Preparation, Characterization and Photocatalytic Application of Carbonate Modified Titania

2013 ◽  
Vol 764 ◽  
pp. 219-235
Author(s):  
Rita Sandeep Dhodapkar ◽  
Nageswara Rao Neti
Keyword(s):  
Titanium Dioxide ◽  
Catalytic Activity ◽  
Pollution Abatement ◽  
Oxygen Demand ◽  
Binding Energies ◽  
Advanced Technology ◽  
Oh Radicals ◽  
Oh Groups ◽  
Adsorption Sites ◽  
Photocatalytic Application

Carbonate is a common pollutant in water and wastewater. A study to understand its influence on the photodegradation rates is necessary especially when TiO2/UV technique is emerging as an advanced technology for pollution abatement. In the present investigation, we report surface modification of titanium dioxide using carbonate ions, characterization of carbonate modified titanium dioxide (CMT) and photocatalytic application of carbonate modified TiO2. Titanium dioxide from two different sources namely BDH, Mumbai and Degussa AG, Germany was used as photocatalyst. The CMT catalysts were characterized using potentiometry, FT-IR and XPS. Approximately, 18.9 mg CO3/g CMT(BDH) and 8.13 mg CO3/g CMT(Degussa) was found loaded as determined by potentiometry. The C 1s and O 1s binding energies observed at 289.2 and 531.3 eV, respectively were attributed to surface carbonate species. The adsorption and photodegradation of Acid Blue I dye examined using neat TiO2 as well as CMT catalysts revealed that carbonate inhibits catalytic activity for color and Chemical Oxygen Demand (COD) removal. The photo degradation rate constant (k, s-1) decreases gradually with increasing concentration of carbonate. Thus, in the absence of carbonate kdye is 5.45 × 10-4 s-1 (R2 = 0.97) and kCOD is 3.50 × 10-5 s-1 (R2 = 0.97). At 100 mg/L CO32-, kdye is 0.16 × 10-4 s-1 (R2 = 0.96) and kCOD is 2.66 × 10-5 s-1 (R2 = 0.98). In addition, the carbonate spiking studies revealed the onset of inhibition soon after the addition of carbonate into reacting suspensions of TiO2. The results suggest that carbonate inhibits catalytic activity through formation of strong surface complex under suitable pH by displacing OH2+ and OH groups from TiO2 surface. This results not only in fewer (OH)surface groups available for h+ trapping for oxidation into OH radicals but also in non-availability of adsorption sites for the dye molecules. A pretreatment to remove carbonate from (waste) water appears necessary prior to application of TiO2/UV technique

Effect of Starch on the Flocculation and Settling Behaviour of Titanium Dioxide Suspensions

1974 ◽  
Vol 9 (1) ◽  
pp. 154-171
Author(s):  
S.N. Ray ◽  
C. Hsi ◽  
B.C. -Y. Lu
Keyword(s):  
Titanium Dioxide ◽  
Suspended Solids ◽  
Settling Velocity ◽  
Pollution Abatement ◽  
Paper Mills ◽  
Paper Making ◽  
Jar Test ◽  
Settling Behaviour ◽  
Dimensionless Function ◽  
Flocculation Rate

Abstract This study concerns the problem of removal of suspended solids from the effluent streams of paper mills by chemical treatment. As titanium dioxide is one of the ingredients used in paper mills and present in the effluent streams, its flocculation and settling behaviour were investigated. Jar test experiments were conducted using alum and organic polyelectrolyte as the flocculants. As starch is also used in the paper making process, its influence on the flocculation and settling behaviour of titanium dioxide was conducted with the concentration of starch varying between 0–3% of the dry solids. The experimental results on flocculation are expressed in terms of dimensionless function Gθϕ and flocculation rate constants. The fraction of solids settled is presented in terms of the settling velocity. Concentration of starch was found to have a significant influence. The amount of alum required could be reduced by 75% by using starch 0.6% of the amount of titanium dioxide in the suspension and at the same time improving the settling velocity two folds. A possible application of this finding in pollution abatement is discussed.

Performance Study of Nano-TiO2 Modified Fabric

2012 ◽  
Vol 549 ◽  
pp. 733-736
Author(s):  
Xiao Mian Chen ◽  
Jing Jing Shi ◽  
Hong Sha Su ◽  
Chun Ting Lin ◽  
En Long Yang
Keyword(s):  
Titanium Dioxide ◽  
Catalytic Activity ◽  
Catalytic Properties ◽  
Antibacterial Property ◽  
Wear Behavior ◽  
Water Repellency ◽  
Innovative Technology ◽  
Water Repellent ◽  
High Catalytic Activity ◽  
Performance Study

The catalytic properties of nano-TiO2 modified fabric suits the demand for self-cleaning in recent years. In this paper, advanced and innovative technology were used to synthesize water sol of titanium dioxide photocatalyst with high catalytic activity for fabric finishing. The wear behavior, antibacterial property and water repellency of treated and untreated fabric were tested. Results indicate that finishing and washing of the titanium dioxide had no effect on wear behavior; finished and washed fabric has a certain antibacterial and water repellent properties.

Effect of Preparation Methods of HPW/SiO2 Mesoporous Composites on its Catalytic Performance in Fuel Oils Desulfurization

2010 ◽  
Vol 148-149 ◽  
pp. 924-928
Author(s):  
Xue Min Yan ◽  
Yuan Zhu Mi
Keyword(s):  
Catalytic Activity ◽  
Self Assembly ◽  
Electrostatic Force ◽  
Oxidative Desulfurization ◽  
Strong Acid ◽  
Catalytic Performance ◽  
Synthesis Mechanism ◽  
Base Interaction ◽  
Preparation Methods ◽  
Oh Groups

Two kinds of mesoporous HPW/SiO2 composites, which have been synthesized respectively by the amino-functionalized (AF) method and evaporation-induced self-assembly (EISA) method, have been used as catalysts in the oxidative desulfurization process of dibenzothiophene(DBT). The catalytic performance results show that the catalyst synthesized by EISA method holds higher catalytic activity than that synthesized by the AF method. The difference of catalytic activity can be attributed to the different synthesis mechanism of two kinds of composites. In the AF method, the bonding force between HPW and SiO2 is strong acid-base interaction, which damages the Keggin structure. Whereas in the EISA process, electrostatic force and hydrogen bonds between W=O groups and Si-OH groups are main bonding forces. The hydrogen bond holds the electron-withdrawing effect, which increases the activity of nonbonding W=O groups in HPW and then results in the enhancement of the catalytic activity.

scholarly journals Heterogeneous Bonding of PMMA and Double-Sided Polished Silicon Wafers through H2O Plasma Treatment for Microfluidic Devices

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 580
Author(s):  
Chao-Ching Chiang ◽  
Philip Nathaniel Immanuel ◽  
Yi-Hsiung Chiu ◽  
Song-Jeng Huang
Keyword(s):  
Plasma Treatment ◽  
Flow Rate ◽  
Gas Flow ◽  
Treatment Time ◽  
Optical Emission ◽  
Microfluidic Devices ◽  
Oh Radicals ◽  
Gas Flow Rate ◽  
Oh Groups ◽  
Plasma Treatment Time

In this work we report on a rapid, easy-to-operate, lossless, room temperature heterogeneous H2O plasma treatment process for the bonding of poly(methyl methacrylate) (PMMA) and double-sided polished (DSP) silicon substrates by for utilization in sandwich structured microfluidic devices. The heterogeneous bonding of the sandwich structure produced by the H2O plasma is analyzed, and the effect of heterogeneous bonding of free radicals and high charge electrons (e−) in the formed plasma which causes a passivation phenomenon during the bonding process investigated. The PMMA and silicon surface treatments were performed at a constant radio frequency (RF) power and H2O flow rate. Changing plasma treatment time and powers for both processes were investigated during the experiments. The gas flow rate was controlled to cause ionization of plasma and the dissociation of water vapor from hydrogen (H) atoms and hydroxyl (OH) bonds, as confirmed by optical emission spectroscopy (OES). The OES results show the relative intensity peaks emitted by the OH radicals, H and oxygen (O). The free energy is proportional to the plasma treatment power and gas flow rate with H bonds forming between the adsorbed H2O and OH groups. The gas density generated saturated bonds at the interface, and the discharge energy that strengthened the OH-e− bonds. This method provides an ideal heterogeneous bonding technique which can be used to manufacture new types of microfluidic devices.

Titanium Dioxide-Supported Sulfonated Low Rank Coal as Catalysts in the Oxidation of Styrene with Aqueous Hydrogen Peroxide

2014 ◽  
Vol 69 (5) ◽  
Author(s):  
Mukhamad Nurhadi ◽  
Jon Efendi ◽  
Lee Siew Ling ◽  
Teuku Meurah Indra Mahlia ◽  
Ho Chin Siong ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Catalytic Activity ◽  
Diffuse Reflectance Spectroscopy ◽  
Low Rank ◽  
Bet Surface Area ◽  
High Catalytic Activity ◽  
Low Rank Coal ◽  
X Ray Diffraction ◽  
Aqueous Hydrogen Peroxide

Titanium dioxide supported sulfonated low rank coal catalyst possesses high catalytic activity in liquid phase oxidation of styrene with aqueous hydrogen peroxide at room temperature. The catalysts were prepared by sulfonation with concentrated sulfuric acid and impregnation of titanium dioxide (500-2500 µmol). The effect of titanium dioxide impregnation and calcinations on the catalysts were studied by X-ray diffraction, UV-vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, BET surface area, field emission scanning electron microscopy and hydrophobicity measurement. The catalytic activity of the catalysts in the oxidation of styrene by aqueous H2O2 without calcination increased when the amount of titanium dioxide increased. Meanwhile, the catalytic activity of the catalyst calcined at 500oC for 2 h was lower than before calcination. It is suggested that the agglomeration of titanium dioxide and hydrophobicity play important role in the catalytic activity of titanium dioxide-supported sulfonated low rank coal in the oxidation of styrene with aqueous H2O2. 

Property of Cu2O-CuO/ZSM-5 nanocomposite and degradation process of azo dye AO7 without sacrificial agent (H2O2)

2016 ◽  
Vol 73 (11) ◽  
pp. 2747-2753 ◽  
Author(s):  
Wusong Kong ◽  
Hongxia Qu ◽  
Peng Chen ◽  
Weihua Ma ◽  
Huifang Xie
Keyword(s):  
Catalytic Activity ◽  
Aqueous Solutions ◽  
Photoelectron Spectroscopy ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Surface Element ◽  
Impregnation Method ◽  
X Ray ◽  
Initial Ph ◽  
Sacrificial Agent

In this study, Cu2O-CuO/ZSM-5 nanocomposite was synthesized by the impregnation method, and its catalytic performance for the destruction of AO7 in aqueous solutions was investigated. The morphology, structure and surface element valence state of Cu2O-CuO/ZSM-5 were characterized by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The operating conditions on the degradation of AO7 by Cu2O-CuO/ZSM-5, such as initial pH values, concentration of AO7 and catalyst dosage were investigated and optimized. The results showed that the sample had good catalytic activity for destruction of AO7 in the absence of a sacrificial agent (e.g. H2O2): it could degrade 91% AO7 in 140 min at 25 °C and was not restricted by the initial pH of the AO7 aqueous solutions. Cu2O-CuO/ZSM-5 exhibited stable catalytic activity with little loss after three successive runs. The total organic carbon and chemical oxygen demand removal efficiencies increased rapidly to 69.36% and 67.3% after 120 min of treatment by Cu2O-CuO/ZSM-5, respectively.

scholarly journals Production of free radicals by the Co2+/Oxone system to carry out diclofenac degradation in aqueous medium

2018 ◽  
Vol 78 (10) ◽  
pp. 2131-2140 ◽  
Author(s):  
Oscar M. Rodríguez-Narváez ◽  
Oracio Serrano-Torres ◽  
Kazimierz Wrobel ◽  
Enric Brillas ◽  
Juan M. Peralta-Hernandez
Keyword(s):  
Free Radicals ◽  
High Performance ◽  
Hplc Analysis ◽  
Apparent Rate Constant ◽  
Oxygen Demand ◽  
Co2 Concentration ◽  
Oh Radicals ◽  
Order Kinetic ◽  
Kinetic Reaction ◽  
Ion Exclusion

Abstract This paper reports the degradation of a solution of 0.314 mM diclofenac (DCF), while using 5–15 mM Oxone as oxidizing agent with the catalytic action of 0.05–0.2 mM Co2+. The best performance was obtained for 10 mM Oxone and 0.2 mM Co2+, achieving the total DCF abatement and 77% removal of chemical oxygen demand after 30 min. Oxidizing of sulfate () and hydroxyl (•OH) radicals was formed by the Co2+/Oxone system. Oxone was firstly oxidized to persulfate ion that was then quickly converted into the above free radicals. For Oxone contents ≥10 mM, the decay of DCF concentration followed a second-order kinetic reaction, but the apparent rate constant changed with the Co2+ concentration used. High-performance liquid chromatography (HPLC) analysis of treated solutions showed the formation of some intermediates, whereas oxalic acid was identified as the prevalent final short-linear carboxylic acid by ion-exclusion HPLC.

Ab-Initio Calculation of the β-SiC/Ni Interface

2001 ◽  
Vol 680 ◽  
Author(s):  
A. Blasetti ◽  
G. Profeta ◽  
S. Picozzi ◽  
A. Continenza ◽  
A. J. Freeman
Keyword(s):  
First Principles ◽  
Ab Initio Calculation ◽  
Surface States ◽  
Binding Energies ◽  
Bonding Mechanism ◽  
Covalent Character ◽  
Adsorption Sites ◽  
Barrier Heights ◽  
Adsorption Energies ◽  
The Stability

ABSTRACTWe investigate the adsorption of a Ni monolayer on the β-SiC(001) surface by means of highly precise first-principles all-electron FLAPW calculations. Total energy calculations for the Si- and C-terminated surfaces reveal high Ni adsorption energies, with respect to other metals, confirming the strong reactivity and the stability of the transition metal/SiC interface. These high binding energies, about 7.3-7.4 eV, are shown to be related to strong p-d hybridization, common to both surface terminations and different adsorption sites, which, despite the large mismatch, may stabilize overlayer growth. A detailed analysis of the bonding mechanism, in terms of density of states and hybridization of the surface states, reveals the strong covalent character of the bonding. We also calculate and discuss the Schottky barrier heights at the Ni/SiC junction for both terminations.

Sign in / Sign up

Export Citation Format

Share Document