共查询到19条相似文献,搜索用时 62 毫秒
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以玫瑰红作为研究机理的目标物,在紫外灯的照射和二氧化钛作催化剂的实验条件下,用重铬酸钾法测定化学需氧量,Apollo 9000型TOC测定仪测TOC,UV-VIS8500型紫外-可见分光光度计测定样品的色度,研究光催化降解机理。结果表明:玫瑰红染料的脱色过程与总有机碳TOC、化学需氧量COD的去除过程是不同步的。在玫瑰红的降解过程中,强氧化自由基首先进攻共轭结构.反应初期主要是脱色过程,TOC在没有很大的变化,生成了无色而又相对稳定的中间产物。反应后期是各芳烃中间产物的开环过程,最终完全降解为无机小分子。 相似文献
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水热法制备了TiO2纳米管,并采用简单加热回流的方法制备了ZnS/TiO2纳米复合材料。采用TEM、XRD分析手段对产物进行表征,并对其光催化降解酸性玫瑰红B(AR)染料废水进行了研究。考察了反应物供给速率、硫化锌复合量、催化剂稳定性、光照对光催化降解效果的影响。研究表明控制反应物供给速率和硫化锌的负载量可使硫化锌在二氧化钛纳米管表面均匀分散。当染料废水初始浓度为10mg/L,ZnS:TiO2=8:1时,ZnS/TiO2复合材料光催化活性最高。且催化剂稳定性较好。 相似文献
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以TiOSO_4为钛源,氨水为沉淀剂,以水解沉淀法制备纳米TiO_2-硅藻土复合材料;结合XRD、SEM、氮气吸-脱附表征手段,对比研究复合材料、纯TiO_2、纳米级TiO_2(P25)对罗丹明B的光催化性能以及复合材料对罗丹明B、刚果红、甲基橙、亚甲基蓝等染料的吸附及光催化降解性能。结果表明:纳米TiO_2-硅藻土复合材料对罗丹明B的光催化性能明显优于纯TiO_2和P25;复合材料对不同污染物的吸附及光催化性能存在显著差异,对阳离子型的亚甲基蓝的吸附及光催化性能最好,对阴离子型甲基橙的吸附及光催化性能最差。 相似文献
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采用电化学阳极氧化法制备了高度有序的TiO2纳米管阵列,并利用纳米管的光致超亲水特性,采用斜面毛细组装技术在无定形TiO2表面自组装ZnO溶胶后退火制备了TiO2/ZnO复合纳米管.探讨了阳极氧化各参数对纳米管形貌的影响.利用X射线衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)等方法对样品的结构和形貌进行了表征.以有机磷农药氯胺磷为光催化降解对象,研究了焙烧温度、管径、管长和TiO2/ZnO复合比例等因素对降解效果的影响.结果表明,焙烧温度、管径以及ZnO复合比例对光催化降解率影响较大.对于管径97 nm、管长315.8nm的TiO2/ZnO纳米管,ZnO最佳复合比例为4.2%(质量分数),5 h后降解率达到78%. 相似文献
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使用市售Degussa P-25TiO2粉末,采用水热合成法制备了1.0%(原子分数)Ag+、Cu2+、Fe3+、Mn2+和V5+掺杂纳米管TiO2催化剂。结果表明,随着煅烧温度增高,样品的比表面积逐渐降低,锐钛矿含量先增后减,禁带宽度逐渐变窄,变化范围与掺杂金属的种类有关。掺杂金属后,纳米管TiO2催化剂的比表面积略有降低,锐钛矿含量略有增大,禁带宽度变窄。向纳米管TiO2中掺杂Ag+、Cu2+、Fe3+和V5+,催化剂的光催化活性提高,而掺杂Mn2+,光催化活性略有降低。550℃煅烧1.0%Fe3+掺杂纳米管TiO2具有最好的催化效果,其254nm光催化臭氧氧化对腐植酸的去除率为77.4%。 相似文献
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为了解决水体中光催化剂的分离和回收问题,对纳米TiO2的改性和固载化及其光催化特性进行了研究。首先以纳米TiO2为原料,采用水热合成法制备TiO2纳米管;再对TiO2纳米管硅烷化,改善其表面性质;然后以聚氨酯(PU)膜片为载体负载TiO2纳米管,制成了负载型PU/TiO2薄膜的光催化材料。采用X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、衰减全反射傅里叶变换红外光谱(ATR-FTIR)和扫描电子显微镜(SEM)等手段对催化剂进行了表征,结果表明硅烷化后的TiO2纳米管能很好地接枝在PU薄膜表面。以300 W高压汞灯为光源,萘普生为目标降解物,研究了负载PU/TiO2薄膜的光催化活性和稳定性,结果表明其对目标物的降解具有较高活性,用乙醇冲洗即可多次重复使用,其催化活性能较长时间保持稳定。 相似文献
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为了解决TiO2纳米粒子难分离,负载的催化剂难回收等问题,首先,将TiO2与海藻酸钠充分混合制成铸膜液,在玻璃板上刮膜,经钙离子交联制备了TiO2-海藻酸钙(T-CA)复合膜。然后,对T-CA复合膜进行了SEM和XRD表征,并研究了T-CA复合膜对染料的光催化降解性能。最后,将T-CA复合膜从染料降解液中取出,浸泡在柠檬酸钠水溶液中,柠檬酸根对钙离子的结合力较强,可使海藻酸盐水凝胶溶解,离心分离TiO2纳米粒子并清洗干燥后,得到了回收TiO2;利用SEM、TEM、FTIR和XRD对回收TiO2进行了表征。结果表明:T-CA复合膜对甲基橙的光催化降解率可达82.37%。回收TiO2与初始的TiO2几乎完全一样,可重新使用且催化能力不变。该方法是一种绿色环保、方便快速的从载体中回收TiO2纳米粒子的方法。 相似文献
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Two types of molybdenum–carbon nanotubes and molybdenum treated carbon nanotubes/titania composites were prepared using a
sol–gel method. These composites were characterized comprehensively by the Brauer–Emett–Teller (BET) surface area, scanning
electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD), transmission electron microscopy
(TEM) and UV-vis absorption spectroscopy. It was found that the photocatalytic degradation of a methylene blue solution could
be attributed to the combined effects caused by the photo-degradation of titania, the electron assistance of carbon nanotube
network, and the enhancement of molybdenum. The proposed redox mechanism of the photodegradation of methylene blue on Mo-CNT/TiO2 composites is suggested. 相似文献
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采用阳极氧化法,在醇(丙三醇、乙二醇)-水-NH4F电解液体系中制备高度有序的TiO2纳米管阵列。采用场发射扫描电子显微镜(SEM)、X射线衍射仪(XRD)对TiO2纳米管阵列的形貌和晶型结构进行表征,讨论了阳极氧化法制备工艺(阳极氧化电压、氧化时间、电解液)对TiO2纳米管的形貌、结构及其甲基橙光催化降解性能的影响;分析了退火温度对TiO2阵列的物相及其光催化性能的影响。研究结果表明,采用高电压、增加氧化时间有利于TiO2纳米管阵列光催化的提高,在其它参数相同的情况下,采用丙三醇作为电解液制备获得的TiO2纳米管阵列较乙二醇体系具有更加优异的光催化性能。 相似文献
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《Materials science & engineering. C, Materials for biological applications》2006,26(5-7):1198-1201
Composites were synthesized by “in-situ” polymerization of polyazomethine, a liquid crystal polymer (LCP), in presence of multi-walled carbon nanotubes (MWNTs) previously dispersed in one of the employed monomers. Fiber processing was carried out by extrusion from the composites containing 1 and 10 wt.% of MWNTs at the mesophase temperature. We have observed that the typical highly oriented internal fibrillar structure can be significantly disrupted by increasing the nanotube content in the composite fibers. Evidences of MWNT alignment were found in the studied LCP/MWNT composites. 相似文献
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Mariem Mohamed Chamakh Deepalekshmi Ponnamma Mariam Al Ali Al-Maadeed 《Journal of Materials Science: Materials in Electronics》2018,29(6):4402-4412
Inorganic nanocarbon hybrid materials are good alternatives for superior electrochemical performance and specific capacitance to their traditional counterparts. Nanocarbons act as a good template for the growth of metal nanoparticles on it and their hybrid combinations enhance the charge transport and rate capability of electrochemical materials without sacrificing the specific capacity. In this study, titanium dioxide nanotubes (TNT) are synthesized hydrothermally in the presence of multi-walled carbon nanotubes (MWCNT) where the latter acts as base template material for the metal oxide nanotube growth. The MWCNT–TNT hybrid material possesses very high dielectric strength and this is used to enhance the dielectric property of the polymer polyvinyledene fluoride (PVDF). Solution mixing was used to prepare the PVDF/MWCNT–TNT nanocomposites by varying the filler concentrations from 0.5 to 2.5 wt%. Excellent vapor sensing was noticed for the PVDF nanocomposites with different rate of response towards commonly used laboratory solvents. The composites and the fillers were characterized for its morphology and structural properties using scanning and transmission electron microscopy, X-ray diffraction studies and infrared spectroscopy. Vapor sensing was measured as relative resistance variations against the solvent vapors, and the dielectric properties of the composites were measured at room temperature during the frequency 102–107 Hz. Experimental results revealed the influence of filler synergy on the properties of PVDF and the enhancement in the solvent vapor detectability and dielectric properties reflects the ability of these composite films in flexible vapor sensors and in energy storage. 相似文献
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A simple approach is reported for the in situ growth of carbon nanotube-containing porous alumina structures by a thermal pyrolysis method. The composite was created by direct on-site growth of carbon nanotubes inside the porous alumina matrix, after introducing both a catalyst (Ni(NO3)2) and a carbon source (camphor) into the cavities of the large matrix brick. Pyrolysis was carried out when the pre-treated brick was heated in a furnace at 850 °C under a H2-Ar atmosphere. The resulting multi-walled carbon nanotubes with average diameters of 30-70 nm and lengths up to several micrometers are dispersed uniformly at each section of the alumina matrix. An improvement in the compression strength of the composites has been obtained, due to the inclusion of carbon nanotubes. 相似文献
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TiO2纳米管的研究进展 总被引:1,自引:0,他引:1
TiO2纳米管由于其新奇的光电、催化、气敏等性能而引起广泛的关注,在太阳能电池、光催化、环境净化、气体传感器等领域有潜在的应用价值.主要综述了TiO2纳米管的最新研究进展情况以及发展现状,介绍了其制备方法、形貌、晶体结构、形成机理及应用前景. 相似文献
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The change in electrical resistance due to mechanical deformation of carbon nanotube (CNT)/polymer composites can be rationalized in terms of two effects: (i) changes in the composite electrical resistivity due to changes in the CNT network configuration and (ii) deformation of the CNTs themselves. The contribution of CNT dimensional changes (ii) to the piezoresistivity of CNT/polymer composites is investigated here. An analytical model based exclusively on dimensional changes which describes the CNT change of electrical resistance in terms of its mechanical deformation is proposed. A micromechanics approach and finite element analysis are performed to correlate the macroscale composite strain to the individual CNT strain. The CNT change of electrical resistance is quantified for different matrix elastic moduli and CNT weight fractions. The CNT/polymer composite is also modeled as an effective continuum material in terms of both its electrical and mechanical responses so that the effect of dimensional changes on the global piezoresistivity can be investigated. Based on the modeling predictions and previous experimental results, it is estimated that the CNT change of resistance due to the macroscale composite strain is marginal (∼5%) compared to the total composite change of resistance commonly measured in the laboratory, suggesting that the dominant effect in the piezoresistivity of CNT/polymer composites is the change in the CNT network configuration. 相似文献