scholarly journals Application of ZnO-Nd Nano-Photocatalyst for the Reactive Red 198 Dye Decolorization in the Falling-Film Photocatalytic Reactor

Toxics ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 254
Author(s):  
Fatemeh Biglar ◽  
Amirreza Talaiekhozani ◽  
Farham Aminsharei ◽  
Junboum Park ◽  
Anahita Barghi ◽  
...  
Keyword(s):  
Average Particle Size ◽  
Combustion Method ◽  
Physical Characteristics ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Average Particle ◽  
Falling Film ◽  
Nano Zno ◽  
Photocatalytic Reactor ◽  
Reactive Red 198

A large amount of Reactive red 198 (RR198) is released yearly into the environment. RR198 is toxic for human and aquatic creatures; therefore, it should be removed from wastewater before releasing into the environment. In this study, the nano ZnO-Nd -photo-catalyst for the first time was synthesized by the combustion method. First, the physical characteristics of the generated nano photocatalyst were evaluated using FESEM, XRD, Bandgap calculation, and FTIR analysis. Then, the ZnO-Nd nano-photocatalyst was suspended into the contaminated water with RR198 dye in a falling-film photocatalytic reactor. The effects of parameters such as the amount of H2O2, catalyst dose, pH, and initial concentration of dye were investigated during the experiments. Finally, the decolorization process with the falling-film photocatalytic reactor was optimized using response surface methodology (RSM). The physical characteristics showed that the average particle size of the synthesized ZnO-Nd was 40 nm. Doping ZnO with Nd reduced the photocatalyst energy bandgap by 14%. The results indicated that the optimum amount of catalyst dose and pH level was 0.1 g/L and 5, respectively. The simultaneous usage of H2O2 and ZnO-Nd with an H2O2/dye ratio of two increased dye removal performance by 90%. The results demonstrated that the developed equations can be applied to predict the performance of the falling-film photoreactor. This study showed that using the nano ZnO-Nd photocatalyst in a falling-film photocatalytic reactor under optimum operating conditions is an appropriate way to remove RR198 from water.

scholarly journals Decolourization of crystal violet using nano-sized novel fluorite structure Ga 2 Zr 2− x W x O 7 photocatalyst under visible light irradiation

2020 ◽  
Vol 7 (3) ◽  
pp. 191632 ◽  
Author(s):  
H. A. Abbas ◽  
Rabab A. Nasr ◽  
Rund Abu-Zurayk ◽  
Abeer Al Bawab ◽  
Tarek S. Jamil
Keyword(s):  
Visible Light ◽  
Band Gap ◽  
Crystal Violet ◽  
Average Particle Size ◽  
Fluorite Structure ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Fluorite Phase ◽  
Average Particle ◽  
Light Illumination

Fluorite-type Zr-based oxides with the composition Ga 2 Zr 2− x W x O 7 ( x = 0, 0.05, 0.1, 0.15 and 0.2) were prepared using the citrate technique. Appropriate characterizations of all prepared materials were carried out. X-ray diffraction clarified that the undoped and W-doped Ga 2 Zr 2 O 7 samples were crystallized in the cubic fluorite phase structure. The average particle size of the samples was in the range of 3–8 nm. The lowest band gap (1.7 eV) and the highest surface area (124.3 m 2 g −1 ) were recorded for Ga 2 Zr 0.85 W 0.15 O 7. The photocatalytic impacts of the prepared systems were studied by removal of crystal violet (CV) dye employing visible light illumination and taking into consideration the initial dye concentrations, duration of visible irradiation treatment, catalysts dose and the dopant concentration. The obtained results showed higher dye removal with the boost of the catalyst dosage. W doping shifted the absorption to the visible light range by decreasing the band gap from 4.95 eV for parent Ga 2 Zr 2 O 7 to 1.7 eV for 15 mol% tungsten-doped Ga 2 Zr 2 O 7 enhancing the photocatalytic decolourization of CV from 4.2% to 83.6% for undoped and 15 mol% W-doped Ga 2 Zr 2 O 7 , respectively, at optimum operating conditions (pH 9, 1 g l −1 catalyst dose and 300 min) while heavily doped W sample containing 20 mol% W showed lower removal than 15 mol% W-doped Ga 2 Zr 2 O 7 . Complete CV degradation using 15 mol% W-doped Ga 2 Zr 2 O 7 was attained with the assistance of 25 mmol l −1 hydrogen peroxide. The reaction is aligned to pseudo-first-order kinetics. Different scavengers were introduced to decide the significance of the reactive species in CV degradation. O 2 − ∙ and h + had the major role in the degradation of CV by Ga 2 Zr 2− x W x O 7 system compared with HO • .

Influence of temperature and humidity on the angle of repose of wood bulk materials

2016 ◽  
Author(s):  
И.В. Бачериков ◽  
Б.М. Локштанов
Keyword(s):  
Field Experiments ◽  
Bulk Material ◽  
Average Particle Size ◽  
Operating Conditions ◽  
Angle Of Repose ◽  
Wood Dust ◽  
Average Particle ◽  
Bulk Materials ◽  
Technical Literature ◽  
The Impact

При проектировании открытых и закрытых хранилищ измельченных сыпучих материалов древесных материалов, таких как щепа и опилки, большое значение имеет угол естественного откоса (статический и динамический) этих материалов. В технической литературе приводятся противоречивые сведения о величине этих углов, что приводит к ошибкам при проектировании складов. В справочных данных не учитываются условия, в которых эксплуатируются емкости для хранения сыпучих материалов, свойства и состояние этих сыпучих материалов. В свою очередь, ошибки при проектировании приводят к проблемам (зависание, сводообразование, «затопление» и т. д.) и авариям при эксплуатации бункеров и силосов на производстве. В статье представлены сведения, посвященные влиянию влажности и температуры на угол естественного откоса сыпучих материалов. На основании лабораторных и натурных экспериментов, проведенных с помощью специально разработанных методик и установок, была скорректирована формула для определения углов естественного откоса (статического и динамического) для измельченных древесных материалов в зависимости от их фракционного и породного состава, влажности (абсолютной и относительной) и температуры. При помощи скорректированной формулы можно определить угол естественного откоса древесных сыпучих материалов со среднегеометрическим размером частицы от 0,5 мм до 15 мм (от древесной пыли до технологической щепы) в различных производственных условиях. Статья может быть полезна проектировщикам при расчете угла наклона граней выпускающей воронки бункеров и силосов предприятий лесной отрасли и целлюлозо-бумажной промышленности. In the design of open and closed storage warehouses chopped wood materials for bulk materials such as wood chips and sawdust, great importance has an angle of repose (static and dynamic) of these materials. In the technical literature are conflicting reports about the magnitude of these angles, which leads to errors in the design of warehouses. In the referencesdoes not take into account the conditions under which operated capacities for storage of bulk materials, and properties and condition of the bulk material. The design errors lead to problems (hanging, arching, «flooding», etc.) and accidents in the operation of hoppers and silos at the mills. The article provides information on the impact of humidity and temperature on the angle of repose of granular materials. On the basis of laboratory and field experiments, conducted with the help of specially developed techniques and facilities has been adjusted formula for determining the angle of repose (static and dynamic) for the shredded wood materials depending on their fractional and species composition, humidity (absolute and relative) and temperature. It is possible, by using the corrected formula, to determine the angle of repose of loose wood materials with average particle size of from 0.5 mm to 15 mm (wood dust to pulpchips) in various operating conditions. The article can be helpful to designers in the calculation of the angle of inclination of the funnel faces produces bunkers and silos forest industries and pulp and paper industry.

Preparation of Magnesium-Based Cobalt-Ferrites (Co1−xMgxFe2O4) Nanoparticles by Sol–Gel Auto Combustion Method

2017 ◽  
Vol 17 (01n02) ◽  
pp. 1760012
Author(s):  
S. Gowreesan ◽  
A. Ruban Kumar
Keyword(s):  
Particle Size ◽  
Structural Parameters ◽  
Sol Gel ◽  
Average Particle Size ◽  
Combustion Method ◽  
Dielectric Behavior ◽  
Powder Xrd ◽  
Average Particle ◽  
Cobalt Ferrites ◽  
Auto Combustion

The scope of the present work is in enhancing the particle size, and dielectric properties of Mg-substituted Cobalt ferrites nanoparticles prepared by sol–gel auto combustion method. The different ratios of Mg-substituted Co Ferrites (Co[Formula: see text]MgxFe2O4([Formula: see text], 0.05, 0.10, 0.15, 0.20 and 0.30)) are calcinated at 850[Formula: see text]C. The synthesized nanoparticles were characterized by powder XRD, FTIR, FE-SEM, EDX techniques and dielectric behavior. The structural parameters were confirmed from powder XRD and the average particle size is obtained from 39 to 67 nm due to the substitution of Mg[Formula: see text] which was calculated by Debye Scherrer’s formula. FE-SEM showed the surface morphology of the different ratio of the sample. The dielectric loss has measured the frequency range of 50[Formula: see text]Hz–5[Formula: see text]MHz. From electrical modulus, conductivity relaxation and thermal activation of charge carriers has been discussed.

Experiment and analysis on chaotic characteristics vibration mill with variable rotational speed

2021 ◽  
pp. 2150052
Author(s):  
Xiaolan Yang ◽  
Yuan Gao ◽  
Minping Jia
Keyword(s):  
Chaotic Motion ◽  
Average Particle Size ◽  
Engineering Application ◽  
Operating Conditions ◽  
Average Particle ◽  
Maximum Lyapunov Exponent ◽  
Motor Speed ◽  
Low Efficiency ◽  
Motion Characteristics ◽  
Vibration Mill

In an attempt to improve the current low efficiency and high consumption situation of vibration mills, this paper analyses the chaotic motion characteristics of the system and the movement of vibration mill. The complex stiffness-dispersion coupling of the system is also studied, so as to investigate the effect of the system’s chaotic motion characteristics on the efficiency improvement and energy consumption reduction. Based on the ADAMS software, this paper establishes a simplified vibration mill mechanical model, analyzes the singularity and stability of the system, and determines the critical speed at which the vibration motor becomes chaotic according to the bifurcation diagram. Then the chaotic state of the grinding machine with sinusoidal variation in its motor speed is studied based on the Poincaré principle, singular attractor and maximum Lyapunov exponent. Lastly, a 200[Formula: see text]h vibration test on diamond powder with an average particle size of 10 [Formula: see text]m was carried out. Test results under the two operating conditions of variable and constant speeds are compared and analyzed. Our results show that with variable speed the vibration mill achieved higher grinding efficiency but smaller particle grain size. The research elaborated in this paper provides a valuable reference for the engineering application of the chaotic characteristics of vibration mill.

Green Route Synthesis of MgO Nanoparticles Using Murraya Koenigii Leaf Extract: An Efficient Photo Catalyst for Malachite Green

2018 ◽  
Vol 24 (8) ◽  
pp. 5801-5804
Author(s):  
K. N. Shravana Kumara ◽  
H. P Nagaswarupa ◽  
K. R. Vishnu Mahesh ◽  
M Mylarappa ◽  
S. C Prashantha ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Average Particle Size ◽  
Diffraction Method ◽  
Combustion Method ◽  
Average Particle ◽  
Murraya Koenigii ◽  
Solution Combustion ◽  
Efficient Catalyst ◽  
Mgo Nanoparticles ◽  
Average Size

The objective of this work is mainly focused on green synthesis and characterization of MgO nanoparticles by low temperature solution combustion method. The Murraya koenigii (Curry leaves) was used as a reducing agent (as fuel). The average size and crystallinity of nano MgO particles are analyzed by X-ray Diffraction method (PXRD) and accurate morphology was studied using Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). From XRD, shows that average particle size of MgO is 40 nm. The synthesized MgO particles used as an efficient catalyst shows rapid color removal and reduction in the concentration of dyes.

Synthesis of La0.8Sr0.2Co0.8Fe0.2O3 Nanopowders and Their Application in Solid Oxide Fuel Cells

2011 ◽  
Vol 8 (5) ◽  
Author(s):  
Changsheng Ding ◽  
Hongfei Lin ◽  
Kazuhisa Sato ◽  
Toshiyuki Hashida
Keyword(s):  
Fuel Cells ◽  
Low Temperature ◽  
Solid Oxide Fuel Cells ◽  
Cathode Material ◽  
Average Particle Size ◽  
Combustion Method ◽  
Solid Oxide ◽  
Electrical Performance ◽  
Average Particle ◽  
Oxide Fuel

La0.8Sr0.2Co0.8Fe0.2O3 (LSCF) nanopowders, which are being investigated as a promising cathode material for low-temperature solid oxide fuel cells (SOFCs), were synthesized by citric acid gel combustion method. The LSCF nanopowders synthesized at 700°C are single perovskite phases and have an average particle size of less than 30 nm. In order to evaluate the use of the synthesized LSCF nanopowders as cathode material of low-temperature SOFCs, anode-supported SOFCs were fabricated from the synthesized LSCF nanopowders and tested in the conditions of humidified hydrogen for anode and oxygen for cathode. The anode-supported single cell with the LSCF cathode sintered at 700°C showed high electrical performance with the maximum power density of 771 mW cm−2 at 600°C. The results show that the synthesized LSCF nanopowders are suitable to be applied as cathode material for low-temperature SOFCs.

Frequency dependence and fuel effect on optical properties of nano TiO2-based structures

2016 ◽  
Vol 30 (18) ◽  
pp. 1650247 ◽  
Author(s):  
Mahdi Ghasemifard ◽  
Misagh Ghamari ◽  
Meysam Iziy
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Average Particle Size ◽  
Combustion Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Nano Tio2 ◽  
Transmission Electron ◽  
Auto Combustion ◽  
Xrd Patterns

TiO2-(Ti[Formula: see text]Si[Formula: see text]O2 nanopowders (TS-NPs) with average particle size around 90 nm were successfully synthesized by controlled auto-combustion method by using citric acid/nitric acid (AC:NA) and urea/metal cation (U:MC). The structure of powders was studied based on their X-ray diffraction (XRD) patterns. The XRD of TS-NPs shows that rutile and anatase are the main phases of TS-NPs for AC:NA and U:MC, respectively. Particle size and histogram of nanopowders were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS). Optical properties of TS-NPs were calculated by Fourier transform infrared spectroscopy (FTIR) and Kramers–Kroning (KK) relation. Plasma frequencies of TS-NPs obtained from energy loss functions depend on fuels as a result of changes in crystal structure, particle size distribution, and morphology.

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.

Research on Preparation, Characterization of Novel Nano-ZnO

2011 ◽  
Vol 311-313 ◽  
pp. 549-554
Author(s):  
Yan Yan Liu ◽  
Dian Mo Zheng
Keyword(s):  
Thermal Decomposition ◽  
Zinc Oxide ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Zinc Acetate ◽  
Average Particle Size ◽  
Molar Ratio ◽  
Average Particle ◽  
Acetate Solution ◽  
Nano Zno

Zinc acetate and ammonium bicarbonate are used as raw material, zinc oxide prepared by direct precipitation of new technology. This paper discusses the effection of the formation in zinc oxide from the reactant concentration of zinc acetate, HCO3-/Zn2+ molarity ratio, reaction temperature, reaction time and condition in thermal decomposition of basic zinc carbonate. Using transmission electron microscopy (TEM), thermogravimetric / differential thermal analysis (TG / DTA) and other methods, preparation of nano-ZnO are characterized. Good conditions for the better system of nano- ZnO are 0.75mol /L in the concentration of zinc acetate solution, 2.5:1 in bicarbonate of ammonia and zinc acetate molar ratio, 45 °C of reaction temperature, 1.0h of reaction time, and 350 °C in thermal decomposition temperature, 3.0h of pyrolysis time. Zinc oxide obtained average particle size is 20 ~ 80nm, for the hexagonal crystal form.

Fabrication of Barium Stannate Tatanate Ceramics via Combustion Technique

2008 ◽  
Vol 55-57 ◽  
pp. 173-176 ◽  
Author(s):  
C. Wattanawikkam ◽  
Theerachai Bongkarn
Keyword(s):  
Perovskite Phase ◽  
Average Particle Size ◽  
Combustion Method ◽  
Lattice Parameter ◽  
Average Particle ◽  
Calcination Temperatures ◽  
Grain Sizes ◽  
Barium Stannate ◽  
Calcined Temperature ◽  
Combustion Technique

The effect of firing temperatures on phase formation and microstructure of barium stannate titanate [Ba(Sn0.1Ti0.9)O3; BST10] ceramics were investigated. BST10 was synthesized via a combustion method, at various calcination and sintering temperatures. It was found that, a single perovskite of BST10 powders was obtained with a calcinations temperature of 1200 oC. The percent of the perovskite phase and the lattice parameter were increased with increasing calcination temperatures. The average particle size was increased from 0.48 to 1.69 µm by increasing the calcined temperature from 600 to 1200 oC. The average grain sizes were increased from 0.99 to 17.77 µm by increasing the sintering temperature from 1250 to 1450 oC. The maximum density and dielectric constant were observed in sintered samples at 1350 oC.

Sign in / Sign up

Export Citation Format

Share Document