Papers by Keyword: Polysulfone Membrane

Abstract: A Cellulase and amylase are important enzymes for hydrolysis of cellulose and starchy material into the glucose. The performance of the mixed cellulose-amylase immobilized on polysulfone membrane (PSF) by cross-linked with glutaraldehyde was investigated. PSF membrane consists of 1-methyl-2-pyrolidone (NMP) as a solvent and using polyvinylpyrolidone (PVP) as an additive was developed. The study highlighted in the surface structure of PSF membrane, stability of the immobilized enzyme and reusability of the immobilized enzyme. Morphology studied using FESEM analysis indicated a good distribution of the pores was formed on the surface of the PSF membrane. The immobilization process shown no effect on the membrane structure and it was stable to be used as a support in immobilization process. The optimum operating condition for enzymatic hydrolysis of mixed cellulase-amylase on PSF membrane was 50°C and pH 5. The maximum glucose produced at the optimum condition was 4.843g/ml. The study also indicated that immobilized mixed cellulase-amylase achieved a maximum rate of reaction at first recycle of reusable before the rate of reaction decreased rapidly after 5 reusable hydrolysis cycles.

Abstract: Produced Water (PW) is a byproduct in the production of oil and gas. With various types of heavy metals and pollutants, it may harm human being and marine life. The objectives of this study are; 1) to study the performance of the fabricated membranes and 2) to verify the results by using the experimental design. The PW samples which is from Dulang field is treated using Polysulfone membranes that prepared by casting solutions consisting of polysulfone (PSf), N-methyl pyrrolidone (nmp), Bentonite, and polyvinyl pyrrolidone (PVP). The influence of PVP (0-7wt%) and Bentonite (0-7wt%) addition were investigated in terms of PW Flux (mL/cm²h) and TDS rejection rate (%). The amount of TDS in PW sample is 12g/L and the PSF membrane successfully reduced it up to 14%. The experimental results then used in Central Composite Model (CCM) under RSM which designate parameters (X) as Operating Pressure (bar), PVP (wt%) and Bentonite (wt%) to compute the optimum response condition (Y) as PW Flux and and TDS rejection rate in Design Expert software. The optimum condition achieved by PSf membrane is where the composition of 4.5wt% PVP, 6.0wt% Bentonite and Operating Pressure of 5.0 bar were used. Both methods showed the value of TDS decreased up to 14% after run through the membranes for several hours. Experimental and predicted result (DoE) for optimum condition is then compared to verify the error. The percent error calculated is 2.4% and 25.5% for PW Flux and TDS Rejection Rate respectively.

Abstract: The functionalization of remaining solvent in polymeric membrane pores is presented in this paper leading to new polymeric membrane materials for biomedical applications. Polysulfone membranes were synthesized from aniline by phase inversion and the remaining traces of aniline in membrane pores were transformed by diazotization reaction and coupled with three different organic dyes - Alizarin S, Rhodamine B, and Methyl Orange. The membranes were structurally and morphological characterized and used for different biomedical applications like specific separation of proteins or glucose from synthetic blood solutions.

Abstract: Introducing ionic liquid [n-C16mim][BF4] as a new structure-controlled additive, Polysulfone (PSf) membranes were prepared by the wet-phase-inversion using [n-C16mim][BF4] into the casting solution (PSf/NMP). The scanning electron microscope and the atomic force microscopy were utilized to visualize the cross-sections of the membranes to gain more better understanding the structure-controlled ability of [n-C16mim][BF4] and surface morphologies of the membrane. The results indicate that the structures of the membranes were typical bilayer asymmetric finger-pores structure. [n-C16mim][BF4] has stronger ability of the pore-forming. Especially, at the 4:76 ratio of [n-C16mim][BF4]/NMP in the polymer solution ,the membrane has the asymmetric structure and good separation properties of the solution flux. The PSf membrane has the 0.45~0.65μm dimpling close to surface layer, and the retention rate and solution flux of the prepared membrane are 95.2% and 137.5 L•h-1•m-2. Meanwhile, [n-C16mim][BF4] partially retained in the prepared Polysulfone membrane reduced the contact angles of Polysulfone membranes, improving the hydrophilic properties of the membranes.

Abstract: The paper studied the effect of different kinds of organic solvents treated polysulfone tubular ultrafiltration membrane on its performances and structure. The results show that the surface of membrane treaded with n-hexane are smoother and less hydrophily, the content of carbon element increased at the same time. On the other hand, the water flux of membrane treated with alkane decrease, but the rejections to MgSO4 and egg protein increase. While the surface of membrane treated with ethanol are rougher and more hydrophily, the contents of carbon and oxygen increase too. The water flux of membrane treated with alcohols increase obviously, but the rejection to egg protein decrease slightly.

Abstract: 1-alky-3-methylimidazolium hexfluorophosphate ([n-Cnmim][PF₆]) and 1-alky-3- methylimidazolium thiocyanate ([n-Cnmim]SCN) (n=4,8,16) were firstly introducing into the casting solution (PSF/NMP), porous polysulfone (PSF) membranes were successfully prepared by the wet-phase-inversion. The scanning electron microscope was utilized to visualize the cross-sections of the membranes, in order to study the influence of ionic liquids with different alkyl chain on the porous structures. The results indicate that the PSF membranes have different structures and separation properties due to ionic liquids with different alky chain. For ionic liquids with the short alkyl chain, the prepared membranes have the porous structure on cross-sections, but no or weak separation properties. However, for ionic liquids with the long alkyl chain, the prepared membranes have both porous structure and good separation properties. According to the structure of a hydrophobic straight-long alkyl and a hydrophilic limidazolium ring, the ionic liquid with long alkyl chain is considered as a surfactant, it can change not only the interface properties between the casting solution and coagulation bath, but also induce the space structures of the polymer chains.

Abstract: Polysulfone (PSf) membranes were prepared by the wet-phase-inversion using 1-hexadecyl-3-methylimidazolium thiocyanate [C16mim][SCN] as an new additive. Scanning electron microscope was utilized to visualize cross-sections of the membranes to gain more better understanding the influence of [C16mim][SCN] on the pore-forming. Moreover, Membrane-forming mechanism using ionic liquid as a pore-former was also discussed. The results showed that ionic liquid [C16mim][SCN] had restrained the demixing of the casting solutions and has the ability of the pore-forming, higher than those of its analogues of PEG400. With increase of concentration of ionic liquid [C16mim][SCN] in casting solutions, the structures of the membranes changed from asymmetric finger pores to the spongy-finger-macrovoid structure of the pores. Compared with PEG400 as a pore-former,[C16mim][SCN] has the pore-forming ability to the membrane at lower concentration of [C16mim][SCN] in the casting solution. Especially, at the 4:76 ratio of [C16mim][SCN]/NMP, the prepared membrane has the asymmetric finger-pores structure, with the 2~6μm pores close to surface layer and the 10~24μm pore for its sublayer. Its retention rate of PEG10000 and solution flux are 97.1% and 48.7 L• h-1• m-2. Meanwhile, ionic liquid can be a plasticizer, according the thermal properties of the membranes.