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针对氨氮排放对环境造成的污染以及给人类带来的危害这一问题,将分子筛吸附与膜技术相结合,以13x分子筛为功能颗粒,以聚醚砜(PES)为膜的基质材料,以二甲基乙酰胺(DMAc)为溶剂,通过相转化法制备了不同13x分子筛填充量的13x/PEs膜吸附剂。研究发现,随着13x分子筛填充量的增加,膜的指状孔变得细密、短小,其吸附容量,断裂强度都在增加,但是水通量逐渐降低。料液温度与pH值对吸附性能的影响表明,该膜吸附剂在293K,pH=7时对氨氮有较好的吸附容量,可达21.69mg/g;吸附热力学研究表明,该类型膜吸附剂对氨氮的吸附等温线符合Langmuir方程。 相似文献
385.
选取白洋淀的沼泽区(烧车淀)与开阔水域区(采蒲台)为研究区域,分析了水体中新生沉降颗粒物组分组成、沉降通量及其来源.结果表明,两种典型水域中水体颗粒物组分差异显著,其中,烧车淀水域颗粒物成分以有机质(OM)为主,质量占比达到49.59%~74.14%;而采蒲台水域颗粒物以无机组分为主,占比为54.52%~79.27%.烧车淀沉降颗粒物中总碳(TC)、总氮(TN)含量分别为(221.16±39.73)g·kg-1和(21.10±1.67)g·kg-1;采蒲台沉降颗粒物中TC和TN的含量分别为(172.28±91.22)g·kg-1和(15.72±8.12)g·kg-1.由固相13C CP/MAS NMR光谱结果分析出白洋淀沉降颗粒物中碳组分以烷基碳、烷氧基碳为主,其中,烧车淀淀面水域颗粒物中以易分解碳烷氧基碳为主(65.65%),采蒲台淀面水域颗粒物中以较稳定烷基碳为主(50.76%).开阔水域区颗粒物沉降通量高于沼泽化区,均值分别为10.63 g·m-2·... 相似文献
386.
During the past five years, industry analysts have proclaimed that metal prices are in the early phase of a ‘super cycle,’ driven primarily by Chinese industrial expansion. Academic economists have generally been very skeptical about the presence of long cycles. A time-series econometric analysis by Cuddington and Jerrett [2008. Super cycles in real metals prices? IMF Staff Pap. 55(4), in press], however, has used band-pass filtering techniques to isolate super cycles in the prices of six metals traded on the London Metal Exchange (the ‘LME6’). This paper extends the search for super-cycle behavior to three additional metal products that are critical in the early phases of industrial development and urbanization: steel, pig iron, and molybdenum (a key ingredient in many steel alloys). There is strong evidence of super cycles in these three metals, although their timing differs to some extent from the super cycles found for the LME6. 相似文献
387.
利用13X沸石分子筛净化含NH+4-N废水的实验研究 总被引:1,自引:0,他引:1
研究了13X沸石分子筛在静态和动态条件下对中低浓度含NH+4-N废水的吸附性能,包括影响吸附的主要因素、沸石对NH+4-N的吸附效果和沸石的再生等。静态实验结果表明,pH值为6.5~7.5,吸附时间35 min,吸附温度20~30℃的条件下,沸石对50 mL NH+4-N初始浓度(C0)为80 mg/L的废水吸附效果最佳,吸附过程符合Langmuir型吸附等温式,饱和吸附量为8.61 mg/g。动态条件下,随水力停留时间增加,沸石对NH+4-N的吸附量上升,最大饱和吸附量可达24.20 mg/g,吸附过程符合Thomas吸附模型。直接焙烧法对吸附后的沸石进行再生活化处理效果良好。实验证明,利用13X沸石净化中低浓度含NH+4-N废水具有良好的工业化应用前景。 相似文献
388.
José Delcán María Orera Rafael Linares Dolores Saavedra Angustias Palomar 《黑龙江环境通报》2004,24(8):635-637
We report a 16-week-gestation foetus obtained by voluntary abortion after prenatal diagnosis, in which a ring chromosome 22 was observed with deletion of the 22q13.3 region. A prenatal study of the amniotic fluid by standard chromosome technique with G bands and FISH (fluorescence in situ hybridisation) was performed. After the abortion, the anatomopathological study of the obtained foetus was carried out. Morphological and histological analysis of the foetus did not reveal severe physical abnormalities, although alterations of the nervous system were observed consisting of corpus callosum, fornix and septum pellucidum agenesia. It could be that the genes in this region that were involved in the development of the central nervous system were responsible for the alterations found in the morphological study. The wide range of manifestations observed in patients with this cytogenetic alteration is probably due to size differences in the deleted region. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
389.
A pregnant woman has two children affected by moderately severe Hb H disease due to compound heterozygosity of South-east Asian deletion and Constant Spring mutation. In her third pregnancy, transabdominal chorionic villus sampling was performed at the tenth gestational week to obtain fetal DNA. The polymerase chain reaction was used for detection of both the South-east Asian deletion and the Constant Spring mutation. Hb H disease was diagnosed in the fetus. After genetic counselling, the couple elected to have the pregnancy terminated. 相似文献
390.