Preparation and application of efficient TiO2/ACFs photocatalyst

Activated carbon fibers （ACFs） supported titanium dioxide （TiO2） photocatalyst was developed by sol-gel method. The surface morphology and microstructure of the photocatalyst were characterized with scan electron microscope（SEM）, X-ray diffraction patterns and specific surface area analysis. The prepared photocatalyst is specially helpful for the removal of low molecular weight organic pollutants in wastewater. Decomposition efficiency of methylene blue solution by TiO2/ACFs catalyst reached almost 100% under 60 min reaction, while the decomposition efficiency by pure TiO2 was only 25% under 3 h reaction. The mineralization of toluene aqueous solution was measured by total organic carbon instrument, and the evolution of intermediate species was detected by gas chromatograph instrument. The results indicated that the prepared photocatalyst not only enhanced the photoactivity of TiO2, but also suppressed the emergence of intermediate species, which may be more deleterious to human. The enhancement of photocatalysis was due to increased efficiency of adsorption and desorption, which were control steps in heterogeneous photocatalysis.     

生物质内在碱金属催化特性的TG-FTIR实验研究

用热重分析仪和傅里叶红外光谱联用(TG-FTIR)技术对稻秆、谷壳及其经过不同预处理的水洗样、硝酸洗样进行实验研究,分析了生物质内在碱金属对其热解过程的影响.对比原样、水洗样和硝酸洗样的热解TG曲线与产气组分发现:内在碱金属的存在对生物质热解具有较大的催化作用,促进了样品半纤维组分的热分解,明显降低了最大反应速率,使样品分解能够在较低温度段完成,提高了热解过程中焦的生成率,强化了去甲烷化反应,促使热解向羟基乙醛、酸类等低小分子液体产物的方向转化,增大了CO_2和CO的生成量.     

Al(III)对糖浆溶液中有机还原物质还原六价铬的影响

通过批实验研究了Al(III)对糖浆溶液化学还原六价铬反应的影响,揭示了不同条件下Al(III)对六价铬还原反应动力学的影响.结果表明:Al(III)能够促进糖浆溶液还原六价铬反应进行;其作用机制是Al(III)与糖浆溶液中有机还原物质及Cr(VI)反应形成三者的络合物,降低糖浆中多酚等有机还原物质还原Cr(VI)的反应活化能,提高六价铬还原反应速率.Al(III)存在时,该六价铬还原反应符合准一级动力学反应; pH 2.0,2.5,3.0,3.5时,添加Al(III)的实验组中六价铬反应速率常数比对应的空白对照组中反应速率常数分别增加了0.0251,0.0139,0.0058, 0.0048h-1.添加Al(III)前后反应体系中六价铬还原的反应活化能(Eа)分别为66.38,62.80kJ/mol.当糖浆浓度不足时,Al(III)能够提高糖浆溶液还原六价铬的反应去除率.     

Photo-degradation of Acid-red 3B dye catalyzed by TiO2 nanotubes

Introduction A s one kind of novel functional m aterial, TiO 2 nanotube has been found potential applications in solar cell (B arbe et al., 1997), sem iconductor device (V inodgopal et al., 1993) and catalyst supports (Idakiev et al., 2005) etc. Since K a…     

Preparation, characterization, and photocatalytic activities of boron- and cerium-codoped TiO2

Boron- and cerium-codoped TiO2 photocatalysts were synthesized using modified sol-gel reaction process and characterized by X- ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, particle size distribution （PSD）, diffuse reflectance spectra （DRS）, and Brunauer-Emmett-Teller （BET）. The photocatalytic activities were evaluated by monitoring the degradation of dye Acid Red B （ARB）. The results showed that the prepared photocatalysts were mixed oxides mainly consisting of titania, ceria, and boron oxide. The structure of TiO2 could be transformed from amorphous to anatase and then to rutile by increasing calcination temperature; the transformation being accompanied by the growth of particle size without any obvious change in phase structure of CeO2. The XPS of B1.6Ce1.0-TiO2 prepared at 500℃ showed that a few boron atoms were incorporated into titania and ceria lattice, whereas others existed as B2O3. Cerium ions existed in two states, Ce^3＋ and Ce^4＋, and the atomic ratio of Ce^3＋/Ce^4＋ was 1.86. When boron and cerium were doped, the UV-Vis adsorption band wavelength showed an obvious shift toward the visible range （〈526 nm）. As the atomic ratio of Ce/Ti increased to 1.0, the absorbance edge wavelength increased to 481 nm. The absorbance edge wavelength decreased for higher cerium doping levels （Ce/Ti=2.0）. The particles size ranged from 122 to 255 nm with a domain at 168 nm （39.4%）. The degradation of ARB dye indicated that the photocatalytic activities of boron- and cerium-codoped TiO2 were much higher than those of P25 （a standard TiO2 powder）. The activities increased as the boron doping increased, whereas decreased when the Ce/Ti atomic ratio was greater than 0.5. The optimum atomic ratio of B/Ti and Ce/Ti was 1.6 and 0.5, respectively.     

Photocatalytic degradation of Acid Blue 62 over CuO-SnO2 nanocomposite photocatalyst under simulated sunlight

The novel CuO-SnO2 nanocomposite oxide photocatalysts were prepared by simple co-precipitation method, and characterized by X- ray diffraction, transmission electron microscopy, N2 adsorption-desorption measurement and UV-Vis diffuse reflectance spectroscopy. The photocatalytic activities of CuO-SnO2, evaluated using the photodegradation of Acid Blue 62 as a probe reaction under the irradiation of Xenon light, were also found to be related to the calcination temperature and the molar ratio of Cu to Sn. The maximum photocatalytic activity of the CuO-SnO2 photocatalyst was observed to be calcined at 500~C for 3 h （the molar ratio of Cu to Sn was 1：1） due to the sample with good crystallization and high surface area. It also showed much higher photocatalytic activity in treatment dye wastewater under simulated sunlight irradiation compared to Degussa P25 TiO2.     

城镇污水处理厂全过程除臭技术

由天津凯英科技发展有限公司开发的城镇污水处理厂全过程除臭技术,适用于活性污泥法及其变型工艺,包括A/O、A2/O、多段多级A/O工艺、氧化沟、SBR等多种处理工艺。主要技术内容 一、基本原理 通过特制填料的接种、诱导和催化作用,利用特制的微生物培养箱,在污水处理厂生物池的活性污泥中培养并增殖出高效的除臭微生物,将含有除臭微生物的污泥回流至污水处理厂进水端。     

生油岩与火成岩的相互作用研究初探—有机酸对火成岩的蚀变及过渡金属对有机质演化的催化作用

在发育火成岩的生油层中 ,微生物和热解作用导致生油岩有机质形成有机酸 ,这些有机酸对火山矿物中的金属元素是一种有效的溶剂和迁移介质 ,特别是能促使其中的过渡金属活化和溶解。这样造成与火成岩共存的生油岩内过渡金属含量显著增加 ,一些过渡金属是有机质成烃演化良好的催化剂。同时火山和热液活动还能向生油层提供过渡金属元素 ,从而使与火成岩共生的生油岩油气生成量大大提高。     

低有机碳含量表层土中Fe2O3对γ-666光解的催化作用

考察5种低有机碳含量天然土中Fe2O3光催化降解γ-666的光解动力学,γ-666的光解符合准一级动力学方程.从所得的γ-666光解动力学常数可知,随Fe2O3质量分数从0.40%增加到5.40%,γ-666的一级光解动力学常数也增大,且两者的线性相关系数为0.952,其在5种天然土中的半衰期随Fe2O3含量的增加依次为133.3h,82.5h,44.1h,28.5h,20.4h.由此可见,低有机碳含量天然土中Fe2O3对γ-666的光解具有明显的催化作用.     

煤燃烧过程中NOx产生机制及影响因素

煤燃烧产生的ＮＯｘ有三个来源，热力型ＮＯｘ快速型ＮＯｘ和燃料型ＮＯｘ，在１３００℃下主要是燃料型ＮＯｘ。燃煤过程中ＮＯｘ的形成是分两步进行，首先燃料中的杂环氮化物受热分解，产生ＮＨ３或ＨＣＮ，随挥发物释放出来，氧化生成ＮＯｘ残留在煤焦中的氮在煤焦燃烧时生成ＮＯｘ。挥发分中的ＮＨ３、ＨＣＮ同时也可以还原ＮＯｘ气体，研究表明脱硫用的石灰石、ＣａＯ或多或少地增加ＮＯｘ的排放，认为是ＣａＯ催化了ＮＯｘ形成