共查询到17条相似文献,搜索用时 281 毫秒
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采用纳米TiO2协同Fenton试剂光催化降解甲基橙,研究了纳米TiO2与Fenton试剂的协同效应,考察了H2O2用量、甲基橙溶液的初始浓度及初始pH值对降解效率的影响,并对其降解动力学规律作了初步探讨。结果表明:纳米TiO2强化了Fenton试剂对甲基橙的降解效率,它们之间产生了较强烈的协同效应。在实验过程中,纳米TiO2协同Fenton试剂光催化降解初始浓度30mg/L、pH=3.0的甲基橙120min,其降解率达到99.4%,分别是同等实验条件下单独纳米TiO2降解率的2.63倍,单独Fenton试剂降解率的2.32倍,是两者算术和的1.2倍。在实验浓度范围内,甲基橙的降解反应符合准一级动力学过程;与Fenton反应相比,在0.2、0.4、0.6g/L纳米TiO2的协同作用下,甲基橙的降解表现反应常数分别提高了1.71、2.51和3.36倍,半衰期相应缩短。另外,H2O2用量、甲基橙溶液初始浓度及初始pH对降解率有一定影响。 相似文献
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光/电Fenton催化降解有毒有机污染物 总被引:3,自引:0,他引:3
在可见光(λ>450nm)照射并通外加电压(E=3V)条件下,以染料酸性桃红(Sulforhodamine B,SRB)及有机无色小分子化合物2,4-二氯苯酚(2,4-dichlomphenol,DCP)为目标物,探索光电Fenton降解其最佳反应条件,结果表明,对1.0×10-5mol/L SRB Fenton试剂(Fe3+/H2O2)在pH=3.0,H2O2浓度为7.49×10-4mol/L,Fe3+为2.48×10-4mol/L时,SRB降解效果最好.通过分析SRB及DCP降解过程紫外.可见光谱(UV-Vis)、红外光谱(FTIR)和总有机碳(TOC)测定,发现光电Fenton体系能使SRB和DCP发生有效的降解,SRB反应300min矿化率达到96.38%,DCP反应90min降解率达到100%.采用酶分析法和苯甲酸荧光分析法分别测定了在光电催化降解有机污染物过程中H2O2和羟基自由基(·OH)的变化,表明此光催化降解过程涉及·OH历程. 相似文献
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以解决西部干旱地区集雨水深度净化为目的,研制了一款平板式太阳能光催化集雨水净水器;以低温水热法在土工布上负载光催化剂,以苯酚为模拟污染物,分别在室内不同条件下及在太阳光下进行光催化氧化实验。结果表明,以自来水(pH=7.2)配制的浓度为2.5mg/L的苯酚、在流量为5.0L/h、光强为1.5mW/cm2的条件下,出水口苯酚的降解率可达52.35%;而在夏季太阳光的照射下,苯酚的降解率可达82.56%;对会宁农村集雨水中挥发酚降解作用明显,出水口挥发酚指标完全达标。 相似文献
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掺Ag复合纳米TiO2光催化性能 总被引:1,自引:0,他引:1
通过溶胶-凝胶法和光还原法制备掺Ag复合纳米TiO2.用XRD表征了TiO2的晶体形态.以典型偶氮结构的甲基橙水溶液为模拟对象,研究掺Ag复合纳米TiO2光催化性能.实验结果表明,TiO2悬浮体系中甲基橙的光催化降解符合Langmuir动力学规律.根据动力学计算,掺Ag复合TiO2和单纯TiO2对甲基橙的降解速率常数分别为27.34mg/(L·h)和14.42mg/(L·H),光催化的活性提高了近2倍.因此有望通过这一技术制备出比单纯TiO2更好的光催化剂. 相似文献
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掺铋纳米TiO_2制备及可见光催化降解有机污染物 总被引:1,自引:0,他引:1
采用在酸性条件下超声沉淀的方法低温制备了Bi掺杂TiO_2纳米粉体,采用X射线光电子能谱(XPS)、X射线衍射(XRD)和透射电镜(TEM)对催化剂进行了初步表征,发现其禁带宽度变窄,主要为锐钛矿(82.7%)和金红石(17.3%)混晶,纳米尺寸为25.8nm。以酸性桃红(SRB)和无色小分子2,4-二氯苯酚(2,4-dichlorophenol,2,4-DCP)作为探针反应,在可见光照射下(λ420nm)测定了SRB降解过程中总有机碳(1OC)的变化,发现SRB的TOC去除率为61.6%。跟踪测定光催化反应体系中氧化物种,表明光催化涉及羟基自由基(·OH)过程,所制备的催化剂在可见光下具有较高的催化氧化活性。 相似文献
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用流延法在石墨板上成功制备出用于光催化的Nafion-纳米TiO_2复合膜。在H_2O_2存在的条件下,用Nafion-纳米TiO_2复合膜对甲基橙染料进行可见光照射处理。结果表明,H2_O_2/Nafion-纳米TiO_2复合氧化工艺中甲基橙降解脱色速率显著提高,两者之间存在明显的协同效应。在协同体系中,酸性媒介比碱性媒介更有利于甲基橙染料光解脱色。实验所用的NO_3~-、Cl~-和SO_4~(2-)等阴离子,均对降解脱色有抑制作用,其中NO_3~-对脱色作用抑制最显著。可见光辐射处理前后,UV-Vis谱图分析表明在H_2O_2/Nafion-纳米TiO_2复合膜处理中甲基橙溶液脱色是因为染料发生氧化光解作用。 相似文献
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本研究以NaOH-乙醇水溶液为溶剂体系对竹木质素进行热降解,主要考察了NaOH浓度、反应温度、反应时间、乙醇用量等条件对竹木质素降解转化为酚类化合物的影响。通过GC-MS及FT-IR对降解产物进行分析检测,得出最佳反应条件为:竹木质素5 g,NaOH浓度(基于乙醇水溶液)20 g/L,乙醇10 mL,反应时间2 h,反应温度240℃。在此条件下,降解产物中总的酚类化合物的相对峰面积为73.88%,残渣率为30.67%。竹木质素的降解主要产物是酚类化合物:苯酚(17.98%)、2-甲氧基苯酚(16.49%)及1,2-苯二酚(10.03%)。与现有文献相比,本文竹木质素在碱性乙醇溶剂体系中降解能够获得较高产量的酚类化合物,有望实现竹木质素的高值化利用。 相似文献
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Amir Mosayebi Mahmood Torabi Angaji Kourosh Bourbour 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2016,38(17):2617-2623
In this study, the effect of ethoxylated nonyl phenols with ethoxy group numbers 4 and 9 (nonyl phenol 4 and nonyl phenol 9), were investigated on the interfacial tension between crude oil and water. The interfacial tensions decreased significantly in a concentration range of 0–1.25 g.l–1. By increasing sodium chloride concentration, the time which was required to reach equilibrium interfacial tension was reduced. Therefore, sodium chloride affected the dynamic interfacial tension. However, ethoxylated nonyl phenols resisted against change of salinity. The effect of mixed surfactants on the decreasing of the interfacial tension was more than an individual surfactant, because of the synergism. The most effective mixture of a two surfactants system was observed when mass ratio of nonyl phenol 9 and nonyl phenol 4 was 0.5. 相似文献
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The aim of this work was to examine photosensitized oxidation of 2-chlorophenol using solar light. Rose bengal, methylene blue and chlorin e6 were used as sensitizers. They were immobilized in the silane gel and used in the form of a thin film covering glass plates. In some lab-scale experiments xenon arc lamps were used as solar simulators.The influence of various experimental conditions (light intensity, the amount of sensitizer, oxygen concentration) on the rate of 2-chlorophenol degradation was investigated. The obtained results indicate a possibility of the application of solar radiation in the middle latitudes for wastewater treatment. The use of silane gel as a carrier for the sensitizer enables the pollutants elimination at a higher rate than in a homogenous system. The stability and durability of immobilized sensitizers were also studied. 相似文献
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With natural sunlight TiO2 (anatase), Fe2O3, CuO, ZnO, ZnS, ZrO2, CdO, HgO, PbO, PbO2 and Al2O3 catalyze the degradation of phenol but MoO3, Co3O4, CdS, SnO2, Sb2O3, La2O3, CeO2, Sm2O3, Eu2O3, Pb2O3 and Bi2O3 do not. The degradation rates increase linearly with phenol-concentration and area of the catalyst bed but decrease linearly with pH. Air is essential for degradation and the catalysts show sustainable photocatalysis. Pre-sonication fails to enhance the photocatalysis. The system does not respond to application of a potential bias for enhancement of the photocatalysis. o-Cresol, m-cresol, p-cresol, o-chlorophenol, m-chlorophenol, p-chlorophenol, o-nitrophenol, p-nitrophenol, o-aminophenol, m-aminophenol, p-aminophenol, catechol, resorcinol and quinol degrade much slower than phenol. The ease of degradation correlates neither with the electron-releasing or withdrawing capacity of the substituent nor with its position in the phenyl ring. Also, the photocatalytic efficiency of the semiconductor is not in accordance with its band-gap energy. 相似文献
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The principle and usefulness of electrochemically assisted photocatalysis has been illustrated with the examples of 4-chlorophenol and Acid Orange 7 degradation in aqueous solutions. Thin nanocrystalline semiconductor films coated on a conducting glass surface when employed as a photoelectrode in an electrochemical cell are effective for degradation of organic contaminants. The degradation rate can be greatly improved even in the absence of oxygen by applying an anodic bias to the TiO2 film electrodes. A ten-fold enhancement in the degradation rate was observed when TiO2 particles were coupled with SnO2 nanocrystallites at an applied bias potential of 0.83 V versus SCE. 相似文献