Cd/CdS光催化降解甲基橙的研究

采用胶体化学法制备表面富镉的Cd／CdS纳米粒子为催化剂对水溶液中甲基橙的光催化降解进行了研究。探讨了光催化反应机理,讨论了光催化剂用量,双氧水的用量,试液的pH值,光照时间与甲基橙脱色率的关系。实验结果表明,当甲基橙起始浓度为20mg／L,Cd／CdS用量为0．500g,双氧水用量为5．88mmol／L,pH值为7．0时,光照6h,甲基橙的脱色率可达到95．5％。     

TiO2纳米棒光催化降解甲基橙的研究

本文以甲基橙为目标降解物考察了催化剂的添加量、甲基橙溶液的pH值、晶化时间、热处理温度等因素对用"软模板"制备的TiO2纳米棒光催化活性的影响.研究表明:当催化剂添加量为0.08g、甲基橙溶液的pH=4、晶化时间为24h、热处理温度为500℃时,TiO2光催化剂的催化效果最佳,达到了85.96%.     

Ag~+掺杂FeVO_4光催化剂的制备及光催化性能

采用液相沉淀法制备了银(Ag+)掺杂钒酸铁(FeVO4)光催化剂。采用XRD、SEM、EDS、BET和XPS等手段对样品的性能进行了表征分析,并以甲基橙为目标降解物,考察了催化剂在节能灯照射下的光催化活性。结果表明,Ag的掺杂没有改变FeVO4晶型,但引起了晶格畸变和膨胀。适量Ag的掺杂可提高FeVO4的光催化性能,在所进行实验的条件下,钒酸银最佳掺杂量为1%(质量分数)时,掺杂后的Fe-VO4对甲基橙溶液的脱色率较未掺杂前提高21%左右。     

SiO2气凝胶/纳米TiO2共混光催化剂降解甲基橙

目的利用甲基橙模拟印刷废水,研究SiO_2气凝胶/纳米TiO_2共混光催化剂对甲基橙的光降解性能。方法采用溶胶-凝胶法制备SiO_2气凝胶,再加入纳米TiO_2通过共混法制备出共混光催化剂,利用扫描电子显微镜、X射线衍射仪、傅里叶变换红外光谱分析技术对样品进行表征。使用共混光催化剂降解甲基橙观察其光催化活性。结果当纳米TiO_2和SiO_2气凝胶的质量比为1∶4,催化剂质量浓度为0.2g/L,甲基橙的初始质量浓度为10 mg/L,p H值为4时,甲基橙的降解率最高。结论利用共混光催化剂降解甲基橙,其光催化效率高,降解率可高达99.85%。     

液相沉淀法制备FeVO_4新型可见光催化剂及其性能研究

采用液相沉淀法制备了FeVO4光催化剂样品,分别研究了不同的制备条件(V/Fe物质的量比、沉淀反应pH值和煅烧温度)对样品的理化性能及其光催化性能的影响.采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和DRS等方法对样品结构和形貌进行分析和表征,并通过在紫外灯和可见光照射下降解一定浓度的甲基橙溶液,评价其光催化活性.实验结果表明:当V/Fe物质的量比为1、pH值为8时生成沉淀,并于800℃煅烧4h后制得三斜型FeVO4,禁带宽度为2.05eV;在40W紫外灯照射下对甲基橙溶液的脱色率最大,100min达94%左右.FeVO4晶粒表面光滑,形状规则,粒径大约为100nm,部分呈棒状晶形,且其在可见光下也具有一定的光催化活性,20W节能灯照射下对甲基橙溶液的脱色率达82.3%左右.     

可见光响应的Fe-TiO_2纳米光催化剂降解甲基橙废水的研究

采用溶胶-凝胶法制备Fe掺杂的TiO_2光催化剂,通过UV-Vis和XRD表征其结构,结果显示该催化剂具有良好的可见光吸收,其主要晶型为锐钛型TiO_2,其晶粒尺寸为14.2-15.0nm。在可见光下,与未掺杂的催化剂相比,Fe掺杂的催化剂可较好地降解甲基橙废水。随着反应溶液pH升高,处理效果降低。Fe掺杂的TiO_2光催化剂可较好地处理实际甲基橙染料废水。     

超声波降解水中甲基橙的实验研究

为开发利用超声降解染料废水技术,建立了以甲基橙为模型化合物的超声降解模拟实验。考察了pH值、甲基橙初始浓度、氧化剂过氧化氢的投加浓度以及超声设备声能密度等实验条件对超声氧化降解甲基橙效果的影响。当甲基橙溶液初始浓度为2 mg.L-1、pH值为2时,按0.01 mL/100 mL浓度投加过氧化氢,在300 W声能密度条件下仅需20 min,甲基橙的降解率可达到91.79%。实验结果表明,超声降解染料废水技术操作简单、高效快速,具有广阔的应用前景。     

纳米La-TiO2光催化降解甲基橙废水的研究

采用溶胶-凝胶法制备了纯TiO2和La掺杂TiO2复合纳米粉体,通过XRD,UV-Vis等测试手段分析了在紫外光照射下,以降解甲基橙为探针反应研究其可见光催化性能。结果显示样品均为锐钛矿相纳米TiO2,稀土元素镧掺杂后纳米TiO2特征衍射峰宽化,强度降低;掺入的La主要以La2O3的形式存在,同时有一部分形成Ti-O-La键;La掺杂可减小TiO2晶粒尺寸及增大催化剂比表面积;与未掺杂的二氧化钛相比较,适当含量的镧掺杂可有效促进TiO2表面光生载流子的分离,从而显著提高其光催化活性。当La/Ti的摩尔比为0.010时,可见光催化性能最好。     

瓶状和棒形的纳米ZnO光催化降解甲基橙的研究

以硝酸锌,醋酸钠为原料,聚乙二醇-10000为表面活性剂,采用溶剂热法合成了瓶状和棒形的纳米ZnO,并用X射线衍射仪(XRD)、透射电镜(TEM)、紫外-可见分光光度计时其进行了表征,结果显示合成的纳米ZnO属于六方纤锌矿的晶体结构,对200～380nm波长范围的紫外光有较强的吸收性能.并以纳米ZnO作为光催化剂对甲基橙进行了光降解实验,研究了催化剂用量、甲基橙初始浓度及电解质(SO2-4、Cl-)等对甲基橙降解率的影响.     

纳米四针状氧化锌晶须光催化降解甲基橙

以纳米四针状氧化锌晶须(T-ZnOw)为光催化剂,以甲基橙为染料模型化合物,研究了T-ZnOw的光催化氧化降解性能.考察了甲基橙溶液的初始浓度、催化剂用量和粒径等因素对光催化氧化降解反应的影响.研究结果表明,纳米T-ZnOw光催化氧化降解甲基橙的反应遵循一级反应动力学规律;光催化剂纳米T-ZnOw的最佳用量为2g/L,此时经60min光催化降解后,甲基橙溶液的色度剩余率仅为8%;T-ZnOw粒子直径越小,光催化活性越高,效果越好.对比实验和重复实验结果表明,纳米T-ZnOw的光催化氧化降解效果比纳米TiO2和普通球形纳米ZnO粉体更好,是一种高效、长寿的光催化剂材料.     

Study on degradation of methyl orange using pelagite as photocatalyst

Pelagite of East Pacific Ocean as a low-price, very high reserve photocatalyst, has been successfully used for the first time to realize total degradation and decoloration of methyl orange within 120 min through photocatalysis. The photocatalysis and degradation performance of pelagite for methyl orange under the effect of various factors has been studied. Results show that pelagite has satisfactory photocatalysis effect in degradation of organic compounds.     

壳聚糖-CdS复合纳米粒子对甲基橙的光催化降解作用

用反相微乳液法制备了壳聚糖-CdS复合纳米粒子,并考察了复合纳米粒子用量、光照条件和溶液pH值等因素对光催化降解甲基橙的影响.结果表明:在100 mL质量浓度为20 mg/L的甲基橙溶液中加入0.30 g复合纳米粒子,可以达到较好的光催化降解效果;甲基橙在光催化降解过程中最大吸收波长464 nm处的吸收峰迅速减弱,并最终消失,且在258 nm和455 nm处出现了新的吸收峰,说明甲基橙发生了降解;溶液pH值对光催化降解甲基橙有一定的影响,在弱酸性条件下降解效率较高;复合纳米粒子比普通CdS降解效率高,2 min时高出50%,400 min时高出21.3%.初步提出了复合纳米粒子光催化降解机理,复合纳米粒子的吸附作用是光催化降解作用的前置步骤.     

Photocatalytic degradation of methyl orange using biologically enhanced tin oxide nanoparticles under UV-irradiation

Tin oxide nanoparticles (size?=?14 nm) have been prepared using DNA, a biological molecule, by co-precipitation method. The SnO₂ catalysts were characterized by X-ray diffraction, scanning electron microscope, transmission electron spectroscopy, fourier transform infra-red spectroscopy, photoluminescence spectroscopy and UV–Vis spectroscopy. The photocatalytic properties of SnO₂ nanoparticles were investigated via methyl orange as a model organic compound under UV light irradiation. The study proves SnO₂ as an efficient catalyst in removing organic pollutants in water.     

Photocatalytic activity of novel AgBr/WO3 composite photocatalyst under visible light irradiation for methyl orange degradation

A novel AgBr/WO(3) composite photocatalyst was synthesized by loading AgBr on WO(3) substrate via deposition-precipitation method and characterized by XRD, SEM and DRS. The as-prepared AgBr/WO(3) was composed of monoclinic WO(3) substrate and face-centered cubic AgBr nanoparticles with crystalline sizes less than 56.8 nm. AgBr/WO(3) had absorption edge at about 470 nm in the visible light region. The optical AgBr content in AgBr/WO(3) was 0.30:1 (Ag/W) at the corresponding apparent rate, k(app), of 0.0160 min(-1) for MO degradation. The highest k(app) was 0.0216 min(-1) for 4 g/L catalyst. The OH acted as active species. Addition of H(2)O(2) within 0.020 mmol/L can efficiently trap electrons to generate more OH and further improved photocatalytic activity of AgBr/WO(3).     

Visible-light responsive zinc ferrite doped titania photocatalyst for methyl orange degradation

Visible-light responsive zinc ferrite doped titania (ZFDT) photocatalysts were prepared by sol-gel method. Diffuse Reflectance Spectroscopy (DRS) result shows that the absorption edge of ZFDT has moved to the visible spectrum range and a very large redshift occurs in comparison with the undoped titania. X-ray diffraction (XRD) results show that zinc ferrite can prevent the transformation of titania from anatase to rutile when the content of zinc ferrite is above 1.5%; while the phase transformation is promoted when its content is below 1.5%. In the latter case, zinc ferrite was assumed to exist as separate zinc and ferric cations in the lattice of titania in the form of oxides, both of which promote the phase transformation as previously reported in other literatures. Field emission scanning electron micrography (FE-SEM) shows that the average particle size of 1.5%ZnFe₂O₄/TiO₂ calcined at 500 °C is about 70 nm. The photocatalytic experimental results exhibit that ZFDT powders can effectively photodegrade methyl orange under visible light irradiation and the maxium photoactivity is achieved when the amount of zinc ferrite is 1.5%.     

多孔棒状FeVO4的制备及可见光催化性能研究

以Fe(NO₃)₃和NH₄VO₃为无机源, 氨水为pH调节剂, 采用水热法制备了多种形貌纯三斜相的多孔FeVO₄。采用X射线衍射、扫描电子显微镜和紫外-可见漫反射光谱等技术表征了样品的物理性质。结果表明, 水热温度和反应液的pH对晶相结构和粒子形貌有较大的影响: 当水热温度为180℃, 反应液的pH为4.0或7.0时, 可制得多孔三斜相FeVO₄纳米棒; 当水热温度为120℃, 反应液的pH为4.0 时制得的三斜相FeVO₄为片状结构; 而当水热温度为180℃, 反应液的pH升至10.0或水热温度变为240℃, 反应液的pH保持4.0不变时均制得含有少量FeVO₄的Fe₂O₃。在可见光照射光催化降解甲基橙的反应中, 具有最高比表面积(10.4 m²/g)的多孔棒状FeVO₄光催化活性最高, 这是因为它具有最高的结晶度、比表面积和表面氧空位密度、多孔结构和最低的带隙能。