共查询到17条相似文献,搜索用时 125 毫秒
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采用模拟生活污水,在室温下研究了蛋白质、多糖、蛋白质/多糖浓度比(P/P)及胞外聚合物(EPS)浓度对膜污染的影响,建立了影响因素与膜压差(Dp)的二项式非线性回归方程. 结果表明,蛋白质和P/P对Dp有很大影响,其相关系数R2分别为0.5367和0.4298,原因是蛋白质很容易在膜表面上沉积且形成二次吸附,造成膜孔变小和堵塞. EPS浓度对Dp的影响较小,R2为0.1185. 多糖浓度对Dp的影响无明显的规律性是因为模拟的生活污水中的多糖浓度高和其沉积或物理吸附作用. 实验得出蛋白质是影响膜污染的最主要因素,可通过改变蛋白质与膜之间的相互作用,降低蛋白质在膜吸附层的沉积. 相似文献
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含钒灰渣酸浸液结晶铵明矾的工艺条件 总被引:4,自引:1,他引:3
为获得含钒灰渣酸浸液结晶铵明矾的优化工艺条件,利用正交优选法研究了Al2(SO4)3浓度、铵/铝摩尔比、冷却速度和结晶温度对铵明矾结晶率的影响,分析了铵明矾晶体和滤液的成分,计算得到了铵明矾的结晶率. 结果表明,4种因素对铵明矾结晶率均有较大影响,Al2(SO4)3浓度、铵/铝摩尔比对铵明矾结晶率影响较为显著. 合理的铵明矾结晶工艺条件为:Al2(SO4)3浓度150~200g/L,铵/铝摩尔比1.2左右,冷却速度15℃/h左右,结晶温度5℃左右. 在此条件下,铵明矾结晶率为89.32%. 相似文献
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蛋白质晶体学的不断发展,使得蛋白质晶体的结晶方法也日趋增多。首次采用了座滴法结晶法,探究不同浓度鸡蛋白溶菌酶溶液,不同温度、NaCl浓度,是否添加mPEG对晶体形貌尺寸的影响。通过显微镜以及扫描电镜观察蛋白质晶体形貌特征,不同条件下的晶体形貌变化,最终获得晶体生长的最适温度以及浓度条件。 相似文献
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利用阳离子膜,以K2CrO4电解结晶制备K2Cr2O7,考察了电流密度、温度、阴极液KOH浓度、阳极液K2CrO4浓度等因素对转化率、电流效率和直流能耗的影响;研究了K2Cr2O7不同浓度、不同转化率下的结晶纯度和收率及搅拌速率、降温速率和晶种加入量等对晶体粒度分布和形貌的影响. 结果表明,最佳电解工艺条件为:电流密度0.2 A/cm2,电解温度80℃,阴极液KOH浓度50 g/L,阳极液K2CrO4浓度400 g/L. K2Cr2O7转化率大于90%时,结晶纯度不低于99.8%. 优化的结晶条件为:溶液初始K2Cr2O7浓度500 g/L,搅拌速率300 r/min,降温速率0.5℃/min,不添加晶种. 所得产品符合GB 28657-2012要求. 相似文献
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研究了离子液体溴化1-辛基-3-甲基咪唑([C8mim]Br)添加剂的聚集状态对蛋白质结晶过程的影响。实验发现[C8mim]Br可以改善溶菌酶晶体形貌,影响晶体数量和晶体尺寸。通过测定不同浓度[C8mim]Br下溶菌酶的溶解度、结晶动力学、聚集状态和ζ-电势,揭示了离子液体[C8mim]Br对溶菌酶结晶的影响机理。结果表明,[C8mim]Br与溶菌酶的作用方式随[C8mim]Br的聚集状态而改变。当[C8mim]Br浓度较低(<0.1 mol/L)时,[C8mim]+与溶菌酶分子之间存在疏水作用,可以促进蛋白质分子聚集,促进结晶过程。当[C8mim]Br浓度较高(>0.1 mol/L)时,[C8mim]+自发聚集成胶束,并与蛋白质分子相互作用形成溶菌酶-胶束复合物;动态光散射(DLS)结果显示结晶过程以溶菌酶-胶束复合物为基本单元聚集,因此结晶过程减缓,晶体质量提高。 相似文献
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结晶过程的原则是争取最大的结晶速度,尽可能提高成品收率,保证晶粒的均匀整齐。而影响结晶的因素有:溶液浓度、晶种质量、晶体生长速率、过饱和度的大小、结晶温度、溶液pH值、溶液杂质等。本文探讨了D-核糖结晶过程中溶液浓度、溶媒(乙醇)含量和降温方式等工艺的优化。 相似文献
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利用所搭建的小型动态制冰装置制取冰浆,实验探讨了结晶时间、载冷剂温度、添加剂种类与浓度、刮削速度等因素对冰浆动态制备过程的影响,研究中基于热平衡方法测得结晶过程不同时刻的含冰率,对所制取的冰浆进行显微拍照,并基于图像处理获取冰晶尺寸的当量直径。实验结果表明,在动态结晶过程的测试时间内,制冰溶液的降温速率受外界条件影响较小,但添加剂种类与浓度对制冰溶液的相变结晶温度以及过冷度影响较大;制冰溶液的含冰率与冰晶尺寸均随时间的增加而增大,其中载冷剂温度、添加剂种类与浓度对溶液含冰率影响较大,而对冰晶尺寸影响最大的因素是刮削速度与添加剂浓度;当结晶过程进行到30 min时溶液的含冰率均达到25%,冰晶尺寸均能达到0.12 mm左右。 相似文献
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Large molecule protein crystals have shown significant benefits in the delivery of biopharmaceuticals to achieve high stability, high concentration of active pharmaceutical ingredients (API), and controlled release of API. However, among the about 150 biopharmaceuticals on the market by 2004, only insulin has been marketed in crystalline form. A major technological challenge is that protein crystallization has a very complicated environment and is affected by many factors. There is currently a lack of knowledge on large scale production of protein crystals. In contrast to the majority of previous work on protein crystallization that was centered on single crystal scale, the current research is focused on computational study of protein crystallization at process scale, investigating the growth behavior of a population of crystals in a crystallizer. Using a newly developed morphological population balance model that can simulate the multidimensional size distributions of a population of crystals, known as shape distribution, an optimization technique is applied to optimize the growth of individual faces with the aim of obtaining desired crystal shape and size distributions. Using a target shape as the objective function, optimal temperature and supersaturation profiles leading to the desired crystal shape were derived. Genetic algorithm was investigated and found to be an effective optimization technique for the current application. Since tracking an optimum temperature or supersaturation trajectory can be easily implemented by manipulating the coolant flowrate in the reactor jacket, the methodology provides a feasible closed-loop mechanism for protein crystal shape tailoring and control. 相似文献
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A new technique for crystallizing proteins is introduced. Solvent removal by freezing‐out is employed to crystallize hen egg white lysozyme from aqueous salt solutions. The crystallization is carried out at moderate salt concentrations (1–10 wt % NaCl) and at pH 4.4–5.2. The required supersaturation for nucleation and crystal growth is achieved by removal of the solvent resulting in a concentration increase with respect to salt, buffer, and protein. A simple tube and shell heat exchanger is used to generate the driving force for crystallization of the ice. The enzymatic activity of the resulting crystals is measured after their dissolution and shows large variations with respect to the crystallization conditions, though no systematic behavior is observed. The effect of the cooling rate applied to the cold finger upon the protein concentration in the ice is investigated. 相似文献
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提高蔗糖结晶效率的研究进展 总被引:2,自引:0,他引:2
结晶是制糖工艺过程中最后也是最关键的一步,它关系着最终成品糖的质量优劣,也关系着整个工艺过程的生产效率和经济效益。因此,如何在保持结晶质量的前提下提高结晶效率是一个十分具有现实意义的研究课题。本文分析了蔗糖结晶的理论,影响结晶的因素有糖液浓度、温度、粘度、纯度和杂质。在此基础上,总结了提高蔗糖结晶效率的途径和一些新的提高结晶效率的方法。 相似文献