首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 171 毫秒
1.
长链脂肪酸魔芋葡甘聚糖酯的制备及乳化性能研究   总被引:4,自引:0,他引:4  
采用非均相酰化法制备了四个系列的长链脂肪酸魔芋葡甘聚糖酯(KGME).DTA图显示了葡甘聚糖酯的晶态结构变化,X 射线衍射分析表明了不同长度的酰链对葡甘聚糖酯晶态结构的影响.初步研究了葡甘聚糖酯在芳香烃及环烷烃两种水包油(O/W)乳液体系中其取代度与乳化力的关系.实验证明在水包油乳液体系中,取代度在某一范围的葡甘聚糖酯显示出较好的乳化能力,且在高盐浓度和酸性情况下,仍给出好的乳化作用.丁香油 水(O/W)乳液体系在室温下静置四个星期未发现破乳分离现象  相似文献   

2.
长链脂肪酸魔芋葡甘聚糖酯及乳化性能研究   总被引:3,自引:1,他引:2  
采用非均相酰化法制备了四个系列的长链脂肪酸魔芋葡甘聚糖酯(KGME)。DTA图显示了葡甘聚糖酯的晶态结构变化,X-射线衍射分析表明了不同长度的酰链对葡甘聚糖酯晶态结构的影响。初步研究了葡甘聚糖酯在芳香烃及环烷烃两种水包油(O/W)乳液体系中其取代度与乳化力的关系。实验证明在水包油乳液体系中,取代度在某一范围的葡甘聚糖酯显示出较好的乳化能力,且在高盐浓度和酸性情况下,仍给出好的乳化作用。丁香油-水(O/W)乳液体系在室温下静置四个星期未发现破乳分离现象。  相似文献   

3.
基于脱乙酰基魔芋葡甘聚糖固定酶的H2O2生物传感器   总被引:4,自引:3,他引:1  
对魔芋葡甘聚糖进行了脱乙酰基改性处理,并用红外光谱表征了其脱乙酰基前后的结构变化.探讨了脱乙酰基魔芋葡甘聚糖溶胶-凝胶的制备条件对其成膜性能及酶固定化的影响.将脱乙酰基魔芋葡甘聚糖用于辣根过氧化物酶的固定,制备出了H2O2生物传感器.传感器在优化的工作条件下线性范围为1.0×10-6 ~6.0×10-4 mol/L,检出限为8×10-7 mol/L,稳定性良好.实验表明脱乙酰基魔芋葡甘聚糖是一种适用于生物传感器领域酶固定化的优良材料.  相似文献   

4.
以交联的魔芋葡甘聚糖微球(KGM)为基质,制备了DEAE型的阴离子交换层析介质,考察了反应物浓度、温度、时间等反应因素对魔芋葡甘聚糖层析介质离子交换容量的影响,确定最优反应参数.结果表明,层析介质的离子交换容量达到3.42mmol/g,蛋白吸附容量高达126.84mg/mL,蛋白洗脱率为90.42%.  相似文献   

5.
陈浩  徐娟  薛爱芳  李胜清  康勤书 《色谱》2007,25(4):598-599
建立了以纤维素酶降解魔芋葡甘聚糖释放阴离子,然后采用离子色谱测定亚硝酸盐含量的方法。考察了纤维素酶降解葡甘聚糖的最佳条件,结果表明:在50 ℃、pH 5.5条件下酶解24 h,可以释放出被包埋的亚硝酸盐。NO-2的检出限为0.039 mg/L,回收率为96.7%~97.8%。运用本法对施用稀土微肥后魔芋中亚硝酸盐的含量进行测定,发现施用稀土微肥能够在一定程度上降低魔芋中亚硝酸盐的含量。  相似文献   

6.
羧甲基交联魔芋葡甘聚糖微球的制备与表征   总被引:6,自引:0,他引:6  
采用交联魔芋葡甘聚糖颗粒(CKGG)合成了羧甲基交联魔芋葡甘聚糖微球(CMCKGG),讨论了羧甲基化过程中的影响因素.用正交设计的方法确定了具有较好交换容量的CMCKGG制备奈件.当碱用量为CKGG量的20%,氯乙酸钠用量为CKGG量的10倍,温度55℃,反应时间8h时,制得的CMCKGG阳离子交换容量为0.7389mmol/g.红外光谱.光学显微镜和扫描电镜的结果表明,该颗粒为蜂窝状多孔微球,粒度均匀.  相似文献   

7.
氧化魔芋葡甘聚糖的结构研究   总被引:14,自引:0,他引:14  
以魔芋精粉为原料采用乙醇纯化法制得纯化魔芋葡甘聚糖,进一步用悬浮法和湿法制备氧化魔芋葡甘聚糖(O-KGM),采用DSC、XRD、SEM、IR、量子化学计算等方法对O-KGM的结构进行预测和表征。结果分析表明,氧化主要发生在糖残基的C(2)及C(3)位,O-KGM的特性粘度降至272.9 cm3/g,约为改性前的1/7,玻璃化温度及晶体熔融温度分别为61.5 和149.36 ℃,同时结晶度略有增加。  相似文献   

8.
铁-芳烃络合物光引发剂的吸收光谱研究陈旭东,黄新华陈用烈,梁兆熙(西南师范大学化学系重庆,630715)(中山大学高分子研究所广州)关键词铁-芳烃络合物,光引发剂,吸收光谱,光解铁-芳烃络合物作为环氧化物阳离子聚合光引发剂已引起人们关注[1,2].我...  相似文献   

9.
硒(Ⅳ)-碘化物-结晶紫体系的共振发光和二级散射光谱刘绍璞,刘忠芳(西南师范大学环境化学研究所,重庆,630715)关键词共振发光,二级散射,反二级散射,硒(Ⅳ)-碘化物-结晶紫体系,硒的测定长期以来,溶液体系的共振发光和二级散射现象常常被人们忽略。...  相似文献   

10.
以数字处理对魔芋葡甘聚糖膜面特征的初步研究   总被引:2,自引:0,他引:2  
陈彦  林晓艳  罗学刚 《化学研究与应用》2002,14(5):557-558,F003
以天然生物材料为原料的绿色环保型膜材料取代塑料薄膜将是今后膜材料的发展趋势[1 4 ] 。从魔芋 (AmorphopallusKonjacK .KoCh)中提取出的魔芋精粉 ,其主要成分为葡甘聚糖 ,其优良的成膜性已引起人们的重视[4 5] 。分形维数在材料研究中得到了广泛的应用[6 ] ,本文以魔芋葡甘聚糖为主要原料制成膜 ,对膜的扫描电镜图象进行数字化处理 ,探讨膜面的微观形貌特征及制膜条件对膜面的影响。1 实验部分1 1 膜的制备以魔芋精粉 (四川安县魔芋精粉厂 )为主要原料 ,并添加明胶增强剂、甘油 (食品级 )增塑剂 (质量比为 1…  相似文献   

11.
 Four different industrial slurries were flocculated with polymeric flocculating agents (port sediment, sewage sludge, sugar beet washings and an aluminum hydroxide suspension). The quantities of flocculating agent employed were optimized with the aid of a patented, portable flocculation and dewatering apparatus. Using sewage sludge as an example, it was possible to arrive at predictions for particular doses of flocculating by means of a combined method of dewatering experiments and electrokinetical measurements. The results of monoflocculation and dual flocculation made it possible to deduce that there are similarities in the flocculation and dewatering behavior of slurries with comparable parameters. Comparison of the sediment particles and the polymer coils revealed a size ratio of 60:1, with the former being the larger. This was then used to devise modifications to the patch charge model and the bridging model as a function of the molar mass of the flocculating agent. The modifications were found to agree well with the experimental findings and the structural conceptions of macromolecular substances. Received: 26 July 1996 Accepted: 29 August 1996  相似文献   

12.
Summary Previous studies have indicated that non-ionic surface active agents, such as n-dodecylhexaoxyethylene glycol monoether, confer considerable protection on silver iodide sols to flocculation by inorganic cations. In the present study the effects of hydrolysis of the flocculating cations, lanthanum, aluminium and thorium have been examined. It was found that with the hydrolysed cations the protective action of the non-ionic surface active agent was considerably diminished. It was deduced that the hydrolysed species are more strongly adsorbed than the nonionic surface active agent and either displace the latter from the surface or form species which are large enough to cause flocculation by interparticle bridging.
Zusammenfassung Vorausgehende Untersuchungen haben gezeigt, daß nichtionische oberflächenaktive Substanzen wie n-Dodecylhexaoxyäthylen-glykol-monoäther beträchtliche Schutzwirkung Silberjodidsolen gegenüber Flokkung durch anorganische Kationen verleihen. In der vorliegenden Untersuchung wird die Wirkung der Hydrolyse flockender Kationen, Lanthan, Aluminium und Thorium, geprüft. Es wurde gefunden, daß durch die hydrolisierten Kationen die Schutzwirkung der nichtionischen oberflächenaktiven Substanz beträchtlich vermindert wird. Daraus ist zu schließen, daß die hydrolisierte Ionenart stärker als das nichtoberflächenaktive Agens adsorbiert wird und deshalb das letztere von der Oberfläche entfernt wird oder genügend große interpartikuläre Brücken, bildet, um Flockung zu verursachen.


With 6 figures and 1 table  相似文献   

13.
The adsorption of the cationic dye acridine orange (AO) by different monoionic laponites leads to changes in the colloid properties of this synthetic mineral in aqueous solutions. The organic cation is adsorbed by the mechanism of cation exchange. Small amounts of adsorbed dye keep the clay in a peptized state with all metallic cations. Greater amounts of AO result in the neutralization of the electric charge of the clay, and its flocculation. In excess AO the charge of the clay platelets becomes positive and the clay is peptized. The colloid properties are studied by absorbance curves in which the absorbance is described as a function of the degree of saturation with constant clay concentrations or with constant dye concentrations. In the absorbance curves three regions can be identified. The transition between the first and second or the second and third regions depend on the exchangeable metallic cation initially present in the clay. The spectrophotometric method is useful in identifying the presence of tactoids and flocculation mechanism, whether it results in card-house or in book-house flocs.  相似文献   

14.
The oil agglomeration of quartz with sodium oleate in the presence of calcium and magnesium ions comprises three consecutive stages: adsorption of cations onto quartz surfaces, which leads to coagulation of the suspension, shear flocculation with sodium oleate and finally, agglomeration of flocs by kerosene. The effects of pH and cation concentration on these stages were investigated and the results were presented comparatively. It was found that all the stages of oil agglomeration of quartz exhibited sharp dependences on pH and cation concentration. That is, these stages generally took place in the pH and concentration ranges in which hydroxy complexes of the cations existed in the suspension. In the case of magnesium ion, the coagulation, shear flocculation and especially oil agglomeration of quartz improved after precipitation of hydroxide. These species of calcium and magnesium ions formed at high pH were adsorbed on the negatively charged surface of quartz, as a result of which the adsorption of sodium oleate became possible and thus the shear flocculation of the particles was achieved. Thereafter, the hydrophobic quartz flocs could be agglomerated by kerosene as bridging liquid. The increase in the shear flocculation efficiency depending on the increase of surface hydrophobicity enhanced the oil agglomeration of quartz with kerosene. The maximum recoveries for all the stages of the quartz were obtained in the presence of 10(-3) M magnesium and 5x10(-3) M calcium ions at pH 11. However, some differences in the behavior of shear flocculation and oil agglomeration of quartz suspension were observed above 10(-3) M concentration of magnesium ion.  相似文献   

15.
The analysis of ammonium, alkali and alkaline-earth trace cations (0.5 ppm) in samples with a calcium, sodium or magnesium matrix (500 ppm) has been achieved using 10 mM imidazole (pH 4.5) electrolyte to which a complexing agent (15-crown-5, oxalic acid or dipicolinic acid) has been specifically added in order to decrease the electrophoretic mobility of the matrix cation and thus to allow the separation of higher mobility cations at sub-ppm concentrations. The influence of several experimental parameters (complexing agent concentration, buffer pH and temperature) have been studied in order to optimize the separation. The complexing agent concentration appears to be the main parameter governing the selectivity of the cations during the analysis of matrix samples. In optimized conditions, we have checked that the separation between minor inorganic cations is not significantly altered by an increase in the matrix cation concentration. As the concentration of the matrix cation increases, the migration times of minor cations remain unchanged even for a 1000 ppm concentration of the matrix cation. Finally, these optimized buffers allow the quantitation of minor cations down to 0.05% (w/w) for calcium- or magnesium- matrix simulated samples and 0.2% (w/w) for sodium-matrix simulated samples.  相似文献   

16.
During oil production and treatment, oil-in-water (O/W) emulsions are formed. These dispersions require treatment prior to disposal. In order to improve oil/water separation processes through any physical process (decanting, flotation, centrifuging etc), the particle size of the dispersed phase should be increased. This may be obtained by a flocculation process, which consists in the agglomeration of several particles or drops using as flocculating agent hydrophilic high molecular weight macromolecules. Poly (ethylene-b-propylene oxide) and poly (vinyl alcohol) polymers have been evaluated as flocculating agents for oily water systems. Their performance is related to the particle size increase of the dispersed phase. In this work, a photometric dispersion analyzer (PDA) has been used to accomplish the oil drop agglomeration. Synthetic as well as produced water was used. Data are in good agreement with previous tests. Qualitative information related to aggregates or particle size distribution of the oily water systems can be obtained using PDA.  相似文献   

17.
壳聚糖对药用膨润土悬浊液的絮凝效果   总被引:1,自引:0,他引:1  
徐清海  赵兵 《应用化学》2001,18(7):578-0
絮凝作用;壳聚糖对药用膨润土悬浊液的絮凝效果  相似文献   

18.
In the intense search for high-energy density cathode materials for use in lithium-ion rechargeable battery technology, LiCoO2 has become the first, and one of the most promising, for commercial applications1. Sol-gel chemistry has recently evolved as a powerful approach for preparing inorganic materials such as glasses and ceramics2. The improved sol-gel process is based on the ability of certain weak acids to form polybasic acid chelates with various cations. These chelates can undergo polyesterification when heated in a polyhydroxyl alcohol to form a solid polymeric resin through which the cations are uniformly distributed. Thus the resin retains homogeneity on the atomic scale and may be calcined at low temperature to yield fine particulate oxides. Using this method, it is possible to obtain phase-pure ultrafine crystalline nanophases after firing the ploymeric precursors at some appointed temperature for several hours. In this work we reported that nanosized LiCoO2 were prepared by the improved sol-gel process.  相似文献   

19.
HCo(CO)4 is known to be the active species in the cobalt-catalyzed hydroformylation reaction. Although it is known that the anion [Co(CO)4] is catalytically inactive, some cobalt carbonyl-containing ionic liquids are surprisingly able to catalyze hydroformylation reactions. However, only ionic liquids with protic cations demonstrate activity, whilst aprotic cations such as BMIM+ result in a completely inactive compound. The four applied cobalt-containing ionic liquids differ only by the cation component. Their different performance in catalytic activity allows the presumption of cooperative effects between the cation and the anion. These fundamental influences of the cation on the hydroformylation kinetics give hints for the reaction mechanism of biphasic hydroformylation reactions as well as on the reaction pathways of the conventional hydroformylation reaction under different reaction conditions.  相似文献   

20.
Humic and fulvic acids from various sources have been shown to give different electropherograms by capillary zone electrophoresis (CZE), depending on the pH of the electrolyte. This CZE work is extended here through investigations involving the titration of humic and fulvic acids with Fe(III) and Cu(II) cations. As increasing amounts of these cations were added to the humic substances (HUS), flocculation of metal-humic complexes occurred. This is believed to be caused by binding of the metal cations with negative carboxyl and phenolic sites on the HUS, resulting in a decrease of the repulsive forces that keep the HUS in a conformation more suitable for water solubility. The flocculated complexes were separated from the supernatant by centrifugation, and the supernatants were characterized as to total organic carbon (TOC) content, molecular weight (MW) using gel permeation chromatography, and average electrophoretic mobility (AEM) using CZE. The extent of flocculation correlated with both TOC and quantitative CZE measurements. The MW of the HUS remaining in solution actually decreased, presumably because of precipitation of larger molecules as they became insoluble because of reactions with the metals. Humic acids showed total precipitation of TOC with both metals at a concentration equivalent to their measured acidity. CZE demonstrated that certain fulvic acid fractions (low molecular weight phenolic acids) remained in solution even at high metal concentrations. In summary, changes in electrophoretic behavior of the soluble HUS could be related to changes in charge-to-mass ratios (charge densities) of both humic and fulvic acids with increasing metal cation concentration (neutralization). The copper treated HUS showed changes in their electrophoretic behavior even at low metal concentrations before flocculation, whereas the iron treated HUS flocculated uniformally over the range of added iron without significant changes in AEM. Thus these changes in CZE patterns illustrate different specific binding sites of the HUS for each metal.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号