Articles
Polymer Pre-treatment for Magnesium Electrode: Effects on Electrochemical Phosphate Recovery
2025 Volume 93 Issue 2 Pages 027007
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2025 Volume 93 Issue 2 Pages 027007
Water-insoluble magnesium phosphate species, possibly magnesium ammonium phosphates (MAPs), are precipitated during the electrolysis of magnesium in aqueous solutions containing ammonium and phosphate ions. Electrolysis and subsequent precipitation have examined for magnesium electrode with pre-treatments, immersion in various biodegradable polymer solutions. Electrolysis at the constant potential of −1.4 V vs. Ag/AgCl occurs on magnesium electrodes in a phosphate-containing solution, providing precipitate on the magnesium electrode, consisting mainly of MAPs. The precipitate mass appears to be related linearly to the integrated charge, irrespective of the pre-treatment used. Pre-treatment of magnesium electrodes in poly(ethylene glycol) (PEG) and poly(vinyl alcohol) (PVA) exerted markedly negative and positive influences, respectively, on the electrolysis and the yield of the precipitate during electrolysis, attributable to changes in the interfacial resistance or surface morphology.
Recovery of phosphate salts from industrial and municipal wastewater has garnered great interest in terms of recycling of phosphorous resources, and the inhibition of eutrophication.1–4 For the purpose of recycling phosphates from wastewater, various methods including chemical precipitation, adsorption, biological method, and electrochemical precipitation, have intensively been investigated. Precipitation of an insoluble phosphate salt is a convenient method for recovering dissolved phosphate from wastewater, and thus the chemical precipitation methods have been applied widely in practical water treatment plants. However, the formation of low-solubility salt such as hydroxyapatite (HAP) or magnesium ammonium phosphates (MAPs) requires an alkaline environment.5–9 Therefore, chemical precipitation of HAP or MAPs must include modification of pH by the addition of alkaline, which causes process cost. In addition, when cations forming hydroxides with low solubility are utilized, the precipitation of their phosphates are competitive to the precipitation of their hydroxide. By contrast, electrolysis in wastewater can lead to precipitation of a phosphate precipitate without the addition of an alkaline additive because hydroxy ions can be generated via collateral water splitting.10–20 Attempts have been made to investigate electrochemical systems from lab-scale to practical water-treatment plants by using various cathodes, anodes, and reactor configurations. The usage of sacrificial anode, such as aluminum,19 iron,19,20 and magnesium21–27 is beneficial for the facile control of metal cation dosage. Among them, magnesium sacrificial anode has advantages on its low corrosion resistance,28 and the direct production of MAPs. Therefore, intensive studies have been conducted on the electrochemical water treatments using magnesium anode in this decade. Anodic oxidation of magnesium has been investigated intensively using several practical wastewater treatment systems. The anodic oxidation of magnesium in a wastewater containing ammonium and phosphate ions provides precipitation of MAPs such as MgNH4PO4·6H2O struvite.21–27 This reaction is assumed to be precipitation driven by electrochemical reaction. This electrochemical process has been investigated intensively at both laboratory-scale and pilot-scale dimensions.
For the improvement of the cycle performance of magnesium secondary batteries, the author has studied the anodic behavior of magnesium in some organic solvent electrolytes.29–31 The composition of a native passivation layer on magnesium surface was analyzed in detail using X-ray photoelectron spectroscopy (XPS): it comprises magnesium hydroxide and carbonate. Additionally, results showed that the layer can be modified by immersion treatment of magnesium in alkyl halides. As indicated by results of this study, organic compounds having Lewis basic moiety are expected to interact with the passivation layer, and to improve the electrochemical reactivity of magnesium.31 Unlike inorganic particles, flexible polymer molecules are expected to adhere to the magnesium surface, and also to act as a binder between inorganic particles and magnesium.
For this study, poly(acrylic acid) (PAA), poly(ethylene glycol) (PEG), and poly(vinyl alcohol) (PVA), water-soluble, environmentally compatible, and having Lewis-basic oxygen which can coordinate magnesium, are chosen as modifiers of the passivation layer. These polymers are expected to serve in multiple roles: some can act as a modifier. Then they can also be used as adhesive for inorganic surface modifiers. Alternatively, these polymers can be assumed to be components of actual wastewater. Therefore, it is important to know positive or negative effects of these polymers on magnesium surfaces. After a magnesium electrode was immersed preliminarily in an aqueous solution of a polymer modifier, the electrochemical responses and the struvite formation for magnesium without or with immersion pre-treatment were evaluated using a miniature electrolysis cell. Subsequently, their influences were compared.
An aqueous solution of 20 mmol dm−3 NH4H2PO4, used as the standard phosphate solution, was prepared by the dissolution of NH4H2PO4 (Kanto Chemical Co., Ltd., Japan) in deionized water. The 20 mmol dm−3 solutions of NH4NO3 (Kanto Chemical Co., Ltd., Japan) were prepared using the same procedure and were used as a control. PAA (MW 25000, Kanto Chemical Co., Ltd., Japan), PEG (MW 1000, Kanto Chemical Co., Ltd., Japan), and PVA (MW 2000, Kanto Chemical Co., Ltd., Japan) were used as a pre-treatment reagent for magnesium electrodes. A polymer was dissolved into deionized water up to 1 g dm−3 of solution for pre-treatment usage. Magnesium plate (99.9 %, 0.1 mm thickness; The Nilaco Corp., Japan) was cut into strips with a prescribed dimension, polished, and washed with deionized water before use as a working electrode. For electrochemical evaluation, the three-electrode cell assembly (011951; BAS Inc., Japan) included a platinum wire counter electrode, and an Ag/AgCl reference electrode. A magnesium strip was inserted in the cell as a working electrode. A piece of filter paper (Advantec No. 5A; Toyo Roshi Kaisha Ltd., Japan) was placed on the working electrode as a separator. The cell was degassed by nitrogen gas bubbling. Pre-treatment of magnesium was conducted by immersing magnesium in a prescribed polymer solution in the cell body 1 h before assembling the three-electrode cell. Constant potential electrolysis (chronoamperometry), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) were conducted to compare the electrochemical performance of the magnesium electrode. The CV measurements were taken for the alternative cell to that used for electrolysis, using the potentiostat (HSV-110), with the 1 mV s−1 scan rate, the potential range from the open circuit potential, and −1.4 V vs. Ag/AgCl. The EIS measurement was conducted for the three-electrode cell before the electrolysis, using a potentiostat with a function generator (Solartron 1286). The applied bias voltage was ±10 mV from the open-circuit potential, and the frequency range was from 2 × 105 Hz to 10−3 Hz. For electrolysis, the potential of magnesium electrode in the three-electrode cell was controlled using a potentiostat (HSV-110; Hokuto Denko Corp., Japan) at −1.4 V vs. Ag/AgCl during 1 h. The change in the magnesium electrode via the electrolysis was estimated from measurements of mass change, Raman spectroscopy (Agility; BaySpec Inc.), scanning electron microscopy (SEM, 30 kV accelerating voltage, S-3500N; Hitachi, Ltd., Japan), and X-ray fluorescence spectroscopy (XRF; Delta, Olympus Co., Ltd., Japan). The pH of electrolyte solution was measured using a pH meter (D-210P; Horiba Advanced Techno Co., Ltd., Japan) with a glass capillary electrode (6069-10C). Collecting the precipitate suspended in the small amount of the solution was difficult. Because a magnesium electrode was placed horizontally at the basement of a cell room, most of precipitate must fall down on the magnesium. Therefore, the electrode mass increases are assumed as approximating the product mass.
The anodic linear sweep voltammograms of magnesium electrodes in 20 mmol dm−3 NH4H2PO4 and 20 mmol dm−3 NH4NO3 solutions are presented with a log scale current axis in Fig. 1a. Because the scanned potential region is higher than the open-circuit potential of the cell (ca. −1.8 V), anodic currents are observed for these profiles. An increase of the anodic current was observed at −1.45 V, particularly in the NH4H2PO4 solution. From this result, the applied potential for the constant-potential electrolysis was found to be −1.4 V vs. Ag/AgCl. This potential is lower (meaning that the overpotential is smaller) than those reported earlier in the literature.22–24
(a) Linear sweep voltammograms of magnesium electrode in 20 mmol dm−3 aqueous solution. Electrolyte: (A: black line) NH4NO3 (B: blue line) NH4H2SO4. (b) Current profiles of constant-potential electrolysis of magnesium electrodes. Potential: −1.4 V vs. Ag/AgCl. Electrolyte: (A: dotted line) 20 mmol dm−3 NH4NO3, (B–E) 20 mmol dm−3 NH4H2PO4. Pre-treatment: (B: gray line) without pre-treatment. (C: green line) immersion in PAA solution. (D: blue line) immersion in PEG solution. (E: orange line) immersion in PVA solution. (c) Nyquist plots of cells for electrolysis containing magnesium electrodes. Inset: enlarged graph for selected area. Frequency range: 2 × 105 Hz–10−2 Hz, Bias: 10 mV. Electrolyte: (A: open circle) 20 mmol dm−3 NH4NO3, (B–E) 20 mmol dm−3 NH4H2PO4. Pre-treatment: (B: black) without pre-treatment. (C: green) immersion in PAA solution. (D: blue) immersion in PEG solution. (E: orange) immersion in PVA solution.
The current profiles on the constant-potential electrolysis of magnesium electrode in 20 mmol dm−3 NH4H2PO4 and 20 mmol dm−3 NH4NO3 solutions are presented for comparison in Fig. 1b. It is noteworthy that the current axis is shown using a log scale also in this figure. The profiles for the electrolysis in NH4H2PO4 solution are considerably different from that in the NH4NO3 solution. The former shows higher anodic current with a peak around 400 s (peak current is ca. 3 × 10−3 A) and the steady-state current of 10−4 A. By contrast, the latter shows lower, on the order of 10−5 A, current with no peaks. Such different profiles correspond to the linear sweep voltammogram (Fig. 1a). The marked difference between these current profiles suggests that higher current can be promoted in the phosphate-containing solution than with the phosphate-free solution. Figure 1b also includes current profiles for electrolysis in 20 mmol dm−3 NH4H2PO4 solution for the immersion pre-treated magnesium electrodes using a polymer solution. The profile differs according to the kind of polymer in the immersion pre-treatment. The immersion pre-treatment in PVA or PAA provides similar peaking profiles to that of the bare magnesium electrode. The peak and the steady-state currents are 3 × 10−3 A and 10−4 A, respectively, for the magnesium pre-treated by PAA; also, they are 8 × 10−3 A and 3 × 10−4 A, respectively, for the magnesium pre-treated by PVA. The electricity amounts presented in Table 1 are estimated from the profiles. As one might infer from the profiles, the magnesium electrode with the PVA pre-treatment exhibits the highest electricity. That with the PAA pre-treatment ranks next, somewhat similar to the magnesium without pre-treatment. Then the electricity for the magnesium pre-treated using PEG is the lowest. Only the solution for the immersion pre-treatment has been different for these results. Therefore, the difference in the surface state of magnesium is regarded as providing variation in the current profile. To obtain information related to the electrode–electrolyte interface, electrochemical impedance has been measured for cells with the magnesium electrodes with or without pre-treatment. Nyquist plots of the electrolysis cells are presented in Fig. 1c. For all the impedance spectra, a similar overlap of collapsed semicircles with a curled feature at low frequency end, which is a typical shape of metal electrode, and the diameter of a semicircle (an intercept of x-axis) of 103–104 Ω indicate the extent of a component of interfacial resistance. For pre-treatment in polymer solutions, the order of the semicircle diameter is, from smallest, PAA, PVA, without pre-treatment, and PEG. The EIS measurement was conducted before each the electrolysis, and thus the difference in the EIS spectra indicates that the pre-treatment of magnesium electrode provides a change in the surface state of magnesium electrode by the pre-treatment. The small current on the electrolysis for the magnesium electrode with the pre-treatment in PEG is explainable by the large interfacial resistance, probably because of the dense passivation layer. The Nyquist plot of a cell with a magnesium electrode without pre-treatment and 20 mmol dm−3 NH4NO3 solution is also included in Fig. 1c. The semicircle of this case is as small as the NH4H2PO4 analogue (and at a similar extent to that of the cell with the magnesium electrode pre-treated in PVA in the NH4H2PO4 solution), even though the current on the electrolysis by this cell is small. The fact that the magnesium electrode was not passivated in the NH4NO3 solution indicates the intrinsic requirement of phosphate ion in the major electrolysis process under the present condition.
| Immersion pre-treatment |
Mass increase/mg |
Electricity/C | pH after electrolysis |
P/Mg peak intensity ratio on XRF |
|---|---|---|---|---|
| w/o | 1.5 | 2.1 | 7.44 | 11.4 |
| in PAA | 0.2 | 1.7 | 6.99 | 2.45 |
| in PEG | 0.5 | 0.06 | 6.09 | 1.79 |
| in PVA | 2.0 | 4.0 | 6.82 | 3.75 |
The mass increases of the magnesium electrodes after the electrolysis are included in Table 1. The precipitation on the magnesium electrode and even dispersion in the solution were observed in each case of the electrolysis of magnesium electrode on 20 mmol dm−3 NH4H2PO4 solutions. The NH4H2PO4 solution (1 cm3) in the test cell contains ca. 2.0 × 10−5 mol of phosphate ion. When it is assumed that the precipitate on the magnesium consists only of struvite, the yields of recovered phosphorus are ca. 34 % for the magnesium electrode without pre-treatment, and ca. 45 % for the magnesium electrode with immersion pre-treatment in PVA. It is interesting that such a marked recovery can be achieved under 1 h operation at low overpotential.
Most earlier reports have described the main component of resulting precipitate as struvite MgNH4PO4·6H2O.21–27 In fact, struvite can be formed as a result of the reaction presented as Eq. 1 together with the dissolution of magnesium (Eq. 2) on the anode and water splitting (Eq. 3) on the cathode.21
| \begin{equation} \text{Mg}^{2 + } + \text{NH}_{4}{}^{ + } + \text{HPO}_{4}{}^{2 - } + 6\text{H$_{2}$O} \to \text{MgNH$_{4}$PO$_{4}$}{\cdot} 6\text{H$_{2}$O} + \text{H}^{ + } \end{equation} | (1) |
| \begin{equation} \text{Mg} \to \text{Mg}^{2 + } + 2\text{e}^{ - } \end{equation} | (2) |
| \begin{equation} 2\text{H$_{2}$O} + 2\text{e}^{ - } \to \text{H}_{2} + 2\text{OH}^{ - } \end{equation} | (3) |
Magnesium ions can be generated by a chemical reaction between magnesium metal and water described in Eq. 4, as evidenced by the formation of bubbles on the magnesium electrode. Although Kruk et al. proposed electrochemical hydrogen formation from monovalent magnesium,21 the hydrogen formation on the anode must be a parallel chemical reaction.
| \begin{equation} 2\text{Mg} + 2\text{H$_{2}$O} \to 2\text{Mg}^{2 + } + 2\text{OH}^{ - } + \text{H}_{2} \end{equation} | (4) |
In the present case, the reactions on the anode and the cathode must be, respectively, magnesium dissolution and water splitting. Therefore, the precipitate obtained on the magnesium electrode without pre-treatment after electrolysis in the NH4H2PO4 solution is expected to be MAPs. Characterization of the magnesium electrode surface with or without immersion pre-treatment after electrolysis has been attempted using X-ray fluorescence spectroscopy (XRF) and Raman spectroscopy. Figure 2 shows the XRF spectra of the surface of the magnesium electrode obtained without and with the immersion pre-treatment after electrolysis in the prescribed solutions. The spectra for the electrolysis in NH4NO3 solution show main peaks at 1.3 keV assigned to Mg Kα, with some minor peaks assigned to impurities of magnesium.17 It is noteworthy that no peak is apparent around 2.1 keV, which is indicative of P Kα for this sample. By contrast, the magnesium electrodes after the electrolysis in the NH4H2PO4 solution clearly show a peak at 2.1 keV, assigned to phosphorous, irrespective of the immersion pre-treatment. The ratios of the peaks for Mg and P, summarized in Table 1, differ by the presence or absence, and by the kind of the immersion pre-treatment. The P/Mg ratio for the magnesium electrode with the immersion pre-treatment in PVA is rather small compared with the case without the pre-treatment, although the former exhibited larger amount of precipitation than the latter. In the case that a P-containing precipitation is not uniform, the P/Mg ratio can be larger than expected by the contribution of magnesium substitute. Figure 3 summarizes the Raman spectra of the magnesium electrodes after electrolysis under various conditions. Comparison with a magnesium electrode after electrolysis in the NH4NO3 solution shows that all the Raman spectra of the magnesium electrode after the electrolysis in the NH4H2PO4 solution show the development of some broad peaks in the Raman shift region around 460–600 cm−1, 890 cm−1, and 920–1120 cm−1. Most of these peaks are broad, probably because the existing compounds are multiple as a result of the use of magnesium phosphates of several kinds, including struvite. Although the most significant symmetric stretching peak for phosphate ion must appear at around 946 cm−1,17 it is difficult to confirm the presence of struvite from a broad peak, suggesting an overlap with asymmetric stretching peak (1052 cm−1) from multiple magnesium phosphates.32 The electrolysis condition used for this study is mild. Therefore, the pH of the solution after electrolysis is as low as 7.47, as presented in Table 1. That finding is consistent with earlier reports describing that struvite cannot form or that it forms with low purity toward other MAPs under the solution of pH below 7.5.22 By contrast, peaks observed around 460–600 cm−1, which can be assigned to symmetric and asymmetric bendings for phosphates, are observed only for magnesium electrodes after electrolysis in the NH4H2PO4 solution. The presence of peaks in this region, as well as the XRF results, suggests the presence of MAP (struvite and some other magnesium phosphates) in the precipitates formed by electrolysis in the NH4H2PO4 solution. These broad peaks are visible also for the magnesium electrodes with the immersion pre-treatments. The pre-treatment in PEG provides a particularly high but broad peak at the 920–1100 cm−1 region, although the electrode is inactive toward electrolysis. By contrast, the magnesium electrode with the pre-treatment in PVA provides rather low peak intensities, even though it shows the greatest mass of the precipitate and the presence of P, as shown in the XRF result.
X-ray fluorescent spectra of magnesium electrode after electrolysis. Electrolyte: (A: dotted line) 20 mmol dm−3 NH4NO3, (B–E) 20 mmol dm−3 NH4H2PO4. Pre-treatment: (B: gray line) without pre-treatment. (C: green line) immersion in PAA solution. (D: blue line) immersion in PEG solution. (E: orange line) immersion in PVA solution.
Raman spectra of magnesium electrode after electrolysis. Electrolyte: (A: dotted line) 20 mmol dm−3 NH4NO3, (B-E) 20 mmol dm−3 NH4H2PO4. Pre-treatment: (B: gray line) without pre-treatment. (C: green line) immersion in PAA solution. (D: blue line) immersion in PEG solution. (E: orange line) immersion in PVA solution.
Figure 4 presents SEM micrographs of the magnesium electrode surfaces after electrolysis in the NH4H2PO4 solution. The precipitate on the surface of the magnesium electrode without immersion pre-treatment by the electrolysis in the NH4H2PO4 solution exhibits the feature of column-like particles, which resemble the particles of struvite described in earlier reports.17,21,25 Similar column-like features are also observed in the SEM image for the magnesium electrode with the immersion pre-treatment in PAA. The magnesium electrode with the pre-treatment in PEG provides a different, rather smooth surface, even after the electrolysis. The magnesium electrode with the pre-treatment in PVA shows different surface morphology after the electrolysis: entangled, 10–20 µm diameter fibers cover the electrode surface; column-like particles are found between and under the fibrous coverage. These fibers are likely to be PVA. Such PVA coverage might inhibit the laser irradiation to the column-like precipitate and might also inhibit Raman scattering from the precipitate. This coverage might be the reason why the Raman peaks are rather suppressed for the magnesium electrode with the pre-treatment in PVA.
SEM micrographs of magnesium electrode after electrolysis in NH4H2PO4 solution. Pre-treatment: (a) without immersion pre-treatment. (b) immersion in PAA solution. (c) immersion in PEG solution. (d) immersion in PVA solution.
Reactions described as Eqs. 3 and 4 can raise the pH of the solution. As presented in Table 1, the pH of the solution after electrolysis is higher than that of the original NH4H2PO4 solution (pH 4.8). The deposition of MAPs must be accelerated by the pH increase, although the resultant pH values were still low compared with the pH at which struvite precipitation is preferred.22,33 The presence of a current peak appears to be consistent with the mechanism, where the current increase in initial stage might be in relation to the increase of pH by the water splitting on the counter electrode, and after the pH achieves the region sufficient to precipitate MAPs, the current decreases to steady-state by the increase of local concentration of the product. Alkaline conversion of the solution is a key issue affecting electrochemical precipitation of MAPs. According to the reaction mechanism described as Eqs. 1–4, electrochemical reactions provide magnesium ions and an alkaline environment, although the formation of MAPs (2) is not a direct electrochemical process. The mass increases of the magnesium electrodes are shown against the electricity consumed during electrolysis in the NH4H2PO4 solution in Fig. 5. The mass increase of the electrode appears to exhibit a linear relation to the electricity, irrespective of the immersion pre-treatment. From the plot slope, the mass increased by a unit of electricity is calculable as 5.2 × 10−4 g C−1. This value corresponds to the equivalence of MgNH4PO4·6H2O of 0.23 mole by one mole of electrons, assuming the precipitate is only struvite. This value suggests that approximately 46 % of the electrons consumed during electrolysis contribute to struvite formation, based on magnesium ions. This value must have a certain deviation depending on the precipitate component: The presence of other MAPs or magnesium phosphates with smaller formula weight, as indicated by the Raman spectra, might decrease the value, but other side reactions might increase the value. The linear relation between the electricity and the precipitate mass suggests that the reaction mechanisms among these cases are similar, where the production of MAPs was induced by the electrochemical reaction and the presence of phosphate, irrespective of the immersion pre-treatment. Only the interfacial resistance, including the mass-transfer resistance, is varied by the surface modification attributable to the polymer. Also, the PVA coverage observed to a great degree after pre-treatment in PVA might increase the local magnesium ion concentration at the interface by suppressing the mass transfer, which can explain enhanced electrolysis. By contrast, pre-treatment in PEG might produce a dense passivation layer on the electrode surface, which would inhibit the electron transfer. Pre-treatment in PAA provides a very similar current profile and precipitate to the case without pre-treatment. Although PAA having acidic moiety was expected to react with magnesium to provide an engineered surface, it appears instead to be inactive toward magnesium. More or less, it has been found that some biodegradative polymers can interact with magnesium and provide either a positive or negative influence on the formation of MAPs via electrolysis, by immersion pre-treatment in its solution. Particularly, PVA covers the magnesium surface, provides a mass-transfer effect beneath the surface, and enhances struvite formation. The findings presented herein might facilitate the selection of polymer components for additional improvement of engineered magnesium surfaces by anchoring organic or inorganic material with a polymer binding material.
Relation between electricity consumption during electrolysis and increased mass after electrolysis in 20 mmol dm−3 NH4H2PO4 solution.
Electrolysis on a magnesium electrode at the constant potential of −1.4 V vs. Ag/AgCl and the formation of a precipitate on magnesium in a 20 mmol dm−3 NH4H2PO4 aqueous solution are influenced by immersion pre-treatment of magnesium in an aqueous polymer solution. The electricity consumed during the constant-potential electrolysis has an apparently linear relation to the mass of the precipitate on the magnesium electrode, containing MAPs, irrespective of the pre-treatment used for the magnesium electrode. The order of the polymer added on the pre-treatment by the amount of electric charge was found to be, from largest, PVA, PAA, and PEG. The magnesium electrode with pre-treatment in PAA provides a similar amount of charge to that without any pre-treatment. Moreover, that with pre-treatment in PVA provides a considerably stronger charge. PVA covers the magnesium surface while retaining a path to charge/mass transfers, whereas PEG produces a thick passivation layer. Assuming that the precipitate comprises struvite, ca. 0.2 mol of precipitate is formed by one mole of electrons, irrespective of the pre-treatment. Additionally, the recovery yields from the phosphate in the solution are ca. 31 % and 41 %, respectively, for the magnesium without pre-treatment and with the pre-treatment in PVA, after 1 h electrolysis at −1.4 V vs. Ag/AgCl.
This work was supported by JSPS KAKENHI Grant Number JP 23K04401. SEM apparatus belongs to the General Research Institute, College of Bioresource Sciences, Nihon University.
Minato Egashira: Conceptualization (Lead), Data curation (Lead), Formal analysis (Lead), Funding acquisition (Lead), Investigation (Lead), Methodology (Lead), Resources (Lead), Writing – original draft (Lead)
The authors declare no conflict of interest in the manuscript.
Japan Society for the Promotion of Science: JP23K04401
M. Egashira: ECSJ Active Member
