PAN fibers.The adhesion of bacterial cells on the surface of the hollow fiber membranes assessed through alcian blue staining and SEM analysis. It was observed that PAN/chitosan membranes (310A and 310C) possessed best antibacterial activities (based on SEM results), qualifying them as a very promising candidates for anti-biofouling coatings.

The preparation of polyamide/polyacrylonitrile thin film composite hollow fiber membranes for dehydration of ethanol mixtures

Abstract In this study, Polyamide (PA)/polyacrylonitrile (PAN) thin-film composite (TFC) hollow fiber membranes were fabricated to investigate the dehydration performances of ethanol mixtures by pervaporation. Amine monomers (ethylenediamine (EDA), 1, 6-hexanediamine (HDA), diethylenetriamine (DETA), and tetraethylenepentamine (TEPA)) with difference number of functional groups or chain length were selected to react with trimesoyl chloride (TMC) to prepare a PA dense thin-film onto the surface of asymmetric PAN hollow fiber membranes by way of interfacial polymerization. Attenuated total reflection infrared spectroscopy (FTIR-ATR), scanning electron microscope (SEM), atomic force microscope (AFM), light transmission, contact angle and positron annihilation spectroscopy (PAS) were used to characterize the physicochemical properties, morphologies and microstructure of the PA thin layer. The pervaporation performances of aqueous ethanol solution showed the permeation flux decreased while water content in permeate increased with increasing number of amine groups. The effects of monomer concentration and reaction time on the pervaporation performances of aqueous ethanol solution through TEPA-TMC/PAN TFC hollow fiber membranes were also investigated. A 342.0 ± 22.3 g/m 2 h permeation flux and 97.6 ± 0.3 wt.% water content in permeate were obtained for the pervaporation of 90 wt.% aqueous ethanol solution at 25 °C through the PA/PAN TFC hollow fiber membrane which was fabricated by immersing PAN hollow fiber membrane into 2 wt.% TEPA aqueous solution for 1 min and then contacting 1 wt.% TMC solution for 0.5 min.

Neuronal membrane bioreactor as a tool for testing crocin neuroprotective effect in Alzheimer’s disease

In this paper a neuronal membrane bioreactor was developed as platform for the in vitro reconstruction of a neuronal network with defined functional, geometric and neuroanatomical features. The bioreactor consists of modified polyacrylonitrile hollow fiber membranes that were assembled in parallel in order to establish two separate compartments: an intraluminal compartment within the fibers, in which the medium flowed, and an extraluminal compartment or shell outside of the fibers where cells were cultured. We explored the ability of the membrane bioreactor to promote the growth and functional differentiation of neuronal cells up to 2weeks.Neuronal cells in the bioreactor covered completely the fiber surface and exhibited a high density of the axonal network reaching a very complex 3D structural organization characterized by the expression of presynaptic vesicle protein synaptophysin. Cells were also functionally active as demonstrated by the oxygen uptake rate and glucose consumption that increased with culture time achieving values of 17.7nmol/min and 879±113nmol/min at day 15, respectively.The neuronal membrane bioreactor was used as in vitro model of Aβ-induced toxicity associated to Alzheimer’s disease to test for the first time in cells the neuroprotective effect of crocin. The administration of the Aβ produced a dramatic decrease of cell viability and induced the reactive oxidative species (ROS) generation and apoptosis. When Aβ-peptide was administered together with crocin a significant dose-dependent inhibition of apoptosis and ROS production was observed pointing out the capability of crocin to prevent the aggregation of Aβ peptide and subsequent neurotoxicity associated to Alzheimer’s disease.

Fabrication of polyacrylonitrile hollow fiber membranes from ionic liquid solutions

PAN hollow fiber membranes with good pore morphology have been fabricated using solvent mixtures of ionic liquids and DMSO, which has a lower toxicity than other commonly used polar organic solvents.

Surface modification of PAN hollow fiber membrane by chemical reaction

In this study, a new method was applied to achieve an efficient surface modification of Polyacrylonitrile (PAN) hollow fiber membrane. The surface modification dealt by immersion of PAN hollow fibers in hydroxylamine solution under various conditions (different solution concentrations and reaction time). The nitrile groups on the surface of the membrane were changed to form the amidoxime (-C(NH2)=N-OH) groups. The surface modified membranes were assessed by pure water permeation test and the rejection of high molecular weight materials like Polyvinylalcohol (PVA) from water. Permeation test results showed that with increasing hydroxylamine concentration, the amount of water permeation reduces slowly, while the PVA-30 kDa rejection has been somewhat increased after surface modification. FTIR/ATR analysis confirms the presence of amidoxime groups on the membrane surface. Also, the water contact angel was decreased from 64 to 34 after reaction. The ability of silver ions absorption was also assessed for modified membrane. Finally, the antifouling property of the modified hollow fibers was assessed by milk solution ultrafiltration. The obtained results showed that the modified hollow fibers present better antifouling properties.

Preparation and characterization of braided tube reinforced polyacrylonitrile hollow fiber membranes

ABSTRACTPolyacrylonitrile (PAN) and polyester (PET) braided hollow tube that used as a special reinforcement are braided from their filaments via two‐dimensional weaving techniques. PAN braided tube reinforced homogeneous PAN hollow fiber membranes and PET braided tube reinforced heterogeneous PAN hollow fiber membranes are prepared by concentric circles squeezed‐coated spinning method. As for PAN hollow fiber membrane, the effects of PAN concentration on the performance of the prepared hollow fiber membranes are investigated in terms of pure water flux, protein rejection, mechanical strength, and morphology observations by a scanning electron microscope (SEM). The interfacial bonding state of the braided tube reinforced PAN hollow fiber membranes is studied by constant speed stretching method. Results show that the breaking strength of two‐dimensional braided tube reinforced PAN hollow fiber membranes is higher than 80 MPa. The structure of separation surface is similar to the structure of an asymmetric membrane. With the increase of polymer concentration, the membrane flux decreases while the retention rate of BSA increase. The membrane porosity and maximum pore size have the same decreasing tendency as the increase of PAN concentration. The results also show that the interfacial bonding state of the PAN two‐dimensional braided tube reinforced homogeneous PAN hollow fiber membranes is better than that of the PET two‐dimensional braided tube reinforced heterogeneous PAN hollow fiber membranes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41795.

Performance assessment and hydrodynamic analysis of a submerged membrane bioreactor for treating dairy industrial effluent

Submerged membrane bioreactor (SMBR) is a relatively advanced technology for waste water treatment that involves integrated aerobic and anaerobic biological processes with membrane filtration. In the present investigation, hydrophobic polyvinylidene fluoride (PVDF) and hydrophilic polyacrylonitrile (PAN) hollow fiber (HF) membranes were tested in an indigenously fabricated SMBR for dairy effluent treatment under aerobic conditions using mixed microbial consortia. Effect of operating parameters such as suction pressure, degree of aeration and trans-membrane pressure (TMP) on membrane performance in terms of flux, rejection of turbidity, BOD and COD besides fouling characteristics was investigated. The observed optimum permeabilities of PVDF and PAN HF membranes were approximately 108 and 115LMHbar−1 with high extent of impurity removal. The rejection of COD was found to be 93% for PVDF and 91% for PAN HF membranes whereas corresponding rejection of BOD was observed to be 92% and 86%. A two-dimensional comprehensive model was developed to predict the hydrodynamic profile inside the module. Regression analysis revealed that the simulation results agreed well with experimental data.

The Preparation of Polyamide/Polyacrylonitrile Composite Hollow Fiber Membranes for Pervaporation

This paper prepared polyamide (PA)/polyacrylonitrile (PAN) thin-film composite hollow fiber membranes via interfacial polymerization by using triethylenetetramine (TETA) and trimesoyl chloride (TMC) as the monomers and asymmetric PAN hollow fiber membrane as the substrate. The effect of hydrolysis of asymmetric PAN hollow fiber membranes on the chemical properties was investigated. The results showed that the chemical properties of PAN hollow fiber membranes were affected by hydrolysis. Moreover, the effects of PA thin film polymerized onto the inner and outer surface of asymmetric PAN hollow fiber membranes on pervaporation performances were also investigated. The results also revealed that the interfacial polymerized PA/PAN composite hollow fiber membranes that were polymerized onto the outer surface of asymmetric PAN hollow fiber membranes can be used in the pervaporation of aqueous alcohol solution.

Development of polyethersulfone and polyacrylonitrile hollow fiber membranes for clarification of surface water and fungal enzyme broth

Hollow fiber membranes are of great commercial interest with several applications at the forefront of research to carryout bioseparations, drinking water purification, wastewater treatment besides liquid phase separations and gaseous separations. An experimental study was carried out to synthesize hollow fiber membranes from polyethersulfone (PES) and polyacrylonitrile (PAN) polymers to fabricate modules for surface water treatment and clarification of fungal enzyme broth. Design drawings of a manual hollow fiber spinning machine and spinneret were prepared to fabricate the necessary equipment for extrusion of hollow fibers. Effect of various spinning conditions on specific macroscopic fiber properties, such as outer diameter and wall thickness and membrane pore structure was studied. Concentrations of 15–20 wt% PES in n-methylpyrrolidone (NMP) and PAN in dimethyl formamide (DMF) solvents with important additives and pore formers were prepared. These polymer solutions were extruded through the spinneret and subjected to phase inversion in a water bath. The membranes were characterized by scanning electron microscopy (SEM) and pure water flux studies. PAN and PES exhibited 99.8 and 95.4% turbidity rejection. PAN exhibited a 5 log reduction of Escherichia coli bacteria for surface water treatment at a low hydraulic pressure of 1 bar with a flux of 54.2 L/m2 h at a water recovery of 80% whereas PES gave a flux of 36.6 L/m2 h with 4 log reduction of E. coli. PAN and PES membranes exhibited 54.9 and 69.3% xylanase enzyme recoveries from fungal broth at reasonable flux with turbidity rejection of 94.8 and 95.7% respectively.

Experimental investigation of aligned groove formation on the inner surface of polyacrylonitrile hollow fiber membrane

The fabrication of textured hollow fiber membrane (HFM) such as fibers with aligned grooves on the inner surface is of great interest especially for nerve regeneration applications. Grooved polyacrylonitrile (PAN) HFMs have been successfully fabricated using a dry-jet wet spinning process. Aligned grooves are formed on the HFM inner surface due to process-induced instability under selected fabrication conditions (air gap distance, polymer solution concentration, and polymer solution and nonsolvent flow rates). The influence of different fabrication conditions has been experimentally investigated to appreciate their relationship with the groove formability. It is found that HFMs with aligned grooves on the inner surface can be fabricated within an identified groove forming region, which is defined by the air gap distance, polymer solution concentration, and polymer solution and nonsolvent flow rates; and within the groove forming region, the number of grooves increases with the air gap distance from 1 to 20cm, and it decreases with the polymer solution concentration and flow rate. The number of grooves is not sensitive to the inner nonsolvent flow rate.