排序方式: 共有52条查询结果,搜索用时 15 毫秒
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在此以ZnFe2O4为磁性内核,利用液体石蜡作有机分散介质、甲醛、戊二醛作交联剂,通过反相悬液交联法制备出了单分散、窄分布的磁性ZnFe2O4壳聚糖核壳微球,并利用其吸附作用来处理苯酚废水溶液,同时使用紫外分光光度计来测其吸光度的变化.分吸附剂的投加量,pH值的变化,吸附时间不同的3种情况来讨论. 相似文献
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壳聚糖季铵盐的合成及其絮凝性能 总被引:39,自引:0,他引:39
对壳聚糖进行季铵化改性制得壳聚糖季铵盐,用于味精废水的絮凝实验证明了其絮凝性能较壳聚糖好,投药量低,pH值适用范围宽,絮体沉降快且含水率低,是一种具有良好反应活性的高分子絮凝剂。 相似文献
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Using chitosan modified soil to flocculate and sediment algal cells has been considered as a promising strategy to combat cyanobacteria blooms in natural waters. However, the flocculation efficiency often varies with algal cells with different zeta potential (ZP) attributed to different growth phases or water conditions. This article investigated the relationship between ZP of Microcystis aeruginosa and its influence to the flocculation efficiency using chitosan modified soil. Results suggested that the optimal removal efficiency was obtained when the ZP was between -20.7 and -6.7 mV with a removal efficiency of more than 80% in 30 min and large floc size of >350 μm. When the algal cells were more negatively charged than -20.7 mV, the effect of chitosan modified soil was depressed (<60%) due to the insufficient charge density of chitosan to neutralize and destabilize the algal suspension. When the algal cells were less negative than -6.7 mV or even positively charged, a small floc size (<120 μm) was formed, which may be difficult to sink under natural water conditions. Therefore, manipulation of ZP provided a viable tool to improve the flocculation efficiency of chitosan modified soil and an important guidance for practical engineering of cyanobacteria bloom control. 相似文献
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冻干壳聚糖微球固定化纤维素酶的研究 总被引:2,自引:0,他引:2
分别以冻干壳聚糖微球和湿壳聚糖微球为载体,戊二醛为交联剂进行纤维素酶的固定化研究,并对2种固定化酶的热稳定性、米氏常数、重复利用次数、pH值加以对比分析。确定酶固定化的适宜条件为:0.03g冻干壳聚糖微球与10mL4g/L戊二醛交联4h后,加入10mg酶固定2h,酶活力回收率为96.3%;0.1g湿壳聚糖微球与10mL 2g/L戊二醛交联2h后,加入6mg酶固定4h,酶活力回收率为62.4%。与游离酶相比,2种固定化酶的米氏常数均降低;具有很好的热稳定性;最适酶解温度分别为60℃,50℃;酶解反应适宜pH范围3.0—4.0,最适pH值均向酸性方向移动。冻干载体更易与酶分子结合,酶活力回收率高于湿载体固定化酶。 相似文献
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Piotr Rychter 《Journal of environmental science and health. Part. B》2013,48(8):681-692
Although there are many reports on the dangers posed by glyphosate, this herbicide is still one of the most popular and widely used total weed killers. Therefore, great effort should be made to minimize exposure to this herbicide and limit its losses into the environment. The aim of this study was to prepare a new formulation consisted of various molecular weight chitosans with glyphosate and their evaluation toward active substance release, phytotoxicity, and preliminary herbicidal efficiency. The phytotoxicity study of the obtained chitosan/glyphosate formulations was determined based on the Organisation for Economic Co-operation and Development 208 guideline. Among all tested formulations evaluated for phytotoxicity, that containing the highest molecular weight of chitosan was found to be the least toxic, showing simultaneously the most effective herbicidal activity against selected weeds. The release rate of glyphosate from the obtained formulations was dependent on the molecular weight and viscosity of chitosan. 相似文献
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壳聚糖双冠醚的合成及其对金属离子的吸附性能研究 总被引:9,自引:0,他引:9
将二苯并16-冠-5氯代乙酸酯冠醚分别接枝到西佛碱型壳聚糖冠醚CT-15C和CT-18C上,制备了1,4-壳聚糖双冠醚CT-15CAC和CT-18CAC,经元素分析、FT-IR红外光谱分析和X-射线粉末衍射分析表征了结构。研究了CT-15CAC和CT-18CAC对Pd^2 、Ag^ 、Pt^4 、Au^3 、Cu^2 、Hg^2 的静态吸附性能,并与CT-15C和CT-18C进行了比较。结果表明,这4种吸附剂对贵金属离子如Au^3 、Ag^ 、Pt^4 、Pd^2 都具有较好的吸附性能,并能在Cu^2 和Hg^2 共存的条件下选择吸附Pd^2 ,而且壳聚糖双冠醚CT-15CAC和CT-18CAC比壳聚糖单冠醚CT-15C和CT-18C具有更好的选择性。 相似文献
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Santosh Kumar Mohmmad Y. Wani Joonseok Koh João M. Gil Abilio J.F.N. Sobral 《环境科学学报(英文版)》2018,30(7):77-84
One of today's major challenges is to provide green materials for a cleaner environment. We have conducted studies on carbon dioxide(CO2) adsorption and conversion to valuable products by an ecofriendly approach based in chitosan/graphene oxide(CSGO) nanocomposite film. Rheological behavior indicates that the CSGO has a better solvation property than the pure chitosan. An adsorption capacity of 1.0152 mmol CO_2/g of CSGO nanocomposite at4.6 bar was observed. The catalytic behavior of the CSGO nanocomposite in the presence of tetra-n-butylammonium iodide(n-Bu4 NI) as co-catalyst was evaluated for the cycloaddition of CO_2 to epoxides, to give cyclic carbonates, in the absence of any solvent. These results strongly suggest that the CSGO nanocomposite may open new vistas towards the development of ecofriendly material for catalytic conversion and adsorption of CO_2 on industrial scale. 相似文献