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91.
Salbutamol is a potent β2-adrenergic receptor agonist widely used in the treatment of bronchial asthma and chronic obstructive pulmonary disease. An increasing number of studies have detected salbutamol in natural water systems worldwide. Studies have shown that sunlight degrades salbutamol resulting in the formation of products; some showing higher toxicity to bacteria Vibrio fischeri than the parent compound. In this contribution, steady-state absorption and emission techniques, high-performance liquid chromatography, and transient absorption spectroscopy are used to investigate the photochemistry of salbutamol in aqueous buffer solutions at controlled pH values. Ground- and excited-state calculations that include solvent effects are performed to guide the interpretation of the experimental results. Salbutamol is sensitive to UVB light absorption in the pH range from 3 to 12, forming products that absorb light at longer wavelengths than the parent compound. Quantum yields of degradation reveal that the deprotonated species is 10-fold more photo-active than the protonated species. In line with this result, the fluorescence quantum yield of the protonated species is more than an order of magnitude higher than that of the deprotonated species. Transient absorption spectroscopy shows that population of the triplet state occurs with a rate constant of 7.1 × 108 s−1 in the protonated species, while a rate constant of 1.7 × 1010 s−1 is measured for the deprotonated species. While degradation of the deprotonated species is not affected by the presence of molecular oxygen, a twofold increase in the photodegradation yield of the protonated species in air-saturated conditions is observed. 相似文献
92.
以制药工业综合废水处理为例对其采用的两级水解酸化复合好氧工艺的处理效果进行评估。按常规指标进行评估,该工艺对于制药综合废水的处理效果达到了设计目的,COD去除率可达到78.2%以上,NH+4-N的去除率达到99.3%,出水质量基本满足"污水综合排放标准(GB8978-1996)"二级标准和"辽宁省污水综合排放标准(DB21.1627-2008)";急性毒性的检测表明,经过该工艺处理后出水为低毒性;三维荧光谱分析(EEM)表明,制药综合废水经生物处理后的可溶性有机物中仍然存在难降解物质,建议增加物化处理以提高处理效果;并且制药废水经处理后的出水中的盐度对排入的生态系统存在风险,建议纳入排放标准以加强管理。 相似文献
93.
磁性生物膜载体的规模化制备、表征和应用 总被引:1,自引:0,他引:1
利用机械力化学表面改性原理设计了卧式双旋搅拌混合反应设备,通过磁铁矿粉和适量浓硫酸的球磨混合反应制备得到磁性生物膜载体,其XRD、IR、SEM和BET表征分析结果表明,磁性生物膜载体表层生成了多羟基硫酸铁为主的活性组分.进而在膜生物反应器实验装置中投加磁性生物膜载体进行了中试实验,结果表明,磁性生物膜载体能与活性污泥中的微生物聚合形成稳定的菌胶团,活性污泥SV30从实验初期89%降到了稳定期的39%,此外,磁性生物膜载体还具有稳定膜生物反应池出水COD,强化脱氮除磷的能力. 相似文献
94.
Although marine and terrestrial emissions simultaneously affect the formation of atmospheric fine particles in coastal areas, knowledge on the optical properties and sources of water-soluble matter in these areas is still scarce. In this work, taking Qingdao, China as a typical coastal location, the chemical composition of PM2.5 during winter 2019 was analyzed.Excitation-emission matrix fluorescence spectroscopy was combined with parallel factor analysis model to explain the component... 相似文献
95.
96.
对灾害研究中几个问题的思考 总被引:2,自引:1,他引:1
对灾害研究中有关的几个问题进行了探讨。认为: 灾害学是最重要的自然社会科学; 人文灾害比自然灾害更具毁灭性; 研究人文灾害中的公路交通事故、核战争问题、人口问题、环境污染问题等具有重要的现实意义和深远的历史意义。 相似文献
97.
Faezeh Ghanati Parviz Abdolmaleki Majid Vaezzadeh Elham Rajabbeigi Mohammad Yazdani 《The Environmentalist》2007,27(4):429-434
In the present research, the effects of static magnetic field, with or without iron on the growth, the activity of certain
enzymes (like polyphenol oxidase and phenyle alanine ammonialyase), the content of phenolic compounds and the essential oil
composition of sweet basil (Ocimum basilicum) were studied. Treatment of plants with static magnetic field with or without iron led to decrease of the growth of plants
as well as decrease in the activity of phenyle alanine ammonialyase and of phenolic compounds content. In addition in those
plants exposed to magnetic field the amount of essential oils, notably of methyl chavicol, was increased. Exposure of plants
to the magnetic field decreased the activity of polyphenol oxidase, whereas treatment of plants with iron when exposed to
magnetic field increased polyphenol oxidase activity. In this group the content of essential oil was reduced. 相似文献
98.
Ashok Kumar Pandey Shri Dhar Pandey Virendra Misra P. N. Viswanathan 《Chemistry and Ecology》1999,16(4):269-282
In order to investigate the role of functional groups present in humic acid(s) (HA) during complex formation, water soluble complexes between HA isolated from soil and metals (Pb, Ca, As, Ni, Cr, Co, Cu, Cd, Fe, Mn, Mg and Zn) were prepared and subjected to infrared (IR) spectroscopy. the IR data revealed the involvement of the - OH group of humic acid in complex formation with all metals except copper and arsenic, whereas the - COOH group of HA was found to be the preferred site of binding for all the metals. the significance of findings in relation to detoxification of environmental pollutants is discussed in this paper. 相似文献
99.
Mauro Mecozzi Demetria Cardarilli Eva Pietrantonio Marina Amici 《Chemistry and Ecology》2001,17(4):239-254
In this paper a method for the study of the qualitative similarity of extractable humic substance (EHS) in marine sediments based on the realisation of UV spectral library of EHS is described. the spectral library was built including the digitised spectra of humic substance extracted from several marine sediments (46 samples) and two samples of standard materials (lignin sulphonate and humic substance) in a Statistica data file. the data matrix was elaborated by means of different multivariate statistic techniques such as Cluster Analysis (CA), Principal Components Analysis (PCA) and the univariate technique Spectral Correlation Analysis (SCA). This approach allows us to show the contribution of different organic compounds (aromatic, lipid and acid) to the composition of EHS and moreover it evidences also the structural characteristics of EHS in terms of similarities in the qualitative composition of samples such as presence of terrestrial and/or vegetal contributions. the UV library is an objective tool to study the qualitative composition of EHS and it represents a complementary approach to the most common methods based on the application of spectroscopic (IR, 13CNMR), potentiometric and chromatographic techniques. 相似文献
100.
As uranium has practically no other industrial uses besides electricity generation, demand is determined by the requirements and stockpiling policies of electric utilities. The uranium market has experienced strong fluctuations and is currently affected by the reductions in nuclear forecasts resulting from the slowdown in electricity demand. Analysing supply/demand indicators proves, however, that in retrospect the development has been relatively smooth and it appears that oversupply is more a consequence of overly optimistic short-term expectations. In the future, especially in the long term, nuclear power policies continue to be concerned with striking a proper balance between increasing production capability and development of new reactor technologies which would be less dependent on the availability of uranium. A bounding scenario approach is applied in this article to the assessment of adequacy of supply under varying assumptions on the total installed nuclear capacity, available resource base and attainable production capability. 相似文献