Preparation and surface modification of hollow fibre membranes for drinking water disinfection and water reclamation (original) (raw)
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Advances in the use of low-pressure, hollow fiber membranes for the disinfection of water
Water Supply, 2005
Low-pressure membranes are often used for disinfection purposes. Using a simple bench-scale testing unit, several membranes were evaluated for their capability to remove microorganisms under specific conditions. Five hollow fiber modified polysulfone membranes ranging in molecular weight cutoff (MWCO) from 10,000 to 300,000 daltons and a 0.2 μm nominal pore size membrane were also evaluated. The 10,000 MWCO membrane removed less virus than the two 100,000 MWCO or the 300,000 MWCO membranes. The data from this study suggests that MWCO and specific flux may not, in all cases, be a good predictor of virus removal.
Desalination, 2008
The use of a submerged membrane bioreactor for the treatment of industrial oil contaminated wastewater was investigated using microfiltration hollow fibre membranes. The membrane bioreactor worked with a hydrocarbon concentration ranging from 600 to 1500 mg/L in a sub-critical flux regime. The sludge concentration ranged from 14 g/L to 28 g/L. During the long-term bioreactor test, three further different membrane modules were tested in order to assess their critical flux in comparable conditions. The membranes investigated were different in materials, pore structure and size. The membranes with larger pore size showed a higher tendency to irreversible fouling. The MBR was able to treat wastewater with high removal efficiency (about 98%), low hydraulic retention time (about 10 h) and high biomass concentration.
Journal of Membrane Science
Polyethersulfone (PES) hollow fiber ultrafiltration (UF) membranes were fabricated using methanol, ethanol, n-propanol as well as water as additives and N-methyl-2-pyrrolidone (NMP) as a solvent. Asymmetric hollow fiber UF membranes were spun by wet and dry/wet phase inversion method from 18 wt.% solids of PES/non-solvent/NMP solutions. The non-solvents were methanol, ethanol, n-propanol and water while the external coagulant was water. Effects of non-solvent and ethanol concentrations in the dope solution and air-gap distance on morphology and separation performance of PES hollow fiber UF membranes were investigated. UF membranes were characterized in terms of their solubility parameter difference, pore size and pore density measurements, scanning electron microscope (SEM) while UF experiments were conducted using polyethylene glycol (PEG 10,000 M W) and two kinds of proteins, lysozyme (14,400 M W) and chicken egg albumin (CEA 45,000 M W) as a solute. It was found that the PES UF membrane morphology changed slowly from long and wide finger-like structure through a thin finger-like structure to the sponge-like structure with some voids as ethanol concentration in the dope solution increased from 0 to 25 wt.% using 90:10 NMP/H 2 O as a bore fluid; pure water permeation fluxes (PWP) increased from 47 to 167 L/(m 2 •h•bar) while rejections of PEG 10,000 and two protein for wet-spun PES hollow fiber membranes were increased within less than 10 wt.% ethanol concentration and then decreased with an increase of ethanol concentration. Experimental results illustrated that PWP flux and solute rejection of the dry/wet-spun fibers were higher than that of the wet-spun fibers when 15 wt.% ethanol and 15 wt.% methanol were used as additives. PWP flux of PES hollow fibers using 25 wt.% n-propanol and 7.5 wt.% water (dry/wet) as additives in the dope solution were higher while their rejections were lower. In addition, the pore sizes of internal surfaces of PES hollow fiber membranes were controlled by adjusting the ethanol or methanol concentration in the dope solution. Using above method, PES hollow fiber UF membrane with high PWP could be prepared while the molecular weight cutoff of PES hollow fiber membranes is approximately 10,000.
Synthesis and Characterization of PVDF/PAN Hollow Fiber Blend Membrane for Surface Water Treatment
Trends and Developments, 2015
An experimental study was carried out to synthesize hollow fiber membranes based on polymer blend made of hydrophobic poly(vinylidene fluoride) (PVDF) and hydrophilic poly(acrylonitrile) (PAN) to enhance flux with retention of antifouling properties, for treating surface water. Effect of spinning conditions on specific macroscopic fiber properties, such as outer diameter, wall thickness and membrane pore structure were studied. Concentrations of 10 wt% PVDF and 10 wt% PAN were dissolved in dimethylformamide (DMF) solvent and this dope solution was extruded through the spinneret. The membranes were characterized by scanning electron microscopy (SEM), pure water flux studies and Bovine Serum Albumin (BSA) rejection studies. At a pressure of 0.2 bar, HF membrane module of 0.07 m 2 surface area exhibited a flux of 59.3 L/m 2 h and BSA rejection of 95.6%. Surface water polluted by domestic waste was subjected to ultrafiltration in the present investigation. An increase in the pressure to 1.5 bar further enhanced the flux to 218.5 L/m 2 h and rejection to 99.55%. A quantity of 5 L influent concentration of 230 FAU turbidity, 92 mg/L suspended solids, 1.3×10 3 (MPN/100 mL) Escherichia coli and 7.2 pH was fed into the Ultrafiltration (UF) system by means of a booster pump at hydraulic
Journal of Environmental Sciences, 2007
Using the surface of poly (sulfone) hollow fiber membrane segments as grafted layer, the hydrophilic acrylamide chain was grafted on by UV-photoinduced grafting polymerization. The gained improvement of surface wettability for the modified membrane was tested by measuring the contact-angle as well as FTIR spectra. Then correlation between the hydrophilic ability of support material and the biofilm adherence ability was demonstrated by comparing the pollutant removal rates from urban wastewater via two identical lab-scale up-flow biological aerated filters, one employed the surface wettability modified poly (sulfone) hollow fiber membrane segment as biofilm carrier and the other employed unmodified membrane segment as biofilm carrier. The experimental results showed that under the conditions of influent flux 5 L/h, hydraulic retention time 9 h and gas to liquid ratio (G/L) 10:1, the removal rates of chemical oxygen demand (COD) and ammonium nitrogen (NH 4 + -N) for the modified packing filter and the unmodified packing filter was averaged at 83.64% and 96.25%, respectively, with the former filter being 5%-20% more than the latter. The effluent concentration of COD, NH 4 + -N and turbidity for the modified packing filter was 25.25 mg/L, 2 mg/L and 8 NTU, respectively. Moreover, the ammonium nitrogen removal performance of the filter packing the modified PSF was compared with the other bioreactor packing of an efficient floating medium. The biomass test indicated that the modified membrane matrixes provided better specific adhesion (3310-5653 mg TSS/L support), which gave a mean of 1000 mg TSS/L more than the unmodified membrane did. In addition, the phenomenon of simultaneous denitrification on the inner surface of the support and nitrification on the outer surface was found in this work.
Effect of Polymeric Additives on the Performances of Polyethersulfone Blend Hollow Fiber Membrane
Proceedings of the Annual International Conference Syiah Kuala University Life Sciences Engineering Chapter, 2012
The article reported the preparation and modification of hydrophobic polyethersulfone (PES) by blending the solution with hydrophilic additives Tetronic 304, Tetronic 704, Tetronic 1307, and Tetronic 908. Polymeric porous membranes are generally prepared by the phase separation of polymer solution. In this work, we prepared hollow fibre membrane by non-solvent induced phase separation (NIPS). Effect of molecular weight of surfactant added on the performance and characteristic of fabricated membrane were investigated. The control PES membrane has the highest contact angle, indicating the lowest hydrophilic. With addition of surfactant Tetronic in the polymer blend hollow fibre membrane, the water contact angle decreased indicates that the membrane surface is more hydrophilic. Scanning electron microscopy (SEM) images for all of the membrane showed the structure of fibre with finger-like macro voids through the cross-section. The sponge-type of structure in the centre path of original membrane was disappearing with addition of Tetronic. Ultrafiltration experiment results showed that water permeability was highest with addition of Tetronic with lowest molecular weight. According to the characteristics of resulting membrane such as hydrophilicity, ultrafiltration performance, and pores structure, surfactant Tetronic was a good additive to produce hydrophilic membrane for drinking water application
Polyvinylidene fluoride hollow fiber membrane and its use for treatment of natural water
Petroleum Chemistry, 2014
In this study, an antifouling poly(vinylidene fluoride) (PVDF) hollow-fiber membrane was fabricated by blending with silverloaded graphene oxide via phase inversion through a dry-jet, wet-spinning technique. The presence of graphene oxide endowed the blended membrane with a high antifouling ability for organic fouling. The permeation fluxes of the blended membrane was 3.3 and 2.9 times higher than those of a pristine PVDF membrane for filtering feed water containing protein and normal organic matter, respectively. On the other hand, the presence of silver improved the antibiofouling capability of the blended membrane. For the treatment of Escherichia coli suspension, the permeation flux of the blended membranes was 8.2 times as high as that of the pristine PVDF membrane. Additionally, the presented blended membrane improved the hydrophilicity and mechanical strength compared to those of the pristine PVDF membrane, with the water contact angle decreasing from 86.1 to 62.58 and the tensile strength increasing from 1.94 to 2.13 MPa. This study opens an avenue for the fabrication of membranes with high permeabilities and antifouling abilities through the blending of graphene-based materials for water treatment.
Preparation, characterization, and performance of a novel hollow fiber nanofiltration membrane
Polymers for Advanced Technologies, 2015
Two generations of aliphatic hyperbranched polyester (HBPE) were synthesized from 2,2-bis(methylol)propionic acid and 1,1,1-trihydroxymethyl propane (TMP) as the core moiety by melt condensation method and were blended with cellulose acetate to prepare asymmetric membrane using a phase inversion process. Characterization of the prepared membranes for thermal behavior and morphological studies also has been made using TGA, DSC and SEM techniques. Water contact angle, pure water flux, water content, hydraulic resistance and molecular weight cutoff determinations were applied in order to study of filtration properties and surface and bulk hydrophilicity of the membranes. (FTIR/ATR) and contact angle results proved existence of (HBPE) on the surface of modified membranes and (FE-SEM) images have good correlation with flux and MWCOs. The result shows that, the surface hydrophilicity of membranes incorporating HBPE is much higher than pure CA or even (PEG-600) modified CA membranes. Furthermore, results show CA-HBPE membranes have lower flux and MWCOs, higher hydraulic resistance and better thermal and mechanical properties in comparison to the membranes modified by linear pore-forming agent.