掺Ag复合纳米TiO2光催化性能

通过溶胶-凝胶法和光还原法制备掺Ag复合纳米TiO2.用XRD表征了TiO2的晶体形态.以典型偶氮结构的甲基橙水溶液为模拟对象,研究掺Ag复合纳米TiO2光催化性能.实验结果表明,TiO2悬浮体系中甲基橙的光催化降解符合Langmuir动力学规律.根据动力学计算,掺Ag复合TiO2和单纯TiO2对甲基橙的降解速率常数分别为27.34mg/(L·h)和14.42mg/(L·H),光催化的活性提高了近2倍.因此有望通过这一技术制备出比单纯TiO2更好的光催化剂.     

纳米TiO2薄膜光催化降解苯酚和氯代苯酚的研究

采用溶胶凝胶法制备纳米TiO2薄膜,研究了初始浓度、pH和外加H2O2对TiO2薄膜光催化降解苯酚、对氯苯酚和2,4-二氯苯酚影响.结果表明,纳米TiO2薄膜对于苯酚和氯代苯酚均有较高的光催化活性,相同条件下,2,4-二氯苯酚的光催化降解速率＞4-氯苯酚＞苯酚.在本实验条件下,随着反应物初始浓度的升高,相同时间内,苯酚和氯代苯酚的降解效率均逐渐降低.在中性条件下,苯酚和氯代苯酚的光催化反应速率均强于酸性条件下,其中pH对苯酚光催化降解的影响幅度最大.适量的H2O2有助于提高苯酚和氯代苯酚光催化降解速率.     

TiO2/沸石光催化性能的研究

以钛酸丁酯为原料,用溶胶-凝胶法制备了TiO2并将之负载到天然沸石上。使用XRD、SEM及比表面积分析仪对样品进行了表征;以甲基橙为光催化降解模型,紫外灯为光源,用褪色率等对光催化剂性能进行了评价;对天然沸石负载TiO2的光催化性能及影响因素进行了探讨。实验表明:300℃焙烧后、含有少量金红石相混晶的锐钛矿TiO2光催化能力最好。甲基橙的初始浓度及光强越大,光解率也越大,在pH约等于6时,光解率达到最大。     

TiO2超声光催化降解荧光增白剂-CBW

均匀沉淀法制备了纳米TiO2，TEM，xRD分别进行了表征。以该纳米TiO2为光催化剂，对超声光催化降解荧光增白剂CBw的反应进行了研究。结果表明，超声波的引入提高了纳米TiO2光催化降解CBw的反应效率；反应符合Langmuir-Hinshelwood动力学模型，表观反应速率常数k1为0．0266min^-1；反应受超声波功率的影响；溶液中添加少量的Fe^3 ，H3PW12O40、H2O2均能够明显地强化CBw的降解反应。     

H_2O_2/Nafion-纳米TiO_2复合膜强化日光光解脱色甲基橙染料研究

用流延法在石墨板上成功制备出用于光催化的Nafion-纳米TiO_2复合膜。在H_2O_2存在的条件下,用Nafion-纳米TiO_2复合膜对甲基橙染料进行可见光照射处理。结果表明,H2_O_2/Nafion-纳米TiO_2复合氧化工艺中甲基橙降解脱色速率显著提高,两者之间存在明显的协同效应。在协同体系中,酸性媒介比碱性媒介更有利于甲基橙染料光解脱色。实验所用的NO_3~-、Cl~-和SO_4~(2-)等阴离子,均对降解脱色有抑制作用,其中NO_3~-对脱色作用抑制最显著。可见光辐射处理前后,UV-Vis谱图分析表明在H_2O_2/Nafion-纳米TiO_2复合膜处理中甲基橙溶液脱色是因为染料发生氧化光解作用。     

二氧化钛光解与滑动弧等离子联合降解偶氮染料研究

采用气液两相滑动弧等离子和二氧化钛光降解技术联合处理酸性橙Ⅱ,研究了二氧化钛浓度、气体类型和溶液初始pH值对酸性橙Ⅱ降解率的影响.结果表明:在电压为10kV,频率为50Hz,电极间最窄距离处为3.5mm条件下,对于浓度是300mg/L的酸性橙Ⅱ溶液,二氧化钛浓度为1.0g/L,初始pH值为酸性或碱性,载体为氧气,协同效应明显,更有利于酸性橙Ⅱ降解率的提高.同时检测了纯水放电条件下,二氧化钛的加入对活性粒子H2O2、O3和OH·生成量的影响,酸性橙Ⅱ降解率的提高是更多活性粒子作用的结果.用红外光谱和GC-MS对降解产物测试分析,推测酸性橙Ⅱ的可能降解途径,即羟基自由基攻击酸性橙Ⅱ分子上的C-N键,导致C-N键的断裂,染料脱色矿化降解.     

纳米Fe3O4催化UV-Fenton降解邻苯二酚的效能及自由基的鉴定

采用纳米Fe3O4催化UV-Fenton降解邻苯二酚,考察了溶液的初始pH值、H2O2投加量、催化剂的投加量和反应温度对邻苯二酚配水中COD的去除效果的影响.其结果表明,在邻苯二酚的浓度为100 mg/L、溶液初始pH为7、H2O2投加量为14.75 mmol/L、催化剂的投加量为0.50 g/L、反应温度30℃的条件...     

Ag/TiO2光催化膜降解高浓度对氯苯酚溶液的研究

依据光催化还原原理 ,在活性碳负载的TiO2 纳米粒子膜表面上制备出载银光催化剂 ,采用该催化剂对初始COD≥ 6 0 0mg·L-1的高浓度 4 氯苯酚水溶液进行降解研究 ,分别考察了光催化剂的用量、反应液初始浓度和初始 pH值等对降解性能的影响 ,并与DegussaP2 5微粉光催化剂等进行比较 ,得出负载型Ag/TiO2 光催化膜具有光催化活性高、固液易分离的特点。     

光／电Fenton催化降解有毒有机污染物

在可见光(λ>450nm)照射并通外加电压(E=3V)条件下,以染料酸性桃红(Sulforhodamine B,SRB)及有机无色小分子化合物2,4-二氯苯酚(2,4-dichlomphenol,DCP)为目标物,探索光电Fenton降解其最佳反应条件,结果表明,对1.0×10-5mol/L SRB Fenton试剂(Fe3+/H2O2)在pH=3.0,H2O2浓度为7.49×10-4mol/L,Fe3+为2.48×10-4mol/L时,SRB降解效果最好.通过分析SRB及DCP降解过程紫外.可见光谱(UV-Vis)、红外光谱(FTIR)和总有机碳(TOC)测定,发现光电Fenton体系能使SRB和DCP发生有效的降解,SRB反应300min矿化率达到96.38%,DCP反应90min降解率达到100%.采用酶分析法和苯甲酸荧光分析法分别测定了在光电催化降解有机污染物过程中H2O2和羟基自由基(·OH)的变化,表明此光催化降解过程涉及·OH历程.     

太阳光光催化降解弱酸性大红的动力学研究

采用自制的反应装置,研究了负载型TiO2膜太阳光光催化降解弱酸性大红的动力学.结果表明:在所研究的范围内,太阳光光催化降解弱酸性大红符合一级动力学反应,可用L-H动力学方程描述,且反应速率常数(K)与C0-1.50、pH-1.147和V成正比;太阳光光催化对染料的降解无选择性且弱酸性大红染料能够被完全矿化为CO2和H2O;一年四季降解实验中,由于冬季太阳光光强太弱,应考虑人工光源作为补偿.     

太阳光TiO_2多孔纳米薄膜光催化降解有机磷农药的研究

锐钛矿型 Ti O2 多孔纳米薄膜可以从含聚乙二醇的钛醇盐溶胶前驱体中通过浸渍提拉法制备 ;涂层的形貌如孔的大小和孔的分布可以通过聚乙二醇的加入量来控制 ,当聚乙二醇的加入量为 0— 2 .0 g时 ,孔径大小在 0— 40 0 nm范围内变化。可见光透过光谱分析表明 :随着 Ti O2 薄膜中孔径增大 ,光的散射增强 ,透光率减小 ,该 Ti O2 镀膜玻璃对于紫外线具有吸收作用。有机磷农药水溶液的太阳光催化降解实验表明 :在 Ti O2 薄膜中引入气孔增强了光催化活性 ,孔的大小和薄膜厚度对光解率有显著的影响。当孔径大小为 1 0 0— 2 0 0 nm,镀膜次数为 1 0— 1 5次时 ,Ti O2 薄膜显示光催化效率高。     

TiO_2/C复合毫米球的制备及可见光催化活性研究

应用溶剂热条件下离子交换方法制备了C掺杂TiO2毫米球光催化剂。并通过元素分析、X射线衍射(XRD)、紫外-可见(UV-Vis)漫反射对其进行了表征。结果表明,TiO2为锐钛矿相,UV-Vis漫反射分析显示,与商业用P25相比,TiO2吸收边带红移,可见光吸收增强,同时证明C以掺杂的方式对TiO2进行了改性。以可见光催化降解甲基橙(MO)考察了材料的光催化活性,与P25相对比,C掺杂TiO2的光催化活性明显提高,并且催化剂可以通过自身重力沉降到反应容器底部,实现自分离。     

Photocatalytic activity of TiO2 nanotube layers coated with Ag and Pt

Abstract

Abstract

Thin films of anatase TiO₂ nanotube arrays (TiO₂ NTs) were prepared in this study. Pt and Ag were coated on the TiO₂ NTs films, which intend to increase the photocatalytic activity under ultraviolet-visible (UV-vis) irradiation. The phase and structure of the films were investigated by X-ray diffraction and scanning electron microscopy. Photocatalytic activity was tested by UV-vis absorption spectroscopy and showed that UV-vis light absorption of the films was remarkably improved by coated Ag and Pt by 72% and 183% respectively. The photocatalytic activities of the films towards degraded methyl orange and HCHO were compared and were all found to follow the sequence Pt/TiO₂ NTs>Ag/TiO₂ NTs>TiO₂ NTs. It was also found that the kinetics of HCHO photocatalytic degradation by the films fits the first order reaction model better and has higher efficiency than that of the methyl orange photocatalytic degradation by the same films.     

Solar-based photoreduction of methyl orange using zeolite supported photocatalytic materials

A new class of novel photocatalysts has been prepared by supporting TiO₂ on the zeolite matrix by various routes of synthesis. Different transition metals like cobalt, nickel, and ruthenium have been incorporated in these photocatalysts, alongwith molybdenum based heteropolyacid (HPA) to improve the photocatalytic activity of these materials. Photoreduction of methyl orange under solar radiation was compared with photoreduction in presence of artificial visible light illumination to evaluate their photocatalytic activity. The quantity of methyl orange photoreduced by the cobalt containing photocatalyst was about 2.40 mg/g of TiO₂ under the influence of sunlight as compared to 4.111 mg/g of TiO₂ under artificial visible light illumination. However, the efficiency of the photocatalyst is high as compared to P25 TiO₂ under solar light (0.508 mg/g of TiO₂). The high photocatalytic activity of these materials is due to the synergistic effect of incorporation of transition metals in combination with TiO₂ and HPA supported by the zeolite matrix. These materials are being evaluated for photocatalytic water splitting.     

不同类型染料化合物太阳光催化降解研究

针对四大类八种水溶性染料和一种化学指示剂，在相同实验条件下，进行了ＴｉＯ２悬浆体系太阳光催化氧化降解规律的研究。在ＵＶ辐照度２１．２８Ｗ／ｍ２的晴天，染料初始浓度均为２０ｍｇ／Ｌ，催化剂投加量１ｇ／Ｌ，溶液平均温度２０℃，经太阳光照射４ｈ，各料染料脱色和总有机碳去除明显。根据表观速率常数算出不同染料光催化降解的难易程度，实验证实了多相光催化氧化技术用于染料废水处理工艺的可行性。     

Photodegradation of methyl tertiary butyl ether (MTBE) vapor with immobilized titanium dioxide

A study on the photocatalytic degradation of methyl tertiary butyl ether (MTBE) vapor was performed with respect to reaction parameters, kinetics, and mechanism. A conventional TiO₂-coated plate system was used for this initial work on vaporized MTBE. On irradiating with UVBLB (5 mW/cm²), 0.6 mg/cm² of TiO₂ (P25) photocatalyst showed the highest reaction rate (0.85 μmol/min) for 25.76 μmole of MTBE (1000 ppmv). The numerical values obtained depended predictably with respect to light intensity, initial concentration, and quantity of P25. The photocatalytic degradation of MTBE followed Lanmuir-Hinshelwood kinetics with a linearity of 0.989. As far as the mechanism of degradation is concerned, attack by generated hydroxyl radicals on the methoxy group in the MTBE structure dominated and proceeded through tert-butyl formate (TBF) as an intermediate, instead of methyl group to proceed through producing 2-methoxy-2-methyl propionaldehyde (MMP). TBF finally degrades to CO₂ through acetone, which was shown easily converted to CO₂. This study shows that the use of sunlight seems to be possible given adequate tools for concentrating the light.     

碳黑改性二氧化钛对气相中甲苯的光催化降解

研究了碳黑改性TiO2对甲苯的吸附和光催化降解性能。并与普通TiO2光催化剂和铝板基材对甲苯的吸附和光催化降解性能相比。结果表明，碳黑改性对甲苯吸附性能与普通TiO2相似，但是其光催化降解性能却有较大提高，并且改性的TiO2光催化剂的催化活性比普通TiO2持续更长的时间。