Pb、N和Fe共掺杂光催化剂制备及处理大红染料废水的应用

采用溶胶-凝胶法制备出Pb、N和Fe共掺杂TiO2光催化剂。通过大红染料溶液的光催化降解反应,考察了制备和反应条件对共掺杂TiO2催化剂活性的影响。结果表明:在500℃,当Pb、N和Fe与Ti的原子比为0.7∶1.5∶0.6∶100,焙烧2h,TiO2光催化剂活性最大,大红染料的降解率达到99%。     

Ce-TiO2光催化剂的制备与性能研究

采用溶胶-凝胶法制备了稀土Ce离子掺杂的纳米TiO2光催化剂(Ce-TiO2),通过XRD、FT-IR、UV-Vis、PL、Nano-sizer纳米粒度分析仪等对Ce-TiO2样品进行了表征和分析,并以亚甲基蓝(MB)作为目标降解物,考察了不同掺杂浓度及经不同温度热处理后的Ce-TiO2样品对MB的光催化降解效果,结果表明所制备样品的晶型均为锐钛矿相和金红石相的混晶相,Ce离子的掺杂拓展了TiO2在可见光区的光谱响应范围,提高了TiO2光催化活性。当pH值为1.5,Ce的掺杂量为n(Ce)∶n(TiO2)=1∶300,热处理温度为600℃条件下制备的样品其催化活性显著高于Degussa P25。     

高效光催化剂的制备及应用研究

制备了一种高效光催化剂,通过采用溶胶-凝胶法,利用非金属离子S和稀土离子Sm共掺杂改性纳米TiO2。以降解甲基橙模拟染料废水为目标,通过UV-vis、XRD、TEM等手段考察了其在紫外光下的光催化活性。结果表明,共掺杂的光催化活性要明显优于单掺杂和不掺杂的,尤以煅烧温度500℃,n(S)∶n(Sm)∶n(Ti)=15∶0.1∶1时,紫外光下光催化活性最佳。     

Ce掺杂TiO2/SiO2的制备及其光催化降解罗丹明B

采用溶胶-凝胶法制备了纯TiO2和掺杂不同含量Ce的TiO2/SiO2复合纳米粒子.并用FT-IR,UV-Vis对样品结构进行了表征,并以罗丹明B(RB)的光催化降解为探针反应,评价了其光催化性能.结果表明,TiO2/SiO2催化剂中形成了新的Ti-O-Si键,Ce的掺杂使TiC2/SiO2光谱响应范围向可见光区拓展.与未掺杂的TiO2/SiO2相比较,掺杂的TiO2/SiO2具有更高的催化性能.Ce掺杂的最佳值为x(Ce)∶x(Ti)=0.0090,光催化剂最佳投放量为30mg.     

Ce掺杂TiO_2的制备及其光催化性能研究

采用溶胶-凝胶法制备了Ce掺杂TiO2光催化剂,通过扫描电子显微镜(SEM)和X射线衍射(XRD)对其结构进行了表征,研究了其在紫外光下对聚丙烯酰胺(PAM)的降粘性能,探讨了催化剂用量、光照时间、煅烧温度和煅烧时间等因素对PAM降粘效果的影响。实验结果表明:Ce掺杂TiO2提高了TiO2的光催化活性;当Ce:TiO2的摩尔比为3∶100、煅烧温度为500℃、煅烧时间为2h、催化剂加入量为2%(质量分数)时Ce掺杂TiO2催化剂的光催化降粘率可达99%以上。     

膨胀珍珠岩负载Fe、Tb共掺杂TiO_2光催化剂的制备及光催化性能研究

以轻质、多孔的膨胀珍珠岩(expanded perlite,EP)为载体,采用溶胶-凝胶法制备了一系列Fe、Tb单掺杂及共掺杂TiO2/EP漂浮型复合光催化剂,并通过XRD和SEM等分析方法对其结构进行表征,以罗丹明B溶液为目标降解物,研究所制备样品的光催化活性。结果表明:TiO2以纳米颗粒的形式牢固负载在EP薄片表面,内部具有蜂窝状多孔结构的EP为TiO2提供高浓度的三维降解环境;Fe、Tb共掺杂对纳米TiO2的晶型转变有较强的抑制作用,减小了晶粒粒径,有效提高了TiO2光催化活性,当Fe-Tb-Ti的摩尔比为0.02∶0.02∶1,催化剂用量为10g/L,罗丹明B溶液的降解效率最高,降解率可达89.2%。     

B、N和Ce共掺杂TiO_2光催化降解染料废水研究

采用B、N和Ce共掺杂TiO_2降解酸性蓝BRL、活性金黄K-2RA、弱酸性黑RB和酸性大红GR 4种染料废水,考察了催化剂用量、染料初始浓度、光照时间和pH值等对其降解率的影响。结果表明:B、N和Ce共掺杂TiO_2除了能使染料快速褪色外,还能将其完全矿化为CO_2,SO_4~(2-)和NH~+_4等离子。酸性大红GR染料和酸性蓝BRL在pH=5、催化剂用量50mg、初始浓度50mg/L、光照180min时降解率分别为98%和94.2%。pH=1、催化剂用量50mg、初始浓度40mg/L、光照时间180min时,活性金黄K-2RA的降解率达94.5%。弱酸性黑RB在pH=2、催化剂用量60mg、初始浓度20mg/L、光照时间210min时,降解率达到最大,为92.6%。     

Ce4+/TiO2溶胶对酸性藏青GGR的光催化降解

以钛酸四正丁酯为前驱体,采用溶胶-凝胶法常温制备稀土离子Ce4+掺杂的TiO2溶胶,用以光催化降解酸性藏青GGR,探究掺杂对TiO2溶胶光催化活性的影响.研究Ce4+掺杂量、pH、溶胶浓度和染料初始浓度对溶胶光催化活性的影响.结果表明:未掺杂TiO2溶胶粒径为29.7nm,随Ce4+掺杂量增加粒径逐渐降低至22.4nm,粒径的减小使得TiO2粒子比表面积加大,光催化活性提高.染料降解率随掺杂量增加而提高,当Ce4+的掺杂量超过1.0％时,降解率下降,说明过量的掺杂会抑制TiO2的光催化活性.溶胶pH会影响溶胶中TiO2晶型和带电情况,pH为1-2时溶胶光催化活性最高.溶胶浓度低光催化反应体系中TiO2受激发产生的电子和空穴少,染料降解率低.染料初始浓度高紫外光透过率小,光能利用率低,染料降解速度慢.当溶胶pH为1-2,溶胶浓度0.2mol·L-1,染料初始浓度59mg· L-1时,未掺杂TiO2溶胶对酸性藏青GGR的降解率为64.5％,摩尔掺杂比1.0％的Ce4+/TiO2对染料的降解率达90.2％.掺杂使TiO2的光催化活性提高了25.7％.     

稀土元素与N共掺杂TiO2光催化剂的研究进展

TiO2作为一种重要的光催化剂,对其进行掺杂改性可有效扩展其光谱响应范围,提高其光催化活性。介绍了稀土元素与N对TiO2进行共掺杂改性的机理及研究现状,分析了共掺杂对TiO2晶体结构、电子结构以及光学性能、氧化还原性能的影响,总结了稀土元素与N共掺杂改性TiO2存在的问题以及今后的研究前景。     

Ni2+掺杂TiO2光催化剂的制备及性能研究

选取Ni 2+掺杂量、冰醋酸、浓硝酸、煅烧温度设计正交实验,采用溶胶-凝胶法制备Ni 2+掺杂TiO2光催化剂,利用Raman、XRD、TEM等检测技术对其进行表征。通过与溶胶-凝胶法制备的纯TiO2纳米光催化剂进行对比,结果表明:Ni 2+掺杂TiO2光催化剂的TEM图像显示为球形粒子集合体,XRD图谱峰值降低,晶粒细化,拉曼光谱谱峰宽化、蓝移。以甲基橙模拟染料废水的降解率考察Ni 2+掺杂TiO2光催化活性,最佳条件下,Ni 2+掺杂TiO2对甲基橙的降解率为87.21%。     

不同形貌α-Fe2O3的水热法制备及性能研究

以Fe(NO_3)_3·9H_2O为原料,聚乙烯吡咯烷酮作为表面活性剂,NaOH、Na_2CO_3、CH_3COONa为形貌改变剂,采用水热法制备出不同形貌的α-Fe_2O_3,并研究了不同因素对产物形貌的影响。利用SEM、EDS、XRD、FTIR等手段对其物相及微观形貌进行表征,并探讨其生长机理。通过光催化降解酸性大红模拟废水考察不同形貌α-Fe_2O_3的光催化性能,实验结果表明,类桑葚状α-Fe_2O_3对酸性大红模拟废水的降解效果最好,降解率高达99.01%,具有潜在的光催化应用前景。     

Aggregation and self-organization of hydrophilic azobenzene dye Langmuir-Blodgett films

Langmuir-Blodgett (LB) films of azobenzene dye of 2-hydroxyl-3-(4-methoxyl)-naphthanilide-azodiphenyl (AS-RL) and its hybrid films with behenic acid (BA) and octadecylamine (ODA) were investigated by tapping mode atomic force microscopy and ultraviolet visible light absorption spectroscopy. Wavy line-shaped or fingerprint-like dye aggregates were observed in the pure dye LB films. BA and ODA were used to modulate and control the structure of the dye aggregates and different patterns resulted in changing the molar ratio of dye molecules in the composites films, such as long lines (AS-RL/BA = 1:2), sheets (AS-RL/ODA = 1:2), wide lines (AS-RL/ODA = 1:1), and ordered lines (AS-RL/ODA = 2:1).     

Electroluminescence of zinc selenium (ZnSe) nanocrystals co-doped with poly[2-methoxy-5-(2'-ethylhexyloxy-p-phenylenevinylene)] (MEH-PPV)

We have synthesized water soluble zinc selenium (ZnSe) nanocrystals by using mercaotoacetic acid (TGA) as the stabilizer. The synthesized ZnSe nanocrystals were co-doped with poly[2-methoxy-5-(2'-ethylhexyloxy-p-phenylenevinylene)] (MEH-PPV) to fabricate an organic/ inorganic hybrid multilayer light-emitting device (LED). The structure of the device was indium-tin-oxide (ITO)/poly (ethylene-dioxythiophene):poly(styrenesul-fonate) (PEDOT:PSS)/MEH-PPV:ZnSe/bathocuproine (BCP)/tris-(8-hydroxylquinoline)-aluminum (Alq3)/Al. We demonstrate that the device has a lower driving voltage and increased current densities and power efficiencies owing to the co-doped ZnSe quantum dots. We obtained good efficiency of the devices when the quality ratio of MEH-PPV and ZnSe quantum dots was 1:1.     

釉面砖表面涂层光催化降解活性大红

以钛酸四正丁酯为前驱体,乙醇为溶剂,釉面砖为载体,利用溶胶-凝胶法制备釉面砖表面涂层材料,从有机染料活性大红BES的pH值,溶液初始浓度,光催化反应时间以及掺杂金属TiO2涂层等方面进行了研究。结果表明,釉面砖表面涂层对活性大红有一定的降解作用,溶液体积30mL,调节其pH值为4,紫外灯照射5h后,降解率可达到60.4%。     

Formation of nanocrystalline matrix of sodium rare earth fluoride up-conversion phosphors

Until now, ytterbium and erbium co-doped sodium yttrium fluoride (NaYF4:Yb, Er) is among the most efficient up-conversion phosphors. Its potential for applications in biological and medical fields has interested many scientists. However, the formation mechanism of the co-doped sodium yttrium fluoride nanoparticles is still unknown. Based on the similarity of rare earth elements, this work started with studying the formation mechanism of NaYF4 nanoparticles without doping in aqueous phase. Effects of reactant concentrations, pH, and reaction time on the particle formation were investigated. As the reaction time increased, NaYF4 nanoparticles grew sporadically. Effect of seeding was also studied. The reaction was not accelerated and the particle size was not altered by seeding. The above investigations suggested that in aqueous solution NaYF4 nanoparticles were formed by the aggregation model. The aggregation of the primary particles may play a key role for the formation and size control of the nanoparticles. Smaller particles were achieved by the presence of chelators of Na2-ethylenediaminetetraacetic acid and sodium nitrilotriacetate. This probably resulted from the adsorption of chelators on the NaYF4 nanoparticles and increased the repulsive force between the primary particles, preventing primary particles to form large particles by aggregation.     

硫酸盐还原法制备La_2O_2S∶Yb,Er及其上转换发光性能

采用硫酸盐还原法制备了Yb、Er双掺的La2O2S粉体,考察了柠檬酸用量、前驱体煅烧温度、碳还原温度、Er3+离子浓度和Yb3+离子浓度对粉体的影响。分别采用X-射线衍射分析(XRD)、扫描电子显微镜(SEM)、比表面积分析(BET)、紫外可见光分光光度计(UVPC)和荧光光谱分析(PL)对粉体的相组成、形貌、颗粒尺寸、反射率和上转换发光性能进行表征。研究结果表明,800℃时可以得到纯相的La2(SO4)3;碳还原温度为900℃以上可以得到纯相的结晶较好的La2O2S;样品的粒径大约为100～200nm,颗粒存在一定的团聚;柠檬酸与硝酸盐的最佳摩尔比为1.5∶1;Er3+离子掺杂浓度为2mol%、Yb3+离子掺杂浓度为12mol%时粉体的上转换发光强度最强。     

Sonochemical degradation of Basic Blue 41 dye assisted by nanoTiO2 and H2O2

The sonolysis of Basic Blue 41 dye in aqueous solution was performed at 35 kHz using ultrasonic power of 160 W and aqueous temperature of 25+1 degrees C within 180 min. The TiO2 nanoparticles were used as a catalyst to assist the sonication process. The effect of experimental parameters such as pH, H2O2 concentration and initial dye concentration on the reaction were investigated. It was recognized that in lower pH values the dye removal rate decreased. However, dye removal increased via increase in H2O2 concentration and lowering the initial dye concentration. All intermediate compounds were detected by integrated gas chromatography-mass spectrometry (GC/MS) and also ion chromatograph (IC). During the decolorization, all nitrogen atoms and aromatic groups of Basic Blue 41 were converted to urea, nitrate, formic acid, acetic acid and oxalic acid, etc. Kinetic studies revealed that the degradation process followed pseudo-first order mechanism with the correlation coefficient (R2) of 0.9918 under experimental conditions. The results showed that power ultrasound can be regarded as an appropriate tool for degradation of azo dyes to non-toxic end products.     

Ba2+共掺杂YPO4∶Tb3+荧光材料的水热合成与荧光性能

采用水热法合成Ba~(2+)共掺杂YPO4∶Tb~(3+)荧光材料,并通过X射线衍射(XRD)、扫描电子显微镜(SEM)和荧光分光光度计等研究了合成样品的物相组成和荧光性能,并分析了Ba~(2+)掺杂量和反应体系pH值等对合成样品的物相结构及荧光性能的影响。结果表明,反应体系pH值和Ba~(2+)掺杂量直接影响所制备样品的结构与性能。少量Ba~(2+)(≤10%,原子分数,下同)共掺杂YPO4∶1%Tb~(3+)样品均为纯相四方晶系磷钇矿结构晶体,过量Ba~(2+)掺杂导致Ba_3(PO_4)_2杂质相的出现;pH值为6的水热环境下可获得高结晶度的单一相Ba~(2+)、Tb~(3+)共掺杂YPO4样品。激发和发射光谱测试结果表明,所制备的YPO4∶1%Tb~(3+),x%Ba~(2+)样品可被225nm的紫外光有效地激发而发射出强烈的Tb~(3+)特征的黄绿色光。一定量的Ba~(2+)共掺杂可以有效地提高YPO4∶1%Tb~(3+)样品的荧光性能,但过量(高于10%)的Ba~(2+)掺杂又会导致Tb~(3+)的荧光猝灭现象出现,最佳的Ba~(2+)共掺杂量为10%。所制备的YPO4∶1%Tb~(3+),10%Ba~(2+)样品在225nm紫外光激发下位于545nm处的发射带强度是YPO4∶1%Tb~(3+)样品的1.8倍。     

Phosphorus and nitrogen co-doped titania photocatalysts with a hierarchical meso-/macroporous structure

Visible light-active phosphorus and nitrogen co-doped meso-/macroporous titania materials were prepared by a simple two-step approach of the direct phosphation with the use of phosphoric acid solution and the succedent nitridation with the use of the urea solution. The prepared materials were characterized by UV–vis, solid-state ³¹P MAS NMR, FT-IR, XPS, XRD, SEM, TEM, and N₂ adsorption analysis. Direct synthesis of phosphorus-doped meso-/macroporous titania materials could inhibit the formation of brookite phase and increase the surface area significantly, resulting in the hierarchical porous framework of nanocrystalline anatase phase with enhanced thermal stability and large porosity, and these features retained during the subsequent nitridation. The incorporation of P and N in the anatase titania lattice in the form of O–Ti–N, O–P–N, and Ti–O–P linkages was evidenced, and the extension of the absorption edges into the visible region and the corresponding narrowing of band gaps were observed in these N and P co-doped meso-/macroporous titanias, giving a higher photocatalytic activity in the degradation of Rhodamine B dye under visible-light irradiation than the samples doped with only N or P. The beneficial effect of hierarchical meso-/macroporous structure is also examined.     

Sorption study of an acid dye from an aqueous solution on modified Mg-Al layered double hydroxides

In this paper, experimental methods and results are reported on the removal of the dye Green Bezanyl-F2B (an acid dye) from MgAlCO(3) (HT) and from intercalated anionic surfactant, "sodium dodecylsulfate (SDS)", into the Mg-Al layered double hydroxides by the calcination-rehydration reaction using Mg-Al oxide precursors calcined at 773 K. Dodecylsulfate hydrotalcite was prepared by the calcination-rehydration method. The surfactant intercalation in the interlayer space of hydrotalcite was investigated by XRD and FT-IR spectroscopy where the resulting materials were found to be similar to those reported in the literature and were used to remove an acid dye from an aqueous solution. Equilibrium time and rate-determining step of the dye Green Bezanyl-F2B sorption were determined. Two simplified kinetic models were tested to investigate the sorption. The adsorption capacity data were also fitted to Langmuir and Freundlich equation as well. The sorption data fitted to the Langmuir model gave good values of the determination coefficient.