scholarly journals Improved Photocatalyzed Degradation of Phenol, as a Model Pollutant, over Metal-Impregnated Nanosized TiO2

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 996 ◽  
Author(s):  
S. Belekbir ◽  
M. El Azzouzi ◽  
A. El Hamidi ◽  
L. Rodríguez-Lorenzo ◽  
J. Arturo Santaballa ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
Diffuse Reflectance Spectroscopy ◽  
Compressive Strain ◽  
Phenol Degradation ◽  
Relative Pressure ◽  
Order Kinetic ◽  
X Ray ◽  
Toc Removal ◽  
Type Iv ◽  
Vis Spectroscopy

Photocatalyzed degradation of phenol in aqueous solution over surface impregnated TiO2 (M = Cu, Cr, V) under UV-Vis (366 nm) and UV (254 nm) irradiation is described. Nanosized photocatalyts were prepared from TiO2-P25 by wet impregnation, and characterized by X-ray diffraction, X-ray fluorescence, transmission electron microscopy, UV-Vis diffuse reflectance spectroscopy, Raman spectroscopy, and adsorption studies. No oxide phases of the metal dopants were found, although their presence in the TiO2-P25 lattice induces tensile strain in Cu-impregnated TiO2-P25, whereas compressive strain in Cr- and V-impregnated TiO2-P25. Experimental evidences support chemical and mechanical stability of the photocatalysts. Type IV N2 adsorption–desorption isotherms, with a small H3 loop near the maximum relative pressure were observed. Metal surface impregnated photocatalysts are mesoporous with a similar surface roughness, and a narrow pore distribution around ca. 25 Å. They were chemically stable, showing no metal lixiviation. Their photocatalytic activity was followed by UV-Vis spectroscopy and HPLC–UV. A first order kinetic model appropriately fitted the experimental data. The fastest phenol degradation was obtained with M (0.1%)/TiO2-P25, the reactivity order being Cu > V >> Cr > TiO2-P25 under 366 nm irradiation, while TiO2-P25 > Cu > V > Cr, when using 254 nm radiation. TOC removal under 366 nm irradiation for 300 min showed almost quantitative mineralization for all tested materials, while 254 nm irradiation for 60 min led to maximal TOC removal (ca. 30%). Photoproducts and intermediate photoproducts were identified by HPLC–MS, and appropriate reaction pathways are proposed. The energy efficiency of the process was analysed, showing UV lamps are superior to UVA lamps, and that the efficiency of the surface impregnated catalyst varies in the order Cu > V > Cr.

scholarly journals Defective TiO2 Core-Shell Magnetic Photocatalyst Modified with Plasmonic Nanoparticles for Visible Light-Induced Photocatalytic Activity

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 672 ◽  
Author(s):  
Zuzanna Bielan ◽  
Agnieszka Sulowska ◽  
Szymon Dudziak ◽  
Katarzyna Siuzdak ◽  
Jacek Ryl ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Phenol Degradation ◽  
Magnetic Core ◽  
Magnetic Photocatalyst ◽  
X Ray ◽  
Transmission Electron ◽  
First Time

In the presented work, for the first time, the metal-modified defective titanium(IV) oxide nanoparticles with well-defined titanium vacancies, was successfully obtained. Introducing platinum and copper nanoparticles (NPs) as surface modifiers of defective d-TiO2 significantly increased the photocatalytic activity in both UV-Vis and Vis light ranges. Moreover, metal NPs deposition on the magnetic core allowed for the effective separation and reuse of the nanometer-sized photocatalyst from the suspension after the treatment process. The obtained Fe3O4@SiO2/d-TiO2-Pt/Cu photocatalysts were characterized by X-ray diffractometry (XRD) and specific surface area (BET) measurements, UV-Vis diffuse reflectance spectroscopy (DR-UV/Vis), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Further, the mechanism of phenol degradation and the role of four oxidative species (h+, e−, •OH, and •O2−) in the studied photocatalytic process were investigated.

scholarly journals Kinetics of Highly Active TiO2 Microspheres Formation in a Presence of Ethylammonium Nitrate Ionic Liquid

2018 ◽  
Author(s):  
Anna Gołąbiewska ◽  
Micaela Checa-Suárez ◽  
Marta Paszkiewicz-Gawron ◽  
Wojciech Lisowski ◽  
Edyta Raczuk ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Surface Area ◽  
Photoelectron Spectroscopy ◽  
High Efficiency ◽  
Diffuse Reflectance Spectroscopy ◽  
Phenol Degradation ◽  
Bet Surface Area ◽  
Synthesis Time ◽  
X Ray ◽  
Highly Active

Spherical microparticles of TiO2 were synthesized by the ionic liquid-assisted solvothermal method at different reaction time (3, 6, 12 and 24h). The properties of the prepared photocatalysts were investigated by means of UV-vis diffuse-reflectance spectroscopy (DRS), BET surface area measurements, scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), and X-ray photoelectron spectroscopy (XPS). The results indicated that the efficiency of phenol degradation was related with a time of the solvothermal synthesis as determined for TiO2_EAN(1:1)_24h sample. Microparticles of TiO2_EAN(1:1)_3h formed during the only 3h of synthesis time revealed really high photoactivity under visible irradiation – 75%. This value increased to 80% and 82% after 12h and 24h, respectively. The photoactivity increase was accompanied by the increase of the specific surface area thus pores size, as well as ability to absorb UV-vis irradiation. The high efficiency of phenol degradation of IL-TiO2 photocatalysts was ascribed to the interaction between the surface of TiO2 and ionic liquid components (carbon and nitrogen).

scholarly journals Enhanced Photocatalytic Degradation of Phenol Using Urchin-Like ZnO Microrod-Reduced Graphene Oxide Composite under Visible-Light Irradiation

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
S. Mary Margaret ◽  
Albin John P. Paul Winston ◽  
S. Muthupandi ◽  
P. Shobha ◽  
P. Sagayaraj
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Phenol Degradation ◽  
Hydrothermal Process ◽  
Light Irradiation ◽  
Light Illumination ◽  
Order Kinetic ◽  
Phenol Solution ◽  
Vis Spectroscopy

In this study, visible-light-driven ZnO microrod-rGO heterojunction composites were successfully synthesized via a facile and scalable hydrothermal process. The prepared photocatalyst heterojunction was examined using different techniques including XRD, SEM, FTIR, UV-Vis spectroscopy, and TGA to reveal their crystal phase, morphology, and other optical properties. The photocatalytic performance of the obtained ZnO-rGO composites was measured by the photodegradation of phenol under visible light illumination. The addition of graphene over the catalyst exhibited an enhanced photocatalytic activity for phenol degradation due to its high surface area and decreasing rate of electron-hole separation. Kinetic studies proved that the degradation of phenol process happened by following the pseudo-first-order kinetic model. The effective conditions for degradation of phenol using ZnO-rGO composite were 0.2 g L-1catalyst dose, pH -4, and initial concentration 20 ppm of phenol solution. Comparing with ZnO microrods, the heterojunction composite degraded the organic pollutants of phenol solution up to 84.2% of efficiency displaying the highest photocatalytic activity, whereas urchin-like ZnO catalyst exhibited much less photocatalytic activity for phenol degradation under visible light irradiation. This result envisages immense properties, showing a great potential industrial application for the removal of phenolic wastewater.

scholarly journals Green synthesis of Ag/TiO2 Nanocomposite Assisted by Gambier Leaf (Uncaria gambir Roxb) Extract

2019 ◽  
Vol 22 (6) ◽  
pp. 250-255 ◽  
Author(s):  
Sry Wahyuni ◽  
Syukri Syukri ◽  
Syukri Arief
Keyword(s):  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Diffuse Reflectance Spectroscopy ◽  
Irradiation Time ◽  
Rutile Phase ◽  
X Ray Diffraction ◽  
Silver Surface ◽  
X Ray ◽  
Synthesis Of Nanoparticles ◽  
Vis Spectroscopy

Studies of green synthesis of nanoparticles mediated by plants extract is extensively explored and studied in recent time due to eco-friendliness, cost-effectiveness, and use a minimum amount of toxic chemicals in the process of inorganic material synthesis. In this study, the immobilization of silver nanoparticles on the surface of titanium dioxide (TiO2) was carried out using Uncaria gambier Roxb. leaf extract as a silver ion (Ag+) reducing agent. The synthesized Ag/TiO2 nanocomposite was characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), and Diffuse Reflectance Spectroscopy (DRS). The formation of silver nanoparticles was confirmed through UV-Vis spectroscopic analysis, which showed a silver surface plasmon resonance (SPR) band at 426 nm. The X-ray diffraction pattern shows that Ag can inhibit the transition of the anatase into rutile phase. The presence of Ag particles in TiO2 can increase the absorption ability from an initial wavelength of 407 nm to 438 nm. Based on the results of Rhodamin B degradation, it can be seen that Ag/TiO2 has a higher photocatalytic activity than bare TiO2 with 99% percent degradation at 120 minutes of irradiation time.

scholarly journals The Effect of Calcination Temperature on Structure and Photocatalytic Properties of WO3/TiO2Nanocomposites

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Joanna Mioduska ◽  
Anna Zielińska-Jurek ◽  
Marcin Janczarek ◽  
Jan Hupka
Keyword(s):  
Photocatalytic Activity ◽  
Calcination Temperature ◽  
Amorphous Phase ◽  
Diffuse Reflectance ◽  
Optical Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
Phenol Degradation ◽  
Xrd Analysis ◽  
Reflectance Spectroscopy ◽  
X Ray

Series of WO3/TiO2nanocomposites were obtained by hydrothermal method followed by calcination in the temperature range from 400°C to 900°C. The characteristics of photocatalysts by X-ray diffractometry (XRD), scanning electron microscope (SEM), and diffuse reflectance spectroscopy (DRS) showed that increasing the calcination temperature from 400 to 900°C resulted in change of photocatalytic activity under UV-Vis light. Moreover, the amount of WO3crystalline phase and amorphous phase in WO3/TiO2aggregates, as revealed by XRD analysis, was dependent on the calcination temperature. The WO3/TiO2samples with 8 mol% load of WO3in respect to TiO2calcinated at 500 and 800°C possess the highest photocatalytic activity in reaction of phenol degradation, which is about 1.2 and 1.5 times that with calcination at 400°C. The increase in calcination temperature above 400°C resulted in increase of WO3crystallinity and reduction of the amount of amorphous phase in the nanocomposite structure. Moreover, the annealing of nanocomposites above 700°C decreases the value of optical band gap energies of obtained WO3/TiO2nanomaterials.

scholarly journals Modification of Carbon Nanotube for Synthesis of Titania Nanotube (Tint)-Carbon Nanotube (Cnt) Composite

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Desi Heltina
Keyword(s):  
Carbon Nanotube ◽  
Cetyl Trimethyl Ammonium Bromide ◽  
Phenol Degradation ◽  
Dispersion Stability ◽  
Ammonium Bromide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Titania Nanotube ◽  
Cetyl Trimethyl Ammonium

Carbon nanotube (CNT) is a material widely chosen for object of research in nano technology. Apart from its good absorbent property, CNT also has a unique structure, superior mechanic and electric properties and its high strength. The property of CNT above is to be expected to improve performance of Titania nanotube (TiNT) composite. Properties of pure CNT are hydrophobic at the surface and low dispersion stability. To improve dispersability of CNT then modification need to be modified. Adding Cetyl trimethyl ammonium bromide (CTAB) surfactant on CNT is a way to increase dispersion stability of TiNT-CNT. The objective of the research was to study influence of adding of Cetyl trimethyl ammonium bromide (CTAB) surfactant to synthesis of TiNT-CNT composite in degrading phenol compound. Pure CNT was added with CTAB surfactant in liquid, then was sonificated and dried. Surfactant Cetyl trimethyl ammonium bromide (CTAB) added CNT then composited with TiNT. Phenol degradation then tested by using TiNT-CNT (CTAB) in reactor for 4.5 hours. Then sample was characterized by employing Field Emission Scanning Electron Microscopy (FESEM), X-ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR) and UV-vis Spectroscopy. The result of experiments from FESEM characterization showed forming of TiNT-CNT composites morphology. From X–ray Diffraction (XRD) characterization showed crystal formed on TiNT-CNT only of anatase crystal. Degradation of TiNT-NT composite (CTAB) to phenol was also studied.

scholarly journals Enhancement of Photocatalytic Activity of ZnO/SiO2by Nanosized Pt for Photocatalytic Degradation of Phenol in Wastewater

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
R. M. Mohamed ◽  
M. A. Barakat
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Phenol Degradation ◽  
Synthetic Wastewater ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

ZnO- nanoparticles were synthesized by a sol-gel technique from and tetraethyl orthosilicate (TEOS). The synthesized samples were further modified by nanosized Pt from H2PtCl6solution through photoassisted deposition (PAD) and impregnation (Img) routes. The obtained samples were characterized by a series of techniques including X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy, N2adsorption, extended X-ray absorption fine structure (EXAFS), and transmission electron microscopy (TEM). The photocatalytic activity of the Pt-ZnO/ was evaluated by photocatalytic degradation of phenol in synthetic wastewater under UV-irradiation. Results obtained revealed that the surface area and the photocatalytic activity of the prepared samples were increased in the order ZnO/ < PAD: Pt-ZnO/ < img: Pt-ZnO/. The surface area decreased from 480 to 460 and 450 m2/g, while the efficiency of the phenol degradation increased from 80 to 85 and 100%, with the ZnO/, Img: Pt-ZnO-, and PAD: Pt-ZnO- samples, respectively.

scholarly journals A composite of clay, cement, and wood as natural support material for the immobilization of commercial titania (P25, P90, PC500, C-TiO2) towards photocatalytic phenol degradation

2020 ◽  
Vol 81 (9) ◽  
pp. 1882-1893
Author(s):  
L. Morjène ◽  
M. Tasbihi ◽  
M. Schwarze ◽  
R. Schomäcker ◽  
F. Aloulou ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
Color Change ◽  
Uv Light ◽  
Phenol Degradation ◽  
Order Kinetic ◽  
Support Material ◽  
Wood Fibers ◽  
Kinetic Rate Constant ◽  
Natural Support ◽  
Photocatalytic Material

Abstract Different types of commercial titania (P25, P90, PC500, and C-TiO2) were immobilized as single or mixed photocatalyst onto the surface of a natural support material made of cement, clay, and wood fibers. The successful immobilization was studied by different techniques showing a composite material with the mechanical properties of the support material and the photocatalytic behavior of the immobilized titania. The supported photocatalyst showed high mechanical stability and was applied to the photocatalytic degradation of phenol as a model pollutant under UV light irradiation. As the most active photocatalytic material, a mixture PC500 and P90 (comp-PC500/P90) was identified with an apparent pseudo first-order kinetic rate constant (kapp) of 0.010 min−1 at a degradation efficiency of 100%. The catalyst was used several times and showed minor loss in activity during four runs due to degradation intermediates adsorbed to the surface, shown by a color change from white to yellow.

scholarly journals Fabrication and photoactivity of ionic liquid–TiO2 structures for efficient visible-light-induced photocatalytic decomposition of organic pollutants in aqueous phase

2018 ◽  
Vol 9 ◽  
pp. 580-590 ◽  
Author(s):  
Anna Gołąbiewska ◽  
Marta Paszkiewicz-Gawron ◽  
Aleksandra Sadzińska ◽  
Wojciech Lisowski ◽  
Ewelina Grabowska ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Visible Light ◽  
Diffuse Reflectance Spectroscopy ◽  
Phenol Degradation ◽  
Active Species ◽  
Photocatalytic Decomposition ◽  
Bet Surface Area ◽  
Light Illumination ◽  
Transmission Microscopy ◽  
X Ray

To investigate the effect of the ionic liquid (IL) chain length on the surface properties and photoactivity of TiO2, a series of TiO2 microspheres have been synthesized via a solvothermal method assisted by 1-methyl-3-octadecylimidazolium chloride ([ODMIM][Cl]) and 1-methyl-3-tetradecylimidazolium chloride ([TDMIM][Cl]). All as-prepared samples were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy (DRS), scanning transmission microscopy (STEM) and the Brunauer–Emmett–Teller (BET) surface area method, whereas the photocatalytic activity was evaluated by the degradation of phenol in aqueous solution under visible light irradiation (λ > 420 nm). The highest photoefficiency (four times higher than pristine TiO2) was observed for the TiO2 sample obtained in the presence of [TDMIM][Cl] for a IL to TiO2 precursor molar ratio of 1:3. It was revealed that interactions between the ions of the ionic liquid and the surface of the growing titanium dioxide spheres results in a red-shift of absorption edge for the IL–TiO2 semiconductors. In this regard, the direct increase of the photoactivity of IL–TiO2 in comparison to pristine TiO2 was observed. The active species trapping experiments indicated that O2 •− is the main active species, created at the surface of the IL–TiO2 material under visible-light illumination, and is responsible for the effective phenol degradation.

scholarly journals Utilization of Carbon Nanospheres in Photocatalyst Production: From Composites to Highly Active Hollow Structures

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2537 ◽  
Author(s):  
Tamás Gyulavári ◽  
Gábor Veréb ◽  
Zsolt Pap ◽  
Balázs Réti ◽  
Kornelia Baan ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Phenol Degradation ◽  
Carbon Sphere ◽  
Carbon Nanospheres ◽  
Purification Method ◽  
X Ray ◽  
Hollow Structures ◽  
Synthesis Parameters

Titanium dioxide–carbon sphere (TiO2–CS) composites were constructed via using prefabricated carbon spheres as templates. By the removal of template from the TiO2–CS, TiO2 hollow structures (HS) were synthesized. The CS templates were prepared by the hydrothermal treatment of ordinary table sugar (sucrose). TiO2–HSs were obtained by removing CSs with calcination. Our own sensitized TiO2 was used for coating the CSs. The structure of the CSs, TiO2–CS composites, and TiO2–HSs were characterized by scanning electron microscopy (SEM), infrared spectroscopy (IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and diffuse reflectance spectroscopy (DRS). The effect of various synthesis parameters (purification method of CSs, precursor quantity, and applied furnace) on the morphology was investigated. The photocatalytic activity was investigated by phenol model pollutant degradation under visible light irradiation (λ > 400 nm). It was established that the composite samples possess lower crystallinity and photocatalytic activity compared to TiO2 hollow structures. Based on XPS measurements, the carbon content on the surface of the TiO2–HS exerts an adverse effect on the photocatalytic performance. The synthesis parameters were optimized and the TiO2–HS specimen having the best absolute and surface normalized photocatalytic efficiency was identified. The superior properties were explained in terms of its unique morphology and surface properties. The stability of this TiO2–HS was investigated via XRD and SEM measurements after three consecutive phenol degradation tests, and it was found to be highly stable as it entirely retained its crystal phase composition, morphology and photocatalytic activity.

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