scholarly journals Volatile Organic Compound (VOC) Removal via Photocatalytic Oxidation Using TiO2 Coated Nanofilms

2017 ◽  
Vol 15 (7) ◽  
pp. 491-501
Author(s):  
Sunun KHAMI ◽  
Wipawee KHAMWICHIT ◽  
Ratthapol RANGKUPAN ◽  
Kowit SUWANNAHONG
Keyword(s):  
Bacterial Cellulose ◽  
Photocatalytic Oxidation ◽  
Uv Light ◽  
Average Particle Size ◽  
Average Particle ◽  
Experimental Conditions ◽  
Electrospinning Technique ◽  
Photocatalytic Reactor ◽  
Toluene Concentration ◽  
Spinning Process

In this paper, toluene removal via photocatalytic oxidation using TiO2 dip coated nanofilms is presented. Nanofilms were synthesized from bacterial cellulose using the electrospinning technique. The physical properties of the nanofilms were analyzed by scanning electron microscopy (SEM). The ratio of bacterial cellulose/nylon used in the spinning process was 0.165:1. The results from SEM showed that the structure of the TiO2 composite nanofilms was rutile crystalline with an average particle size of 20 nm, and synthesized nanofilms had an average size of 20 - 30 nm. The band gap energies of TiO2-dip coated nanofilms ranged from 3.18 - 3.21 eV. SEM results of TiO2 coated nanofilms suggested that the TiO2 was rather uniformly distributed onto the surface of the nanofilms. The actual amount of TiO2 coated on the nanofilms was estimated using thermogravimetric analysis (TGA) for 1x1 cm2 surface area. It was found that 0.1852, 0.2897 and 0.7275 mg of TiO2 were coated on the surface of the nanofilms for 1, 2.5 and 5 % (weight) TiO2 dosage, respectively. The photocatalytic activity of the nanofilms was tested for the removal of gaseous toluene in a photocatalytic reactor. Experimental conditions were set as follows: UV light intensity of approximately 2.7 mW.cm-2, flow rate of 0.2 L.min-1, and an initial toluene concentration of about 200±20 ppm, and a retention time at 200 min. The degradation rate of toluene increased with increasing dosage of TiO2 from 1, 2.5 and 5 %. The nanofilms at a 5 % dosage yielded the highest removal efficiency of 92.71 %, followed by the 2.5 and 1 % dosage, respectively.

Fe3O4 Magnetic Preparation by Bauxite Ore Washing Fine Mud

2014 ◽  
Vol 1010-1012 ◽  
pp. 961-965
Author(s):  
Jian Qiang Xiao ◽  
Guo Wei He ◽  
Yan Jin Hu
Keyword(s):  
Particle Size ◽  
Aging Time ◽  
Average Particle Size ◽  
Xrd Analysis ◽  
Test Methods ◽  
Raw Material ◽  
Molar Ratio ◽  
Average Particle ◽  
Experimental Conditions ◽  
Particle Size Analyzer

Bauxite waste sludge as a raw material, the use of reverse chemical coprecipitation synthesize Fe3O4. Researching temperature, precipitation concentration, aging time and Fe2+/Fe3+ molar ratio effect on the particle size, morphology. Optimal experimental conditions: temperature 70 °C, the precipitant NaOH mass ratio of 10%, aging time 3h, Fe2+/Fe3+ molar ratio of 2:3. Test methods using a laser particle size analyzer, XRD analysis of the products were characterized, the product is Fe3O4, the average particle size of 0.11mm.

Photocatalytically Active Cotton Fabrics Produced with Anatase Synthesized Using a Low-Temperature Sol-Gel Process

2018 ◽  
Vol 762 ◽  
pp. 408-412
Author(s):  
Raivis Eglītis ◽  
Gundars Mežinskis
Keyword(s):  
Photocatalytic Activity ◽  
Uv Light ◽  
Sol Gel ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Sol Gel Process ◽  
Anatase Nanoparticles ◽  
Pre Treatment

In this work two different hydrosols were used to impregnate a commercially available cotton fabric with anatase nanoparticles to give it photocatalytic activity. To increase the activity, different pre-treatment methods were applied. The nanoparticle size was determined using dynamic light scattering and x-ray diffraction and the fabrics were examined using scanning electron microscopy. Photocatalytic activity was measured using the degradation of methyl-orange while irradiating the samples with UV light. The synthesis method allowed to produce anatase with an average particle size of 32 to 37 nm depending on the synthesis method used.

Mechanical properties and erosive behaviour of 10TiO2-Cr2O3 coated CA6NM turbine steel under accelerated conditions

2019 ◽  
Vol 16 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Khushdeep Goyal
Keyword(s):  
Mechanical Properties ◽  
Mass Loss ◽  
Average Particle Size ◽  
Average Particle ◽  
Slurry Erosion ◽  
Experimental Conditions ◽  
Content Type ◽  
Uncoated Steel ◽  
Erosion Test ◽  
Turbine Steel

Purpose This paper aims to evaluate the mechanical properties and slurry erosion behaviour of 10TiO2-Cr2O3 coated turbine steel. Design/methodology/approach Slurry erosion experiments were performed on the coated turbine steel specimens using slurry erosion test rig under accelerated conditions such as rotational speed, average particle size and slurry concentration. Surface roughness tester, Vickers microhardness tester and scanning electron microscope were used to analyse erosion mechanism. Findings Under all experimental conditions, 10TiO2-Cr2O3 coated steel showed better slurry erosion resistance in comparison with Al2O3 coated and uncoated steel specimens. Each experimental condition indicated a significant effect on the erosion rate of both coatings and uncoated steel. The surface analysis of uncoated eroded specimen revealed that plastic deformation, ploughing and deep craters formation were the reasons for mass loss, whereas microchipping, ploughing and microcutting were the reasons for mass loss of coated specimens. Originality/value The present investigation provides novel insight into the comparative slurry erosion performance of high velocity oxy fuel deposited 10TiO2-Cr2O3 and Cr2O3 coatings under various environmental conditions. To form modified powder, 10 Wt.% TiO2 was added to 90 Wt.% Cr2O3.

DEVELOPMENT OF A NON-CONTINUOUS MICRO-FLOW OPTO-WETTING DROPLET MANIPULATION TECHNOLOGY

2005 ◽  
Vol 17 (06) ◽  
pp. 293-299 ◽  
Author(s):  
MING-YIH LEE ◽  
HUNG-CHIA LIN ◽  
HUNG-WEI CHIANG ◽  
WEI-XUN LEE ◽  
XIAN-DONG HUANG
Keyword(s):  
Surface Tension ◽  
Uv Light ◽  
Liquid Droplet ◽  
Average Particle Size ◽  
Base Material ◽  
Material Surface ◽  
Average Particle ◽  
Hydrophilic Property ◽  
Manipulation System ◽  
Droplet Manipulation

The aim of this study is to develop a non-continuous droplet manipulation technology in contrast to conventional continuous flow micro-fluidic systems. The droplets were manipulated based on the proposed opto-wetting effect. In addition, an experimental ultraviolet (UV) light actuated droplet manipulation system was developed for verifying the opto-wetting droplet manipulation. The proposed opto-wetting effect was achieved by utilizing ultraviolet to activate oxidation-reduction mechanism of nano-TiO2 photo catalyst coated base material. The water-affinity of the base material will changed due to the decreased free-energy of the material surface. Therefore, the contact angle between the liquid droplet and base material will also be changed which facilitates droplet manipulability. The main components of the proposed ultraviolet (UV) light actuated droplet manipulation system include ultraviolet masking device, moving platform and main frame structure. System software and user interface were designed by using Microsoft Visual Basic 6.0 toolkit. Upon completion of the proposed system, experiments were carried out to verify system functionalities. Follow by the controlled variable optimization using Taguchi method and liquid droplet manipulation experiments. The experiment results indicate that by exposure to 6.8mW UV light, the surface tension and hydrophilic property of nano-TiO2 (anatase type, 3.5% concentration, PH 1.5, and with average particle size of 69 nm) coated base material will changed. The change of surface tension and hydrophilic property were critical for droplet manipulation. The moving speed of the liquid droplet was measured as 3.33mm/sec. The results suggest that the opto-wetting system may be effective to overcome the shortcoming of traditional opto-electrowetting technique. The proposed opto-wetting droplet manipulation system could potentially applied for manipulating biomedical or pathological test specimens in the future.

Improvement of TiO2/LDPE Composite Films for Photocatalytic Oxidation of Acetone

2014 ◽  
Vol 931-932 ◽  
pp. 235-240 ◽  
Author(s):  
Kowit Suwannahong ◽  
Sanya Sirivithayapakorn ◽  
Pongsak Noophan ◽  
Wipada Sanongraj
Keyword(s):  
Composite Film ◽  
Photocatalytic Oxidation ◽  
Fourier Transforms ◽  
Uv Light ◽  
Composite Films ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Closed Chamber ◽  
Acetone Concentration ◽  
Ftir Spectrometer

Titanium dioxide with coupling agent (ETES) was applied as a photocatalyst for a synthesis of the TiO2/LDPE composite film. The physical properties of TiO2/LDPE composite film were analyzed by a Scanning Electron Microscope (SEM). TiO2 particles were impregnated into the polymer matrix film as a LDPE composite film. The results from the X-ray Diffraction (XRD) technique revealed that the structure of TiO2/LDPE composite film were anatase crystalline. The chemical structure of the TiO2/ LDPE composite films were analyzed by an ATR-Fourier transforms infrared (ATR-FTIR) spectrometer. Wavenumber of FTIR spectra at 719 cm1 indicated the Ti-O-Ti bond. Band gap energies of the films ranged from 3.19-3.29 eV. The photocatalytic activity of the film was tested for removal of gaseous acetone in a closed chamber. Experimental conditions were set as follows: a UV light intensity of approximately 2.7 mW.cm-2, flow rate of 2 L.min-1, and an initial acetone concentration of about 435±20 ppm. While the catalyst dosage was varied from 3% to 15% (wt. cat/wt. film).The degradation rate of acetone increased when increasing dosage of TiO2 from 3% to 10%, then decreased a little bit when increasing the dosage to 15%. The TiO2/LDPE composite film at the dosage of 10% yielded the highest removal efficiency of 75%, followed by the film at the dosage of 15%, 5%, and 3%, respectively.

scholarly journals Synthesis and Characterization of Electrospun Nanocomposite Nanofibers with Ag Nanoparticles for Photocatalysis Applications

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Srujan Mishra ◽  
S. Phillip Ahrenkiel
Keyword(s):  
Photocatalytic Activity ◽  
Ag Nanoparticles ◽  
Photocatalytic Oxidation ◽  
Uv Light ◽  
Dark Field ◽  
Mixed Phase ◽  
Methyl Red ◽  
Fiber Morphology ◽  
Electrospinning Technique ◽  
Red Dye

Polycrystalline mixed-phase TiO2nanofibers embedded with 2.0% w/v Ag nanoparticles was prepared by the electrospinning technique. Calcination of dry Ag nanoparticles-titanium (IV) isopropoxide/PVP electrospun nanofiber mats in air at for 24 h yielded polycrystalline TiO2/Ag nanofibers. The morphology and distribution of silver nanoparticles were observed by transmission electron microscopy (TEM), scanning TEM (STEM), and high-angle annular dark-field (HAADF) imaging. Mixed-phase anatase and rutile TiO2nanofibers were produced with Ag nanoparticles. High-resolution TEM lattice-fringe measurements showed good agreement with Ag (111), anatase (101), and rutile (110) phases. The photocatalytic activity of TiO2/Ag nanofibers was compared to the photocatalytic activity of pure TiO2nanofibers by studying the photodegradation of methyl red dye under UV light irradiation, in a photoreactor. UV-visible absorbance spectra showed that the rate of decay of the dye in case of photodegradation by TiO2/Ag nanofibers was 10.3 times higher than that by pure TiO2nanofibers. The retaining of the fiber morphology along with the increased surface area due to the addition of Ag nanoparticles can be believed to enhance the photocatalytic oxidation of methyl red dye.

scholarly journals Photocatalytic Degradation of Rhodamine B and Malachite Green by Cobalt Sulfide Nanoparticles

2022 ◽  
Vol 34 (2) ◽  
pp. 331-341
Author(s):  
Gunjan Chauhan ◽  
Manjeet Sharma
Keyword(s):  
Malachite Green ◽  
Rhodamine B ◽  
Degradation Rate ◽  
Uv Light ◽  
Average Particle Size ◽  
Single Step ◽  
Cobalt Sulfide ◽  
Cds Nanoparticles ◽  
Average Particle ◽  
Cobalt Sulphide

Present study reports the simple and cost effective thermolytic method for the synthesis of cobalt sulphide nanoparticles (CoS NPs). The PXRD spectrum of cobalt sulphide (CdS) nanoparticles exhibited four peaks indexed to (100), (101), (102) and (110) crystal planes. The average particle size observed from DLS and PXRD was in the range 4.81-12.20 nm. A blue shift in band gap was observed from UV-visible spectra. The FESEM and TEM studies revealed that cobalt sulfide nanoparticles are of cubic and rectangle shapes. FTIR spectra of hexadecylamine (HDA) capped CoS NPs exhibited ν(N-H) absorption around 3350-3240 cm–1. The stretching frequency due to ν(Co-S) appeared in the region 334-332 cm–1. Proton NMR (1H) spectra of CoS NPs showed signals at nearly same positions as in case of capping agent, suggesting its capping nature. ESI-MS analyses of cobalt sulphide nanoparticles displayed peak at m/z = 124.93 corresponding to the [CoS2]+ ion. Thermogravimetric curves showed single step decomposition corresponding to 84.28% weight loss and 15.72% as final residue due to cobalt oxide. The degradation rate of rhodamine B and malachite green dyes after irradiating with sunlight showed 92-94% degradation while irradiated with UV-light of 4.8 eV show much slower degradation rate.

scholarly journals Methylene Blue Dye Photocatalytic Degradation over Synthesised Fe3O4/AC/TiO2 Nano-Catalyst: Degradation and Reusability Studies

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2360
Author(s):  
Seyedehmaryam Moosavi ◽  
Rita Yi Man Li ◽  
Chin Wei Lai ◽  
Yusliza Yusof ◽  
Sinyee Gan ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Uv Light ◽  
Agricultural Waste ◽  
Average Particle Size ◽  
Blue Dye ◽  
Average Particle ◽  
Step Procedure ◽  
Nano Catalyst ◽  
One Step ◽  
The Stability

In this study, activated carbon (AC) from coconut shell, as a widely available agricultural waste, was synthesised in a simple one-step procedure and used to produce a magnetic Fe3O4/AC/TiO2 nano-catalyst for the degradation of methylene blue (MB) dye under UV light. Scanning electron microscopy revealed that TiO2 nanoparticles, with an average particle size of 45 to 62 nm, covered the surface of the AC porous structure without a reunion of its structure, which according to the TGA results enhanced the stability of the photocatalyst at high temperatures. The photocatalytic activities of synthesised AC, commercial TiO2, Fe3O4/AC, and Fe3O4/AC/TiO2 were compared, with Fe3O4/AC/TiO2 (1:2) exhibiting the highest catalytic activity (98%). Furthermore, evaluation of the recovery and reusability of the photocatalysts after treatment revealed that seven treatment cycles were possible without a significant reduction in the removal efficiency.

A discussion on advanced methods of energy conversion- Magnetohydrodynamic power generation - An experimental study of gas borne suspensions of thermionic emitters as m .h.d. working fluids

1967 ◽  
Vol 261 (1123) ◽  
pp. 490-495 ◽  
Keyword(s):  
Atmospheric Pressure ◽  
Average Particle Size ◽  
Experimental Studies ◽  
Barium Oxide ◽  
Inert Gases ◽  
Average Particle ◽  
Experimental Conditions ◽  
Working Fluids ◽  
Electrical Conductivities ◽  
Oxide Particles

The use of gaseous suspensions of thermionically emitting particles as alternatives to alkali metal seeded gases for use as m.h.d. working fluids is discussed briefly. Theoretical relations proposed by Sodha & Bendor (1964) are used to show that suspensions of barium oxide in argon can have significantly higher electrical conductivities than thermally ionized caesium-argon mixtures at temperatures below about 2000 °K. This advantage is emphasized at pressures above atmospheric pressure. Experimental studies to check the theoretically predicted conductivities are described. A technique has been developed for the preparation of submicron suspensions of barium oxide and other alkali earth oxides in inert gases. A suspension of barium oxide particles in argon has been shown to have a conductivity of 0-1 mho/m at atmospheric pressure and 1600 °K. This value is low, because of the relatively large average particle size, 0-3 ^m diameter, but is of the same order as the theoretical conductivity for the experimental conditions.

scholarly journals High Current Density Chronopotentiometric Electrosynthesis and SEM Characterization of Hexanethiol-Monolayer-Protected Silver Planar Nanotriangles (Ag@C6SH)

2016 ◽  
Vol 2016 ◽  
pp. 1-12
Author(s):  
DJafar Vatan Khah Dowlat Sara ◽  
Ahmad Rouhollahi ◽  
Seied Mahdi Pourmortazavi ◽  
Mojtaba Shamsipur
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Average Particle Size ◽  
Average Particle ◽  
Nonaqueous Media ◽  
Experimental Conditions ◽  
Vis Spectroscopy ◽  
Optimized Conditions ◽  
First Time

This work reports for the first time electrosynthesis of hexanethiol capped silver nanotriangles cores (Ag@C6SH NCs) by a rapid, clean, and simple Double Pulse Chronopotentiometric (DCP) method in nonaqueous media, using a Taguchi orthogonal arrayL8design to identify the optimized experimental conditions. It was found that the size and shape of the product could be tuned by the current density, electrolysis time, electrode distance, and amount of NaBH4% used. The Ag@C6SH NCs in different shapes and sizes (in the range of 30 to 44 nm as an average estimation) were synthesized, under different experimental conditions. Finally, the as-prepared nanoclusters electrosynthesized at optimized conditions were characterized by SEM, XRD, and UV-Vis spectroscopy. The average particle size of the triangular/pyramidal shape (Ag@C6SH NCs), obtained under optimized experimental conditions, was30.5±2.0 nm but the majority of nanoparticles in TC3SEM are so much finer.

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