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将亚铁离子嵌入Nation膜中利用Fe^3+/Fe^2+光催化降解亚甲基蓝,脱色率达90%。研究探讨了降解亚甲基蓝时H2O2以及pH值的影响。亚甲基蓝光催化降解氧化反应符合一级动力学规律,表观速率常数为0.5689min^-1。 相似文献
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水钠锰矿在自然界分布广泛、容易制备、光谱响应宽,受到越来越多的关注并被应用于环境治理领域。该研究通过电沉积法高效快速制备了水钠锰矿电极,研究其在可见光下对亚甲基蓝的光催化降解效果,通过添加空穴(h+)捕获剂甲酸和羟基自由基(·OH)捕获剂异丙醇分析光催化降解机理。结果表明,通过X射线衍射(XRD)和拉曼光谱证实合成物质为水钠锰矿,并且无其他矿物结晶相。紫外可见漫反射吸收谱显示水钠锰矿电极可吸收300~700 nm的光。通过Tauc方程计算得水钠锰矿电极直接带隙为2.8 V,间接带隙为2.4 V。在1.0 V恒定电压下,黑暗中反应3.5 h后亚甲基蓝的吸附率为11.0%,而光照下亚甲基蓝的降解率为67.0%,并且12h后降解率可达98.5%。光照下亚甲基蓝的降解率显著提高,印证了水钠锰矿具有良好的表面光催化性质。分别向反应体系中添加0.7%的甲酸和1.0 mmol/L的异丙醇后,亚甲基蓝的降解率降低到47.7%和34.6%;经动力学计算得出甲酸对h+的淬灭率为35.944%,异丙醇对·OH的淬灭率为56.760%。通过加入捕获剂发现水钠锰矿主要通过光生h+和·OH对亚甲基蓝进行氧化降解作用,其中·OH的氧化作用强于h+。 相似文献
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多孔TiO2薄膜电极/泡沫镍硬模板制备及其光电催化性能 总被引:1,自引:1,他引:0
以泡沫镍为载体,活性炭为造孔剂,采用硬模板法制备泡沫镍负载多孔TiO2薄膜(Porous TiO,films/foam nicel,PTFN)电极,并利用XRD和SEM等测试手段对其结构进行表征.同时,通过亚甲基蓝溶液的光电催化降解反应,对其光电催化活性进行评价,并探讨阳极偏压、通气速率、亚甲基蓝初始溶液浓度和活性炭造孔剂量对降解效率的影响规律.结果表明:相对于未加模板造孔剂的TiO2薄膜电极的光电催化性能,泡沫镍负载多孔TiO2薄膜具有更好的光电催化性能,原因是高比表面积电极有利于为光电催化提供高浓度的亚甲基蓝分子,使反应速率加快;另外,存在最佳的光电催化降解条件,即当外加阳极偏压为3 V,通气速率为40 L·h-1,n(活性炭造孔剂最):n(前驱体中钛)(即C/Ti)为10%,亚甲基蓝溶液初始浓度为1mg·L-1时,光电催化降解效率最高.同时,研究发现,亚甲基蓝在光电催化降解过程中,通过自由基的氧化发生了C=N键的断裂去甲基化,最后被降解为H2O、CO2和SO42-、NO3-、Cl-离子. 相似文献
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光催化降解亚甲基蓝的影响因素及动力学研究 总被引:1,自引:0,他引:1
进行了亚甲基蓝在硫化镉上的暗吸附反应,并作Langmuir拟合和Freundlich拟合计算其吸附速率常数。通过实验证明硫化镉光催化降解亚甲基蓝符合一级动力学反应。在低光强下,反应速率常数随着光强的增大而增大,两者之间存在显著的线性关系。改变光催化反应温度,计算表观活化能Ea为19.13kJ/mol,证明温度对反应影响较小。 相似文献
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为优化大气细粒子中阴离子表面有机活性物质的亚甲蓝分光光度法和乙基紫分光光度分析法,分别从样品前处理和分析测定两方面对分析方法进行优化,并采用2种优化方案对北京市大气细粒子样品进行分析测定. 结果表明:①2种优化方案的最佳超声提取频率、最佳初始水浴温度和最佳超声提取时间均分别为40 Hz、30 ℃和35 min;②亚甲蓝优化方案的最佳显色剂使用量为0.70 mg,其中中性亚甲蓝和酸性亚甲蓝使用量均为0.35 mg,最佳静置时间为30~45 min;③乙基紫优化方案的最佳显色剂使用量为0.098 mg,最佳静置时间为30 min,最佳辅助性试剂使用量分别为pH=5的醋酸盐缓冲液0.4 mL,乙二胺四乙酸二钠10 μmol,硫酸钠0.25 mmol. 采用2个优化方案测得的北京市大气细粒子样品中ρ(MBAS)(MBAS为亚甲蓝活性物质)和ρ(EVAS)(EVAS为乙基紫活性物质)分别为0.14~0.39和0.14~0.47 μg/m3. 与亚甲蓝优化方案相比,乙基紫优化方案的试验操作更简便、标准曲线线性关系更好,更适合大气细粒子中阴离子表面有机活性物质的测定. 相似文献
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Poly(pheniothiazine) films were prepared on a porous carbon felt (CF) electrode surface by an electrooxidative polymerization of
three phenothiazine derivatives (i.e.,Tthionine (TN), Toluidine Blue (TB) and Methylene Blue (MB)) from 0.1 mol/L phosphate buffer
solution (pH 7.0). Among the three phenothiazies, the poly(TB) film-modified CF exhibited an excellent electrocatalytic activity for
the oxidation of nicotinamide adenine dinucleotide reduced form (NADH) at +0.2 V vs. Ag/AgCl. The poly(TB) film-modified CF
was successfully used as working electrode unit of highly sensitive amperometric flow-through detector for NADH. The peak currents
(peak heights) were almost unchanged, irrespective of a carrier flow rate ranging from 2.0 to 4.1 mL/min, resulting in the measurement
of NADH (ca. 30 samples/hr) at 4.1 mL/min. The peak current responses of NADH showed linear relationship over the concentration
range from 1 to 30 mol/L (sensitivity: 0.318 A/( mol/L); correlation coefficient: 0.997). The lower detection limit was found to be
0.3 mol/L (S/N = 3). 相似文献
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Application of Ruditapes Philippinarum conglutination mud (RPM) for decolorizing synthetic dye solutions was studied. RPM showed good activity for decolorization of Methylene Blue, Crystal Violet, Malachite Green, and Ink Blue. The amount of the RPM had great effect on the decoloration rate of the dye solutions. However, the decoloration rate did not continue to increase when the amount of mud exceeded the optimum dose. The temperature of the dye solution had a remarkable effect on the decolorization rate of Ink Blue solution, but had little effect on the other three dye solutions. The initial pH of the dye solutions evidently affected the decolorization rate of Malachite Green solution, but had less effect on the other three. The decolorization rate of the dye solutions increased significantly with treatment time within 8 hr, but tended to be steady after 8 hr for Methylene Blue, Crystal Violet and Malachite Green solutions, and after 12 hr for Ink Blue solution. The decolorization efficiencies for the four dye solutions under the optimum conditions were all above 90%. Seventeen strains screened from RPM showed flocculation ability for kaolin clay suspension. Out of them, the flocculation rate of strain ZHT3-9 and strain ZHT4-13 were up to 88.14% and 86.01%, respectively. ZHT3-9 was studied, and its decolorization rate for Methylene Blue, Crystal Violet, and Malachite Green reached 90.02%, 89.21%, and 80.29%, respectively. By morphological, physiological and biochemical characteristics analysis and 16S rRNA sequencing, the strain ZHT3-9 was identified as Arthrobacter sp. 相似文献
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A rapid and simple method for determination of persulfate in aqueous solution was developed. The method is based on the rapid reaction of persulfate with Methylene Blue(MB) via domestic microwave activation, which can promote the activation of persulfate and decolorize MB quickly. The depletion of MB at 644 nm(the maximum absorption wavelength of MB) is in proportion to the increasing concentration of persulfate in aqueous solution. Linear calibration curve was obtained in the range 0–1.5 mmol/L, with a limit of detection of 0.0028 mmol/L. The reaction time is rapid(within 60 sec), which is much shorter than that used for conventional methods. Compared with existing analytical methods, it need not any additives, especially colorful Fe2+, and need not any pretreatment for samples, such as p H adjustment. 相似文献
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Involvement of chloride anion in photocatalytic process 总被引:3,自引:3,他引:0
The effect of Cl^- on photocatalytic degradation(PCD) of pollutants is an important factor since it is ubiquitous in nature. In general, Cl^- showed an inhibition on photodegradation due to its scavenging HO- radicals. In this paper, experiments were carried out to examine the effects of CI on the PCD of Methylene Blue (MB) and Orange II (OII) in aqueous TiO2 suspensions under UV light illumination. It was found that low concentration of Cl^- ( 〈 0.01 mol/L) showed little influence on both dyes, however, high concentration of Cl^- ( 〉 0.10 mol/L) had a very different influence on the decolorization of dyes: a significant inhibition for MB but a great promotion for Oll. In the presence of 0.50 mol/L Cl^- , the rate decreased by 70% for MB while increased 7.5-fold for Oll. Furthermore, two bands in the ultraviolet region of Oll were rapidly broken down. The proposed mechanism was discussed in detail. 相似文献
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Adsorption of Methylene Blue on magnesium silicate: Kinetics, equilibria and comparison with other adsorbents 总被引:1,自引:1,他引:0
Franco Ferrero 《环境科学学报(英文版)》2010,22(3):467-473
Batch adsorption from aqueous solutions in a slightly basic medium of Methylene Blue, up to 2500 mg/L, onto synthetic magnesium silicate (Florisil) of three particle size ranges (mean diameters of 112, 200 and 425 μm) was compared to the corresponding adsorption onto activated carbon and Amberlite XAD-2. The best fit of the kinetic results was achieved by a pseudo second-order equation. The equilibrium data were found to be well represented by the Langmuir isotherm equation. Amberlite XAD-2, an unspecific adsorbent capable of adsorbing exclusively through a surface effect, exhibited a poor dye uptake, confirming that the adsorption mechanism on Florisil was due to electrostatic attraction and ion exchange. Moreover, the comparison between Florisil and the other adsorbents was performed on the basis of the evaluation of the surface area and pore volume occupied by the adsorbed dye. 相似文献
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Sustainable method towards magnetic ordered mesoporous polymers for efficient Methylene Blue removal
The difficulty in achieving high removal efficiency for contaminants in textile wastewater over a wide range of pH impedes the progress of its treatment technique greatly. Herein, a facile and sustainable strategy was adopted for constructing magnetic ordered mesoporous polymers (M-OMPs) without the assistance of organic solvent and catalyst. The prepared M-OMPs were endowed with high special surface area and good superparamagnetism simultaneously, and exhibited high removal efficiency (>99%) for Methylene Blue (MB) within a short time (10 min) at a concentration of 50 mg/L. What's more, high removal efficiency was achieved over a wide range of pH 2-12 and the adsorption capacity for MB on M-OMPs was substantially retained even after 5 adsorption-desorption cycles, further demonstrating the application potential of M-OMPs in the decontamination of textile wastewater. 相似文献
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For the paper industry, the disposal and management of the yielded sludge are a considerable challenge. In our work, the paper mill sludge-derived magnetically separable heterogeneous catalyst (PMS-Fe-380) was prepared easily through a facile synthesis method. The morphology and structure of PMS-Fe-380 were fully characterized by means of X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and Brunauer–Emmet–Teller analysis. The catalytic activity of PMS-Fe-380 was evaluated by degradation of Methylene Blue (MB). The reusability and stability of PMS-Fe-380 were evaluated in five repeated runs, which suggested that PMS-Fe-380 manifested excellent stability of catalytic activity. Moreover, leaching tests indicated that the leached iron is negligible (< 0.5 mg/L). This study provides an alternative environmentally friendly reuse method for paper mill sludge and a novel catalyst PMS-Fe-380 that can be considered as a promising heterogeneous Fenton-like catalyst. 相似文献