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Intensification of photocatalytic pollutant abatement in microchannel reactor using TiO2 and TiO2‐graphene
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Natan Padoin Luísa Andrade Joana Ângelo Adélio Mendes Regina de Fátima Peralta Muniz Moreira Cíntia Soares 《American Institute of Chemical Engineers》2016,62(8):2794-2802
A microfluidic device was applied to the photocatalytic degradation of methylene blue as a model pollutant. Titanium dioxide nanoparticles (TiO2–P25) and a synthesized composite TiO2‐graphene catalyst were immobilized on the inner walls of a borosilicate glass microfluidic chip. The deposition evolution of the nanoparticles was evaluated by monitoring the optical profile of the system. It was found that a higher initial reaction rate was obtained in the microreactor containing composite catalyst (TiO2‐GR) on the inner walls, but both systems (TiO2 and TiO2‐GR) achieved similar reaction rates when the steady‐state was reached. Decolorization rate of methylene blue in our microfluidic chips was found to be approximately one order of magnitude higher than equivalent macroscopic systems reported in the literature at similar experimental conditions. Additionally, computational simulations were performed to investigate the physics involved in these processes. The model was experimentally validated for further scale‐out studies. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2794–2802, 2016 相似文献
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纳米TiO_2的制备及光催化性能的研究 总被引:2,自引:1,他引:1
以TiCl4为钛源,用正交实验设计方法,探究了水解法制备TiO2最佳反应条件,即烧结温度为600℃,盐酸用量为1.7 mL,pH值为8。同时研究了催化剂用量和时间对TiO2光催化降解甲基橙的降解率的影响,实验结果表明,当催化剂用量为4 g/L,光催化时间为60 min时,降解率可达到90%以上。 相似文献
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G. E. Imoberdorf G. Vella A. Sclafani L. Rizzuti O. M. Alfano A. E. Cassano 《American Institute of Chemical Engineers》2010,56(4):1030-1044
The radiation field of a packed‐bed photocatalytic reactor filled with quartz wool coated with titanium dioxide was modeled using the Monte Carlo technique and the following information: the radiation flux emitted by the lamps, the diameter size distribution of the quartz fiber cloth, the mass of quartz fibers and of TiO2 that was immobilized on the fiber surface as well as the refractive index, and the spectral absorption coefficient of the materials of the system. Modeling predictions were validated with radiometer measurements of the transmitted radiation through the reactor, the root mean square error being <9.7%. Finally, by means of a parametric study, the validated model was used to analyze the effect of the design variables, such as the radii of the quartz fibers, thickness of the TiO2 coatings, and amount of TiO2‐coated quartz wool, on the distribution and nonuniformity of the radiative energy distribution inside the reactor. © 2009 American Institute of Chemical Engineers AIChE J, 2010 相似文献
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TiO2覆膜沸石光催化剂制备及其降解造纸废水 总被引:1,自引:0,他引:1
以钛酸四丁酯和乙醇为原料,采用溶胶-凝胶(Sol-Gel)法制备以天然沸石为载体的负载型TiO2光催化剂,并利用X射线衍射(XRD)和扫描电镜(SEM)等对其进行结构表征. 通过自行设计的光催化反应器考察了溶胶-凝胶体系的组成、焙烧温度及焙烧时间、废水pH值、光催化剂用量和光反应时间等因素对光催化剂降解造纸废水性能的影响,同时讨论了该催化剂的可重复利用性,确定了天然沸石负载型TiO2的制备及处理造纸废水的最佳实验条件:无水乙醇/钛酸四丁酯体积比4.0,冰醋酸/钛酸四丁酯体积比0.1,水/钛酸四丁酯体积比0.15,硝酸/钛酸四丁酯体积比0.1,焙烧温度300℃、焙烧时间4.0 h,造纸废水pH 4.0,光催化剂用量50 g/L,光照时间8.0 h,在此条件下造纸废水COD去除率可达81.93%. 相似文献
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Modeling heterogeneous photocatalytic inactivation of E. coli using suspended and immobilized TiO2 reactors
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Majdi Kacem Vincent Goetz Gael Plantard Nathalie Wery 《American Institute of Chemical Engineers》2015,61(8):2532-2542
A study was carried out to develop a kinetic model of the photocatalytic inactivation of Escherichia coli using different TiO2 catalysts. The model developed is based on a reaction scheme that involves effectively coupling mass‐transfer fluxes between bacteria and catalyst surface on one hand and bacterial degradation reaction on the other. The photocatalytic results were derived from experiments led in a batch reactor under both dark and Ultra Violet (UV) irradiation conditions. Using a reference catalyst, the robustness of the developed model was tested under solar conditions. The experimental data validated the model as successfully able to reproduce evolutions in the viable bacteria concentration in the range of parameters studied without any further adjustment of the kinetic parameters. The model was used to simulate the bacterial degradation kinetics under different working conditions to describe the partitioning of both bacterial adhesion and photocatalytic reaction in the solution to be treated © 2015 American Institute of Chemical Engineers AIChE J, 61: 2532–2542, 2015 相似文献
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《Journal of the European Ceramic Society》2022,42(5):2496-2504
A glass hollow fiber membrane coated with TiO2 was successfully synthesized by dip-coating and calcination. In addition, the effects of the calcination temperature, number of coating layers, and treatment method on the photocatalytic removal of methylene blue from wastewater by the membrane were investigated. The results showed that the TiO2-coated membrane calcined at 550 °C was uniform. It showed good photocatalytic and anti-fouling properties. As compared to the basement membrane, the TiO2-coated membrane showed significantly improved photocatalytic removal of methylene blue. It showed a methylene blue removal degree as high as 97.2% and could be recycled multiple times by a simple treatment. The methylene blue removal degree of the membrane remained 92.3-93.6% after five recycling operations. Therefore, the membrane prepared via the simple method proposed in this study could be used as an efficient photocatalyst to remove methylene blue from wastewater. 相似文献
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Serge Corbel Nidhal BecheikhThibault Roques-Carmes Orfan Zahraa 《Chemical Engineering Research and Design》2014
The main objective of this paper was to evaluate the influence of mass transfer on the photocatalytic efficiency at a low flow rate in the order of several mL per hour. Several continuous flow microchannel reactors have been used to study the degradation of salicylic acid (SA) taken as a model pollutant. The photocatalytic degradation of salicylic acid, under UV illumination of 1.5 mW cm−2, was assessed from the outlet concentration measured by liquid chromatography HPLC. It was shown that the degradation of SA by UV was limited by mass transfer. Numerical simulations have allowed establishing a relationship of the Sherwood number valuable for all the microchannel geometries. Computational fluid dynamics with Comsol Multiphysics is useful for predicting the degradation yield for a given geometry of the microreactor. The best representation of the experimental data is obtained by introducing a kinetic law taking into account mass transfer limitation. 相似文献
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石英棒负载TiO2膜光催化降解苯酚影响因素研究 总被引:4,自引:0,他引:4
采用浸涂粉末沉积-焙烧法在石英光导棒的表面制备了TiO2膜,并利用该固定膜催化剂光催化降解苯酚溶液,考察了各种反应条件对苯酚降解效果的影响。结果表明,曝气状态下的处理效果要显著优于非曝气状态。在1.05~8.28L/h范围内改变循环流量,苯酚的降解率随流量的增大而升高,当循环流量增大到一定程度(5.04L/h)时,外扩散不再成为反应的限制因素。以乙醇作为自由基清除剂,加入0、1mL和10mL体积分数为80%乙醇的苯酚降解率分别为94.10%、73.03%和65.83%。H2O2的投加量在0.05~5mL/L之间改变,苯酚降解率随H2O2投加量的增加而提高,但是在投加量超过0.1mL/L后,降解率趋于稳定。 相似文献
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Characteristics of photocatalytic oxidation of gaseous 2‐propanol using thin‐film TiO2 photocatalyst
Chiu‐Ping Chang Jong‐Nan Chen Ming‐Chun Lu 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2004,79(11):1293-1300
This work presents a photocatalysis‐based method to treat and purify air because of its broad applicability to common, oxidizable, air contaminants. The effect of oxygen content, temperature, water vapor, and 2‐propanol concentration on the TiO2 surface was investigated. The rate of 2‐propanol decomposition increased with increasing the oxygen content, but was reduced at temperatures higher than 100°C. When water vapor concentration was in the range of 10–355 mmol m?3, the rate of 2‐propanol decomposition was proportional to the water content. However, an opposite result was observed at a higher concentration of water vapor. 2‐Propanol was photooxidized to acetone, and eventually to carbon dioxide and water. The kinetic model of 2‐propanol photooxidation was successfully developed by the competitive Langmuir–Hinshelwood rate form, incorporating the inhibition effect coming from the formation of acetone. Copyright © 2004 Society of Chemical Industry 相似文献
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S,Fe共掺杂纳米TiO_2的制备及其光催化性能 总被引:2,自引:0,他引:2
以水热法制得了S,Fe共掺杂的纳米TiO2光催化剂(TiO2-S-Fe),XRD分析表明,其为锐钛矿晶型,S,Fe掺杂能抑制TiO2粒径的生长;UV-vis漫反射表明,TiO2-S-Fe对可见光吸收增强,吸收带边明显红移;XPS显示S,Fe共掺杂,使得TiO2表面羟基氧含量提高,从而提高催化剂活性;可见光降解甲基橙溶液结果表明,共掺杂样品光催化效果优于单掺样品,S和Fe共掺杂对提高TiO2可见光活性具有协同效应。当Fe3+∶S∶Ti(摩尔比)=0.005∶1∶1,180℃下水热反应3 h时,制得的TiO2-S-Fe可见光催化活性比纯TiO2的活性提高了约10倍。 相似文献
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Although photocatalyzed total oxidation reaction of hydrocarbon species has been discussed in the literature, most of these studies were performed to obtain an appropriate reaction mechanism. Studies on the kinetics of this type of reaction are rare. Using titanium dioxide as the photo catalyst, the kinetics of the total oxidation of methane, ethane, ethene, as well as propene, have been investigated using a continuous‐stirred tank reactor. In the experiments, the hydrocarbon concentrations, the oxygen concentration, and the irradiation intensity were varied. The results obtained are evaluated on the basis of a kinetic model to derive rate equations which can be used for reactor design. 相似文献
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Marcin Piątek Anna Gancarczyk Marzena Iwaniszyn Przemysław J. Jodłowski Joanna Łojewska Andrzej Kołodziej 《American Institute of Chemical Engineers》2017,63(6):1799-1803
Based on experimental results of gas flow resistance through two metal foams, NC 2733 and Ni 2733, a modeling is performed to adjudicate governing flow mechanism. Two essential models are considered: developing laminar flow within short capillary channel (i.e., foam pore) and flow around solid body (foam strut modeled as cylinder or sphere), each of them of some variants. Foam geometry was studied using computer microtomography. The model of flow around a sphere (diameter equal to strut thickness) gives the best conformity with experiments. © 2017 American Institute of Chemical Engineers AIChE J, 63: 1799–1803, 2017 相似文献
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T.A. McMurray J.A. Byrne P.S.M. Dunlop E.T. McAdams 《Journal of Applied Electrochemistry》2005,35(7-8):723-731
Titanium dioxide (TiO2) photocatalysis is a possible alternative/complementary technology for water purification. Attempts to increase the overall
efficiency of the process include using higher energy UV to gain better quantum efficiency and electrochemically assisting
the process by the application of an external electrical potential. In this work, nanocrystalline TiO2 films, prepared on borosilicate glass and indium-doped tin oxide (ITO) borosilicate glass, were used to investigate the photocatalytic
and electrochemically assisted photocatalytic oxidation of formic acid under UVA and UVB irradiation. The experiments were
carried out in a stirred tank reactor with high mass transfer characteristics. The rate of formic acid oxidation under UVB
irradiation was 30% greater as compared to UVA irradiation. A maximum Φapp of 9% was obtained under UVA irradiation in 100% O2 under open circuit or +1.0 V (SCE) applied potential. A maximum Φapp of 20.3% was obtained under UVB irradiation with 100% O2 using TiO2 on borosilicate glass. Φapp was 19% for +1.0 V, 100% O2, using TiO2 on ITO borosilicate glass under UVB irradiation. The increase in oxidation rates and Φapp with UVB irradiation are due to the higher extinction coefficient of TiO2 at shorter wavelengths and/or the promotion of conduction band electrons to higher more stable states, thus reducing the
rate of recombination of charge carriers. The use of a UVB source as compared to a UVA source results in a significant increase
in the rate of oxidation and increased apparent quantum yields, however, a cost analysis of the process would be required
to determine the economic viability of employing UVB sources. Electrochemically assisted photocatalysis may prove beneficial
in large-scale reactors where mass transfer limitations exist. 相似文献
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研究了在UV/TiO2悬浮体系中光催化降解碱性品红。考察了碱性品红浓度、悬浮液pH值和外加无机盐对降解效果的影响。实验结果表明,当碱性品红质量浓度分别为20.0mg/L,30.0mg/L,40.0mg/L时,光照180min后,悬浮液中剩余的碱性品红质量浓度分别为1.8mg/L,2.3mg/L,3.4mg/L。pH=9.00时降解效果最好,当初始碱性品红质量浓度为30mg/L时,光照180min后,悬浮液中剩余的碱性品红质量浓度为0.8mg/L;pH=3.00的降解效果最差,光照180min后,悬浮液中剩余的碱性品红质量浓度为6.8mg/L;无机盐对降解效果有不同程度的负面影响。对降解机理的探讨表明光催化反应发生在光催化剂表面。 相似文献
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XZ Li H Liu LF Cheng HJ Tong 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2004,79(7):774-781
A new photocatalyst, named TiO2 microspheres, prepared by a sol‐spraying‐calcination method, can freely suspend with air bubbling in its aqueous suspension and easily settle down from a water phase under gravity. The experimental results demonstrated that TiO2 microspheres had better adsorption capacity than conventional TiO2 powders, due to large surface area, large pore volume, and also a porous structure. The photocatalytic activity of TiO2 microspheres in aqueous suspension was evaluated using salicylic acid (SA) as a model substrate. It was found that the Langmuir–Hinshelwood model in its integral form described the kinetics of SA photocatalytic degradation in the TiO2 microsphere suspensions better than its simplified form as a first‐order reaction model, since the significant substrate adsorption on the catalysts was not negligible. The kinetics of SA photocatalytic degradation with different initial concentrations and pH was further investigated. The experiments demonstrated that the change of pH could significantly affect the adsorption of SA in the TiO2 microsphere suspensions. The effects of substrate adsorption rate and photoreaction rate on the overall performance of photocatalytic degradation is also discussed on the basis of experimental data. Copyright © 2004 Society of Chemical Industry 相似文献
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用溶胶凝胶法将TiO2负载于颗粒活性炭(AC)上,500℃焙烧得到TiO2/AC催化剂,用比表面积测定仪(BET)、扫描电镜(SEM)和XRD表征其结构。在连续流反应器中以紫外灯为光源,光催化氧化处理阿奇霉素废水,并优化工艺参数。结果表明,在TiO2/AC中w(TiO2)=1.24%、pH=4,水力停留时间90 min条件下,阿奇霉素去除率≥94.1%,反应器连续运行240 h催化剂活性无明显下降。 相似文献