scholarly journals Effects of Constant Electric Field on Biodegradation of Phenol by Free and Immobilized Cells of Bradyrhizobium japonicum 273

2021 ◽  
Vol 5 (4) ◽  
pp. 75
Author(s):  
Evgenia Vasileva ◽  
Tsvetomila Parvanova-Mancheva ◽  
Venko Beschkov ◽  
Zlatka Alexieva ◽  
Maria Gerginova ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Electric Field ◽  
Benzene Ring ◽  
Bradyrhizobium Japonicum ◽  
Immobilized Cells ◽  
Constant Electric Field ◽  
Anode Potential ◽  
Phenol Biodegradation ◽  
Catechol 1,2 Dioxygenase ◽  
Granulated Activated Carbon

It is shown that bacteria Bradyrhizobium japonicum 273 were capable of degrading phenol at moderate concentrations either in a free cell culture or by immobilized cells on granulated activated carbon particles. The amount of degraded phenol was greater in an immobilized cell preparation than in a free culture. The application of a constant electric field during cultivation led to enhanced phenol biodegradation in a free culture and in immobilized cells on granulated activated carbon. The highest phenol removal efficiency was observed for an anode potential of 1.0 V/S.H.E. The effect was better pronounced in a free culture. The enzyme activities of free cells for phenol oxidation and benzene ring cleavage were very sensitive to the anode potential in the first two steps of the metabolic pathway of phenol biodegradation catalyzed by phenol hydroxylase—catechol-1,2-dioxygenase and catechol-2,3-dioxygenase. It was observed that at an anode potential of 0.8 V/S.H.E., the meta-pathway of cleavage of the benzene ring catalyzed by catechol-2,3-dioxygenase became competitive with the ortho-pathway, catalyzed by catechol-1,2-dioxygenase. The obtained results showed that the positive effect of constant electric field on phenol biodegradation was rather due to electric stimulation of enzyme activity than electrochemical anode oxidation.

Phenol biodegradation by the strain Pseudomonas putida affected by constant electric field

2019 ◽  
Vol 17 (4) ◽  
pp. 1929-1936
Author(s):  
V. Beschkov ◽  
Z. Alexieva ◽  
Ts. Parvanova-Mancheva ◽  
E. Vasileva ◽  
M. Gerginova ◽  
...  
Keyword(s):  
Electric Field ◽  
Pseudomonas Putida ◽  
Constant Electric Field ◽  
Phenol Biodegradation

scholarly journals Electroadsorption of Bromide from Natural Water in Granular Activated Carbon

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 598
Author(s):  
David Ribes ◽  
Emilia Morallón ◽  
Diego Cazorla-Amorós ◽  
Francisco Osorio ◽  
María J. García-Ruiz
Keyword(s):  
Activated Carbon ◽  
Electric Field ◽  
Adsorption Capacity ◽  
Natural Water ◽  
Granular Activated Carbon ◽  
Open Circuit ◽  
Filter Press ◽  
Anodic Treatment ◽  
Positive Polarization ◽  
Two Stages

The adsorption and electroadsorption of bromide from natural water has been studied in a filter-press electrochemical cell using a commercial granular activated carbon as the adsorbent. During electroadsorption experiments, different voltages were applied (2 V, 3 V and 4 V) under anodic conditions. The presence of the electric field improves the adsorption capacity of the activated carbon. The decrease in bromide concentration observed at high potentials (3 V or 4 V) may be due to the electrochemical transformation of bromide to Br2. The anodic treatment produces a higher decrease in the concentration of bromide in the case of cathodic electroadsorption. Moreover, in this anodic electroadsorption, if the system is again put under open circuit conditions, no desorption of the bromide is produced. In the case of anodic treatment in the following adsorption process after 24 h of treatment at 3 V, a new decrease in the bromide concentration is observed as a consequence of the decrease in bromide concentration after the electrochemical stage. It can be concluded that the electroadsorption process is effective against the elimination of bromide and total bromine in water, with a content of 345 and 470 µg L−1, respectively, reaching elimination values of 46% in a single-stage electroadsorption process in bromide and total bromine. The application of the electric field to the activated carbon with a positive polarization (anodic electroadsorption) increases the adsorption capacity of the activated carbon significantly, achieving a reduction of up to 220 µg L−1 after 1 h of contact with water. The two stage process in which a previous electrochemical oxidation is incorporated before the electroadsorption stage significantly increased the efficiency from 46% in a single electroadsorption step at 3 V, to 59% in two stages.

Removal of trace contaminants using molecularly imprinted polymers

2006 ◽  
Vol 53 (11) ◽  
pp. 205-212 ◽  
Author(s):  
M. Le Noir ◽  
B. Guieysse ◽  
B. Mattiasson
Keyword(s):  
Activated Carbon ◽  
Molecularly Imprinted Polymers ◽  
The Other ◽  
Molecular Imprinted Polymers ◽  
Molecularly Imprinted ◽  
Imprinted Polymers ◽  
Trace Contaminants ◽  
High Concentrations ◽  
Trace Concentrations ◽  
Granulated Activated Carbon

This work was conducted to study the potential of molecularly imprinted polymers (MIPs) for the removal of oestradiol at trace concentrations (1 ppm–1 ppb). An MIP synthesised with 17β-oestradiol as template was compared to non-imprinted polymers (NIP) synthesised under the same conditions but without template, a commercial C18 extraction phase and granulated activated carbon. At 1 ppb oestradiol was recovered by 98±2% when using the MIP, compared to 90±1, 79±1, and 84±2% when using the NIP, a C18 phase, or granulated activated carbon, respectively. According to these levels, the MIP was capable of producing an effluent with a quality 5–10 times higher than the other materials. The same levels of oestradiol recovery were achieved with the MIP when supplying 17β-oestradiol at 0.1 ppm. Phenolic compounds added as interferences bound less to the MIP than to the NIP, confirming the selectivity of the MIP. Oestradiol biodegradation was also demonstrated at high concentrations (50 ppm), showing the pollutants can be safely destructed after being enriched by molecular extraction. This study demonstrates the potential of molecular imprinted polymers as a highly efficient specific adsorbent for the removal of trace contaminants.

scholarly journals Phonon residual resistance of pure crystals

2015 ◽  
Vol 29 (29) ◽  
pp. 1550206
Author(s):  
A. I. Agafonov
Keyword(s):  
Electric Field ◽  
Constant Electric Field ◽  
Finite Thickness ◽  
Mean Free Path ◽  
Residual Resistivity ◽  
Boltzmann Transport ◽  
Residual Resistance ◽  
Temperature Resistance ◽  
Electron Mean Free Path ◽  
The Ideal

In this paper, using the Boltzmann transport equation, we study the zero temperature resistance of perfect metallic crystals of a finite thickness d along which a weak constant electric field E is applied. This resistance, hereinafter referred to as the phonon residual resistance, is caused by the inelastic scattering of electrons heated by the electric field, with emission of long-wave acoustic phonons and is proportional to [Formula: see text]. Consideration is carried out for Cu, Ag and Au perfect crystals with the thickness of about 1 cm, in the fields of the order of 1 mV/cm. Following the Matthiessen rule, the resistance of the pure crystals, the thicknesses of which are much larger than the electron mean free path is represented as the sum of both the impurity and phonon residual resistances. The condition on the thickness and field is found at which the low-temperature resistance of pure crystals does not depend on their purity and is determined by the phonon residual resistivity of the ideal crystals. The calculations are performed for Cu with a purity of at least 99.9999%.

UREASE ACTIVITY IN CASE OF CONTAMINATION OF HAPLIC CHERNOZEM WITH COPPER ACETATE IN THE CONDITIONS OF THE MODEL EXPERIMENT

2020 ◽  
Author(s):  
E.S. Fedorenko ◽  
◽  
V.V., Zinchenko ◽  
A.V. Gorovtsov ◽  
T.M Minkina
Keyword(s):  
Activated Carbon ◽  
Enzymatic Activity ◽  
Model Experiment ◽  
Urease Activity ◽  
Copper Acetate ◽  
Carbon Sorbent ◽  
Ambiguous Effect ◽  
Different Doses ◽  
Granulated Activated Carbon

The influence of carbon sorbent on enzymatic activity of Haplic Chernozem was studied in the conditions of model contamination with copper acetate. An ambiguous effect of granulated activated carbon applied in different doses on urease activity was found.

scholarly journals Динамика фотоиндуцированного вращения сферической частицы в постоянном электрическом поле

2019 ◽  
Vol 89 (1) ◽  
pp. 5
Author(s):  
А.И. Грачев
Keyword(s):  
Dipole Moment ◽  
Electric Field ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
Dipole Moments ◽  
Constant Electric Field ◽  
Rotation Effect ◽  
General Terms ◽  
Nonspherical Shape ◽  
Rotation Dynamics

AbstractThe rotation of a spherical particle in a constant electric field (an effect found earlier) has been analyzed. The particle is illuminated to induce the electric dipole moment of the sphere. The dynamics of the rotation effect has been considered in general terms to refine conditions for adiabatic rotation. The features of the particle’s nonadiabatic rotation have been demonstrated with a sphere placed in a medium with an infinitesimal viscosity. It has been shown that the nonadiabatic rotation dynamics to a great extent depends on a relationship between the electrical and photoinduced dipole moments of the sphere. The rotation dynamics of a particle with a slightly nonspherical shape has been briefly analyzed.

scholarly journals Two Types of Oscillations of the Holstein Polaron Uniformly Moving Along a Polynucleotide Chain in a Constant Electric Field

2019 ◽  
Vol 14 (2) ◽  
pp. 477-487
Author(s):  
A.N. Korshunova ◽  
V.D. Lakhno
Keyword(s):  
Electric Field ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Constant Electric Field ◽  
Weak Electric Field ◽  
Uniform Motion ◽  
Main Task ◽  
Charge Motion ◽  
Bloch Oscillations ◽  
One Dimensional

In connection with the development of molecular nanobioelectronics, the main task of which is the construction of electronic devices based on biological molecules, the problems of charge transfer in such extended molecules as DNA are of increasing interest. The relevance of studying the charges motion in one-dimensional molecular chains is primarily associated with the possibility of using these chains as wires in nanoelectronic devices. Current carriers in one-dimensional chains are self-trapped electronic states, which have the form of polaron formations. In this paper we investigate the motion of the Holstein polaron in the process of its uniform motion along the chain in a constant electric field. It is known that during uniform motion along the chain in a weak electric field, the polaron experiences small oscillations of its shape. These oscillations are associated with the discreteness of the chain and are due to the presence of the Peierls-Nabarro potential in the discrete chain. Previous investigations have shown that for certain parameters of the chain, there is the possibility of uniform charge motion in a constant electric field over very large distances. The charge motion with a constant velocity is possible for small values of the electric field intensity. With an increase in the electric field intensity, the charge goes into an oscillatory regime of motion with Bloch oscillations. The calculations performed in this work showed that the elements of Bloch oscillations also appear during stationary motion of the polaron along the chain. Thus, it is shown that the Holstein polaron, uniformly moving along the chain in a constant electric field, experiences not only Peierls-Nabarro oscillations, but also low-amplitude oscillations with a Bloch period.

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