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Nanoscale bimetallic Ni/Fe particles were synthesized from the reaction of sodium borohydride (NaBH4) with reduction of Ni^2+ and Fe^2+ in aqueous solution. The obtained Ni/Fe particles were characterized by TEM (transmission electron microscope), XRD (X-ray diffractometer), and N2-BET. The dechlorination activity of the Ni/Fe was investigated using p-chlorophenol (p-CP) as a probe agent. Results demonstrated that the nanoscale Ni/Fe could effectively dechlorinate p-CP at relatively low metal to solution ratio of 0.4 g/L (Ni 5 wt%). The target with initial concentration ofp-CP 0.625 mmol/L was dechlorinted completely in 60 rain under ambient temperature and pressure. Factors affecting dechlorination efficiency, including reaction temperature, pH, Ni loading percentage over Fe, and metal to solution ratio, were investigated. The possible mechanism of dechlorination ofp-CP was proposed and discussed. The pseudo-first- order reaction took place on the surface of the Ni/Fe bimetallic particles, and the activation energy of the dechlorination reaction was determined to be 21.2 kJ/mol at the temperature rang of 287-313 K. 相似文献
113.
Chunyan Yu Hua Wang Xuan Liu Xie Quan Shuo Chen Jianlin Zhang Peng Zhang 《环境科学学报(英文版)》2014,26(7):1383-1388
To elucidate the effect of nitrite ion (NO2^-) on the photodegradation of organic pollutants, a 300 W mercury lamp and Pyrex tubes restricting the transmission of wavelengths below 290nm were used to simulate sunlight, and the photodegradation processes of 2,4-dichlorophenoxyacetic acid (2,4-D) with different concentrations of NO2^- in freshwater and seawater were studied. The effect of reactive oxygen species (ROS) on the photolysis of 2,4-D was also demonstrated using electron paramagnetic resonance (EPR). The results indicated that the 2,4-D photolysis reaction followed the first-order kinetics in freshwater and seawater under different concentrations of NO2^-. Meanwhile, the photochemical reaction rate of 2,4-D increased with increasing concentration of NO2^-. When the concentration of NO2^- was lower than 23 mg/L, the photodegradation rate of 2,4-D in seawater was higher than that in freshwater. However, when the concentration of NO2^- was reached 230 mg/L, 2,4-D degradation slowed down in seawater. It was important to note that EPR spectra showed NO2 radical was generated in the NO5 solution under simulated sunlight irradiation, indicating that 2,4-D photodegradation could be induced by NO2. These results show the key role of NO2^- in photochemistry and are helpful for better understanding of the phototransformation of environmental contaminants in natural aquatic systems. 相似文献
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甘油投加对餐厨垃圾厌氧产酸性能的影响 总被引:1,自引:0,他引:1
餐厨垃圾厌氧发酵产生的挥发性脂肪酸(VFAs)可以作为合成聚羟基脂肪酸酯(PHA)的底物,PHA的性能与VFAs的组成密切相关.为改善PHA产品的性能,本文研究了甘油投加对餐厨垃圾产酸性能的影响.在餐厨垃圾厌氧消化半连续流反应器运行稳定的基础上,探讨了不同C/N对厌氧发酵有机物转化及VFAs产量和组成的影响.结果表明,投加甘油会降低发酵体系的pH,提高VFAs的产量,相比于对照组,C/N比为25/1时,VFAs产量提高了10.3%.C/N10.69/1(对照组)、15/1、20/1和25/1时,发酵液奇数碳VFAs所占总VFAs的比例分别为54.23%、61.16%、64.78%和66.79%.甘油的投加可以提升丙酸、戊酸等奇数碳VFAs所占比例,有利于改善PHA产品性能. 相似文献
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<正>蜂蜜"食疗"在我国已有几千年的历史。新鲜成熟的蜂蜜可直接服用,也可将其配成水溶液,因为水溶液比纯蜂蜜更易吸收。喝蜂蜜水有着抗菌消炎、促进组织细胞再生,促进消化,改善睡眠,提高免疫力等多方面作用。不过,喝蜂蜜水也有禁忌,喝不对小心惹病伤身。空腹不宜饮用蜂蜜水蜂蜜水中含有相应的糖分,不是以单纯水的形式存在。这些糖分有增加胃酸分泌的作用,胃酸过多对于胃黏膜有损伤。长期空腹喝蜂蜜水,容易使体内酸性增加, 相似文献
118.
Hailin Wang Haoqing Tang Zhaotie Liu Xin Zhang Zhengping Hao Zhongwen Liu 《环境科学学报(英文版)》2014,26(9):1879-1884
Montmorillonite (MMT) modified with chitosan (CTS, molecular weight = S x 104) was applied to remove heavy metal cations by using Co2+ as a model ion. An increase in MMT interlayer distance observed from X-ray diffraction indicates the intercalation of CTS into MMT. Together with the results of scanning electron microscopy and Fourier transform infrared spectroscopy, it was concluded that the composite material of CTS and MMT (CTS-- MMT) was prepared successfully. The mass ratio of CTS to MMT had a strong influence on the adsorption performance of CTS-MMT. The highest adsorption value of 150 mg/g was obtained over the composite material with CTS to MMT mass ratio of 0.25, which is much higher than those reported in other studies. The adsorption isotherms and kinetic results indicated that Co2+ was adsorbed over CTS-MMT in a multilayer model, and the chemical sorption of Co2+ was determined to be the rate-limiting step. 相似文献
119.
Yuhshan Ho 《环境科学学报(英文版)》2014,26(12):2571-2572
Recently, ling et al. (2013) published the paper entitled as above. In Section 2.3, Adsorption kinetics of MBT, authors noticed that "The pseudo first-order kinetic model (Eq. (1)) and the pseudo second-order kinetic model (Eq. (2))" were used (Do,an et al., 2007; Eftekhari et al., 2010): 相似文献
120.
不同磷源及其浓度对铜绿微囊藻生长和产毒的影响 总被引:1,自引:1,他引:0
研究了以低浓度磷酸氢二钾和β-甘油磷酸钠为外加磷源时铜绿微囊藻生长及藻毒素产生的规律.通过分析铜绿微囊藻生长过程中细胞数量、培养基和藻细胞中总磷含量、培养基pH及微囊藻毒素-LR和微囊藻毒素-RR的含量,确定了2种磷源对铜绿微囊藻生长及胞内藻毒素含量的变化规律.结果显示,以β-甘油磷酸钠为磷源时,培养过程中藻细胞数及藻细胞内毒素含量均低于以磷酸氢二钾为磷源时的藻细胞数及藻细胞内毒素含量,表明在低浓度范围内磷酸氢二钾比β-甘油磷酸钠更能促进藻的生长,同时也能促进胞内藻毒素的生成. 相似文献