TiO2光催化降解低浓度溴氰菊酯

用高压汞灯为光源,以二氧化钛光催化降解有机溴杀虫剂－溴氰菊酯,研究了ＴｉＯ２用量、ＰＨ值、等对降解的影响及采用太阳光做光源处理溴氰菊酯的可行性。说明以高压汞灯及太阳光作光源,ＴｉＯ２催化降解敌杀死是有效的。     

H2O2—Fe^2＋／TiO2—H2SO4处理废有机溶剂的研究

放射性废有机溶剂是核设施产生的中低放废液，研究了废有机溶剂（ＴＢＰ／ＯＫ）在Ｈ２Ｏ２－Ｆｅ＾２＋／ＴｉＯ２体系中的氧化分解行为，分析了Ｈ２Ｏ２、催化剂（Ｆｅ＾２＋／ＴｉＯ２）、温度、ｐＨ值等因素对反应进程和效果的影响，还对主控因素进行四因素三水平的正交实验，最终确定了废有机溶剂氧化分解的适宜工艺条件。在此基础上进行的“热实验”表明，废有机溶剂氧化分解后其所携放射性核素主要富集在分解残液中，基本没有     

太阳光下降解久效磷的催化剂研究

以ＴｉＯ_２为基体,用掺杂某些金属或离子的方法,提高ＴｉＯ_２;在太阳光下的催化活性。从多种掺杂催化剂中,筛选出太阳光下降解人效磷的有效催化剂 Ｆｅ~３＋／ＴｉＯ_２,经 ３ ｈ阳光照射,久效磷的矿化率达 ９０％。 Ｆｅ~（３＋）在待降解液中的最适宜浓度为 ２．０×１０~（－４）ｍｏｌ／Ｌ。     

日光下黄砂负载TiO2降解邻氯苯酚水溶液

研究了以黄砂为载体,ＴｉＯ２为催化剂,以太阳光为光源对邻氯苯酚水溶液进行光催化降解的可行性。结果表明,锐钛型ＴｉＯ２邓邻氯苯酚有显著的光催化降解作用;ＴｉＯ２的催化活性在焙烧温度３００℃时最高。     

Fe^2＋—H2O2氧化法处理氨基J酸工业废水的研究

用Ｆｅ＾２＋－Ｈ２Ｏ２氧化法处理氨基Ｊ酸工业废水。结果表明,当溶液ｐＨ＝１－３,Ｈ２Ｏ２和Ｆｅ＾２＋用量分别为Ｈ２Ｏ２：Ｆｅ＾２＋１０：１,Ｈ２Ｏ２：ＣＯＤＣｒ＝２ｇ：ｇ时,Ｊ酸废水的ＣＯＤＣｒ去除率达６６．７％,氨基去除率达６８．４％。处理后的废水ＢＯＤ５／ＣＯＤＣｒ＝０．５,已达到生化处理的要求。该法可作为氨基Ｊ酸废水的预处理方法。     

电化学法去除SO2／NOx的研究进展

本文对采用电化学方法去除ＳＯ２／ＮＯｘ废气这一新的研究方法进行了综述,在用酞花青钴（ＣｏＰｃ）修饰的碳气体扩散电极上,ＳＯ２在空气中的体积百分数在２０％以下时可以完全被氧化为硫酸,以连二硫酸盐（Ｓ２Ｏ４＾２－４）作还原剂,Ｆｅ＾２＋－ＥＤＴＡ作络合剂时,ＮＯ可以９０％以上的程度还原为ＮＨ＾＋４与ＮＨ２（ＳＯ３Ｈ）等低价含氮化合物,产物中未见Ｎ２、Ｎ２Ｏ与ＮＯ２等气体,氧化产物ＳＯ＾２－３（或ＨＳＯ     

共存离子对硫酸盐还原菌（SRB）处理含铬废水的影响研究

报道了用硫酸盐还原菌（ＳＲＢ）处理含铬（ＶＩ）废水时，共存离子Ｓｒ＾２＋，Ｃｄ＾２＋，Ｚｎ＾２＋，ＵＯ＾２＋２，Ａｇ＾＋和Ｃｌ＾－，ＳＯ２－４，ＣＯ＾２－３，ＳｉＦ＾２－６，ＥＤＴＡ柠檬酸根等存在的时的影响，在铬（ＶＩ）为５０μｇ／ｍＬ，菌量一定的条件下，铬的去除率可达８５％以上，共存离子与铬（ＶＩ）的摩尔比为４时影响较为显著，Ｃｄ＾２＋和Ａｇ＾＋使铬的去除量降低，ＵＯ＾２＋２，Ｓｒ＾２＋，Ｚｎ＾     

水溶液中残留四环素的光催化降解的实验研究

由于抗菌素具有抑制微生物生存的作用，通常处理工业废水最有效的“生物氧化降解法”却无法用来有效处理四环素废液，简述了半导体光催化剂在紫外光照射下降解难溶或难分解有机物基本原理，以半导体ＴｉＯ２和ＺｎＯ粉粒为光催化剂进行催化降解四环素废液的实验，其结果表明：半导体ＴｉＯ２光催化降解效果比较好；另外，Ｈ２Ｏ２可以作为ＴｉＯ２光催化剂的助氧化剂来加快四环素的降解，该实验结果有助于光催化剂的深入研究和太阳能     

载银TiO2半导体催化剂对印染废水的光降解研究

以新型载银ＴｉＯ２为催化剂，采用高压汞灯为光源对实际印染废水进行了光催化降解的研究。研究结果表明，用新型载银催化剂（简称ＴＳＡ）对印染废水和精炼废水进行深度处理的效果比用ＴｉＯ２为好。在光照１２０分钟条件下，用ＴＳＡ催化剂对印染和精炼废水生化处理出水进行光催化降解，废水的ＣＯＤｃｒ去除率分别达到７５．３％和８３．４％，比同样光降解条件下用单一ＴｉＯ２催化剂时废水的ＣＯＤｃｒ去除率提高２２．９％和２     

A^2／O生物膜法在油脂厂废水处理中的应用

Ａ＾２／Ｏ生物膜法是一种高浓度易降解有机废水处理的新工艺。用于油脂厂废水的处理,经过半年多的试运行,处理效果良好,在进水ＣＯＤ、超过设计水质时,出水ＣＯＤｃｒ超过设计水质时,出水ＣＯＤｃｒ仍能达到排放标准,ＮＨ４＾＋－Ｎ的去除率可达９０％以上,基本无污染冰生。     

负载TiO2/Fe3+的玻璃纤维反应器光催化苯酚

以玻璃纤维为载体,将TiO2负载到其表面形成了空间玻璃纤维反应器,引入Fe3+作为掺杂改性离子,形成了负载TiO2/Fe3+的空间玻璃纤维光催化反应器,并以高压汞灯为光源进行了光催化降解水中苯酚的实验研究,考察了影响苯酚光催化降解的因素,确定了在UV365～250 W光源照射下,pH为3～5,O2通入量1.0 L/(min.L),反应器内上升流速为0.7 m/min等实验条件下,初始浓度为30 mg/L的苯酚废水经120 min光催化反应后,降解率可达到85%,矿化率可达80%。     

Superior photodecomposition of pyrene by metal ion-loaded TiO₂ catalyst under UV light irradiation

BACKGROUND: The photocatalytic degradation of pyrene under UV (125 W Hg-Arc, 10.4 mW/cm2) irradiation of TiO2 aqueous suspension has been found to be highly improved with the dissolved transition metal ions like Cu2+, Fe3+, Ag+, and Au3+, etc. As the reduction potential of these metals lies below the conduction band (CB) position (?0.1 eV) of TiO2, the photoexcited electron transfer occurs more readily and reduces electron–hole recombination rate. Therefore, it has a beneficial influence on the photocatalytic ability of TiO2 because of rapid Fermi energy equilibrium between the CB of TiO2 and its surface adsorbed metal ions. RESULTS AND DISCUSSION: The Fermi level is referred to as the electrochemical potential and plays an important role in the band theory of solids. When metal and semiconductor are in contact, electron migration from photoirradiated semiconductor to the deposited metal occurs at the interface until two Fermi levels equilibrate and enhanced the photocatalytic activity of semiconductor photocatalyst. Ni2+ having more negative reduction potential (?0.25 eV) than the CB of TiO2 imparts negligible co-catalytic activity to TiO2 photoreaction. It also revealed that loading of Au3+ ions displayed higher degradation rate of pyrene than Au photodeposition. Furthermore, when the amount of dissolved Fe+3 and Au3+ ions gradually increases from 0.1 to 2 wt.%, the pyrene photodecomposition rate also become faster.     

The enhancement of TiO2 photocatalytic activity by hydrogen thermal treatment

In this study, conventional TiO2 powder was heated in hydrogen (H2) gas at a high temperature as pretreatment. The photoactivity of the treated TiO2 samples was evaluated in the photodegradation of sulfosalicylic acid (SSA) in aqueous suspension. The experimental results demonstrated that the photodegradation rates of SSA were significantly enhanced by using the H2-treated TiO2 catalysts and an optimum temperature for the H2 treatment was found to be of 500-600 degrees C. The in situ electron paramagnetic resonance (EPR) signal intensity of oxygen vacancies (OV) and trivalent titanium (Ti3+) associated with the photocatalytic activity was studied. The results proved the presence of OV and Ti3+ in the lattice of the H2-treated TiO2 and indicated that both were contributed to the enhancement of photocatalytic activity. Moreover, the experimental results presented that the EPR signal intensity of OV and Ti3+ in the H2-treated TiO2 samples after 10 months storage was still significant higher than that in the untreated TiO2 catalyst. The experiment also demonstrated that the significant enhancement occurred in the photodegradation of phenol using the H2-treated TiO2.     

Photocatalytic degradation of dichlorvos in aqueous TiO<Subscript>2</Subscript> suspensions

Introduction  

In the present work, we explored the kinetics of dichlorvos (2,2-dichlorvinyl dimethyl phosphate, DDVP) decay through UV-A light-induced TiO₂ photocatalysis at pH 4 and 9, and the formation of degradation intermediates and final products under specific experimental conditions. Experimental observations and theoretical considerations allowed us to suggest the degradation mechanism of DDVP by the UV/TiO₂ process in aqueous solution.     

Enhanced photocatalytic degradation of VOCs using Ln3+-TiO2 catalysts for indoor air purification

Two types of lanthanide ion-doped titanium dioxide (Ln3+-TiO2) catalysts including La3+-TiO2 and Nd3+-TiO2 were prepared by a sol-gel method. The effects of the lanthanide ion doping on the crystal structure, surface area, adsorption properties, pore size distribution, and surface chemical state of the catalysts were investigated by means of XRD, BET, and XPS. As results, the crystal size decreased significantly, while the specific surface area, t-plot total surface area, micropore volume, and the total pore volume increased owing to the lanthanide ion doping. The nitrogen adsorption-desorption isotherms of the catalysts showed that the N2 adsorption ability of the Ln3+-TiO2 catalysts was better than the TiO2 catalyst. Among them, the 0.7% Ln3+-TiO2 catalysts demonstrated the highest adsorption ability. The photocatalytic activity of the catalysts was investigated in the experiments of the photocatalytic degradation of benzene, toluene, ethylbenzene and o-xylene (BTEX) in a gaseous phase. The photocatalytic efficiency of the TiO2 catalysts with the lanthanide ion doping was remarkably enhanced by BTEX removal. The 1.2% Ln3+-TiO2 catalysts achieved the highest photocatalytic activity. The enhanced photodegradation of BTEX is possibly due to the improved adsorption ability and the enhanced electron-hole pairs separation due to the presence of Ti3+ on the surface of Ln3+-TiO2 catalysts and the electron transfer between the conduction band/defect level and lanthanide crystal field state.     

超声波-TiO_2光催化联合处理垃圾渗滤液

采用超声波强化TiO2光催化技术处理垃圾渗滤液。研究了TiO2催化剂用量、光照作用、超声波作用、pH值、曝气作用等因素对垃圾渗滤液中COD和氨氮去除率的影响。结果表明,在TiO2粉末的投加量为2 g/L、pH值为11时,先采用功率为292.5 W的超声波辐射3 min,再以高压汞灯(250 W)照射3 min,垃圾渗滤液中的COD和NH3-N去除率分别达到50.1%和75%。若在同一条件下进行饱和曝气可以使NH3-N去除率进一步达到85.3%,但会降低COD的去除率。     

Photochemical and photocatalytic degradation of gaseous toluene using short-wavelength UV irradiation with TiO2 catalyst: comparison of three UV sources

The feasibility of the use of short-wavelength UV (254+185 nm) irradiation and TiO2 catalyst for photodegradation of gaseous toluene was evaluated. It was clear that the use of TiO2 under 254+185 nm light irradiation significantly enhanced the photodegradation of toluene relative to UV alone, owed to the combined effect of photochemical oxidation in the gas phase and photocatalytic oxidation on TiO2. The photodegradation with 254+185 nm light irradiation was compared with other UV wavelengths (365 nm (black light blue lamp) and 254 nm (germicidal UV lamp)). The highest conversion and mineralization were obtained with the 254+185 nm light. Moreover, high conversions were achieved even at high initial concentrations of toluene. Catalyst deactivation was also prevented with the 254+185 nm light. Regeneration experiments with the deactivated catalyst under different conditions revealed that reactive oxygen species played an important role in preventing catalyst deactivation by decomposing effectively the less reactive carbon deposits on the TiO2 catalyst. Simultaneous elimination of photogenerated excess ozone and residual organic compounds was accomplished by using a MnO2 ozone-decomposition catalyst to form reactive species for destruction of the organic compounds.     

Noble metal catalysts for methane removal

Using a bench-scale rig, the activities of Pt, Pd and Pt+Pd catalysts supported on gamma-Al(2)O(3) and on TiO(2) (anatase) for the complete oxidation of methane (300 ppmv) in air have been measured as a function of temperature; values of T(10), T(50) and T(90) together with the Arrhenius parameters (activation energy and pre-exponential factor) are reported. Pt is less active than Pd when deposited on the surface of the TiO(2), but more active when deposited on gamma-Al(2)O(3), however when combined, the Pt+Pd mixture is more active than either metal individually. The T(10) for Pt+Pd/gamma-Al(2)O(3) was being as low as 228 degrees C. The significance of the Arrhenius parameters, for metal containing catalysts is that they exhibit compensation with increasing activation energy, while securing a more rapid increase in conversion from 0% to 100% when the temperature is increased.     

Photocatalytic reactions of pyrene at TiO2/water interfaces

The photocatalytic oxidation of pyrene preadsorbed on TiO2 is examined in aqueous suspension under UV irradiation. Chemical oxygen demand measurements, UV-VIS spectrophotometer, infrared spectrometer and GC-MS analytical techniques were used to monitor the formed intermediates. During the oxidation processes, the ring-open reaction, hydroxylation and ketolysis occurred to produce some intermediate products (4-oxapyrene-5-one, 1,6- or 1,8-pyrenediones, 4,5-phenanthrenedialdehyde, cyclopenta[def]phenanthrene). Some factors affecting the photodegradation rate were also studied. The results were different from other studies: The pH of the dispersion, ratio of Py/TiO2:water had little effect on the photooxidation rate of pyrene catalyzed by TiO2, while the surface coverage, addition of Fe3+ affected it greatly.     

Comparison of advanced oxidation processes and identification of monuron photodegradation products in aqueous solution

The photodegradation of monuron (3-(4-chlorophenyl)-1,1-dimethylurea) in aqueous solutions under simulated solar irradiation has been conducted by different advanced oxidation processes (UV/H(2)O(2), UV/H(2)O(2)/Fe(2+), UV/H(2)O(2)/TiO(2), UV/TiO(2), dark H(2)O(2)/Fe(3+)). The degradation rates were always higher for the homogeneous catalysis in photo-Fenton reactions (UV/H(2)O(2)/Fe(2+)) compared to the heterogeneous photocatalytic systems (TiO(2)/UV and UV/H(2)O(2)/TiO(2)). Optimal concentrations of Fe(2+) and H(2)O(2) for the abatement of the herbicide in the photo-Fenton system were found to be 1 mM Fe(II) and 10 mM H(2)O(2). Several intermediary products were identified using large volume injection micro-liquid chromatography with UV detection (mu-LC-UV), mu-LC-MS and GC-MS techniques and a degradation mechanism has been proposed.