共查询到18条相似文献,搜索用时 202 毫秒
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利用响应面分析法对影响酵母抽提液中总氮截留率和海藻糖透过率的主要因素进行分析,优化超滤工艺,得到最佳超滤条件:料液质量浓度10 g/dL,料液温度42℃,操作压力0.31MPa,在最佳超滤条件下得到酵母抽提物蛋白质截留率96.5%,海藻糖透过率94.8%,所得RSA图可直观地反映各因素与蛋白氮截留率和海藻糖透过率的关系. 相似文献
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采用减压膜蒸馏技术在较低真空度下浓缩NaCl水溶液,研究了真空度,料液温度,料液流速以及料液浓度对膜通量与截留率的影响。结果表明,随着膜下游真空度增加,膜通量线性增大;料液温度显著影响膜通量;随着料液浓度增加,膜通量严重衰减;实验条件下聚丙烯中空纤维膜表现出很好的疏水性,NaCl的截留率接近100%。 相似文献
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比较截留分子量(MWCO)为1000D 和3000D 的卷式超滤膜在去除L- 乳酸发酵液中蛋白质等杂质过程中对蛋白质截留率和乳酸透过率的影响,研究超滤时间、操作压力、蛋白质质量浓度及操作温度等操作工艺参数对膜通量的影响,分析膜通量随时间的变化规律,建立描述膜通量与操作压力、蛋白质浓度关系的数学模型。结果表明:MWCO 为3000D 的膜更适合用于超滤L- 乳酸发酵液,其膜通量随着超滤时间的延长衰减;随着操作压力和温度的增加而升高,随着蛋白质质量浓度的增加而降低,所建立的数学模型与实验结果吻合良好。 相似文献
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核苷酸是DNA、RNA的组成单元,是一类在代谢上极为重要的生化物质,在食品、医药、农业、精细化工中有着广泛的应用。研究了采用高分子分离膜技术处理核苷酸的可能性,考察了操作压力、料液浓度、料液流速、运行时间等条件对膜分离性能的影响。结果表明,纳滤膜对核苷酸有很好的截留性能,对无机盐杂质有很好的透过效果。膜的渗透通量以及对核苷酸和无机盐离子的截留性能,随操作压力和进料流量的提高而上升,并且随进料浓度的上升而下降。在0.6MPa下,对核苷酸的截留率达到90%以上,对无机盐的截留率在50%,在实验的运行时间内膜性能基本稳定。 相似文献
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Pineapple juice samples were ultrafiltrated using a polysulfone 10,000 molecular weight cut-off (MWCO) membrane. However, to facilitate operations, the ultrafiltration experiments were preceeded by fractionation of juice samples using sequentially Microfiltration/Diafiltration and Ultrafiltration/Diafiltration with 8 μm; 0.4 μm; 0.2 μm and 0.1 μm membranes, using three specific experimental procedures. the 10,000 MWCO membrane was cleansed using a 40°C IN NaOH solution for a minimum of 30 min, to restore optimal membrane water permeation flux. the effects of selective fractionation processes, pretreatments (using antifoaming agent, hemicellulase, and ammonium sulfate saturation), on permeation rates, concentration levels, protein rejection and protein yields were determined. Water permeation fluxes, measured before and after each UF operation showed a dramatic flux drop from 313 L/hm2 to 91 L/hm2 within seven successive 10,000 MWCO membrane experiments. This occurred inspite of suitable membrane washing conditions, pretreatments and selective fractionation processing of samples. the modification, mainly due to fouling, of the integrity of the 10,000 MWCO membrane relative to concentration level was investigated. 相似文献
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Deposits formed on the membrane during ultrafiltration of aqueous solutions of individual whey proteins were examined under a scanning electron microscope. Gamma-globulin formed granules which agglomerated and stacked into layers to form a porous matrix on the membrane. Beta-lactoglobulin and bovine serum albumin both formed sheets on the membrane and formed multimers which were identified by sodium dodecyl sulfate gel electrophoresis. Beta-lactoglobulin also formed strands where deposits were not thick. Alpha-lactalbumin formed smooth spherical particles which did not hinder water permeation greatly. Studies of ultrafiltration rate indicated that beta-lactoglobulin and gamma-globulin were most significant in causing permeation flux decline by surface fouling. 相似文献
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The primary waste water discharged from pilot plant scale sweet potato starch manufacturing was processed by ultrafiltration (UF). The UF permeate was then concentrated by reverse osmosis (RO). Growth of microorganisms in waste water would reduce the flux of UF. When the feed velocity of UF was higher than 2.5 m/sec, its positive effect on permeation rate was no longer existent. Relationships between transmembrane pressure and permeate flux were linear at all tested concentrations. UF filtered protein and calcium reduced two-thirds of the biochemical oxygen demand (BOD) and half the chemical oxygen demand (COD) at weight concentration ratio (WCR) of 5. With RO the rest of the components were recovered and BOD and COD were reduced more than 99% and 98%, respectively, at a WCR of 6. 相似文献