Liquid water can be described as a dielectric  with the wide band gap  where Fermi level as an identifier of water oxidation-reduction potential (ORP) is easily varied by action of the galvanic cell with the strongly polarized one electrode and the other in the quasi-equilibrium with water solution. Such cell works as ORP changer of any aqueous solution by a forced shift of Fermi level in the band gap at an expense of insignificant deviation ( ) of water composition from the stoichiomentric one ( ) . This variation is occupied between two allowed local electron states in the band gap of liquid water such as an occupied-by-electron energy level of hydroxide anion OH− and the vacant one of hydroxonium ion H3O+.
These electronic levels are located symmetrically nearby the band-gap middle with the energy difference between them of 1.75 eV . This theoretical concept allows eliminating the inconsistencies  in reconciling the electrochemical properties of these well-known aqueous ions in the frame of electronic band structure. Then, Fermi level as an electrochemical potential indicates the tendency of liquid water to donate or accept proton. If is high, there is a strong tendency for liquid water to donate protons, i.e. it is reducing. Opposite, if is low in the aqueous medium, there is the strong tendency for that to accept protons when this matter is oxidizing .
It is interesting to understand how galvanic modifying of seawater can be useful for a practical application of such approach. The solution to this problem is the subject of the given work.
2. The Band Structure of Seawater
We have shown in  that a weak aqueous solution of any atomic impurity i (at its little concentration) has a local electronic level in the band gap.
At the same time, such inherent constituents of liquid water as ions of hydroxonium H3O+ and hydroxide OH− emerge there due to the self-dissociation of water molecules in the reversible chemical reaction 
These water constituents have the electronic levels  and located symmetrically nearby the middle of the band gap as shown in Figure 1(a). The electronic levels of sodium and chlorine of their little impurities in liquid water are shown here too. They are obtained by Equations (1):
where is Boltzmann constant equal to 8.617 × 10−5 eV/K; T is Kelvin temperature; e is the charge of electron; is the solubility of neutral sodium atoms in liquid water  ; is its ionic mole fraction and is the one of chlorine equal to 1.0 M; is the standard ORP of sodium in the aqueous solution and is the one of chlorine  ; is the mole fraction of chlorine atoms in the aqueous solution at , , .
The electronic levels in Equations (1) and (2) are obtained according to standard electrode reactions  :
Figure 1. The band structure of seawater for the stoichiometric state (a) with Fermi level (red full line) in the middle of band gap and for the non-stoichiometric ones (b) with Fermi levels and defined by Equations (4) and (5); the blue boxes are the valence bands with the top and the dotted ones are the conduction bands with the bottom ; the blue full lines denote energy levels: , , , and occupied by electron; the dotted ones are these local levels in the vacant state.
The correspondent Fermi levels and are shown in Figure 1(b) and obtained from Equation
The Standard Hydrogen Electrode (SHE) is described by the electrode reaction 
with the mole fractions: and . Here is the constant of hydrated dissociation of hydrogen molecule in water up to H∙H2O. Then in , we have obtained . These estimations agree with the experimental data  shown in Figure 2 for Total Electron Yield (TEY) of the X-ray Absorption (XA) by water with and the vacant electron levels: , , and denoted by dotted lines where is the bottom of conduction band. The electron yield of salt NaCl into the identification of level is positive due to the synergetic effect of ions and on separating radioactive pairs into basic and acidic micro-domains of the salt solution. The electron yield of acid HCl into the same identification is negative due to the inhibitory action of hydroxonium ions onto radioactive formation of pairs in the acidic solution.
Figure 2. The oxygen K-edge TEY-XA spectra presented by authors of  together for pure liquid water (black line), 4 M HCl (red line) and 4 M NaCl (blue line) in aqueous solution; the vertical dotted lines denote the vacant electron levels: , , and .
3. The Chemical Stability of Seawater
The population [H3O] and [OH] of the energy levels and by electron and hole respectively can be defined by the proportions of the species concentrations and as shown in  . They are given by Maxwell-Boltzmann distribution of electrons and holes in the corresponding energy levels  :
Using Equations (8) and (9), we can transform the index
of non-stoichiometric water saline by NaCl and electrically charged ( ) to the form
where , , and the dissociation constant at is defined by the known dissociation ratio 
for the mole fractions of hydroxonium and hydroxide ions.
As seen in Equation (11), the non-stoichiometric index z of seawater at is controlled by . Then, we can present Equation (11) in the form
at , , , and  for .
Then, Equation (13) allows plotting Fermi level in seawater as a function of its non-stoichiometry z shown in Figure 3 by the green dotted line for , , , , , , and .
4. Discussion of the Obtained Results
4.1. The Electro-Reduced Seawater
For electrochemical reduction of seawater, one can use the galvanic cell under the voltage of ~2 V between the strongly polarized anode and the quasi-equilibrium cathode. In this case, we will always have a negative bulk charge near the polarized anode as shown in Figure 3.
One can see that the region of chemical water stability is enlarged to the hyper-stoichiometric state ( ). It is easily achieved when is occupied by electron and hydroxonium radicals are joined to hydroxide anions forming in seawater the hydrated electrons .
Figure 3. The changed z-dependence of Fermi level (red full line) in the band gap (see Figure 1) of negatively charged ( ) seawater (red dotted line) obtained by the electrochemical cell under the voltage of ~2 V between the quasi-equilibrium cathode and the strongly polarized anode at , ; the green dotted line is the z-dependence of Fermi level in neutral seawater ( ); the vertical dotted lines denote the confines of chemical water stability; the blue line denote the local electronic levels and for hydroxonium ion/radical (H3O+/H3O) and hydroxide anion OH− respectively.
It is well known   that increasing mole fraction of different charges (ions of sodium and chlorine as well hydrated electrons) in seawater blocks the formation of gas hydrates there because these charges shift the equilibrium curve of gas-hydration towards low temperature. At the same time, the hydrated electrons are increasing as kinetic inhibitors of this process that do not change the chemical composition of seawater and can be gotten by its electro-reduction in the mentioned asymmetric electrochemical cell with the polarized anode and the cathode in equilibrium with the aqueous medium.
As seen in Figure 3, Fermi level is shifting higher the energy level and the hydroxonium ions formed in the anode layer by reaction 
forcedly migrate in the bulk of seawater due to the action field between anode and negative bulk charge and are discharged in the cathode region to radicals by the quasi-equilibrium cathode reaction
These radicals join to hydroxide anions and form negative equilibrium bulk charges by reaction
that keep seawater in the stable hypo-stoichiometric state (see Figure 3) with the high mole fraction of the hydroxide anions ( ) as proton acceptors and the hydroxonium radicals as electron donors in the bulk of seawater.
Thus, electrochemical processing of these very active antioxidants can be more effective than the gaseous hydrogen can do them in the aqueous solution ( ) for holding the negative ORP of water chemistry by the kinetically-limited reaction of hydrogen dissociation 
This effect of water processing appears also and in the alternative electrochemical cell with the strongly polarized cathode and the quasi-equilibrium anode as shown that in the next paragraph for comparing with the formation of strong oxidizers by the kinetically-limited reaction of oxygen dissociation
4.2. The Electro-Oxidized Seawater
As seen in Figure 3, the region of non-stoichiometric composition z of water ( ) is limited by the narrow interval where Fermi level is changed in the band gap up to 1.5 eV. Such forced variation of can be carried out by the electrochemical cell with the voltage of ~2 V between the strongly polarized cathode and the anode in quasi-equilibrium with medium. The external potential applied to the strongly polarized cathode intensively generated hydroxide anions in the narrow cathode layer (see Figure 4) by standard reactions:
At the same time, Fermi level (red full line in Figure 4) is shifting to the energy level and the hydroxide anions migrate forcedly in the bulk of seawater due to the action of electric field between cathode and the positive bulk charge.
The anions are discharged with forming hydroxyls by quasi-equilibrium anodic reaction
and hydroxonium radicals diffused out of the cathode layer in the bulk of electrochemical cell put electrons to hydroxyl radicals by reaction
All this forms the positive bulk charge in seawater near the cathode by reaction
at the condition
Figure 4. The changed z-dependence of Fermi level (red full line) in the positively charged ( ) seawater (red dotted line) obtained by the electrochemical cell under the voltage of ~2 V between the strongly polarized cathode and the quasi-equilibrium anode at , ; the green dotted line is the z-dependence of Fermi level in neutral seawater ( ); the vertical dotted lines denote the confines of chemical water stability; the blue line denote the local electronic levels and for hydroxonium ion H3O+ and hydroxyl/hydroxide species (OH/OH−) respectively.
which indicates on the strong acidic reaction of the chemically stable hypo-stoichiometric seawater with the high mole fraction ( ) of hydroxyls as strongest oxidizers. They are able to generate molecules of hypochlorite acid HClO from hydroxyls and chlorine anions by the quasi-equilibrium reaction in the anodic region (see Figure 4)
and to joint the salt ions and together in the electro-oxidized seawater by reaction 
that essentially decreases their mole fraction in aqueous solution and shifts the equilibrium curve of hydrating the neutral species as and gaseous molecules towards high temperatures.
The advantages of this approach are the high efficiency and simplicity of oxidation process, low cost, and there is no need for special sorbents because seawater itself becomes the reagent for removing of pollutants.
The electro-reduced seawater can be easily obtained by galvanic cell under the voltage of ~2 V between the strongly polarized anode and the quasi-equilibrium cathode. In this cell, the negative bulk charge is appeared near polarized electrode due to occupation of by electron and joining of hydroxonium radicals to the hydroxide anions in forming hydrated electrons .
Then, increasing content of different charges in seawater can block the formation of gas-hydrates there because these charges (as kinetic inhibitors of this process) shift the equilibrium curve of gas-hydration towards low temperatures.
At the same time, the negative bulk charge keeps seawater in the stable hypo-stoichiometric state with high mole fraction of hydroxide anions ( ) as proton acceptors.
Opposite, the hydroxonium radicals as electron donors are very active antioxidants more effective than gaseous hydrogen.
It is shown that the region of non-stoichiometric composition of water ( ) is limited by the very narrow interval where Fermi level is changed in the band gap up to 1.5 eV. At the strong polarization of cathode in the electrochemical cell, the high mole fraction of formed hydroxyls ( ) will essentially decrease content of ions in seawater by forming neutral species .
It is shown that the electron yield of NaCl into the identification of energy level is positive due to the synergetic effect of ions and on separating radioactive pairs into basic and acidic micro-domains of seawater. The electron yield of acid HCl into the same identification is negative due to inhibitive action of hydroxonium ions onto radioactive formation of pairs in the aqueous solution of acid.
The author thanks the Russian Foundation of Basic Research (RFBR) for supporting this work (grant #19-08-00149a) and appreciates his colleagues for active discussing all the aspects of galvanic modifying the chemical properties of seawater.
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