scholarly journals Photocatalytic degradation of Rhodamine-B under visible light region by ZnO nanoparticles loaded on activated carbon made from longan seed biomass

2020 ◽  
Vol 9 (3) ◽  
pp. 1-8
Author(s):  
Hung Nguyen Van ◽  
Nguyet Bui Thi Minh ◽  
Linh Bui Thi Thuy ◽  
Nghi Nguyen Huu ◽  
Tuoi Nguyen Thanh ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Visible Light ◽  
Rhodamine B ◽  
Kinetic Studies ◽  
Band Gap Energy ◽  
Light Illumination ◽  
Light Region ◽  
Seed Biomass ◽  
Longan Seed ◽  
Xrd Patterns

In the present study, the synthesis of ZnO/LSAC through pyrolysis of the carbonized material prepared from longan seed, zinc acetate in alkaline medium. The obtained materials was characterized by means of XRD, SEM, TEM, BET and UV-Vis-DRS. The XRD patterns of ZnO/LSAC nanocomposites were assigned to wurtzite structure of ZnO with crystallite size about 15 to 30 nm. SEM and TEM observations showed the spherical ZnO particles formed on the activated carbon. The band gap energy and specific surface area of ZnO/LSAC were found to be 2.79 eV and 294.4 m2/g, respectively. The photocatalytic activities of the prepared materials were evaluated for the degradation of Rhodamine B (RhB) dye. The removal of RhB was found to be pH dependent, and the optimized removal efficiency reached to 93.75% and the mineralization level was over 84,09% at initial RhB concentration of 40 mg.L-1 andpH 7 following 120 min under visible-light illumination. The kinetic studies showed the decolorizationof RhB followed pseudo first-order kinetics with the rate constant were determined kapp= 1.67Í10-2 min−1

scholarly journals Structural and optical properties of AgCl-sensitized TiO2 (TiO2 @AgCl) prepared by a reflux technique under alkaline condition

Cerâmica ◽  
2018 ◽  
Vol 64 (370) ◽  
pp. 190-196 ◽  
Author(s):  
V. A. Mu’izayanti ◽  
H. Sutrisno
Keyword(s):  
Visible Light ◽  
Surface Area ◽  
Alkaline Condition ◽  
Visible Light Region ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Light Region ◽  
Vis Spectroscopy ◽  
Xrd Patterns ◽  
Tio2 Rutile

Abstract The AgCl-sensitized TiO2 (TiO2@AgCl) has been prepared from the precursor of TiO2-rutile type which on its surface adsorb chloride anion (Cl-) and various amounts of silver using AgNO3 as starting material: AgNO3/(AgNO3+TiO2) mass ratio of 0.00, 1.14, 3.25, 6.38 and 10.32%. Reflux under alkaline condition was the employed technique. All samples were characterized by X-ray diffraction (XRD) and diffuse reflectance UV-vis spectroscopy. The sample without the addition of AgNO3 was analyzed by scanning electron microscope and surface area analyzer. The morphology of the sample showed a distribution of microspheres of approximately 0.5 to 1.0 µm and the specific surface area was 68 m2/g. XRD patterns indicated that the sample without the addition of AgNO3 contained two types of TiO2: rutile (major) and anatase (minor), whereas the samples with the addition of AgNO3 consisted of one phase of AgCl and two types of TiO2: rutile and anatase. The bandgaps of the samples were in the range of 2.97 to 3.24 eV, which were very close to the bandgap of intrinsic TiO2 powder. The presence of 0.8, 2.6 and 4.4 wt% of AgCl in each sample resulted in an additional bandgap in visible light region of 1.90, 1.94 and 2.26 eV, respectively, whereas the presence of 9.4 wt% of AgCl in the sample resulted in two bandgaps in visible light region of 1.98 and 1.88 eV.

Effect of Transition Metal Oxide Doping (Cr, Co, V) in the Photocatalytic Activity of TiO2 for Congo Red Degradation under Visible Light

2014 ◽  
Vol 69 (5) ◽  
Author(s):  
P. W. Koh ◽  
L. Yuliati ◽  
S. L. Lee
Keyword(s):  
Transition Metal ◽  
Visible Light ◽  
Congo Red ◽  
Sol Gel ◽  
Rutile Phase ◽  
Band Gap Energy ◽  
Electron Recombination ◽  
Doped Tio2 ◽  
Light Region ◽  
Electron Scavenger

Comparative study of Cr, Co or V-doped TiO2 was carried out. The photocatalysts were synthesized via sol-gel method. The results indicated that the dopants of Cr, Co, and V induced anatase to rutile phase transition of TiO2 at different dopant amounts of 1, 4, 2 mol%, respectively. Besides that, the existence of dopant extended the absorption wavelength of TiO2 to visible light region, thus making it a visible-driven photocatalyst. The doped transition metal exhibited different oxidation states on the TiO2 surface. The prepared photocatalysts were tested over photodegradation of Congo Red. Amongst all, Cr-doped TiO2 (3 mol%) was the best photocatalyst attributed to the presence of 45% rutile phase, reduced band gap energy of 2.30 eV and formation of Cr6+, which acted as an electron scavenger to delay the hole-electron recombination. 

scholarly journals Water treatment with CoZnAl-LDH and its mixed metal oxide

2021 ◽  
Author(s):  
Mina Sharifi-Bonab ◽  
Soheil Aber ◽  
Dariush Salari ◽  
Fatemeh Khodam
Keyword(s):  
Metal Oxide ◽  
Visible Light ◽  
Analytical Techniques ◽  
Kinetic Studies ◽  
Mixed Metal Oxide ◽  
Acid Orange 7 ◽  
Mixed Metal ◽  
Light Region ◽  
Co Precipitation ◽  
Adsorption Desorption

Abstract CoZnAl-layered double hydroxide (LDH) was synthesized by homogeneous co-precipitation. CoZnAl-Mixed Metal Oxide (MMO) was prepared by calcining the LDH. The samples' structure and morphology were studied by analytical techniques including X-ray diffraction, N2 adsorption-desorption isotherm, scanning electron microscopy and UV–visible spectroscopy. Acid orange 7 (AO7) adsorption by as-prepared samples was studied. CoZnAl-MMO showed 526.32 mg/g adsorption capacity, higher than that of CoZnAl-LDH, 243.9 mg/g. Kinetic studies confirmed the pseudo-second-order and pseudo-first-order AO7 adsorption kinetics of the LDH and MMO, respectively. AO7 adsorption onto both LDH and MMO fitted the Langmuir isotherm model well. Band gap calculation confirmed the ability of this nano-MMO to operate in the visible light region. It displayed synergetic adsorption-photocatalytic performance under visible-light and the removal efficiency was about 97%.

Synthesis of Indium Sulfide/Zinc Oxide Composites Films and their Photocatalytic Activities

2019 ◽  
Vol 886 ◽  
pp. 146-153
Author(s):  
Natkritta Boonprakob ◽  
Anchalee Masa-Ad
Keyword(s):  
Zinc Oxide ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Rhodamine B ◽  
Composite Films ◽  
Weight Ratio ◽  
Composite Catalyst ◽  
Zno Films ◽  
Light Illumination ◽  
Indium Sulfide

Indium sulfide and zinc oxide (In2S3-ZnO) films have successfully synthesized by doctor blading method coupling with low temperature precipitation-reflux rout. The weight ratio of In2S3 was varied from 0-70 wt.%. Physical characterization results obtained from various analytical techniques exhibit the well crystallinity phase of cubic β-In2S3 and wurtzite ZnO structure from XRD patterns. TEM micrograph of 35% In2S3-ZnO sample showed the small ZnO particles are embedded into β-In2S3. The obtained results exhibited the phase well crystallinity of cubic β-In2S3. A strong adsorption spectra shifted toward visible light region and the narrower optical band gap results of In2S3-ZnO composite films suggesting that synthesized samples could be used as the visible-light-driven photocatalyst. The photocatalytic activity of rhodamine B had been investigated over entire composite films under visible light illumination. It can be seen that the entire In2S3-ZnO composite catalyst films revealed degradation of rhodamine B performance obviously higher than pure ZnO and pure In2S3. Moreover, the highest photocatalytic activity was found from 35% wt. In2S3-ZnO film which showed 69.5% degradation within 4 h under visible light irradiation.

Characterization and activity of visible-light driven TiO2 photocatalyst doped with tungsten

2010 ◽  
Vol 62 (9) ◽  
pp. 2128-2133 ◽  
Author(s):  
T. Putta ◽  
M. C. Lu ◽  
J. Anotai
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Anatase Phase ◽  
Sol Gel ◽  
Light Illumination ◽  
Visible Light Region ◽  
Light Region ◽  
Acid Type ◽  
Visible Light Driven ◽  
Amorphous Tio2

This research aimed to expand the activity of TiO2 down to the visible light region by modifying the sol-gel conditions and doping with tungsten. The optimum conditions for calcination temperature, acid type, and heating rate were 200°C, HNO3, and 1°C/min, respectively. The undoped TiO2 synthesized under these conditions could significantly absorb the visible light whereas the commercial Degussa P-25 could not. The absorptivity decreased sequentially as the wavelength increased from 400 to 700 nm. Within 6 h of 2-W blue-light illumination, 23% of 0.1 mM 2-chlorophenol was removed. The XRD result showed that the crystalline was anatase phase. The visible-light absorption property of the TiO2 became even better when doped with tungsten. At the optimum W to TiO2 ratio of 0.5%, the degradation of 0.1 mM 2-chlorophenol increased to 53% indicating a higher photocatalytic activity. Both crystalline and amorphous TiO2 could exhibit the photocatalytic activity under the visible light region.

scholarly journals Studies on the Removal of Rhodamine B and Malachite Green from Aqueous Solutions by Activated Carbon

2008 ◽  
Vol 5 (4) ◽  
pp. 844-852 ◽  
Author(s):  
A. Edwin Vasu
Keyword(s):  
Activated Carbon ◽  
Aqueous Solutions ◽  
Malachite Green ◽  
Rhodamine B ◽  
Kinetic Studies ◽  
Solution Ph ◽  
Carbon Particles ◽  
Rate Determining Step ◽  
High Concentrations ◽  
Hoff Equation

Activated carbon prepared from tamarind fruit shells by direct carbonization was used for the removal of rhodamine B and malachite green dyes from aqueous solutions. Adsorption studies were performed by varying such parameters as dye concentration, pH of the dye solution, time and temperature. The equilibrium adsorption data obtained were used to calculate the Freundlich, Langmuir and Redlich-Peterson isotherm parameters. Increase in pH of the solution pH resulted in increased adsorption of both the dyes. Kinetic studies indicate that the pseudo-second order model can be used for describing the dynamics of the sorption processes. Film diffusion of the dyes was the rate determining step at low dye concentrations while diffusion of dyes through the pores the carbon particles determined the overall uptake at high concentrations. Thermodynamic parameters of the endothermic sorptions were evaluated using van’t Hoff equation. Desorption studies with acids were also performed in order to regenerate the used carbons.

scholarly journals Enhancing the photocatalytic activity of Cu0.25Zn0.75S nanodisks by metallic Ag loading in the visible-light region

RSC Advances ◽  
2019 ◽  
Vol 9 (24) ◽  
pp. 13787-13796 ◽  
Author(s):  
Jinyang Zhang ◽  
Fuyan Kang ◽  
Hao Peng ◽  
Jing Wen ◽  
Xiaogang Zheng
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Organic Pollutants ◽  
Visible Light Irradiation ◽  
Rhodamine B ◽  
Methyl Violet ◽  
Light Irradiation ◽  
Visible Light Region ◽  
Ciprofloxacin Hydrochloride ◽  
Light Region

Ag-loaded Cu0.25Zn0.75S (Ag/Cu0.25Zn0.75S) photocatalysts were synthesized for the photodegradation of organic pollutants such as rhodamine B (RhB), methyl violet (MV) and ciprofloxacin hydrochloride (CIP) under visible-light irradiation.

scholarly journals One Pot Synthesis of CoTiO3-TiO2 Composite Nanofibers and its Application in Dye Degradation

2021 ◽  
pp. 1597-1607
Author(s):  
M. Shamshi Hassan
Keyword(s):  
Visible Light ◽  
Composite Nanofibers ◽  
Dye Degradation ◽  
Band Gap Energy ◽  
One Pot ◽  
Light Region ◽  
Composite Photocatalysts ◽  
One Step ◽  
Ft Ir ◽  
The One

CoTiO3-TiO2 composite nanofibrous photocatalysts were synthesized by means of the one-step electrospinning method. The samples were characterized by a range of different methods (XRD, SEM, EPMA, FT-IR, UV-DRS, and TEM). Photocatalytic activity was performed for the degradation of rhodamine 6G under visible light. The results showed that CoTiO3-TiO2 composite photocatalysts were successfully synthesized. The average sizes of the diameters of the composite nanofibers were found to be 300 to 400 nm. The UV–Vis diffuse reflectance spectra of the CoTiO3-TiO2 composite showed an absorption wavelength, in the visible light region, having a band gap energy value of 2.21 eV. The CoTiO3-TiO2 composite showed higher photocatalytic efficiency than that of pristine TiO2; which can be attributed to the heterojunctional interaction between CoTiO3 and TiO2.

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