Efficient photocatalytic degradation of methylene blue over BiVO4/TiO2 nanocomposites

BiVO₄/TiO₂ nanocomposites were successfully synthesized by coupling the modified sol-gel method with hydrothermal method. The samples were physically characterized X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer, Emmett and Teller (BET)-specific surface area, UV–vis diffuse reflectance spectrophotometry, zeta potential, and photoluminescence techniques. The BiVO₄/TiO₂ nanocomposites exhibited good photocatalytic activity in degradation of methylene blue under simulated solar light irradiation. The photodegradation of methylene blue demonstrated that 0.5BiVO₄/0.5TiO₂ photocatalyst exhibited much enhanced photoactivity than pure BiVO₄ and TiO₂. Based on the obtained results, the as-prepare BiVO₄/ TiO₂ nanocomposite possessed great adsorptivity of methylene blue, extended light adsorption range, and efficient charge separation properties. Overall, this work could provide new insights into the fabrication of a BiVO₄/TiO₂ composite as high performance photocatalyst and promise as a solar light photocatalyst for dye wastewater treatment.     

掺锌纳米TiO_2光催化降解亚甲基蓝研究

选用掺杂锌的纳米TiO2作为光催化剂对亚甲基蓝进行降解研究。制备工艺参数对样品光催化降解亚甲基蓝的活性具有很大影响,焙烧温度为500℃,Zn2+掺入量为0.5%,催化剂的加入量为1 g/L时光催化剂对亚甲基蓝的降解效果最好;亚甲基蓝的初始浓度为5 mg/L降解速率较快。     

A novel cellulose-derived carbon aerogel@Na2Ti3O7 composite for efficient photocatalytic degradation of methylene blue

A scale-up and sustainable method was developed to fabricate novel photocatalyst cellulose-derived carbon aerogel@Na₂Ti₃O₇ composite (CAT) by in situ growth of Na₂Ti₃O₇ nanowhisker on the surfaces of fibers. With a three-dimensional (3D) mesoporous network interconnected structure and a high specific surface area (248.92 m²/g), CAT exhibited excellent photocatalytic activity and methylene blue (MB) removal rate (98.3%). The photocatalytic experimental results showed that the CAT could degrade MB in the aqueous solution within 90 min. Compared with most reported catalysts, CAT exhibited a higher MB removal rate and shorter catalytic time. Therefore, the photocatalyst CAT based on environmentally friendly and low-cost cellulose displayed great application potential in the degradation of MB.     

N、Mo共掺杂TiO_2光催化剂的制备及对亚甲基蓝降解性能研究

以硫脲、钼酸铵和钛酸四丁酯为原料,利用溶胶-凝胶法制备了未掺杂的和N、Mo共掺杂的TiO2光催化剂。用紫外-可见吸收光谱对制备的催化剂样品进行了表征,考察了不同条件下光催化剂对亚甲基蓝溶液的光催化活性。试验结果表明,N、Mo共掺杂使TiO2催化剂的吸收带边位置发生了红移;在可见光条件下,0.125 gN、Mo共掺杂TiO2(n(N)∶n(Mo)=2∶1)、pH值为6.20、温度为30℃的体系对质量浓度为20 mg/L的亚甲基蓝溶液的脱色效果最好。     

Preparation of aerochitin‐TiO2 composite for efficient photocatalytic degradation of methylene blue

An aerochitin–titania (TiO₂) composite was successfully synthesized and characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, field emission scanning electron microscopy, and N₂ adsorption isotherms. The photocatalytic activity of the composite was investigated on the degradation of the model organic pollutant, methylene blue (MB) dye, under UV irradiation. The aerochitin–TiO₂ composite showed excellent adsorptive and photocatalytic activity with a degradation degree of 98% for MB. The first‐order rate constants for the photodegradation MB by TiO₂ nanoparticles and aerochitin–TiO₂ composite were found to be (3.49 ± 0.04) × 10^?3 and (1.82 ± 0.02) × 10^?2 min^?1. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45908.     

Kinetics of photocatalytic degradationof methylene blue over TiO2 particles in aqueous suspensions

The kinetics of photodegradation of methylene blue over UV light illuminated titania particles in aque-ous suspensions has been studied with different initial methylene blue concentrations and TiO_2 particle sizes.Thedegradation rate increases with the decrease of initial concentration and particle size.A quasi-experienced modelfor photodegradation rate is derived based mainly on the coinstantaneous effects of different initial concentrationsand partic1e sizes.The mathematica1 re1ationships of model parameters with initia1 concentration and particle sizeare given.The model results of the photodegradation rate of methylene blue are coincident with the experimentaldata.     

纳米TiO_2的制备及其光催化性能

以钛酸四丁酯为原料,采用溶胶 凝胶法制备了纳米级TiO2颗粒,通过甲苯在样品上的光催化氧化过程评价了样品的光催化活性。考察了制备过程中的焙烧温度对样品颗粒的晶型、粒径和光催化性能的影响。X射线衍射结果表明,焙烧温度低于500℃时得到的样品都是锐钛矿型TiO2,700℃下得到的已基本是金红石型;随着焙烧温度的升高样品的粒径增大,光催化活性下降;甲苯在TiO2上的气相光催化氧化符合一级反应规律。     

小沙粒/TiO2的制备及其光催化降解亚甲基蓝性能的研究

为避免粉状光催化剂的团聚和流失,提高其回收率,通过溶胶-凝胶法+焙烧法制备小沙粒/TiO2光催化剂.通过SEM和XRD等对材料的形貌和晶型进行分析和测试,并用亚甲基蓝降解实验考察其光催化活性.结果表明,TiO2质量分数12％时,光催化效果最好.紫外光作用20 min时,亚甲基蓝降解率达98.77％.制备的光催化剂具有良...     

Synergy effect in the photocatalytic degradation of methylene blue on a suspended mixture of TiO2 and N-containing carbons

N-containing carbon materials were obtained from waste plum stones submitted to pyrolysis under Ar flow at 700 °C or to activation under steam at 800 °C and enriched with nitrogen by heating in a NH₃/air mixture at 270 °C or in NO at 300 °C. In situ mixtures of TiO₂ and carbons were prepared by the slurry method and methylene blue photodegradation was chosen as a model reaction to verify the influence of N-containing carbons on the photocatalytic activity of TiO₂ under artificial visible light irradiation. From the kinetics of methylene blue degradation an important synergy effect between both solids was detected with a remarkable increase up to a factor of 5.3 higher in the photocatalytic activity on TiO₂–C than that on TiO₂ alone. A mechanism for the photoassisting role of N-containing carbons upon the photoactivity of TiO₂ under visible light is discussed.     

活性炭负载TiO2的甲苯光催化降解性能研究

以竹炭活性炭颗粒为载体，采用溶胶-凝胶法制备TiO₂溶胶，以浸渍和微波辐照的方法实现催化剂的固定，高温活化制备了负载型TiO₂光催化剂。采用XRD、FSEM和FT-IR等分析方法对催化剂样品进行了表征。以甲苯为目标污染物，在紫外光照下模拟污染物的吸附与降解情况，探究了甲苯初始浓度和空气流量对光催化降解效果的影响。并通过在紫外光照下通入洁净空气、微波辐照和高温处理三种方法研究了催化剂的再生效果。结果表明，该方法制备的TiO₂为锐钛矿晶型，晶粒大小约为18 nm。甲苯的降解效率最高达到80%，其去除量先随负荷增加而上升，以后随负荷的进一步增加，甲苯的光催化去除量反而下降。微波辐照是实现催化剂再生的最为理想的方法。     

Efficient preparation of polymer‐based hollow spheres for the photocatalytic degradation of methylene blue

Titanium dioxide hollow spheres were synthesized by utilizing polystyrene‐co‐methacrylic acid latex particles coated with titanium isopropoxide. Hollow spheres prepared with different ruthenium salt concentrations showed considerable levels of organic pollutant degradation upon UV irradiation. In the present study, methylene blue (MB) was selected as a model for these pollutants. Thus its degradation indicated the activity of the hollow spheres as photocatalysts for decomposing the pollutants. The efficiencies of these photocatalysts were determined in terms of chemical oxygen demand removal. During these experiments, several conditions were monitored such as the effects of pH, ruthenium salt concentration, and initial MB load concentration. The prepared particles were characterized by using transmission electron microscopy and scanning electron microscopy. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers     

活性炭纤维负载TiO2光催化降解甲醛研究

用浸渍-提拉法将TiO₂负载到活性炭纤维(ACF)上,在254 nm的紫外光源下,利用复合材料进行吸附光催化氧化甲醛气体动态实验研究。结果表明,甲醛的降解率随进口气量的增加有所下降;随TiO₂负载质量分数的增加,复合材料的比表面积由830 m²·g^-1降低到128.31 m²·g^-1;反应温度升高,去除率下降;当湿度小于40%时,随着湿度的增加,甲醛去除率增大;湿度继续增加时,光催化反应速率反而降低;活性炭负载TiO2光催化降解甲醛过程长时间使用会产生催化剂失活。     

Physical properties and photocatalytic performance of TiO2 coated stainless steel plate

This research was conducted for the development of TiO₂ thin film coated stainless steel useful in environmental and sanitary fields such as removal of indoor air pollutants and prevention of harmful microorganisms in the kitchen and bathroom. For this purpose, the research was focused on the examination of physical properties of coated surfaces as well as the photocatalytic performance of the steel plates. The coated steel’s cohesiveness and anti-corrosion effect were good enough to be used even in the hard environments. To test the photocatalytic performance of the TiO₂ thin film coated stainless steel plate, photodegradations ofm-xylene, a typical air pollutant produced by automobiles, andE. coli, under 365 nm UV irradiation, were conducted. The TiO₂ coated stainless steel plate considerably enhanced the degradation efficiencies ofm-xylene andE. coli.     

New aluminum mesh from recyclable material for immobilization of TiO2 in heterogeneous photocatalysis

This study presents a new aluminium mesh made out of soda can rings as a support for titanium dioxide (TiO₂) in the degradation of the synthetic dyes Bordeaux Red (BR) and Tartrazine (TT). Three pre-treatments including calcination and acidification steps were investigated in order to select the most efficient immobilization procedure for photocatalysis application. Raw and titania-aluminum meshes were characterized by scanning electron microscopy, x-ray diffraction, diffuse reflectance, and Fourier transform infrared spectroscopy. The material presented itself as a suitable alternative in the immobilization of titania for wastewater treatment. Preliminary tests selected H₂O₂/TiO_{2(suspension)} oxidation systems under natural sunlight and germicidal lamps (UVC) exhibiting 97.2% and 99.5% of degradation in 180 minutes, respectively. Immobilized TiO₂ systems reached high degradation rates (>99%) after 180 minutes in both UVC and solar light-based processes. An experimental planning study was carried out for the processes in order to find the best operational conditions and pseudo-first-order model fit well the removal data (discolouration rates of in the order of 0.0274 and 0.0145 min⁻¹ for UVC and solar light systems, respectively). Parameters such as TOC, COD, and turbidity, revealed a great improvement in the environmental quality of the water after the treatment and acute toxicity bioassays demonstrated a significant decrease in toxicity for both systems after the treatments. The TiO₂-meshes demonstrated high performance in the removal after five cycles of operation. Therefore, the new immobilization procedure demonstrated that the TiO₂-aluminum mesh is a feasible option for wastewater treatment and photocatalysis.     

TiO2-coated glass hollow fiber membranes: preparation and application for photocatalytic methylene blue removal

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.     

Room temperature photocatalytic oxidation of liquid cyclohexane into cyclohexanone over neat and modified TiO2

The oxidation of liquid cyclohexane by O₂ over UV-illuminated TiO₂ at room temperature has been studied in a static slurry reactor. From the effects of the mass of catalyst, the temperature, the radiant flux, the concentration of C₆H₁₂ (using acetonitrile as a solvent), it is concluded that the reaction is photocatalytic. Using mainly the 365 nm-ray of a mercury-lamp, an initial quantum yield of 0.1 is found for pure cyclohexane and radiant fluxes < ca.5mWcm^–2 (6×10¹⁵ photons s^–1 cm^–2). A high selectivity to cyclohexanone is observed (83%), the other products being cyclohexanol (5%) and CO₂ (12%). The low amount of cyclohexanol is explained by the higher rate of oxidation of this alcohol compared to that of cyclohexane. Smaller oxidation rates are observed when TiO₂ is loaded with 0.5 to 10 wt%Pt and the cyclohexanone/cyclohexanol ratio decreases to ca. 4. Finally, the C₆H₁₂ oxidation has been employed as a test reaction to confirm the detrimental effect of the doping with several tri or pentavalent cations upon the photocatalytic activity of TiO₂.     

Molybdate‐doped copolymer coatings for corrosion prevention of stainless steel

The polypyrrole and polyaniline copolymer coating (PPy‐PAni) and PPy‐PAni doped with sodium molybdate copolymer coating ( ) were synthesized on stainless steel by cyclic voltammetry. The effect of molybdate on the passivation of stainless steel was investigated by linear sweep voltammetry in 0.2 mol L^?1 of oxalic acid. The corrosion prevention performances of these copolymer coatings for stainless steel were investigated by linear sweep voltammetry, electrochemical impedance spectroscopy in 1 mol L^?1 of sulfuric acid, and potentiodynamic polarization in 0.1 mol L^?1 of hydrochloric acid. Copolymer coating doped with molybdate could accelerate the formation of the passive oxide film and have better corrosion prevention efficiencies than PPy‐PAni coating on stainless steel. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40602.     

One-pot self-assembled TiO2/graphene/poly(acrylamide) superporous hybrid for photocatalytic degradation of organic pollutants

We report the development of TiO₂/graphene/poly(acrylamide) superporous hybrid by a radical polymerization reaction and explore its environmental application as photocatalyst of organic pollutants. During the polymerization reaction, graphene nanosheets and TiO₂ nanoparticles homogeneously distribute on the hydrogel, in which TiO₂ nanoparticles with a uniform size are densely anchored onto graphene and self-assembled into different structures with various graphene contents. The resultant TiO₂/graphene/poly(acrylamide) superporous hybrid experiences tremendous adsorption toward dye pollution before photodegradation, and it also displays similar photodecomposition efficiency with pristine TiO₂. Moreover, the TiO₂/graphene/poly(acrylamide) superporous hybrid is recyclable, which demonstrates the potential of hybrid as an attractive photocatalyst for wastewater treatment. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47033.