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1.
This paper describes an innovative method for the immobilization of acylase I, which was entrapped into the CA-CTA micropore membrane. The most suitable casting solutions proportion for immobilizing the enzyme was ob tained through orthogonal experiment. Properties of the enzyme membrane were investigated and compared with those of free enzyme and blank membrane. The thermal stability and pH stability of the enzyme inside the membrane were changed by immobilization. The optimum pH was found to be 6.0, which changes 1.0 unit compared with that of free acylase I. The optimum temperature was found to be about 90 ℃C, which is higher than that of free acylase I (60 ℃). Experimental results showed that immobilization had effects on the kinetic parameters of acylase I. 相似文献
2.
以聚偏氟乙烯为膜材料,二甲基亚砜为溶剂,通过相转化法制备不对称结构的聚偏氟乙烯微孔膜.考察不同凝胶浴组成浓度对膜结构和性能的影响.结果表明,二甲基亚砜容纳非溶剂水的能力非常弱.以二甲基亚砜为溶剂时,所成膜均为指状孔和球晶共存的结构.凝胶浴的组成将影响成膜机理,随着凝胶浴浓度的不断增大,凝胶分相延迟发生,指状孔的尺寸也随之增大,因此成膜孔隙率和水通量都逐渐升高.当凝胶浴为60%DMSO时,所成膜的孔隙率为78%,水通量达到623 L/m2h. 相似文献
3.
采用溶液共混和相转移技术,经二乙烯三胺五乙酸（DTPA）和三聚氰胺（MA）共价键合作用,制备了具有螯合配位作用的改性聚偏氟乙烯共混膜（DTPA-MA／PVDF）,研究了DTPA-MA／PVDF共混膜对水溶液中Ni^2＋的吸附性能、吸附热力学及吸附动力学。结果表明,DTPA-MA／PVDF共混膜对Ni^2＋具有优良的吸附性能,吸附量随温度升高而下降。热力学参数△G^0〈0、△H^0〈0、△S^0〉0,证实了DTPA-MA／PVDF共混膜对Ni^2＋的吸附为自发的放热过程。DTPA-MA／PVDF共混膜对Ni^2＋的等温吸附较好地符合Langmuir等温吸附模型,D-R等温吸附表明该吸附过程为离子交换反应,该吸附过程的动力学符合准二级动力学方程。经4次吸附／脱附循环后,DTPA-MA／PVDF共混膜对Ni^2＋吸附量仍大于0．025mg／cm^2,脱附率仍超过90％。 相似文献
4.
含有单体牛细胞色素c氧化酶的脂质双层膜，被成功地固定在金石英晶体微平衡电极上．在较宽的pH值、温度和缓冲浓度范围内观察到了氧化酶修饰电极上的直接电子迁移．氧化酶修饰电极在80℃以上时保持直接电子迁移性质。将电极冷却到室温时，氧化酶仍保持电子迁移能力．在22～80℃范围内。温度变化可引起细胞色素c氧化酶的相转移，估计出了相转移前后的相应反应活化能通过射流分析，研究了在溶液含有亚铁细胞色素c氧化酶的电氧化过程中。乙腈同细胞色素c氧化酶的结合．结果显示：浓度1．3M具有常数Ki时。细胞色素c氧化酶和乙腈形成配合物．每个细胞色素c氧化酶配一个乙腈分子。乙腈同细胞色素氧化酶的结合过程是可逆过程． 相似文献
5.
1Introduction Generally,ultrafiltration(UF)asaseparationtech nologyofhighefficiencyandlowenergyconsumption haswidelybeenappliedinvariousindustries.Inin dustrialapplications,therearesixbasicUF modules[1]:(1)tubular,withinnerchannel diameters>4mm;(2)hollowfibers,withinnerdia metersof0.2-3mm;(3)plateunits;(4)spiral woundmodules;(5)pleated sheetcartridges;and(6)rotarymodules.However,hollowfiberUFmoduleis oneofmostimportantmodulesbecauseofitshigh areapackingdensity.Besides,UFtechnologyalsois us… 相似文献
6.
Enrichment of semi-volatile organic acids from aqueous solutions by multiple-effect membrane distillation 总被引：1，自引：0，他引：1
Multiple-effect membrane distillation(MEMD) process for enriching semi-volatile organic acids from their individual aqueous solutions was performed by using a hollow fiber-based air gap membrane distillation(AGMD)module with the function of internal heat recovery.Aqueous solutions of glyoxylic acid,glycolic acid,lactic acid,pyruvic acid,malonic acid and glutaric acid were used as model feed.For a feed of 1%(mass fraction),each acid could be enriched for 8-20 times,which depended on the surface tension of the concentrate.The operation performance of MEMD process was characterized by permeation flux J,performance ratio PR and acid rejection rate R.The effects of cold feed-in temperature,heated feed-in temperature,feed-in volumetric flow rate and feed-in concentration on MEMD performance were experimentally evaluated.Maximum values of J,PR and R were 4.8 L/(h·m 2),9.84 and 99.93%,respectively.Moreover,MEMD process demonstrated a fairly good stability in a long-term experiment lasting for 30 d when aqueous solution of 4%(mass fraction) lactic acid was used as a feed. 相似文献
7.
Ultrafiltration (UF) technique is prospective asalternative for conventional processes such as coagula-tion, flocculation, sedimentation and/or flotation,rapid and slowsand filtration[1]. Recentdevelopmentsin reducing energy consumption by (semi) dead-endfiltration and prevention of membrane fouling by back-washing (combined with chemicals), make UF moreand more an interestingoption forthe treatmentof sur-face water on a large scale[2]. At present, UF full-scale applications are evenlyspread… 相似文献
8.
为了获得高产纤维素酶菌株,有效地开发和利用纤维素资源.本研究通过对野外采集的大型真菌进行分离纯化,获得了16个菌株.利用CMC固体培养、刚果红染色,测量水解圈与菌落直径的比值(H/C值),对获得的菌株进行初筛;通过液体发酵培养,测定其上清液中的滤纸酶活力(FPA),对菌株进行复筛,最终获得了纤维素酶活性较高的菌株01.以稻草和羧甲基纤维素为碳源,研究了培养温度、pH值、培养时间对真菌菌株01产纤维素酶的影响.结果表明,该菌株产纤维素酶的最适培养温度为27℃,pH值为5.0,培养时间为6 d,菌株01的滤纸酶活性达到580.0 IU/mL.因此,真菌01可作为纤维素酶研究和饲料加工等生产的备选菌株. 相似文献
9.
The retention of sulfamethoxazole （SMZ） by nanofiltration （NF） membranes is strongly influenced by the pH value of the solution. The retention of SMZ reaches its peak value when the solution pH rises above its PKa2 value as the compound transforms into a negatively charged species. Charge repulsion is the main mechanism involved in SMZ removal by NF membranes. In this study, the removal of SMZ by NF membranes, as a function of solution chemistry, was examined at pH 8.9 to investigate the effect of solution conditions on charge repulsion. The results show that the retention of negatively charged SMZ is relatively independent of SMZ concentration, and an increase in the ionic strength of the solution causes a relatively small reduction in retention. A small effect of humic acid （HA） on SMZ retention was noticed at pH 8.9, which can be explained by a small but insignificant improvement in the zeta potential of the membrane caused by HA at high pH values. However, it was found that SMZ concentration in the feed decreased significantly in solutions containing tannic acid （TA）. The Adams-Bohart model was applied to our experimental data and was found to be suitable for describing the initial part of the breakthrough curves. The adsorptive parameters of the membrane were determined. 相似文献
10.
针对密集多通道无机陶瓷膜处理汽车发动机乳化液废水开展了中试试验,并通过工程检验,获知该类废水处理的适宜设计参数为:膜面流速取4-6 m/s,压力控制为0.3 MPa,温度控制在45℃左右;在相应的操作条件下,COD、含油量等均达到了后续污水处理的水质要求,效果明显。 相似文献
11.
赵亚丽 《晋城职业技术学院学报》2012,5(4):91-94
液膜分离是一种高效低成本的金属离子预富集手段,本文采用组成为载体P-204（8％）,表面活性剂Span-80（3％）,膜稳定剂液体石蜡（0．5％）,膜溶剂煤油（88．5％）,内相HC1的浓度2．0mol／L的液膜萃取体系,考察了萃取时间、外水相酸度、转速、乳水比的分离条件对镉萃取率的影响。,实验优化后的萃取条件为萃取时间10min、外水相pH=4．50、乳水比1：4、搅拌速度200r／min;将液膜分离与火焰原子吸收相结合检测镉、铜离子,结果表明,此法灵敏度高、检测限低、检测范围宽。 相似文献
12.
研究前驱物浓度、超重力大小、反应时间、反应温度和反应介质体系的条件对Co3O4前驱物形貌的影响,发现制备花状Co3O4前驱物的最优条件是Co(NO3)2·6H2O和CO(NH2)2在1000/g超重力场、溴苯/水溶液体系、100℃条件下水热反应反应30min,通过前驱物的热分解制得Co3O4,采用SEM和XRD对样品的形貌和物相进行表征。将Co3O4粉末分别与乙炔黑、聚四氟乙烯(PTFE)按一定质量比混合压在镍网上,制成电极片,通过CV测试其电性能,结果发现超重力越大,制备的材料的交流阻抗值越小。 相似文献
13.
水解沉淀法制备纳米TiO2及其表征 总被引：1，自引：0，他引：1
以TiOSO4为原料制备纳米TiO2 并对其进行XRD、BET、TEM研究 .结果表明 ,pH值与热处理温度对晶粒大小及晶型结构有很大影响 .在 5 0 0℃热处理条件下 ,pH =5时的纳米粉末比表面积为 10 1.3 9m2 ·g-1,粒径 10nm左右 ;pH =10时的纳米粉末比表面积为 95 .48m2 ·g-1,粒径 3 0nm左右 .在 75 0℃时的金红石晶型转变对粒径的长大有很大的促进作用 . 相似文献
14.
王怀宇 《邢台职业技术学院学报》2008,25(3):64-66
本文以PAC／PAM复合絮凝剂处理洗毛废水进行小试。研究表明PAC与废水形成（20-30）μm的小絮体,PAM主要起到连接小絮体形成矾花。自由絮凝时,当COD：PAC：PAM为8．43：1：0．013、PH为5、水温为45℃时,COD、SS去除率分别达到97％、92％。 相似文献
15.
16.
用于乙醇-水分离的SA-PVA/PSF中空纤维渗透汽化复合膜 总被引：1，自引：1，他引：0
Using polysulfone (PSF) hollow fiber ultrafiltration membranes as the substrate, sodium alginate (SA) and polyvinyl alcohol (PVA) blend solutions as the coating solution, and maleic anhydride (MAC) as the cross-linked agent, SAPVA/PSF hollow fiber composite membranes were prepared for the dehydration of ethanol-water. The effects of different sodium alginate concentration in the coating solutions and different operating temperatures on pervaporation performance were investigated. The experimental results showed that pervaporation performance of the SA-PVA/PSF composite membranes for ethanol-water solution exhibited a high separation factor although they had a relatively low permeation flux. As SA concentration in SA-PVA coating solution was 66.7% and the operating temperature was 40 ℃, SA-PVA/PSF hollow fiber composite membrane (PS4) had a separation factor of 886 and flux of 12.6 g/(m2·h). Besides, SA-PVA/PSF hollow fiber composite membranes (PS3 and PS4) were used for the investigation of the effect of ethanol concentration in the feed solution on pervaporation performance. 相似文献
17.
1 Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｆｌｏｃｃｕｌｅｎｔｐｒｅｃｉｐｉｔａｔｉｏｎｉｓａｎｅｃｏｎｏｍｉｃａｌａｎｄｃｏｎｖｅ ｎｉｅｎｔｍｅｔｈｏｄｗｉｄｅｌｙａｄｏｐｔｅｄｂｙａｎｕｍｂｅｒｏｆｃｏｕｎｔｒｉｅｓａｓａｎａｉｄｔｏｉｍｐｒｏｖｅｔｈｅｗａｔｅｒｑｕａｌｉｔｙ .Ｔｈｅｐｏｌｙｍｅｒｆｌｏｃｃｕｌｅｎｔｍａｋｅｓａｖｅｒｙｉｍｐｏｒｔａｎｔａｃｔｉｏｎｉｎｗａｔｅｒｔｒｅａｔ ｍｅｎｔｂｅｃａｕｓｅｏｆｇｏｏｄｆｌｏｃｃｕｌｅｎｔｐｅｒｆｏｒｍａｎｃｅ,ｄｅｃｏｌｏｒａｎｔｐｏｔｅｎｃｙａ… 相似文献
18.
研究不同氮源、盐度、温度、光照、pH值条件下一株沼泽红假单胞菌的生长情况。结果表明,①作为培养基氮源,氯化铵要比硫酸铵更适宜该菌生长;②在8‰～32‰盐度范围内,该光合细菌生长最适的盐度为8‰,8～16‰是该光合细菌生长较为适合的盐度;③在22～34℃温度范围,最适的温度是31℃;④该光合细菌在室外日光下（60 000lx,26～38℃）下生长稍快于室内阴凉处,但变化并不是很大;⑤在pH 4.5,5,5.5和6的酸碱范围内,pH 6最适宜该光合细菌生长。环境条件对该光合细菌的生长有重要影响。 相似文献
19.
LIU Cai-qin CHEN Qi-he CHENG Qian-jun WANG Jin-ling HE Guo-qing 《Journal of Zhejiang University. Science. B》2007,8(5)
The work is intended to achieve optimum culture conditions of α-galactosidase production by a mutant strain Aspergillusfoetidus ZU-G1 in solid-state fermentation (SSF). Certain fermentation parameters involving moisture content, incubation temperature, cultivation period of seed, inoculum volume, initial pH value, layers of pledget, load size of medium and period of cultivation were investigated separately. The optimal cultivating conditions of α-galactosidase production in SSF were 60%initial moisture of medium, 28 ℃ incubation temperature, 18 h cultivation period of seed, 10% inoculum volume, 5.0～6.0 initial pH of medium, 6 layers of pledget and 10 g dry matter loadage. Under the optimized cultivation conditions, the maximum α-galactosidase production was 2037.51 U/g dry matter near the 144th hour of fermentation. 相似文献
20.
采用碱浸酸析的方法从红橘果皮中提取橙皮苷．通过对碱的种类、添加量、料液比、提取时间、反应体系pH值及提取温度等因素的研究,确定提取橙皮苷的最佳工艺条件为：温度在30℃,在25g的橘皮粉中加入750g蒸馏水,1．75g氢氧化钙,搅拌浸提0．5h,酸析的pH值为3,粗产品收率为4．2％．粗产品经过重结晶分离提纯,收率达到56％,产品结构经过IR鉴定． 相似文献