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In aqueous solution [2-(diethylamino)ethyl]dextran hydrochloride (EA) was reacted with potassium metaphosphate (MPK) to form a series of water-insoluble macromolecular complexes (MC) at different hydrogen-ion concentrations (EA–MPK system). EA was also reacted with MPK in the presence of CaCl2 (EA–MPK–CaCl2 system). The structure and properties of MC obtained were compared with each other; elemental analysis, IR spectroscopy, solubilities, thermogravimetric analysis, and scanning electron microscopy were used to characterize these complexes. The molecular structure and properties of each MC were dependent on the hydrogen-ion concentration and whether the Ca2+ ion coexisted. It was suggested that MC prepared at acidic pH were composed of a relatively loose network including a small quantity of MPK, whereas those prepared at neutral and alkaline pH were composed of a relatively tight network including a large quantity of MPK. This seemed to be due to changes in the degree of dissociation and the conformation of EA and MPK with the hydrogen-ion concentration. MC in the EA–MPK–CaCl2 system were supposed to have a rather tightly bound network structure due to the Ca2+ ion as compared with those in the EA–MPK system. © 1993 John Wiley & Sons, Inc. 相似文献
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Corina Mihut Dinyar K. Captain Francis Gadala‐Maria Michael D. Amiridis 《Polymer Engineering and Science》2001,41(9):1457-1470
Large amounts of post‐consumer carpet are discarded every year. Most of this waste is currently landfilled, while a small percentage is incinerated. The face carpet fibers, consisting primarily of nylon 6 and nylon 6,6, represent the majority component in the carpet waste. Recent financial incentives and environmental constraints have motivated the industrial sector to develop recycling strategies for these fibers. Depolymerization into their constituent monomers is the most complex recycling route, but at the same time it produces the most valuable product. A second alternative involves the use of solvents for the extraction of carpet fiber components in their polymeric form. Finally, a third recycling option yields thermoplastic mixtures by melt blending the carpet waste. The recent literature on the recycling of nylon from carpet waste is reviewed in this paper. The paper also includes a section focusing on the current state of carpet recycling at the Industrial level. 相似文献
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生物转化过程具有条件温和、过程绿色、产品高值等优势,是未来废弃物高值化利用的重要途径。塑料是人工合成的有机高分子材料,已作为基础材料融入人类生活的方方面面。而海量剧增的废弃塑料已造成严重的环境污染与资源浪费。由于废弃塑料组分复杂、降解能垒高、胁迫因子多、回收经济性差,单一的生物技术尚无法对其进行即时处理,因此,基于学科交叉与过程集成,综合利用多种废塑料回收技术,建立多元化、个性化、交叉化的塑料回收新路线成为提升我国废弃塑料资源回收与利用水平、发展循环经济的重要途径。本文以生物技术为核心,综述了目前生物-物理、生物-化学以及生物-信息等技术交叉在塑料废弃物回收方面的研究进展,并针对性地分析了学科交叉研究中存在的瓶颈,探讨了未来亟需攻克的技术难点,以期为废塑料的高效回收利用提供新的思路和理论指导。 相似文献
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生物强化技术处理化工碱渣废水 总被引:1,自引:0,他引:1
石油化工行业碱渣废水主要来自乙烯、柴油、汽油、液化气等产品碱洗精制、酸化提酚后的废水,该类废水水质复杂,含盐量和污染物浓度高,含硫化物、酚等有毒有害物质,其处理方法一直是困扰化工行业的一大难题,国内企业通常采用焚烧法、湿式氧化法、罐储滴排进常规污水处理设施等方法进行处理。但几种方法分别存在投资大、处理费用高、设备易腐蚀、易产生二次污染以及对常规污水处理设施造成较大冲击、影响正常处理效果等缺点。QBR生物强化技术不同于普通生物处理工艺,做为一种高效生物处理技术,不仅对碱渣进行高效的无害化处理,还节省了工程的投资及运行费用。 相似文献
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Melter feed viscosity during conversion to glass: Comparison between low‐activity waste and high‐level waste feeds 下载免费PDF全文
Tongan Jin Jaehun Chun Derek R. Dixon Dongsang Kim Jarrod V. Crum Charles C. Bonham Bradley J. VanderVeer Carmen P. Rodriguez Brigitte L. Weese Michael J. Schweiger Albert A. Kruger Pavel Hrma 《Journal of the American Ceramic Society》2018,101(5):1880-1891
During nuclear waste vitrification, a melter feed (a slurry mixture of a nuclear waste and various glass forming and modifying additives) is charged into the melter where undissolved refractory constituents are suspended together with evolved gas bubbles from complex reactions. Knowledge of flow properties of various reacting melter feeds is necessary to understand their unique feed‐to‐glass conversion processes occurring within a floating layer of melter feed called a cold cap. The viscosity of two low‐activity waste (LAW) melter feeds were studied during heating and correlated with volume fractions of undissolved solid phase and gas phase. In contrast to the high‐level waste (HLW) melter feed, the effects of undissolved solid and gas phases play comparable roles and are required to represent the viscosity of LAW melter feeds. This study can help bring physical insights to feed viscosity of reacting melter feeds with different compositions and foaming behavior in nuclear waste vitrification. 相似文献
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废水中EDTA与总重金属含量的同时测定 总被引:2,自引:0,他引:2
在被EDTA和重金属离子污染的废水中,由于它们之间的络合作用,很难用简单的方法测出二者的含量。本文在强酸性和加入助萃络合剂的条件下,使EDTA与重金属离子分离。采用离子缔合萃取法,将水中的重金属离子萃于有机相,用分光光度法可测定出水中EDTA的总浓度。另取一份平行样,加入过量且定量的EDTA标准溶液,同水中未与EDTA络合的重金属离子络合,再进行返滴定。通过萃取与返滴定的巧妙结合,可求出水中重金属离子的总量。本法操作简便、快速,不需大型仪器,特别适合于被EDTA和(或)重金属离子污染的废水测定。 相似文献
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微电解复合工艺处理工业废水的研究进展 总被引:3,自引:0,他引:3
分析了铁屑微电解机理、影响微电解反应效果的主要因素、废水可生化性的提高、微电解复合工艺的研究进展.对于工业废水的处理,以微电解工艺作为预处理工艺,和其他各种生化工艺组成复合工艺,可实现工业废水达标排放的目的. 相似文献
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