Cu-coupled Fe/Fe3C covered with thin carbon as stable win-win catalysts to boost electro-Fenton reaction for brewing leachate treatment

Chemosphere ◽  
2022 ◽  
pp. 133532
Author(s):  
Xu Yang ◽  
Zhimin Chen ◽  
Shichao Du ◽  
Huiyuan Meng ◽  
Zhiyu Ren
Keyword(s):  
Fenton Reaction ◽  
Leachate Treatment ◽  
Thin Carbon

scholarly journals The comparison of efficiency of Fenton and photo-Fenton treatment of stabilised landfill leachate / Porównanie efektywności oczyszczania odcieków z ustabilizowanego składowiska odpadów komunalnych w procesie Fentona i foto-Fentona

2015 ◽  
Vol 26 (3) ◽  
pp. 49-53 ◽  
Author(s):  
Anna Kwarciak-Kozłowska ◽  
Aleksandra Krzywicka
Keyword(s):  
Landfill Leachate ◽  
Fenton Reaction ◽  
Ferrous Sulphate ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Ammonia Removal ◽  
Mass Ratio ◽  
Leachate Treatment ◽  
Initial Ph ◽  
Removal Efficiencies

Abstract The goal of this article was to compare the efficiency of Fenton and photo-Fenton reaction used for stabilised landfill leachate treatment. The mass ratio of COD:H2O2 was fixed to 1:2 for every stages. The dose of reagents (ferrous sulphate/hydrogen peroxide) was different and ranged from 0.1 to 0.5. To determine the efficiency of treatment, the BOD (biochemical oxygen demand COD (chemical oxygen demand), TOC (total organic carbon) , ammonia nitrogen and BOD/COD ratio was measured. The experiment was carried out under the following conditions: temperature was 25ºC, the initial pH was adjusted to 3.0. Every processes were lasting 60 minutes. The most appropriate dose of reagents was 0.25 (Fe2+/H2O2). It was found that the application of UV contributed to increase of COD, TOC and ammonia removal efficiencies by an average of 14%.

Landfill leachate treatment by a photoassisted fenton reaction

1997 ◽  
Vol 35 (4) ◽  
pp. 239-248 ◽  
Author(s):  
Soo-M. Kim ◽  
Sven-U. Geissen ◽  
Alfons Vogelpohl
Keyword(s):  
Landfill Leachate ◽  
Radiation Intensity ◽  
Fenton Reaction ◽  
Energy Input ◽  
Degradation Rate ◽  
Ph Value ◽  
Uv Light ◽  
Molar Ratio ◽  
Leachate Treatment ◽  
Specific Energy Input

A combination of the classical Fenton reaction (Fe(II)+H2O2) with UV light, the photoassisted Fenton reaction, has been investigated for the treatment of landfill leachate. The investigation has been carried out with an experimental set-up to establish the optimal treatment conditions. The degradation rate of organic pollutants is strongly promoted by the photoassisted Fenton reaction. The degradation rate depends on the amount of H2O2 and Fe(II) added, pH value, and radiation intensity. At a specific energy input of 80 kW m−3 the oxidation rate was increased to six times the rate without radiation (0 kW m−3). At the higher radiation intensity of 160 kW m−3 the degradation rate was about two times faster than at that of 80 kW m−3. Due to the regeneration of the consumed Fe(II) ions through the irradiation, the amount of ferrous salt to be added can be remarkably reduced. The optimum conditions were obtained with 1.0 × 10−3 mol 1−1 Fe(II) added, a pH value of 3, and a molar ratio of COD: H2O2 = 1:1. At a COD volume loading of less than 0.6 kg m−3 h−1, a COD degradation of more than 70% could be obtained with an energy input of 80 kW m−3.

The characteristics of coagulation of fenton reaction in the removal of landfill leachate organics

1998 ◽  
Vol 38 (2) ◽  
pp. 209-214 ◽  
Author(s):  
J. Yoon ◽  
S. Cho ◽  
Y. Cho ◽  
S. Kim
Keyword(s):  
Molecular Weight ◽  
Landfill Leachate ◽  
Fenton Reaction ◽  
Treatment Process ◽  
The Other ◽  
Primary Role ◽  
Fenton Process ◽  
Leachate Treatment ◽  
Enhanced Coagulation ◽  
Organic Removal

The need to improve the Fenton process, which is one of the leachate treatment trains at Metropolitan Landfill in Korea was raised. This study was intended to compare the Fenton reaction with coagulation in removing landfill leachate organics of specific size. The organics fractionated by ultrafiltration and measured by TOC, were selected for evaluating the characteristics of the removal of organics. From this study it was found that the organic removal pattern in the Fenton reaction was quite similar to coagulation. Both reactions removed large leachate organics more readily and selectively. For example, coagulation removed 59~73% of organics larger than molecular weight (MW) of 500 and only up to 18% of organics less than MW of 500. On the other hand, the Fenton process removed 72-89% of organics larger than MW of 500 and only up to 43% of organics less than MW of 500. It was interpreted that the coagulation step in the Fenton process had a primary role in selective removal of leachate organics, though the Fenton reaction is not coagulation. However, since the efficiency of organic removal in the Fenton reaction was higher than coagulation, the Fenton process in Metropolitan Landfill leachate treatment process may be called “a type of enhanced coagulation”.

Landfill Leachate Treatment by Fenton, Photo-Fenton Processes and their Modification

2012 ◽  
Vol 15 (1) ◽  
Author(s):  
Agata Krzysztoszek ◽  
Jeremi Naumczyk
Keyword(s):  
Reaction Kinetics ◽  
Landfill Leachate ◽  
Empirical Formula ◽  
Fenton Reaction ◽  
Cod Removal ◽  
Leachate Treatment ◽  
Modified Fenton

AbstractEfficiency of leachate treatment in Fenton, photo-Fenton processes and their modifications was studied. Process was modified by leachate acidification, followed by the precipitate separation and continuing the processes. Acidification to pH 2.0 and 3.0 led to 34.3% and 18.9% COD removal respectively. The efficiency of the processes was decreasing as follows: modified photo-Fenton pH 2.0 (96.5% COD removal) > photo-Fenton pH 2.0 (95.0%) > modified photo-Fenton pH 3.0 (89.2%) > photo-Fenton pH 3.0 (85.9%) > modified Fenton pH 2.0 (79.5%) > Fenton pH 2.0 (77.6%) > modified Fenton pH 3.0 (64.8%) > Fenton pH 3.0 (63.5%). At the beginning of the processes the coagulation contribution was higher (up to 73% of total COD removal), while finally it was exceeded by Fenton reaction contribution (up to 66% of total COD removal). Empirical formula for Fenton reaction kinetics was proposed.

Object Wave Determination by Single-Sideband Methods

1973 ◽  
Vol 31 ◽  
pp. 266-267
Author(s):  
Kenneth H. Downing ◽  
Benjamin M. Siegel
Keyword(s):  
Phase Shift ◽  
Carbon Films ◽  
Object Wave ◽  
Electron Wave ◽  
Phase Object ◽  
Heavy Atoms ◽  
Single Sideband ◽  
Thin Carbon ◽  
Additional Phase Shift ◽  
Additional Phase

Under the “weak phase object” approximation, the component of the electron wave scattered by an object is phase shifted by π/2 with respect to the unscattered component. This phase shift has been confirmed for thin carbon films by many experiments dealing with image contrast and the contrast transfer theory. There is also an additional phase shift which is a function of the atomic number of the scattering atom. This shift is negligible for light atoms such as carbon, but becomes significant for heavy atoms as used for stains for biological specimens. The light elements are imaged as phase objects, while those atoms scattering with a larger phase shift may be imaged as amplitude objects. There is a great deal of interest in determining the complete object wave, i.e., both the phase and amplitude components of the electron wave leaving the object.

Interpretation of irradiation-induced changes in electron diffractograms and images of extinction contours at low temperatures

1984 ◽  
Vol 42 ◽  
pp. 268-269
Author(s):  
E. Knapek ◽  
H. Formanek ◽  
G. Lefranc ◽  
I. Dietrich
Keyword(s):  
Low Temperatures ◽  
Carbon Films ◽  
Organic Crystals ◽  
Wide Spread ◽  
Lens System ◽  
Preparation Conditions ◽  
Thin Carbon ◽  
Electron Diffractograms ◽  
Diffraction Patterns ◽  
Induced Changes

A few years ago results on cryoprotection of L-valine were reported, where the values of the critical fluence De i.e, the electron exposure which decreases the intensity of the diffraction reflections by a factor e, amounted to the order of 2000 + 1000 e/nm2. In the meantime a discrepancy arose, since several groups published De values between 100 e/nm2 and 1200 e/nm2 /1 - 4/. This disagreement and particularly the wide spread of the results induced us to investigate more thoroughly the behaviour of organic crystals at very low temperatures during electron irradiation.For this purpose large L-valine crystals with homogenuous thickness were deposited on holey carbon films, thin carbon films or Au-coated holey carbon films. These specimens were cooled down to nearly liquid helium temperature in an electron microscope with a superconducting lens system and irradiated with 200 keU-electrons. The progress of radiation damage under different preparation conditions has been observed with series of electron diffraction patterns and direct images of extinction contours.

Hydrated form of some clay minerals observed using a film sealed environmental cell

1978 ◽  
Vol 36 (1) ◽  
pp. 72-73
Author(s):  
N. Kohyama ◽  
K. Fukushima ◽  
A. Fukami
Keyword(s):  
Clay Minerals ◽  
Morphological Changes ◽  
Carbon Film ◽  
Electron Microscopic Observation ◽  
Adsorbed Water ◽  
Electron Microscopic ◽  
Hydrated Form ◽  
Thin Carbon ◽  
Environmental Cell ◽  
Thin Carbon Film

Since the interlayer or adsorbed water of some clay minerals are quite easily dehydrated in dried air, in vacuum, or at moderate temperatures even in the atmosphere, the hydrated forms have not been observed by a conventional electron microscope(TEM). Recently, specific specimen chambers, “environmental cells(E.C.),” have been developed and confirmed to be effective for electron microscopic observation of wet specimen without dehydration. we observed hydrated forms of some clay minerals and their morphological changes by dehydration using a TEM equipped with an E.C..The E.C., equipped with a single hole copper-microgrid sealed by thin carbon-film, attaches to a TEM(JEM 7A) with an accelerating voltage 100KV and both gas pressure (from 760 Torr to vacuum) and relative humidity can be controlled. The samples collected from various localities in Japan were; tubular halloysite (l0Å) from Gumma Prefecture, sperical halloysite (l0Å) from Tochigi Pref., and intermediate halloysite containing both tubular and spherical types from Fukushima Pref..

Alkaline Dissociation Products of Lumbricus Terrestris Hemoglobin Viewed with the STEM

1981 ◽  
Vol 39 ◽  
pp. 434-435
Author(s):  
O. H. Kapp ◽  
M. Ohtsuki ◽  
N. Robin ◽  
S. N. Vinogradov ◽  
A. V. Crewe
Keyword(s):  
Carbon Film ◽  
Lumbricus Terrestris ◽  
Uranyl Acetate ◽  
Acetate Solution ◽  
Oxygen Carriers ◽  
Complex Molecules ◽  
Thin Carbon ◽  
Thin Carbon Film ◽  
Multiple Copies ◽  
Hill Coefficients

Annelid extracellular hemoglobins are among the largest known proteins (M.W = 3.9 x 106), and together with the hemocyanins are the largest known oxygen carriers. They display oxygen affinities generally higher than those o vertebrate hemoglobins with Hill coefficients ranging from slightly higher than unity to values as high as 5-6. These complex molecules are composed of multiple copies of as many as six different polypeptides and posse: approximately 150 hemes per molecule.The samples were diluted to 100-200 μg/ml with distilled water just before application to a thin carbon film (∽15 Å thick). One percent (w/v) uranyl acetate solution was used for negative staining for 2 minutes and dried in air. The specimens were examined with the high resolution STEM. Their general appearance is that of a hexagonal bilayer (Fig. 1), each layer consisting of six spheroidal subunits. The corner to corner hexagonal dimensic is approximately 300 Å and the bilayer thickness approximately 200 Å.

Scanning Secondary Electron Microscopy of Myofibrils Using Transmission Techniques

1975 ◽  
Vol 33 ◽  
pp. 556-557
Author(s):  
M. K. Lamvik
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Carbon Films ◽  
Photographic Recording ◽  
Transmission Electron ◽  
Thin Carbon ◽  
The Common ◽  
Scanning Electron ◽  
Better Than ◽  
Cellular Organelles

When observing small objects such as cellular organelles by scanning electron microscopy, it is often valuable to use the techniques of transmission electron microscopy. The common practice of mounting and coating for SEM may not always be necessary. These possibilities are illustrated using vertebrate skeletal muscle myofibrils.Micrographs for this study were made using a Hitachi HFS-2 scanning electron microscope, with photographic recording usually done at 60 seconds per frame. The instrument was operated at 25 kV, with a specimen chamber vacuum usually better than 10-7 torr. Myofibrils were obtained from rabbit back muscle using the method of Zak et al. To show the component filaments of this contractile organelle, the myofibrils were partially disrupted by agitation in a relaxing medium. A brief centrifugation was done to clear the solution of most of the undisrupted myofibrils before a drop was placed on the grid. Standard 3 mm transmission electron microscope grids covered with thin carbon films were used in this study.

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