scholarly journals Evaluation of Hydrocalumite-Like Compounds as Catalyst Precursors in the Photodegradation of 2,4-Dichlorophenoxyacetic Acid

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Manuel Sánchez-Cantú ◽  
Clara Barcelos-Santiago ◽  
Claudia M. Gomez ◽  
Esthela Ramos-Ramírez ◽  
Ma. de Lourdes Ruiz Peralta ◽  
...  
Keyword(s):  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Nitrogen Adsorption ◽  
Dichlorophenoxyacetic Acid ◽  
X Ray ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Adsorption Desorption ◽  
Oxide Ions ◽  
Environmentally Friendly Method ◽  
Simple Economic

Three hydrocalumite-like compounds in a Ca/Al ratio of 2 containing nitrate and acetate anions in the interlaminar region were prepared by a simple, economic, and environmentally friendly method. The solids were characterized by X-ray powder diffraction (XRD), thermogravimetric (TG) analysis, nitrogen adsorption-desorption at −196°C, scanning electron microscopy (SEM), infrared spectroscopy (FTIR), and UV-Vis Diffuse Reflectance Spectroscopy (DRS). The catalytic activity of the calcined solids at 700°C was tested in the photodegradation of 2,4-dichlorophenoxyacetic acid (2,4-D) where 57% degradation of 2,4-D (40 ppm) and a mineralization percentage of 60% were accomplished within 150 minutes. The photocatalytic properties were attributed to mayenite hydration, since the oxide ions in the cages are capable of reacting with water to form hydroxide anions capable of breaking down the 2,4-D molecules.

Preparation of Fe3O4/TiO2 magnetic mesoporous composites for photocatalytic degradation of organic pollutants

2017 ◽  
Vol 75 (7) ◽  
pp. 1523-1528 ◽  
Author(s):  
Hongfeng Zhang ◽  
Xiu He ◽  
Weiwei Zhao ◽  
Yu Peng ◽  
Donglan Sun ◽  
...  
Keyword(s):  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Magnetic Composite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mesoporous Composites ◽  
Uv Lamp ◽  
Adsorption Desorption

Fe3O4/TiO2 magnetic mesoporous composites were synthesized through a sol-gel method with tetra-n-butyl titanate as precursor and surfactant P123 as template. The as-prepared Fe3O4/TiO2 composites were characterized by X-ray diffraction, diffuse reflectance spectroscopy, nitrogen adsorption-desorption isotherm and pore size distribution. The as-synthesized products were applied as photocatalysis for the degradation of Acid Black ATT and tannery wastewater under UV lamp irradiation. Fe3O4/TiO2-8 composites containing Fe3O4 of 8 wt% were selected as model catalysts. The optimal catalyst dosage was 3 g/L in this photocalytic system. The magnetic Fe3O4/TiO2 composites possessed good photocatalytic stability and durability. This approach may provide a platform to prepare a magnetic composite to optimize the catalytic ability.

scholarly journals Ultrasound-Assisted Rapid ZIF-8 Synthesis, Porous ZnO Preparation by Heating ZIF-8, and Their Photocatalytic Activity

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Pham Dinh Du ◽  
Nguyen Trung Hieu ◽  
Tran Vinh Thien
Keyword(s):  
Photocatalytic Activity ◽  
Room Temperature ◽  
Diffuse Reflectance ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
Zeolitic Imidazolate Framework ◽  
X Ray ◽  
Photocatalytic Activities ◽  
Ft Ir ◽  
Adsorption Desorption

Zeolitic imidazolate framework-8 (ZIF-8) is synthesized quickly at room temperature in methanol with the support of ultrasound. Porous ZnO is also prepared via the thermal treatment of ZIF-8. The photocatalytic activities of the obtained materials are demonstrated via methylene blue (MB) decomposition under UV radiation. The obtained materials are characterized by means of X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), nitrogen adsorption/desorption isotherms, UV-Vis diffuse reflectance spectra (DR-UV-Vis), and photoluminescence spectra. The results indicate that ZIF-8 and the materials obtained from ZIF-8 by heating in the air have photocatalytic activity under UV irradiation. The ZnO sample obtained by ZIF-8 calcination at 660°C for 5 h has the highest photocatalytic activity. However, the MB degradation photocatalytic efficiency of the ZnO samples is even lower than that of the ZIF-8 samples, indicating that ZIF-8 is an effective photocatalyst in the treatment of environmental pollution.

Fabrication, Characterization and Photocatalytic Capability of ZnAl2O4 Nanospheres

2012 ◽  
Vol 518-523 ◽  
pp. 736-739 ◽  
Author(s):  
Ling Zhao ◽  
Xin Yong Li ◽  
Ji Zhao
Keyword(s):  
Diffuse Reflectance ◽  
Gas Adsorption ◽  
Diffuse Reflectance Spectroscopy ◽  
Phase Method ◽  
Chemical Solution ◽  
X Ray ◽  
Specific Morphology ◽  
Wet Chemical ◽  
Adsorption Desorption ◽  
Solution Phase Method

Developing photocatalysts with specific morphology promises good opportunities to discover the geometry dependent properties. Porous and spherical shaped superstructure of ZnAl2O4 was successfully synthesized by a facile wet chemical solution-phase method. Their surface morphology and structure were investigated by X-ray powder diffraction, scanning electron microscopy, energy dispersive spectra and Brunauer-Emmet-Teller N2 gas adsorption-desorption isotherms. The optical property of the ZnAl2O4 nanospheres were studied by UV-vis diffuse reflectance spectroscopy. The ZnAl2O4 nanospheres exhibited a good photocatalytic activity in degrading rhodamine B.

TiO2 Hollow Spheres Obtained under Autogenic Pressure at Elevated Temperature

2009 ◽  
Vol 79-82 ◽  
pp. 525-528 ◽  
Author(s):  
Ke Xun Li ◽  
Hong Liang Li ◽  
Jun Hua Zhao ◽  
Ying Chun Zhu ◽  
Xiu Song Zhao
Keyword(s):  
Elevated Temperature ◽  
Diffuse Reflectance ◽  
Hollow Spheres ◽  
Nitrogen Adsorption ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surfactant Additive ◽  
Tio2 Hollow Spheres ◽  
Adsorption Desorption

Carbon/TiO2 composites were prepared via the reaction under Autogenic Pressure at Elevated Temperature (RAPET) using alkoxides as precursor, and then porous TiO2 hollow spheres were derived after removing the carbon ingredient by calcination at 600°C. The influence of surfactant additives, including the addition ratio and the nature of the surfactants, on the morphology and the structures of the Carbon/TiO2 composites and the derived TiO2 were also studied with scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-Vis diffuse reflectance spectrophotoscopy (DRS) and nitrogen adsorption-desorption measurements. The results revealed that the morphology of the products turned to spherical and then fusiform and the structures turned from hollow to solid with the increasing of surfactant additive. The BET surface area of the hollow TiO2 was modified from 12m2/g to 57m2/g after calcinations. The XRD investigation indicates that the phases of the TiO2 in both the carbon/TiO2 composites and the derived TiO2 hollow spheres are anatase.

scholarly journals Enhanced Degradation of Rhodamine B by Metallic Organic Frameworks Based on NH2-MIL-125(Ti) under Visible Light

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7741
Author(s):  
Hong-Tham Nguyen Thi ◽  
Kim-Ngan Tran Thi ◽  
Ngoc Bich Hoang ◽  
Bich Thuy Tran ◽  
Trung Sy Do ◽  
...  
Keyword(s):  
Visible Light ◽  
Rhodamine B ◽  
Diffuse Reflectance ◽  
High Efficiency ◽  
Diffuse Reflectance Spectroscopy ◽  
Active Species ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fundamental Properties ◽  
Adsorption Desorption

Samples of the bimetallic-based NH2-MIL-125(Ti) at a ratio of Mn+/Ti4+ is 0.15 (Mn+: Ni2+, Co2+ and Fe3+) were first synthesized using the solvothermal method. Their fundamental properties were analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectra, scanning electron microscopy (SEM), N2 adsorption–desorption measurements, and UV–Vis diffuse reflectance spectroscopy (UV-Vis DRS). The as-acquired materials were used as high-efficiency heterogeneous photocatalysts to remove Rhodamine B (RhB) dye under visible light. The results verified that 82.4% of the RhB (3 × 10−5 M) was degraded within 120 min by 15% Fe/Ti−MOFs. Furthermore, in the purpose of degrading Rhodamine B (RhB), the rate constant for the 15% Fe/Ti-MOFs was found to be 2.6 times as fast as that of NH2-MIL-125(Ti). Moreover, the 15% Fe/Ti-MOFs photocatalysts remained stable after three consecutive cycles. The trapping test demonstrated that the major active species in the degradation of the RhB process were hydroxyl radicals (HO∙) and holes (h+).

The Synthesis and Photocatalytic Performance of Samarium Doped Mesoporous Titania

2018 ◽  
Vol 876 ◽  
pp. 15-19
Author(s):  
Jian Wen Shi ◽  
Dan Dan Ma ◽  
Ya Jun Zou
Keyword(s):  
Diffuse Reflectance ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Reflectance Spectroscopy ◽  
Mesoporous Titania ◽  
X Ray Diffraction ◽  
Structure Directing Agent ◽  
X Ray

The meso-porous TiO2 and Sm-doped meso-porous TiO2 were synthesized by a sol-gel method. Polyethylene glycol, with different added content, was added as a structure-directing agent. The prepared meso-porous TiO2 was characterized by nitrogen adsorption, X-ray diffraction and ultraviolet-visible diffuse reflectance spectroscopy, and the photocatalytic performance was evaluated by the decomposition of methyl orange. The results revealed that PEG plays a key role in creating porous structure during the heat-treatment. The photocatalytic performance of TiO2 is improved by adding proper content PEG, and Sm-doping can further promote the photocatalytic performance.

Preparation and Luminescence of Host-Guest (SBA-15)-(Arsenano-III) Nanocomposite Materials

2013 ◽  
Vol 785-786 ◽  
pp. 537-541
Author(s):  
Xiao Dong Li
Keyword(s):  
Low Temperature ◽  
Absorption Spectra ◽  
Molecular Sieves ◽  
Diffuse Reflectance ◽  
Nitrogen Adsorption ◽  
Nanocomposite Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Prepared Composite ◽  
Adsorption Desorption

The nanosized channels of SBA-15 molecular sieves were used as template and arsenano-III (ASA-III) was trapped inside the SBA-15 molecular sieves by means of liquid grafting method. The prepared nanocomposite materials were characterized by the powder X-ray diffraction, low temperature nitrogen adsorption-desorption and solid diffuse reflectance absorption spectra. The powder X-ray diffraction indicated the structure of the (SBA-15)-(ASA-III) still remains two-dimensional hexagonal mesostructrure. The low temperature nitrogen adsorption-desorption research showed that the ASA-III was present on the inner surface and partially occupied the channels of the molecular sieve. The UV-Vis solid state diffuse reflectance absorption spectra of the prepared composite materials showed the steroconfinmment effect of the host SBA-15 channels on the guest ASA-III and the guest was in the channels of the SBA-15 host. Luminous spectra showed that the prepared (SBA-15)-(ASA-III) nanocomposite materials have the investigating optical properties.

scholarly journals Effect of the Metal Deposition Order on Structural, Electronic and Catalytic Properties of TiO2-Supported Bimetallic Au-Ag Catalysts in 1-Octanol Selective Oxidation

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 799
Author(s):  
Yulia Kotolevich ◽  
Ekaterina Pakrieva ◽  
Ekaterina Kolobova ◽  
Mario H. Farías ◽  
Nina Bogdanchikova ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Catalytic Properties ◽  
Diffuse Reflectance Spectroscopy ◽  
Density Functional Theory Method ◽  
Nitrogen Adsorption ◽  
X Ray ◽  
A Charge ◽  
Adsorption Desorption ◽  
Ag Catalysts

Au and Ag were deposited on TiO2 modified with Ce, La, Fe or Mg in order to obtain bimetallic catalysts to be used for liquid-phase oxidation of 1-octanol. The effects of the deposition order of gold and silver, and the nature of the support modifying additives and redox pretreatments on the catalytic properties of the bimetallic Au-Ag catalysts were studied. Catalysts were characterized by low-temperature nitrogen adsorption–desorption, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy and ultraviolet-visible diffuse reflectance spectroscopy. It was found that pretreatments with hydrogen and oxygen at 300 °C significantly decreased the activity of AuAg catalysts (silver was deposited first) and had little effect on the catalytic properties of AgAu samples (gold was deposited first). The density functional theory method demonstrated that the adsorption energy of 1-octanol increased for all positively charged AuxAgyq (x + y = 10, with a charge of q = 0 or +1) clusters compared with the neutral counterparts. Lanthanum oxide was a very effective promoter for both monometallic and bimetallic gold and silver catalysts in the studied process.

scholarly journals The impregnation of ZnO onto ZSM-5 derived from red mud for photocatalytic degradation of methylene blue

2022 ◽  
Vol 32 (1) ◽  
Author(s):  
Hellna Tehubijuluw ◽  
Riki Subagyo ◽  
Yuly Kusumawati ◽  
Didik Prasetyoko
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Degradation ◽  
Red Mud ◽  
Diffuse Reflectance Spectroscopy ◽  
Degradation Products ◽  
Nitrogen Adsorption ◽  
Liquid Chromatography Mass Spectrometry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Desorption

AbstractPhotocatalytic degradation of Methylene Blue (MB) by zinc oxide/zeolite socony mobile-5 (ZnO/ZSM-5) composites was investigated. The ZSM-5 material was synthesized from red mud by a two-step hydrothermal method to which ZnO loadings at different mass ratios were subsequently performed. Characterizations using X-ray diffraction (XRD), Fourier transform infrared spectroscopy, and scanning electron microscopy were carried out to identify the formation of ZSM-5 and ZnO/ZSM-5. ZSM-5 and ZnO/ZSM-5 have cubic microcrystallite morphologies. ZnO loading in the ZnO/ZSM-5 composites was successfully performed and confirmed by the appearance of wurtzite peaks in the XRD spectra that matched the Joint Committee on Powder Diffraction Standards data. The presence of ZnO in ZSM-5 leading resulted in a decrease in the surface area and pore size as confirming by nitrogen adsorption-desorption isotherm experiments. The band gap of the samples was measured using UV-Vis diffuse reflectance spectroscopy. The optimum photocatalytic degradation of MB was observed at a ZnO loading of 34% w/w dubbed 34-ZnO/ZSM-5. The influence of the initial concentration of MB was also investigated at 80, 90, and 100 mg L− 1 using 34-ZnO/ZSM-5 and ZSM-5. Liquid chromatography–mass spectrometry characterization was performed to analyze the degradation products.

Optimized photocatalytic degradation of caffeic acid by sol–gel TiO2

2015 ◽  
Vol 71 (6) ◽  
pp. 878-884 ◽  
Author(s):  
Xiomara L. García-Montelongo ◽  
Azael Martínez-de la Cruz ◽  
David Contreras ◽  
Héctor D. Mansilla
Keyword(s):  
Caffeic Acid ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Tio2 Anatase ◽  
Tetragonal Crystal ◽  
Tetragonal Crystal Structure ◽  
Diffuse Reflectance Infrared ◽  
Adsorption Desorption

TiO2 anatase powder was prepared by means of the sol–gel method with titanium(IV) butoxide as precursor. The formation of a tetragonal crystal structure of TiO2 anatase at 500 °C was confirmed by X-ray powder diffraction. The characterization of the samples synthesized was complemented by scanning electron microscopy, diffuse reflectance infrared Fourier transform spectroscopy, nitrogen adsorption–desorption isotherms (Brunauer–Emmett–Teller) and diffuse reflectance spectroscopy. The photocatalytic activity of the TiO2 anatase powder was evaluated in the degradation of caffeic acid in aqueous solution under ultraviolet radiation. A central composite circumscribed design was used to assess the weight of the experimental variables, pH and amount of catalyst in the percentage of caffeic acid degraded and the optimal conditions. The optimized conditions were found to be pH = 5.2 and a load of TiO2 of 1.1 g L−1. Under these conditions more than 90% of caffeic acid degradation was achieved after 30 min of lamp irradiation. At this time the mineralization reached was almost 60%.

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