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721.
采用纳米TiO2光催化与生物降解相结合的方法,考察了3种1,3-二烷基咪唑类氯型离子液体的降解过程,并用HPLC-MS方法鉴定了光催化降解的碎片和可能的结构。结果表明,在相同条件下3,种离子液体光催化降解的速率次序为1-丁基-3-甲基咪唑氯盐(BmimCl)〉1-己基-3-甲基咪唑氯盐(HmimCl)≈1-辛基3-甲基咪唑氯盐(OmimCl)。BmimCl的光催化降解曲线符合一级动力学方程,最佳催化剂用量为0.5 g/L。HPLC-MS分析表明,光催化降解是咪唑开环氧化的过程,生成众多部分氧化碎片。离子液体水溶液的光催化预处理有利于提高其后续的活性污泥生物降解性能。 相似文献
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Lihua Pang Qianhui Lin Shasha Zhao Hao Zheng Chenguang Li Jing Zhang Cuizhu Sun Lingyun Chen Fengmin Li 《Frontiers of Environmental Science & Engineering》2023,17(8):94
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Shengqi Zhang Qian Yin Siqin Wang Xin Yu Mingbao Feng 《Frontiers of Environmental Science & Engineering》2023,17(7):91
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Zhonglan Yang Lingyu Bai Shiming Su Yanan Wang Cuixia Wu Xibai Zeng Benhua Sun 《环境科学学报(英文版)》2021,33(2):43-50
During the aging process, ferrihydrite was transformed into mineral mixtures composed of different proportions of ferrihydrite, goethite, lepidocrocite and hematite. Such a transformation may affect the fixed ability of arsenic. In this study, the stability of Fe-As composites formed with As(V) and the minerals aged for 0, 1, 4, 10 and 30 days of ferrihydrite were systematically examined, and the effects of molar of ratios Fe/As were also clarified using kinetic methods combined with multiple spectroscopic techniques. The results indicated that As(V) was rapidly adsorbed on minerals during the initial polymerization process, which delayed both the ferrihydrite conversion and the hematite formation. When the Fe/As molar ratio was 1.875 and 5.66, the As(V) adsorbed by ferrihydrite began to release after 6 hr and 12 hr, respectively. The corresponding release amounts of As(V) were 0.55 g/L and 0.07 g/L, and the adsorption rates were 92.43% and 97.50% at 60 days, respectively. However, the As(V) adsorbed by the transformation products aged for 30 days of ferrihydrite began to release after adsorbed 30 days. The corresponding release amounts of As(V) were 0.25 g/L and 0.03 g/L, and the adsorption rates were 84.23% and 92.18% after adsorbed 60 days, for the Fe/As=1.875 and 5.66, respectively. Overall, the combination of As(V) with ferrihydrite and aged products transformed from a thermodynamically metastable phase to a dynamically stable state within a certain duration. Moreover, the aging process of ferrihydrite reduced the sorption ability of arsenate by iron (hydr)oxide but enhanced the stability of the Fe-As composites. 相似文献
728.
Zhe Zhang Yue Zhang Dong C. Yang 《Journal of environmental science and health. Part. B》2018,53(7):476-485
To investigate the degradation activity of the manganese ABC transporter, vegetative catalase 1 and acetoin dehydrogenase E1 from Bacillus subtilis YB1, the proteins were prokaryotically expressed and purified. Assay results showed that the three enzymes were able to degrade nicosulfuron (2- (4,6-dimethoxypyrimidine-2-pyrimidinylcarbamoylaminosulfonyl) -N,N-dimethylnicotinamide), with vegetative catalase 1 exhibiting the highest activity. To further examine the degradation pathway, the degradation products of the three enzymes and the YB1 strain were detected by liquid chromatography-mass spectrometry(LC-MS). The nicosulfuron degradation products of the three enzymes were consistent with those of the YB1 strain, indicating the presence of two pathways: one due to cleavage of sulfonylurea bridges and ring-opening of 1-(4,6-dimethoxy-pyrimidin-2-yl)-3-(2-methyliminomethanesulfonyl-acetyl)-ureaas the pyrimidine ring, yielding the product; and the another due to cleavage of a sulfonylurea bridge, yielding 4,6-dihydroxy pyrimidine (111 m/z), 2-ylamine ?4,6-dimethoxy pyrimidine and ((4-(dimethycarbamoyl)pyridine-2-yl)sulfonyl)carbamic acid as products, which were further degraded to 4,6-dihydroxy pyrimidine and N,N-dimethyl-2-sulfamoyl-isonicotinamide. The above results reveal a major contribution of extracellular enzymes to the degradation of nicosulfuron by the YB1 strain. Our data help in elucidation of the mechanism of nicosulfuron bio-degradation and may facilitate the construction of engineered strains. 相似文献
729.
城市污水中有关新型微污染物PPCPs归趋研究的进展 总被引:7,自引:0,他引:7
药品和个人护理用品 (PPCPs) 是最近十年引起关注的新型有机微量污染物,其引起的环境安全风险受到人们越来越多的关注。一些研究发现,城市污水处理厂出水中存在着一定浓度的PPCPs,城市污水排放是PPCPs进入环境的一条重要途径。从城市污水中PPCPs的分析方法、迁移转化和减量化技术研究等三个方面综述了有关PPCPs在城市污水中归趋的研究进展,介绍了我国城市污水中PPCPs的研究现状;并对在我国进行相关研究提出了建议,以期推动相关研究的开展。 相似文献
730.