Papers by Keyword: Hollow Fiber

Abstract: The most significant pollutant produced from agricultural industry in Kalimantan, Indonesia is Palm Oil Mill Effluent (POME). Due to the high levels of suspended particles and organic matter, POME has become a brownish color with high turbidity, color, chemical oxygen demand, and oil and grease content. To recycle the POME wastewater as clean water, these pollutants must be eliminated. In this study, we compare the effectiveness of hollow fiber (HF) and flat sheet (FS) membrane to remove total dissolved solid (TDS) and turbidity from POME with varied filtration pressure. HF and FS membrane were prepared from PVDF and nylon66 polymer, respectively. The PVDF HF membrane was modified using TiO₂ and SBE (spent bleaching earth) to improve HF membrane properties to maintaining fouling. Meanwhile, FS membrane was added by pectin to increase the hydrophilic properties. Overall membrane’s morphology was determined by Scanning Electron Microscopy (SEM) to investigate the membrane structure. Both of HF and FS membrane were operated via ultrafiltration (UF) under cross flow system. The filtration pressures were varied at 1-3 bar and followed by flux and rejection evaluation. The results show both HF and FS membranes has stability flux. In addition, TDS rejection up to 25% while turbidity is excellent high over 95% for all membranes. The fabrication HF membrane has finger like-sponge structure and FS membrane exhibits sponge asymmetric structure. Overall, all membranes perform highest water flux (FS membrane) while highest rejection conducted by HF membrane for POME wastewater treatment.

Abstract: The operating efficiency of asymmetric porous and composite membranes with a thin non-porous selective layer was compared in the processes of CO₂ absorption and desorption in gas-liquid membrane contactors using aqueous solutions of monoethanolamine (MEA) with low concentration (<14 %). Composite membranes were prepared by direct deposition of poly (1-trimethylsilyl-1-propyne) (PTMSP) in a hollow fiber membrane module. The effects of gas flow rate and MEA solvent linear velocity on the CO₂ mass transfer were evaluated. Porous membranes were shown to be more effective in the process of CO₂ absorption, because they allow to remove more than 90 % of CO₂ from the gas mixture during one pass of the solvent through the contactor. Composite membranes were more promising for CO₂ desorption, since they provide half as much of the solvent vapor losses with comparable desorbed CO₂ fluxes (0.12-(STP)/(m²·h)). The contributions of membrane and liquid phase to the overall mass transfer resistance during the CO₂ absorption process were estimated. It was demonstrated that deposition of a thin selective layer from a highly permeable PTMSP with a thickness of only 3 μm increases the membrane contribution to the total mass transfer resistance from 10-20 % to 60-80 %.

Abstract: PES is used as raw material for the preparation of membrane in this paper. Through gas-assisted-phase separation and synergetic pore-forming technology, the influence of the content of CaCO₃ in foaming pore-forming agent and the content of N,N-DMAc in coagulation bath on membrane property is studied. The results indicate that this method prepares PES hollow fiber membrane with uniform macroporous structure in which the cross section is wedge-shaped and running through internal and external surface. The addition of CaCO₃ can improve membrane property and the increase in the content of DMAc also has a great positive influence on membrane property.

Abstract: Hydrogel fiber with spatiotemporal properties such as great aspect ratio, large surface area/volume ratio, orientation and knittability, has been considered as the potential application materials in the field of biomedicine area. On the basis of dynamic-crosslinking-spinning we reported before, a novel GO/PEG-PEGDA core-sheath hydrogel fiber was fabricated continuously. Moreover, uniform rGO-PEGDA hollow fiber was obtain after reduction process. The diameter of core and sheath can be controlled separately by adjusting extrusion rate of core solution and sheath solution, respectively. This novel series GO hybrid hydrogel fibers with core-shell or hollow structure have potential application on nerve and muscle tissue engineering.

Abstract: Polysulfone is synthetic polymer widely used as basic material for dialyzer membrane and hydrophobic so it tends to cause fouling. Cellulose acetate is non-synthetic, hydrophilic polymer which has low tendency of fouling and has good thermal stability and permeability so it is considered as alternative material for hollow fiber dialyzer. A proper hollow fiber can be achieved by setting a proper temperature of coagulation bath along the spinning process. This research aims to understand the effect of coagulation bath temperature variations on the physical characteristic such as pore size, tensile strength, swelling rate and creatinine clearance of cellulose acetate – D-glucose monohydrate hollow fibers. Hollow fibers were fabricated using spinneret at temperature variations 5°C, 10°C, 15°C dan 20°C. Physical characteristics were estimated by doing morphology test using SEM, tensile test, swelling test towards Simulated Body Fluid (SBF) and filtration test towards creatinine. Result revealed that the hollow fibers from 5°C coagulation bath temperature gives the best characteristic and performance with tensile strength 27,421 N mm^-2, pore size 0,0295–0,0858 nm, swelling rate 4,18%, elongation rate 4,4 %, flux rate 1,6032–1,7956 mL cm^-2 min^-1 and creatinine clearance rate 40,14–48,30% so it is potential to be applied as dialyzer membrane.

Abstract: Heart failure is a serious major health problem with high number of mortality per year. Bypass is one of the solutions that has often been taken. Nowadays, synthetic materials have been fabricated from polymers to solve the disadvantages which are provided by autograft, allograft and xenograft. The aim of this research is to make a synthetic vascular graft with great physical strength, high biocompatibility, and good affordability. The method of this research was mixing PLGA and collagen by magnetic stirrer. This composite were shaped by spinneret with water as coagulant. Then it was coated by chitosan with 3 variations of weight (1 %wt, 2 %wt, and 3 %wt) to increase hemo and cytocompatibility, proliferation, and cell attachment in order for the vascular graft candidates to be more biocompatible. Mechanical strength for each variation was 5,306 MPa (chitosan 1 %wt), 3,433 MPa (chitosan 2 %wt) and 3,745 MPa (chitosan 3 %wt). All the tensile values were higher than human vascular tensile strength. Toxicity test showed that the living cells in all variations were more than 60% in number, thus the vascular graft is not toxic.Hemolytic assay showed that the lowest coagulation was provided by sample with 3 %wt chitosan.

Abstract: In the present work, the rheological properties in terms of shear stress and viscosity of Kaolin/Polyether-Sulfone (PESf) of varying ratio were investigated by a rotating rheometer. The shear rate of Kaolin/PESf sample was measured at increasing interval shear rate. By assuming that the fluid behaves like a typical Non-newtonian polymeric liquid, the consistency index, K and flow index, n were able to be determined. Thus, the rheology behaviors of the kaolin/PESf suspension could be investigated at a wider range of shear rate. The shear stress was found to increase with increasing shear rate, with the rate of change quite apparent at low shear rate. At higher shear rate, the shear stress increases definitively with the increase of kaolin content. On the other hand, the viscosity decreased at a faster rate initially and slows down to monotonous rate as the shear rate increases. Evidently at increasing shear rate, the viscosity tends to become constant as the deviation become smaller which is also known as zero shear rate viscosity region.

Abstract: PDMAEMA/PSF nanofiltration (NF) membranes were prepared through interfacial polymerization of poly [2-(N,N-dimethyl amino) ethyl methacrylate](PDMAEMA) on porous polysulfone (PSF) substrate membranes. The effects of aqueous solution’s pH and crosslinking time and on separation performances of the PDMAEMA/PSF NF membrane were investigated. The results show that the rejection and flux of the PDMAEMA/PSF NF membrane show pH-sensitive behavior in NF process. Importantly, the membrane show a different separation between inorganic salts and small organic molecules.

Abstract: An effective and sensitive method to determinate four parabens was developed by using graphene oxide (GO)-reinforced hollow fiber (HF) solid-phase microextraction combined with HPLC-PDA. Scanning electron microscope characterizations indicated that graphene oxide was successfully synthesized and modified in the pores of HF by ultrasonication. The conditions including extraction time, desorption time were optimized. The liner ranges of parabens were 0.01-5.00 μg/mL via the proposed management with a limitation of detection of 0.005 μg/mL. The extraction procedure based on GO-HF was successfully used for the determination of parabens in beer.

Abstract: This paper reports the effect of constant heating and progressive on carbon dioxide permeation characteristics in asymmetric hollow fiber polysulfone membranes. Glassy polymers are easily plasticized with the presence of plasticizing agents such as carbon dioxide. Constant heating were applied to the membranes to suppress CO₂ induced plasticization. Membranes treated with constant temperature heating exhibits lower pressure-normalize flux for both carbon dioxide and methane compared to untreated membranes. This was probably due to densification of membrane skin layer during heating process. Denser skin layer increases the resistance in the membrane which resulted in decreased of pressure-normalize flux. A higher density of membrane skin layer was achieved by progressive temperature heat treatment. This further increased the resistance in the membrane resulted in a lower value of pressure normalized-flux. With the application of different feed pressure, an almost linear value of CO₂ pressure-normalize flux shows that plasticization is successfully suppressed by heat treatment. From the results provided in this study, it can be concluded that plasticization of polysulfone hollow fiber membrane is successfully suppressed by heat treatment process.