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71.
木瓜蛋白酶降解甲壳胺的研究 总被引：4，自引：0，他引：4
采用一种木瓜蛋白酶过甲壳胺进行降解。研究了酶用量、pH值、温度、时间四个因素对反应的影响。其中,温度的影响作用显著,时间具有较小的影响作用(pH:3.0～6.0;温度:30°～60℃;时间:2～8h)。实验结果表明降解反应不遵循简单的动力模式。在pH4.0、40°C、8h、1.5mg/mL木瓜蛋白酶的条件下,分子量为(5～10)×105时用甲壳胺可容易地被木瓜蛋白酶降解为高度解聚的甲壳胺。 相似文献
72.
甲壳胺对褐藻胶胶液的絮凝作用及其在漂浮工艺中的应用研究 总被引：1，自引：0，他引：1
研究了甲壳胺作为絮凝剂对褐藻胶胶液的絮凝作用及漂浮效果。结果表明,甲壳胺对褐藻胶胶液具有较强的絮凝作用,其中,１０ｐｐｍ甲壳胺用量的漂浮效果较好,可大大缩短漂浮时间,对清胶液的透光率,粘度和胶收率均有不同程度的提高。 相似文献
73.
制备条件对聚乙烯醇-壳聚糖凝胶性能的影响 总被引：1，自引：0，他引：1
以戊二醛为交联剂,由聚乙烯醇(PVA)和壳聚糖(CTS)混合交联得到一种水凝胶,考察了聚乙烯醇和壳聚糖的配比、交联剂用量和反应时间对聚乙烯醇/壳聚糖凝胶吸水率的影响。通过单因素实验,得出了聚乙烯醇/壳聚糖凝胶具有最佳溶胀性能时的条件:聚乙烯醇与壳聚糖的摩尔比为6∶1,交联剂戊二醛的体积分数为0.05%,反应时间9h。测定了该凝胶在不同pH值下的吸水率和吸附铜离子的性能,得出聚乙烯醇/壳聚糖凝胶在酸性介质的吸水率远远大于碱性介质,对铜离子(Cu2+)的吸附量比壳聚糖凝胶提高了33.7%,因此该凝胶吸附剂在工业废水处理重金属离子方面具有一定的优越性。 相似文献
74.
ZHOU Li XU Junming SONG Yimin GAO Yuanyuan CHEN Xiguang 《中国海洋大学学报(英文版)》2007,6(3):249-254
The captopril/Chitosan-gelatin net-polymer microspheres(CTP/CGNPMs) were prepared using Chitosan(CTS) and gelatin(GT) by the methods of emulsification,cross-linked reagent alone or in combination and microcrystalline cellulose(MCC) added in the process of preparation of microspheres,which aimed to eliminate dose dumping and burst phenomenon of microspheres for the improvement of the therapeutic efficiency and the decrease of the side effects of captopril(CTP). The results indicated that CTP/CGNPMs had a spherical shape,smooth surface and integral structure inside but no adhesive phenomena in the preparation. The size distribution ranged from 220 μm to 280 μm. The CTP release test in vitro demonstrated that CTP/CGNPMs played the role of retarding the release of CTP compared with ordinary CTP tablets. The release behaviors of CGNPMS were influenced by preparation conditions such as experimental material ratio(EMR) and composition of cross linking reagents. Among these factors,the EMR(1/4),CLR(FA SPP) and 0.75% microcrystalline cellulose(MCC) added to the microspheres constituted the optimal scheme for the preparation of CTP/CGNPMs. The ER,DL and SR of CTP/CGNPMs prepared according to the optimal scheme were 46.23±4.51%,9.95±0.77% and 261±42%,respectively. The CTP/CGNPMs had the good characteristics of sustained release of drug and the process of emulsification and cross-linking were simple and stable. The CGNPMs are likely to be an ideal sustained release formulation for water-soluble drugs. 相似文献
75.
采用壳聚糖对酸性蓝黑B模拟废水进行处理,研究了溶液的酸度、吸附时间、溶液的初始浓度和溶液温度等对吸附效率的影响。结果表明,壳聚糖对酸性蓝黑B具有优良的吸附效果,在溶液初始浓度小于400 mg/L,pH=3.5~6,温度约为30~40℃,吸附处理30~40 m in,COD去除率可达90%以上。 相似文献
76.
Fenton 试剂降解壳聚糖废液的初步研究 总被引：1，自引：0，他引：1
通过单因素分析实验 ,研究了 Fenton试剂降解壳聚糖制备废液过程中各影响因子的作用机制 ,初步得出了其最佳作用范围。通过正交匹配实验 ,确定了最佳操作条件为 :初始 p H=2 .5,终了p H=1 0 ,1 0 g Fe/ L的 Fe2 溶液 1 5m L,30 % H2 O2 2 m L,t(搅拌 ) =80 min,t(静置 ) =8h,T=348K,经验证 COD去除率达到 58.91 %。在常温下 ,利用紫外扫描法简单分析了 Fenton试剂对醋酸钠难降解有机物的降解效率 ,达到了 1 6.39%。 相似文献
77.
78.
羧甲基壳聚糖水凝胶制备及在药物控释中的应用 总被引：8，自引：0，他引：8
研究羧甲基壳聚糖水凝胶(CMCS-GA)对阿司匹林的吸附性能及其在药物控释系统中的应用。以羧甲基壳聚糖作为骨架材料,采用戊二醛交联法制备CMCS-GA,进而制备阿司匹林载药凝胶。测定凝胶在人工肠液中的溶胀动力学特点,观察载药凝胶在人工肠液中的体外释放行为。在pH=7.4的人工肠液中CMCS-GA 2 h达最大溶胀度1.38。CMCS-GA的载药量为4.6 mg/g,凝胶在人工肠液中96 h的累积释放度为99.91%,具有优良的缓释性能,药物的体外释放模型符合一级动力学方程。 相似文献
79.
甲壳素是一种天然高分子多糖，具有与纤维素相近的骨架结构，其资源丰富，用途广泛(方波，1998)。但由于分子内和分子间存在很强的氢键作用力，因而不能熔融，也不溶于普通溶剂(如水、乙醇等)(董炎明等，2002)，实际应用中较多的是其部分或全部脱乙酰化产物——壳聚糖。壳聚糖虽然可以溶于酸性水溶液，但不能直接溶于水中，且在酸性水溶液中不稳定，也不溶于一般的有机溶剂，这在很大程度上限制了它的应用(董炎明等，2002)。所以，水溶性壳聚糖衍生物的研制正成为一个新的研究方向。壳聚糖分子中C2位上的-NH2，C3、C6位上的-OH，均具有较强的反应活性，在适当条件下可进行多种化学修饰，如酰基化、羧烷基化、硫酸酯化、烷基化、羟烷基化及氰烷基化等。引入上述功能性基团，可增加壳聚糖的溶解性和功能性，拓宽了壳聚糖的应用范围。这些衍生物的制备研究已成为壳聚糖应用开发的主要方向之一。 相似文献
80.
Reliable methods have been developed for the quantitative estimation of chitin, chitosan and chitin deacetylase in sediment samples, as well as two methods for the estimation of chitinase in these samples. The differing substrates used in the latter two methods have produced distinct ‘depth profiles’ for chitinase activity which suggest the presence of more than one chitinolytic system in the sediments of the Ythan estuary. Studies on the mineralization of chitin in these sediments have revealed a complex system with a number of unexpected features. The rate of chitin degradation was reduced in late summer, possibly due to the heavy seaweed growth which covers the mud flats at this time, although the potential degradative activities of the enzymes chitinase and chitin deacetylase were higher in summer than in winter. The proportional rates of degradation of chitin, chitosan and cellulose were similar in both the absence and presence of seaweed overgrowth, although the apparent rates of degradation of these substrates were higher in the absence of seaweeds. Core samples have indicated that the major input of chitin to the sediment ecosystem occurs via deposition at the surface, while the input of chitosan (the deacetylated polymer) occurs via its production within the sediment, primarily within the upper 5 cm of sediment. The concentrations of both these polymers decreased sharply below an ‘interface’ between aerobic and anoxic sediments. 相似文献