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排序方式: 共有118条查询结果,搜索用时 31 毫秒
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环境中排放的重金属离子Cu!对水生和陆生生物有强的毒害性。饮用水中Cu!的浓度高于1.0mg·L-1时,将会导致人畜得血色沉着病和胃肠粘膜病[1]。Cu!无法进行生物降解,除去废水中Cu!的常见方法有离子交换、置换、化学沉淀等[2],然而这些方法需要消耗大量的化学试剂,成本高。近来,研 相似文献
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光同时诱导水中Cr(Ⅵ)的还原与橙黄Ⅱ的氧化;染料;橙黄Ⅱ;Cr(Ⅵ);光还原;光降解 相似文献
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Photoreduction of nitro compounds is accompanied by formation of various radical products that can react with the starting
nitro compound, thus causing deviation of the decomposition kinetics from the first-order kinetics with respect to the nitro
compound. The results of quantum chemical modeling of the reactions of nitro compounds with radicals and the pathways of further
transformations of radical adducts formed in the reactions are presented.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 202–206, February, 2006. 相似文献
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G. A. Gaddy J. L. McLain E. S. Steigerwalt R. Broughton B. L. Slaten G. Mills 《Journal of Cluster Science》2001,12(3):457-471
Fibers and films prepared from blends of poly(vinyl alcohol) and poly(acrylic acid) were found to be suitable matrices for the solid-state photoreduction of silver ions in the presence of air. Fast generation of nanometer-sized silver crystallites was observed when fibers of polymer blends crosslinked with dimethyl sulfoxide were irradiated with 350nm light. Optical determinations of the formation kinetics were carried out using thin films of noncrosslinked as well as lightly and heavily crosslinked polymer blends. Small Ag clusters were detected initially, which were stable in the dark but transformed into larger metal particles upon further illumination. Both formation processes occurred only under high light intensity illumination and the kinetic data were inconsistent with monophotonic mechanisms. 相似文献
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Chesnokov S. A. Cherkasov V. K. Abakumov G. A. Kurskii Yu. A. Shurygina M. P. Mamysheva O. N. Shavyrin A. S. 《Russian Chemical Bulletin》2003,52(3):718-724
Photoreduction of o-benzoquinones in the presence of p-bromo-N,N-dimethylaniline under irradiation ( > 500 nm) affords the corresponding pyrocatechols and hydroxyphenyl ethers. The latter are unstable and, in turn, decompose in the dark reaction to pyrocatechols. The ratio between pyrocatechol and hydroxyphenyl ether formed upon the photoreaction is determined by the structure of o-quinone, namely, the presence and bulk of substituents in positions 3 and 6 of the ring. The yield of pyrocatechol is maximal (60—65%) if the substituents are the same (H and H, But and But) or insignificantly differ (Pri and But), regardless of its bulk. 相似文献
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Dr. Sara Realista Janaína C. Almeida Sofia A. Milheiro Dr. Nuno A. G. Bandeira Dr. Luis G. Alves Dr. Filipe Madeira Prof. Dr. Maria José Calhorda Dr. Paulo N. Martinho 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(50):11670-11679
Three CoII octaazacryptates, with different substituents on the aromatic rings (Br, NO2, CCH), were synthesised and characterised. These and the already published non-substituted cryptate catalysed CO2 photoreduction to CO and CH4 under blue visible light at room temperature. Although CO was observed after short irradiation times and a large range of catalyst concentrations, CH4 was only observed after longer irradiation periods, such as 30 h, but with a small catalyst concentration (25 nm ). Experiments with 13C labelled CO2 showed that CO is formed and reacts further when the reaction time is long. The CCH catalyst is deactivated faster than the others and the more efficient catalyst for CH4 production is the one with Br. This reactivity trend was explained by an energy decomposition analysis based on DFT calculations. 相似文献
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二氧化碳(CO2)光催化还原技术因兼具解决能源和全球变暖问题的潜力而受到关注。金属铁络合物作为分子型催化剂,具有价格低廉、量子效率高、结构可调控和选择性好等优势,表现出优异的CO2光催化还原性能,成为CO2光催化还原领域的研究热点。本文综述了近年来基于金属铁络合物光催化二氧化碳还原研究进展。介绍了铁金属络合物(如:铁卟啉、铁多吡啶、五齿铁配合物)CO2均相光催化还原体系,总结了体系的构成以及作用机理等,着重关注了体系的催化效率和产物的选择性。此外,综述了以半导体纳米材料/量子点作为光敏剂,金属铁络合物作为催化剂的非均相催化体系的研究进展。最后,对该领域未来的研究方向和所面临的挑战做出展望。 相似文献