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排序方式: 共有253条查询结果,搜索用时 140 毫秒
191.
192.
可见光催化剂BiVO_4 降解废水中直接耐酸大红4BS 总被引:4,自引:3,他引:1
以直接耐酸大红4BS模拟染料废水为目标污染物,研究了BiVO_4对直接耐酸大红4BS(简称4BS)的吸附效果以及废水初始质量浓度、废水pH和BiVO_4的加入量对光催化降解效果的影响.实验结果表明:当废水初始质量浓度为40 mg/L、废水pH为6.38、BiVO_4加入量为1.0 g/L时,4BS的降解率可达98.9%;BiVO_4重复使用5次后4BS的降解率可达80.0%以上;COD的变化趋势说明4BS被催化剂吸附和光催化降解的过程是循序渐进的. 相似文献
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194.
以钛酸丁酯为前驱物、无水乙醇作溶剂、二乙醇胺作为抑制剂,采用溶胶-凝胶法制备TiO2溶胶,在NN3气流中直接进行热处理,制备一系列不同焙烧温度的淡黄色的掺氮纳米TiO2粉体。经XRD、UV-Vis和FTIR分析表明,实验制得的TiO2-xNx在350、400、450、500和550℃热处理3 h后仍为锐钛型;450℃保温3 h掺氮样品具有最佳的紫外-可见光响应,其吸收边红移至720 nm左右。罗丹明B的可见光降解实验及产物分析表明,掺氮样品具有良好的可见光催化活性。 相似文献
195.
Synthesis and enhanced visible-light responsive of C,N,S-tridoped TiO2 hollow spheres 总被引:1,自引:0,他引:1
C,N,S-tridoped TiO2 hollow spheres (labeled as C,N,S-THs) were synthesized using carbon spheres as template and C,N,S-tridoped TiO2 nanoparticles as building blocks. The structure and physicochemical properties of the catalysts were characterized by X- ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis diffuse reflectance spectrum (DRS), N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy (XPS) and Photoluminescence emission spectroscopy (PL). The results showed that the hollow spheres had average diameter of about 200 nm and the shell thickness was about 20 nm. The tridoped TiO2 hollow spheres exhibited strong absorption in the visible-light region. C,N,S-tridoped could narrow the band gap of the THs by mixing the orbit O 2p with C 2p, N 2p and S 3p orbits and shift its optical response from ultraviolet (UV) to the visible-light region. PL analysis indicated that the electron-hole recombination rate of TiO2 hollow spheres had been effectively inhibited when doped with C, N and S elements. The photocatalytic activities of the samples were evaluated for the degradation of X-3B (Reactive Brilliant Red dye, C.I. Reactive Red 2) aqueous solution under visible-light (λ 〉 420 nm) irradiation. It was found that the C,N,S-tridoped TiO2 hollow spheres indicated higher photocatalytic activity than commercial P25 and the undoped counterpart photocatalyst. 相似文献
196.
Ashok Kumar Chakraborty Md Emran Hossain Md Masudur Rhaman K M A Sobahan 《环境科学学报(英文版)》2014,26(2):458-465
A nanoheterojunction composite photocatalyst Bi2O3/TiO2working under visible-light(λ 420 nm) was prepared by combining two semiconductors Bi2O3 and TiO2 varying the Bi2O3/TiO2molar ratio. Maleic acid was employed as an organic binder to unite Bi2O3 and TiO2 nanoparticles. The SEM, TEM, XRD and diffuse reflectance spectra were utilized to characterize the prepared Bi2O3/TiO2nanoheterojunction. The nanocomposite exhibited unusual high photocatalytic activity in decomposing 2-propanol in gas phase and phenol in aqueous phase and, evolution of CO2 under visible light irradiation while the end members exhibited low photocatalytic activity. The composite was optimized to 5 mol% Bi2O3/TiO2. The remarkable high photocatalytic efficiency originates from the unique relative energy band position of Bi2O3 and TiO2 as well as the absorption of visible light by Bi2O3. 相似文献
197.
Zhiqiao He Liyong Zhan Fangyue Hong Shuang Song Zhengying Lin Jianmeng Chen Mantong Jin 《环境科学学报(英文版)》2011,23(1):166-170
I-doped titanium dioxide nanospheres (I-TNSs) were synthesized via a two-step hydrothermal synthesis route, their potential for the
e cient utilization of visible light was evaluated. The prepared anatase-phase I-TNSs had a bimodal porous size distribution with a
Brunauer-Emmett-Teller surface area of 76 m2/g, a crystallite size of approximately 14 nm calculated from X-ray di raction data, and
a remarkable absorption in the visible light region at wavelengths > 400 nm. The photocatalytic activity of the samples was evaluated
by decoloration of Methyl Orange in aqueous solution under visible light irradiation in comparison to the iodine-doped TiO2 (I-TiO2).
The I-TNSs showed higher photocatalytic e ciency compared with I-TiO2 after irradiation for 180 min even though the latter had a
much greater surface area (115 m2/g). It was concluded that the surface area was not the predominant factor determining photocatalytic
activity, and that the good crystallization and bimodal porous nanosphere structure were favourable for photocatalysis. 相似文献
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199.
以尿素为氮化碳(g-C3N4)合成的前驱体,柠檬酸(CA)作为还原剂,以一步溶剂热法制备铋修饰BiOBr/g-C3N4异质结型复合光催化剂(简称Bi/BiOBr/g-C3N4).通过调控CA的投加量,实现了对Bi/BiOBr/g-C3N4可见光催化的可控制备,并以RhB为目标污染物研究其光催化活性.结果表明:1被还原在BiOBr表面上的Bi金属含量随还原剂CA投加量增加而增加,CA最佳投加量为2 mmol,Bi/BiOBr/g-C3N4的光生载流子的分离效率最高、禁带宽度最窄(2.43 eV).而未采用CA改性的BiOBr/g-C3N4,其禁带宽度为2.8 eV.2投加CA能调控BiOBr形貌(如结晶度、尺寸大小以及晶粒平均厚度),进而调控其光催化活性.当CA投加量为2 mmol时,BiOBr纳米微球大小适中,结晶度最高,晶粒平均厚度最小.3Bi修饰BiOBr/g-C3N4光催化剂对RhB的可见光降解率高达99.8%,其光催化降解速率达到0.097 k·min-1,是BiOBr/g-C3N4光催化速率(0.026 k·min-1)的3.73倍.4Bi/BiOBr/g-C3N4异质结光降解机理是:在Bi金属等离子体效应、BiOBr表面氧空缺与异质结的协同作用下,提高了Bi/BiOBr/g-C3N4异质结对可见光吸收能力和光生载流子的分离效率,从而实现对RhB的高效降解. 相似文献
200.
Bi2WO6可见光催化降解染料废水实验研究 总被引:1,自引:0,他引:1
采用水热法合成了新型的可见光催化剂Bi2WO6,以活性蓝M-2GE染料废水为目标污染物,研究了催化剂的用量、污染物初始浓度、溶液pH、盐效应等因素对光催化降解效果的影响.结果表明,在优化实验条件下(催化剂的投加量为3g·L-1、pH值中性偏酸性、反应90min),对目标污染物的去除率可达到99%;溶液中盐浓度的增加对降解有抑制作用;催化剂对不同初始浓度活性蓝M-2GE染料的去除过程遵循一级动力学方程;催化剂重复使用后催化效果有所下降,但仍然可以保持在90%左右.因此,用水热法合成的催化剂Bi2WO6具有良好的可见光活性. 相似文献