Rotating ring-disk voltammetric investigations on the degradation rate of the nickel(III)-glycylglycyl-L-histidine complex

2007 ◽  
Vol 85 (12) ◽  
pp. 1064-1069 ◽  
Author(s):  
María V Alipázaga ◽  
Denise Lowinsohn ◽  
Mauro Bertotti ◽  
Nina Coichev
Keyword(s):  
Chemical Process ◽  
Degradation Rate ◽  
Collection Efficiency ◽  
Homogeneous Oxidation ◽  
Key Words Nickel ◽  
Ec Mechanism ◽  
Voltammetric Behavior ◽  
Degradation Reaction ◽  
Fast Chemical ◽  
Electrode Technique

The voltammetric behavior of the Ni(II)/glycylglycyl-L-histidine complex and the degradation of the electrogenerated Ni(III) species were investigated by cyclic voltammetry. Results of electrochemical and spectrophotometric experiments indicated some differences in the nature and reactivity of Ni(III) complexes formed by two independent routes, i.e., anodic oxidation of Ni(II) and homogeneous oxidation by an autocatalytic reaction in a medium containing oxygen and S(IV) (H2SO3, HSO[Formula: see text], and SO[Formula: see text]). The Ni(III) species formed electrochemically reacts in a fast chemical process (EC mechanism) and the observed rate constant of the degradation (k = 0.17 s–1) was determined by a rotating ring-disk electrode technique measuring kinetic collection efficiency values as a function of the rotation rate. Key words: nickel, glycylglycyl-L-histidine, sulfite, degradation reaction, rotating ring-disk voltammetry.

Chemical Recycling of Epoxide-Anhydride Hardened Networks Using Near-Critical Water

2013 ◽  
Vol 658 ◽  
pp. 153-157 ◽  
Author(s):  
Yu Yan Liu ◽  
Song Quan Wu ◽  
Li Li ◽  
Yu Ting Liu ◽  
Guo Hua Shan
Keyword(s):  
Epoxy Resin ◽  
Degradation Rate ◽  
Diglycidyl Ether ◽  
Gas Chromatography Mass Spectrometry ◽  
Chemical Recycling ◽  
Reaction Products ◽  
Degradation Behaviour ◽  
Bisphenol A Diglycidyl Ether ◽  
Stainless Steel Reactor ◽  
Degradation Reaction

The degradation behaviour of an anhydride-cured bisphenol A diglycidyl ether (DGEBA) epoxy resin in near-critical water was studied in this paper. The experiments were performed in a stainless steel reactor (100ml) without stirring. Epoxy resin could be decomposed successfully at 270°C for 30 min. The degradation rate of epoxy resin increased with an increase in reaction temperature and reaction pressure. The degradation reaction products were characterized by gas chromatography-mass spectrometry (GC-MS). The degradation reaction was associated with the scission of ester and ether bonds which further destabilizes the epoxy network.

Compared to Two Kinds of Methods for the Degradation of an Anthraquinone Dye Reactive Brilliant Blue KN-R

2014 ◽  
Vol 955-959 ◽  
pp. 2254-2260
Author(s):  
Hui Yu ◽  
Chun Ji Jin ◽  
Ruo Chen Sun ◽  
Ming Liu ◽  
Yuan Le Yang
Keyword(s):  
Microbial Fuel Cells ◽  
Degradation Rate ◽  
Brilliant Blue ◽  
Order Kinetic ◽  
Anthraquinone Dye ◽  
Degradation Rates ◽  
Two Systems ◽  
Degradation Reaction ◽  
Electric Generation ◽  
Two Stages

Taking anthraquinone dye reactive brilliant blue KN-R as a target pollutant, this paper studied KN-R degradation rates and electric generation performances in the system of Fe2+/PDS and Fe2+/PDS-MFC. The Fe2+/PDS system is that persulfate (PDS) is activated by ferrous iron (Fe2+) ,while Fe2+/PDS-MFC system is using Fe2+/PDS system as the cathode of microbial fuel cells (MFC) .The results showed that in the two systems, the KN-R degradation rate was increased and then decreased with the increase of initial Fe2+dosage. With the increase of pH, the KN-R degradation rapid declines. In the two systems, both of the KN-R degradation reaction was divided into two stages. In addition, the process of reaction conforms to the first-order kinetic equation. Compared with Fe2+/PDS system, the Fe2+/PDS-MFC system’s ability to degrade pollutants have little change, the main advantage of Fe2+/PDS-MFC system is able to obtain higher and more stable power. Under an optimal condition, the maximum power density achieved 294.07 mW/m2, the KN-R degradation rate was 96.90%.

Study on UV/O3 of Methyl Violet Wastewater

2012 ◽  
Vol 518-523 ◽  
pp. 3208-3211
Author(s):  
Ya Na Liu ◽  
Hui Tian ◽  
An Heng Si
Keyword(s):  
Free Radicals ◽  
Degradation Rate ◽  
Ph Value ◽  
Methyl Violet ◽  
Research Process ◽  
Solution Ph ◽  
Initial Concentration ◽  
First Order ◽  
Alkaline Conditions ◽  
Degradation Reaction

Ultraviolet ozone process was used to eliminate Methyl Violet, the effects of the type of research process, the initial solution pH, dye concentration and free radical quenching agent N-butanol on its degradation rate were studied. The experimental results showed that: comparing to UV, O3, UV/O3 three types of technology, UV and O3 technology had significant synergies, the degradation rate of Methyl Violet solution achieve 99.58% at 50min for the initial concentration of 100mg/L. increasing pH value resulted in increasing degradation rate, the degradation rate achieved 99. 8% at 50min under alkaline conditions. The remove rate decreased with increasing initial concentrations. Quenchers of free radicals inhibited the generation of hydroxyl radical and induced decreasing degradation rate. The degradation reaction of Methyl Violet by UV/O3 followed first-order law.

Effect of Ultrasonic Frequency on Chlorpyrifos Degradation in Sonolytic Ozonolysis

2014 ◽  
Vol 587-589 ◽  
pp. 578-581
Author(s):  
Jin Zhu ◽  
Chang Ping Zhu ◽  
Bin Wang ◽  
Run Hang Gong ◽  
Qing Gong Ren ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Degradation Rate ◽  
Degradation Kinetics ◽  
Degradation Pathway ◽  
Frequency Effect ◽  
Ultrasonic Frequency ◽  
Kinetics Parameters ◽  
First Order ◽  
First Order Kinetics ◽  
Degradation Reaction

The degradation of chlorpyrifos is investigated with the treatments of sonolysis, ozonolysis, and sonolytic ozonolysis at various frequencies. Results show that there exists frequency effect in sonolytic ozonolysis. In sonolytic ozonolysis, the maximum degradation rate is obtained at 495 kHz, and the degradation kinetics is fitted to the first-order kinetics model well. However, the most significant synergistic effect between ultrasonic and ozone is at 124 kHz. The kinetics parameters indicate that chlorpyrifos is much more labile to ultrasonic at 495 kHz, while ozone is much more soluble at 124 kHz. The hydrolysis and oxidation are deduced to contribute to the degradation reaction and the degradation pathway for chlorpyrifos degradation is proposed.

Synthesis of NdFeO3 Perovskites in a Reverse Microemulsion and its Visible Light Photocatalytic Activity

2011 ◽  
Vol 282-283 ◽  
pp. 593-596 ◽  
Author(s):  
Ying Juan Hao ◽  
Bo Li ◽  
Rui Hong Liu ◽  
Fa Tang Li
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Degradation Rate ◽  
Irradiation Time ◽  
Photocatalytic Property ◽  
Reverse Microemulsion ◽  
Xrd Pattern ◽  
Degradation Reaction ◽  
Visible Light Degradation ◽  
Visible Light Photocatalytic

The synthesis of NdFeO3 perovskites in a reverse microemulsion and its photocatalytic property for visible light degradation reaction of methylene blue were investigated, respectively. When the irradiation time prolonged from o to 90 minutes, the degradation rate for methylene blue could achieve 60%. XRD pattern shows that a well-crystallized perovskite structure is observed for the NdFeO3 sampled prepared. The TEM characterization result indicates that the dimension of NdFeO3 nanopowders is in the range of 35~45 nm, which is consistent with the calculation result using the Scherrer equation.

Experimental Study of Photosynthetic Bacterial Degradation of Direct Red 4BS Wastewater

2013 ◽  
Vol 329 ◽  
pp. 61-65
Author(s):  
Zheng Fan ◽  
Guo Liang Zhang ◽  
Zhi Yang Wang ◽  
Zhi Yan Pan ◽  
Yan Li
Keyword(s):  
Light Intensity ◽  
Sodium Acetate ◽  
Degradation Rate ◽  
Inoculum Size ◽  
Bacterial Degradation ◽  
Solution Ph ◽  
Initial Concentration ◽  
First Order Kinetics ◽  
Low Concentrations ◽  
Degradation Reaction

The photosynthetic bacteria direct red 4BS solution pH, light intensity, inoculum size, the concentration of sodium acetate, and the initial concentration of direct red 4BS degradation rate. The results show that: the initial concentration of 80 mg / L, the inoculation amount of 25% (v / v), pH 8.0, the light intensity 3000lx, sodium acetate, 1.6mg / L under the conditions, after 96 hours of direct red 4BS degradation rate up to 87.5%. Sodium acetate in the reaction can increase the degradation rate, experiments show that: the process of degradation of sodium acetate and direct red 4BS ratio of 20: 1 (m / m) the degradation rate is better. Direct Red 4BS low concentrations, the reaction kinetics of the degradation reaction are first-order kinetics.

Phenol Degradation by Catalytic Wet Hydrogen Peroxide Oxidation on Fe/Active Carbon Catalyst

2012 ◽  
Vol 433-440 ◽  
pp. 147-152
Author(s):  
Ying Chun Yang ◽  
Yuan Gang Lu ◽  
Zhi Xiang Ye ◽  
Li Ping He ◽  
Jing Yu
Keyword(s):  
Hydrogen Peroxide ◽  
Active Carbon ◽  
Degradation Rate ◽  
Ph Value ◽  
Phenol Degradation ◽  
Kinetic Studies ◽  
Reaction Rate Constant ◽  
Peroxide Oxidation ◽  
Hydrogen Peroxide Oxidation ◽  
Degradation Reaction

A catalyst based on Fe/active carbon (Fe/AC) and H2O2 as oxidant for the catalytic wet hydrogen peroxide oxidation of phenol in aqueous solution was investigated. The results indicate that the degradation rate of phenol(20mg/L) reach 90.5% in the presence of Fe/AC(2g/L) and hydrogen peroxide (0.5 %) at pH value 7 after 5 hours under normal temperature and atmospheric pressure. Kinetic studies of the degradation reaction show that the degradation rate of phenol nearly follows the first-order reaction. The reaction rate constant and activity energy are 0.4162 min-1 and 23.64 kJ/mol at 25°C, respectively.

To What Extent are Inelastically Scattered Electrons Useful in the Stem?

1973 ◽  
Vol 31 ◽  
pp. 286-287 ◽  
Author(s):  
H. Rose
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Electron Correlation ◽  
Quantum Noise ◽  
Collection Efficiency ◽  
Scanning Transmission Electron Microscope ◽  
Electron Cloud ◽  
Scanning Time ◽  
Transmission Electron ◽  
Scanning Transmission

The scanning transmission electron microscope offers the possibility of utilizing inelastically scattered electrons. Use of these electrons in addition to the elastically scattered electrons should reduce the scanning time (dose) Which is necessary to keep the quantum noise below a certain level. Hence it should lower the radiation damage. For high resolution, Where the collection efficiency of elastically scattered electrons is small, the use of Inelastically scattered electrons should become more and more favorable because they can all be detected by means of a spectrometer. Unfortunately, the Inelastic scattering Is a non-localized interaction due to the electron-electron correlation, occurring predominantly at the circumference of the atomic electron cloud.

High energy resolution spectrometer for the dedicated STEM

1984 ◽  
Vol 42 ◽  
pp. 558-559 ◽  
Author(s):  
P.E. Batson
Keyword(s):  
Collection Efficiency ◽  
Core Loss ◽  
Beam Current ◽  
High Energy ◽  
High Energy Resolution ◽  
Acquisition Time ◽  
Good Definition ◽  
Loss Analysis ◽  
Definition Of ◽  
Acceleration Voltage

Use of the STEM to obtain precise electronic information has been hampered by the lack of energy loss analysis capable of a resolution and accuracy comparable to the 0.3eV energy width of the Field Emission Source. Recent work by Park, et. al. and earlier by Crewe, et. al. have promised magnetic sector devices that are capable of about 0.75eV resolution at collection angles (about 15mR) which are great enough to allow efficient use of the STEM probe current. These devices are also capable of 0.3eV resolution at smaller collection angles (4-5mR). The problem that arises, however, lies in the fact that, even with the collection efficiency approaching 1.0, several minutes of collection time are necessary for a good definition of a typical core loss or electronic transition. This is a result of the relatively small total beam current (1-10nA) that is available in the dedicated STEM. During this acquisition time, the STEM acceleration voltage may fluctuate by as much as 0.5-1.0V.

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