Solar Light Induced Photocatalysis for Treatment of High COD Pharmaceutical Effluent with Recyclable Ag-Fe Codoped TiO2: Kinetics of COD Removal

A wide range of active pharmaceutical ingredients (API) is found in various water streams. These synthetic non-biodegradable organics create trouble in conventional wastewater treatment due to toxicity. There is a strong need to develop substitute technology such as visible light driven photocatalysis with a reusable photocatalyst to completely oxidize these substances into carbon dioxide and water. Sol-gel method was used for synthesis of Fe doped TiO2 and Ag-Fe codoped TiO2 nanoparticles with 0.5 wt% Fe and Ti/Ag molar ratio 30 (Ag-Fe CT 30). The morphology and structure of nanoparticles were studied using various analytical techniques. Ag-Fe CT 30 photocatalyst has exhibited excellent photocatalytic activity compared to commercial TiO2, undoped TiO2 and Fe doped TiO2 nanophotocatalysts under solar and UV irradiation for removal of an antifungal drug intermediate, Difloro triazole acetophenone (DFTA) from water. COD reduction efficiency was highest with Ag-Fe CT 30 under solar and UV irradiation proves the potential of Ag-Fe CT 30 photocatalyst to absorb both UV as well as visible radiations. Ag-Fe CT 30 has shown good stability for 4 runs without much decline in the efficacy. This study provides insights on the solar application of a reusable Ag-Fe CT 30 photocatalyst for the treatment of high strength COD wastewater. Kinetics of COD reduction by photocatalysis has been determined.

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Kinetic model of photoinitiated copolymerization of monofunctional monomers till high conversions

Chemistry & Chemical Technology ◽

10.23939/chcht03.01.001 ◽

2009 ◽

Vol 3 (1) ◽

pp. 1-6

Author(s):

Yuriy Medvedevskikh ◽

◽

Galyna Khovanets’ ◽

Iryna Yevchuk ◽

◽

...

Keyword(s):

Kinetic Model ◽

Uv Irradiation ◽

Glycidyl Methacrylate ◽

Laser Interferometry ◽

Polymerization Process ◽

Molar Ratio ◽

Hydroxyethyl Methacrylate ◽

Wide Range ◽

Kinetics Of

Regularities of kinetics of photoinitiated copolymerization till high conversions in the systems of monofunctional methacrylate comonomers (hydroxyethyl methacrylate (HEMA), glycidyl methacrylate (GMA)) have been investigated by laser interferometry in a wide range of experimental factors (molar ratio of comonomers, photoinitiator concentration, intensity of UV-irradiation). Kinetic model of photoinitiated copolymerization of methacrylates till high conversions has been proposed on the basis of microheterogeneity conception of the polymerization process.

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Green Synthesis of N/Zr Co-Doped TiO2 for Photocatalytic Degradation of p-Nitrophenol in Wastewater

Catalysts ◽

10.3390/catal11020235 ◽

2021 ◽

Vol 11 (2) ◽

pp. 235

Author(s):

Hayette Benkhennouche-Bouchene ◽

Julien G. Mahy ◽

Cédric Wolfs ◽

Bénédicte Vertruyen ◽

Dirk Poelman ◽

...

Keyword(s):

Visible Light ◽

Tio2 Nanoparticles ◽

Sol Gel ◽

Visible Region ◽

Chemical Properties ◽

Pure Tio2 ◽

Molar Ratio ◽

Xps Spectra ◽

Doped Tio2 ◽

Co Doped

TiO2 prepared by a green aqueous sol–gel peptization process is co-doped with nitrogen and zirconium to improve and extend its photoactivity to the visible region. Two nitrogen precursors are used: urea and triethylamine; zirconium (IV) tert-butoxide is added as a source of zirconia. The N/Ti molar ratio is fixed regardless of the chosen nitrogen precursor while the quantity of zirconia is set to 0.7, 1.4, 2, or 2.8 mol%. The performance and physico-chemical properties of these materials are compared with the commercial Evonik P25 photocatalyst. For all doped and co-doped samples, TiO2 nanoparticles of 4 to 8 nm of size are formed of anatase-brookite phases, with a specific surface area between 125 and 280 m2 g−1 vs. 50 m2 g−1 for the commercial P25 photocatalyst. X-ray photoelectron (XPS) measurements show that nitrogen is incorporated into the TiO2 materials through Ti-O-N bonds allowing light absorption in the visible region. The XPS spectra of the Zr-(co)doped powders show the presence of TiO2-ZrO2 mixed oxide materials. Under visible light, the best co-doped sample gives a degradation of p-nitrophenol (PNP) equal to 70% instead of 25% with pure TiO2 and 10% with P25 under the same conditions. Similarly, the photocatalytic activity improved under UV/visible reaching 95% with the best sample compared to 50% with pure TiO2. This study suggests that N/Zr co-doped TiO2 nanoparticles can be produced in a safe and energy-efficient way while being markedly more active than state-of-the-art photocatalytic materials under visible light.

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Sol-Gel Immobilisation of Lipases: Towards Active and Stable Biocatalysts for the Esterification of Valeric Acid

Molecules ◽

10.3390/molecules23092283 ◽

2018 ◽

Vol 23 (9) ◽

pp. 2283 ◽

Cited By ~ 5

Author(s):

Soledad Cebrián-García ◽

Alina Balu ◽

Araceli García ◽

Rafael Luque

Keyword(s):

Microwave Irradiation ◽

Sol Gel ◽

Valeric Acid ◽

Added Value ◽

Conventional Heating ◽

Molar Ratio ◽

Highly Active ◽

Industrial Sectors ◽

Wide Range ◽

Acid Esterification

Alkyl esters are high added value products useful in a wide range of industrial sectors. A methodology based on a simple sol-gel approach (biosilicification) is herein proposed to encapsulate enzymes in order to design highly active and stable biocatalysts. Their performance was assessed through the optimization of valeric acid esterification evaluating the effect of different parameters (biocatalyst load, presence of water, reaction temperature and stirring rate) in different alcoholic media, and comparing two different methodologies: conventional heating and microwave irradiation. Ethyl valerate yields were in the 80–85% range under optimum conditions (15 min, 12% m/v biocatalyst, molar ratio 1:2 of valeric acid to alcohol). Comparatively, the biocatalysts were slightly deactivated under microwave irradiation due to enzyme denaturalisation. Biocatalyst reuse was attempted to prove that good reusability of these sol-gel immobilised enzymes could be achieved under conventional heating.

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Synthesis, Characterization and Photocatalytic Activity of Nb-Doped TiO2 Nanoparticles

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.455-456.110 ◽

2012 ◽

Vol 455-456 ◽

pp. 110-114 ◽

Cited By ~ 1

Author(s):

Xuan Dong Li ◽

Xi Jiang Han ◽

Wen Ying Wang ◽

Xiao Hong Liu ◽

Yan Wang ◽

...

Keyword(s):

Aqueous Solution ◽

Photocatalytic Activity ◽

Methyl Orange ◽

Photoelectron Spectroscopy ◽

Sol Gel ◽

Molar Ratio ◽

X Ray Diffraction ◽

Doped Tio2 ◽

X Ray ◽

Vis Spectroscopy

Nb-doped TiO2 powders with different concentrations of Nb have been synthesized by a sol-gel method and characterized by a series of technologies including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-vis spectroscopy. The photocatalytic activity of Nb-doped TiO2 is evaluated by degradation efficiency of methyl orange in aqueous solution. The results indicate that the photocatalytic activity of Nb-doped TiO2 synthesized with a Nb/Ti molar ratio of 5% is higher than that of TiO2 under the visible light.

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Unravelling a Novel Sol-Gel Transition Mechanism in Polymer Self-Assemblies: An Order-Order Transition Based on Specific Molecular Interactions Between Hydrophilic and Hydrophobic Polymer Blocks

10.26434/chemrxiv.14362892 ◽

2021 ◽

Author(s):

Lukas Hahn ◽

Theresa Zorn ◽

Josef Kehrrein ◽

Tobias Kielholz ◽

Benedikt Sochor ◽

...

Keyword(s):

Self Assembly ◽

Sol Gel ◽

Analytical Techniques ◽

Order Transition ◽

Dynamics Simulation ◽

Aqueous Polymer ◽

Transition Mechanism ◽

Wide Range ◽

Spherical Micelles ◽

Sol Gel Transition

Using a wide range of state-of-the art analytical techniques and molecular dynamics simulation, a novel mechanism for macromolecular interactions are described. Distinct interactions between the hydrophilic and hydrophobic blocks in amphiphilic triblock copolymers lead to an order-order transition from spherical micelles to worm-like micelles upon cooling the aqueous polymer solutions below room temperature. Macroscopically, this this leads to reversible gelation. This novel mechanism represent a novel building block to better understand polymer self-assembly.<br>

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Photocatalytic Reduction of Methyl Orange Using Titania Photocatalyst Codoped with Nitrogen and Gadolinium under Visible Light Illumination

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.79-82.2127 ◽

2009 ◽

Vol 79-82 ◽

pp. 2127-2130 ◽

Cited By ~ 1

Author(s):

Song Tao Gu ◽

Xin Wang ◽

Qiang Liu ◽

Hao Quan Liu ◽

Gui Jun Jiang ◽

...

Keyword(s):

Photocatalytic Activity ◽

Methyl Orange ◽

Visible Light ◽

Synergistic Effects ◽

Sol Gel ◽

Visible Region ◽

Light Illumination ◽

Active Nitrogen ◽

Doped Tio2 ◽

Codoped Tio2

A visible-light-active nitrogen and gadolinium codoped TiO2 catalyst was synthesized by the sol-gel route. For comparison, Gd-doped sample, N-doped sample, and pure titania were prepared through the same method, without adding the corresponding dopants. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD) and Uv-vis spectra. The results showed that the codoped photocatalyst exhibited a smaller size than the undoped titania. The transformation from anatase to rutile was suppressed by doping with N and Gd atoms. Furthermore, the absorbance spectra of N, Gd-codoped TiO2 exhibited a significant red shift to the visible region. The photocatalytic activity of N, Gd-codoped TiO2 was evaluated by photodegradation of methyl orange under visible light irradiation. This codoped sample exhibited enhanced photocatalytic activity compared to N-doped TiO2, Gd-doped TiO2, and pure TiO2. The improvement of the photocatalytic activity was ascribed to the synergistic effects of the N and Gd co-doping.

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Crystallization Kinetics of Li+-Doped TiO2 Films Prepared by Sol-Gel Dip Coating

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.105-106.750 ◽

2010 ◽

Vol 105-106 ◽

pp. 750-753

Author(s):

Feng Zhou ◽

Ying Qing Fu ◽

Kai Ming Liang

Keyword(s):

Crystallization Behavior ◽

Tio2 Thin Film ◽

Sol Gel ◽

Dip Coating ◽

X Ray Diffraction ◽

Tio2 Thin Films ◽

Doped Tio2 ◽

X Ray ◽

Li Ion ◽

Kinetics Of

The crystallization behavior and microstructure of Li+-doped TiO2 thin films prepared by sol-gel dip coating were investigated by means of differential themal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The crystallization apparent activation energy (E) both in the absence and in the presence of Li+ ion was also measured with Kissinger method. As a result the E values of Li+-doped TiO2 thin film were decreased, thus the crystallization of non-crystalline to anatase and antase to rutile was promoted.

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Hydrothermally treated cement-based building materials. Past, present, and future

Pure and Applied Chemistry ◽

10.1351/pac200274112131 ◽

2002 ◽

Vol 74 (11) ◽

pp. 2131-2135 ◽

Cited By ~ 6

Author(s):

A. Ray

Keyword(s):

Building Materials ◽

Analytical Techniques ◽

Drying Shrinkage ◽

High Strength ◽

Thermal Methods ◽

Building Products ◽

Blended Cements ◽

Phase Development ◽

Wide Range

Hydrothermally cured or autoclaved cement-based building products have provided many challenges to researchers, manufacturers, and users since their inception nearly 100 years ago. The advantages, including the development of high strength within a few hours and a reduction of drying shrinkage, of the hydrothermal curing process have resulted in a variety of building products; inevitably, the technology of their production has undergone many stages of refinement. With the advent of nonconventional starting materials for the production of modern cements, and the push to utilize renewable resources to form blended cements, the chemical and physical make-up of hydrothermally cured building materials have changed considerably in recent years and will continue to change. It is, therefore, important to understand the chemical reactions taking place in an autoclave, and the consequent phase developments, if building materials produced by this process continue to be successful in the long term. A wide range of analytical techniques exists for characterizing the phase development in cement-based materials. The purpose of this paper is to illustrate the strength of thermal methods, especially when used in combination with other analytical techniques, in the understanding of hydrothermal reactions.

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Preparation and Properties of CoFe2O4 Synthesized by the Modified Citrate-Gel Method

Materials Science Forum ◽

10.4028/www.scientific.net/msf.644.39 ◽

2010 ◽

Vol 644 ◽

pp. 39-42 ◽

Cited By ~ 5

Author(s):

E.M. Múzquiz-Ramos ◽

Dora A. Cortés-Hernández ◽

O.A. Herrera-Romero ◽

José C. Escobedo-Bocardo

Keyword(s):

Heat Treatment ◽

Particle Size ◽

Magnetic Properties ◽

Citric Acid ◽

Saturation Magnetization ◽

Sol Gel ◽

Molar Ratio ◽

Spinel Type ◽

Wide Range ◽

Auto Combustion

In this work, the synthesis of CoFe2O4 via sol-gel auto-combustion method, using iron nitrate, cobalt nitrate and citric acid, with subsequent heat treatment in air was studied. The effects of the molar ratio of the metal nitrates to citric acid and the heat treatment temperatures on the magnetic properties have been investigated. The X-ray diffraction patterns showed peaks consistent with cubic spinel-type structure. The average crystallite sizes were determined from the (311) peak of the diffraction pattern using Scherrer equation. Particle sizes in the range of 18-44 nm were obtained. The crystallite size increases with annealing temperature. Magnetic properties, such as saturation magnetization (Ms), remanent magnetization (Mr) and coercivity field (Hc) were measured at room temperature using a vibrating sample magnetometer. Saturation magnetization was found to increase with particle size, whereas coercivity was found to reduce exponentially as the particle size was increased, apart from the Hc of the sample treated at 300 °C. The present work shows that magnetic properties vary over a wide range by changing the synthesis conditions.

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