CN111682229A - Humic acid-Fe composite modified anode, preparation method and application thereof, and seabed microbial fuel cell - Google Patents
Humic acid-Fe composite modified anode, preparation method and application thereof, and seabed microbial fuel cell Download PDFInfo
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Abstract
The invention provides a Humic Acid (HA) -Fe composite modified anode, a preparation method and application thereof, and a seabed microbial fuel cell, and belongs to the technical field of fuel cells. The HA-Fe composite modified anode comprises an electrode matrix and humic acid-Fe (III) complex loaded on the surface of the electrode matrix. According to the invention, humic acid on the surface of the electrode matrix is used as a nutrient substrate, the attachment of multiple groups of bacteria can be promoted, the humic acid comprises electrogenic bacteria, the oxide of iron (III) HAs high affinity with the sediment electrogenic bacteria, can be identified as a natural electron acceptor by cytochrome on an outer membrane of the electrogenic bacteria, and can be used for carrying out direct extracellular electron transfer, HA HAs the characteristic of complexing heavy metal ions, the humic acid and the iron (III) ions are cooperated to accelerate the electron transfer efficiency, the electron transfer dynamics of an anode/biomembrane interface is improved, and the obtained composite modified anode HAs high electrochemical performance and also obviously improves the output power of a battery.
Description
Technical Field
The invention relates to the technical field of fuel cells, in particular to a humic acid-Fe composite modified anode, a preparation method and application thereof, and a seabed microbial fuel cell.
Background
With the development of oceans going deep, the problem of long-term power supply of ocean instruments becomes a technical bottleneck of long-term work of the ocean instruments. As a novel power supply, the Marine segment microbial fuel cells (MSMSMSFCs) are expected to solve the problem of long-term power supply of Marine instruments. MSMFCs are special microbial fuel cells with the whole marine environment as a reaction chamber, the anode is placed in seabed sediments, the cathode is placed in seawater, the sediment/seawater interface is used as a natural proton exchange membrane, and the cathode and the anode are connected with a load through an external circuit. The natural anaerobic environment of the sediment and rich organic matters are very favorable for the growth of the electricity-generating microorganisms, the electricity-generating microorganisms degrade the organic matters in the sediment through metabolism to release protons and electrons, and the dissolved oxygen in the seawater receives the reactions of the protons and the electrons at the cathode to generate water, so that the chemical energy is converted into electric energy and the equipment of an external circuit is driven to operate.
MSMFs have the advantages of simple structure, sufficient and renewable fuel and mild reaction conditions, and are expected to be used as seabed long-term power sources. How to improve the output power of the MSMFCs is the focus of current research, wherein, anode modification is a common method for improving the performance of the battery. Common methods for modifying MSMFCs anodes are to combine an electron transfer mediator on the surface of an anode material to increase the electron transfer rate or to increase the output power by selecting an anode material with high specific surface area. Humic Acid (HA) is a marine natural organic substance widely existing, takes an aromatic ring as a framework, and contains a plurality of oxygen-containing functional groups, wherein carboxyl (-COOH) and phenolic hydroxyl (ph-OH) are main active groups. Humic acid has redox capability, can be used as an electron transfer mediator to improve the electron transfer rate, reduce the internal resistance of a battery and improve the electricity generation performance of MSMFCs, but the lower output power of the MSMFCs still limits the further application of the MSMFCs.
Disclosure of Invention
In view of the above, the invention aims to provide a humic acid-Fe composite modified anode, a preparation method and application thereof, and a seabed microbial fuel cell. The humic acid-Fe composite modified anode provided by the invention has high battery output power and high electrochemical performance.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a humic acid-Fe composite modified anode which comprises an electrode substrate and a humic acid-Fe (III) complex loaded on the surface of the electrode substrate.
Preferably, the load amount of the humic acid-Fe (III) complex in the humic acid-Fe composite modified anode is 10 wt.% to 80 wt.%.
Preferably, humic acid in the humic acid-Fe (III) complex is reacted with Fe3+In a molar ratio of 1: 1.5 to 2.2.
The invention also provides a preparation method of the humic acid-Fe composite modified anode, which comprises the following steps:
pretreating the electrode to obtain an electrode matrix;
mixing humic acid and soluble Fe3+Mixing salt and water, adjusting the pH value to 6-7, and performing a complexing reaction to obtain a suspension;
carrying out electrophoretic deposition by taking the electrode substrate as an anode, a platinum electrode as a cathode and the suspension as dispersion liquid to obtain the humic acid-Fe composite modified anode;
or
And brushing the turbid liquid on the surface of the electrode substrate, and drying to obtain the humic acid-Fe composite modified anode.
Preferably, the pretreatment comprises acetone ultrasonic cleaning, ethanol ultrasonic cleaning, first water washing, first drying, nitric acid soaking, second water washing and second drying which are sequentially carried out.
Preferably, the time of the complexation reaction is 1-3 h.
Preferably, the electrode distance of the electrophoretic deposition is 2-4 cm, the direct current voltage is 5-30V, and the time is 1-2 h.
Preferably, after the electrophoretic deposition, the electrophoretic deposition product is washed and soaked with water in sequence, and then dried.
The invention also provides the application of the humic acid-Fe composite modified anode in the technical scheme or the humic acid-Fe composite modified anode prepared by the preparation method in the technical scheme in a submarine microbial fuel cell.
The invention also provides a submarine microbial fuel cell, which comprises the humic acid-Fe composite modified anode in the technical scheme or the humic acid-Fe composite modified anode prepared by the preparation method in the technical scheme, wherein the humic acid-Fe composite modified anode is placed in submarine sediments, the cathode is placed in seawater, and the interface of the submarine sediments and the seawater is used as a natural proton exchange membrane.
The invention provides a Humic Acid (HA) -Fe composite modified anode (HA-Fe composite modified anode), which comprises an electrode matrix and a humic acid-Fe (III) complex loaded on the surface of the electrode matrix. According to the invention, on one hand, humic acid on the surface of an electrode substrate can be used as a nutrient substrate to promote attachment of multiple groups of bacteria, including electrogenic bacteria (such as dissimilatory metal reducing bacteria), iron (III) oxide HAs high affinity with sediment electrogenic bacteria, can be identified as a natural electron acceptor by cytochrome on an outer membrane of the sediment electrogenic bacteria to carry out direct extracellular electron transfer, and on the other hand, HA HAs the characteristic of complexing heavy metal ions, and the humic acid and iron (III) ions cooperate to accelerate electron transfer efficiency and improve electron transfer kinetics of an anode/biomembrane interface. The data of the embodiment shows that the HA-Fe composite modified anode provided by the invention can obviously improve the performance of the submarine microbial fuel cell, and the number of surface microorganisms is the largest and is 1.8 times of that of an unmodified blank anode and 1.2 times of that of an HA modified anode; the redox activity is 6.1 times of that of a blank anode and 1.9 times of that of an HA anode, and the relative kinetic activity is 13.1 times of that of the blank anode and 3.0 times of that of the HA anode respectively;the polarization resistance is strongest, and the maximum power density of the constructed MSMFCs after stabilization is 165.3 mW.m-26.5 times of blank cell and 1.95 times of HA anode, and the minimum can reach 147.9 mW.m-2. Mechanistic analysis shows HA and Fe3+The electron transfer synergy of (a) is responsible for the high electrochemical performance of the anode and the high output power of the MSMFCs.
Furthermore, a large amount of humic acid and iron ions naturally exist in the ocean, so the humic acid and iron (III) ions loaded on the surface of the electrode substrate have a regeneration function, and the continuous improvement of the electrochemical stability of the anode and the stable power of the battery are facilitated. The data of the embodiment shows that the MSMFCs constructed by the HA-Fe composite modified anode can stably run for more than 3 months, and the battery power is kept at 150 mW.m-2Left and right.
The invention also provides a preparation method of the humic acid-Fe composite modified anode, which comprises the following steps: pretreating the electrode to obtain an electrode matrix; mixing humic acid and soluble Fe3+Mixing salt and water, adjusting the pH value to 6-7, and performing a complexing reaction to obtain a suspension; carrying out electrophoretic deposition by taking the electrode substrate as an anode, a platinum electrode as a cathode and the suspension as dispersion liquid to obtain the humic acid-Fe composite modified anode; or brushing the suspension on the surface of the electrode substrate, and drying to obtain the humic acid-Fe composite modified anode. The preparation method provided by the invention is simple, is easy to amplify and has important application prospect.
Drawings
FIG. 1 is a surface topography of a blank carbon felt;
FIG. 2 is a surface topography of an HA-modified anode;
FIG. 3 is a surface topography of the HA-Fe composite modified anode;
FIG. 4 is an infrared spectrum of a blank anode, an HA-modified anode and an HA-Fe composite modified anode;
FIG. 5 is a surface contact angle test chart of a blank anode;
FIG. 6 is a surface contact angle test chart of HA modified anode;
FIG. 7 is a surface contact angle test chart of the HA-Fe composite modified anode;
FIG. 8 is a fluorescent photograph of surface microorganisms of a blank anode;
FIG. 9 is a fluorescent photograph of surface microorganisms of an HA-modified anode;
FIG. 10 is a fluorescence photograph of surface microorganisms of the HA-Fe composite modified anode;
FIG. 11 is a cyclic voltammogram of a blank anode, an HA-modified anode, and an HA-Fe composite modified anode;
FIG. 12 is Tafel curves for a blank anode, an HA-modified anode, and an HA-Fe composite modified anode;
FIG. 13 is an electrochemical impedance fit curve for a blank anode, an HA-modified anode, and an HA-Fe composite modified anode;
FIG. 14 is an equivalent circuit diagram of a blank anode, an HA-modified anode, and an HA-Fe composite modified anode;
FIG. 15 is a polarization curve for a blank anode, an HA-modified anode, and an HA-Fe composite modified anode;
FIG. 16 is a cell power density curve for a blank anode, an HA-modified anode, and an HA-Fe composite modified anode;
FIG. 17 is a schematic diagram of the quinone-phenol conversion reaction;
FIG. 18 is the HA-Fe composite modified anode action mechanism diagram.
Detailed Description
The invention provides a humic acid-Fe composite modified anode which comprises an electrode substrate and a humic acid-Fe (III) complex loaded on the surface of the electrode substrate.
In the invention, the load capacity of the humic acid-Fe (III) complex in the humic acid-Fe composite modified anode is preferably 10 wt.% to 80 wt.%, and more preferably 30 wt.% to 60 wt.%.
In the invention, humic acid and Fe in the humic acid-Fe (III) complex3+Is preferably 1: 1.5 to 2.5, more preferably 1: 2.
in the present invention, the electrode substrate is preferably a carbon felt, a carbon fiber brush, a graphite felt or a graphite fiber brush, and the source of the electrode substrate is not particularly limited in the present invention, and commercially available products well known to those skilled in the art may be used. The specification of the electrode substrate is not particularly limited in the present invention, and in a specific embodiment of the present invention, the electrode substrate is preferably cut into a square of 3cm × 3 cm.
The invention also provides a preparation method of the humic acid-Fe composite modified anode, which comprises the following steps:
pretreating the electrode to obtain an electrode matrix;
mixing humic acid and soluble Fe3+Mixing salt and water, adjusting the pH value to 6-7, and performing a complexing reaction to obtain a suspension;
carrying out electrophoretic deposition by taking the electrode substrate as an anode, a platinum electrode as a cathode and the suspension as dispersion liquid to obtain the humic acid-Fe composite modified anode;
or
And brushing the turbid liquid on the surface of the electrode substrate, and drying to obtain the humic acid-Fe composite modified anode.
The invention carries out pretreatment on the electrode to obtain the electrode matrix. In the present invention, the pretreatment preferably includes acetone ultrasonic cleaning, ethanol ultrasonic cleaning, first water washing, first drying, nitric acid soaking, second water washing, and second drying, which are performed in sequence. In the invention, the time for the acetone ultrasonic cleaning and the ethanol ultrasonic cleaning is preferably 30min, and the parameters of the ultrasonic cleaning are not particularly limited. In the present invention, the temperature of each of the first drying and the second drying is preferably 90 ℃, and the time of each of the first drying and the second drying is not particularly limited in the present invention. In the invention, the nitric acid is preferably concentrated nitric acid, the temperature of the nitric acid soaking is preferably 90 ℃, the time is preferably 2 hours, the nitric acid soaking is used for removing surface impurities and improving the hydrophilicity, and the nitric acid soaking is preferably carried out under the condition of water bath oscillation. The concentration of the concentrated nitric acid is not particularly limited in the present invention, and a concentrated nitric acid known to those skilled in the art may be used. In the present invention, the end point of the second water washing is preferably washed until the water-washed product is neutral.
The invention uses humic acid and soluble Fe3+After mixing salt and water, adjusting the pH value to 6-7,and carrying out complexation reaction to obtain suspension. In the invention, the time of the complex reaction is preferably 1-3 h, the temperature is preferably room temperature, and no additional heating or cooling is required. In the present invention, the soluble Fe3+The salt is preferably Fe2(SO4)3Or Fe (NO)3)3。
In the present invention, the mixing is preferably performed by mixing humic acid and water to obtain a humic acid suspension, and adding soluble Fe to the humic acid suspension3+The salt water solution is stirred at room temperature, and the rotation speed and the stirring time of the stirring are not specially limited, so that the raw materials can be uniformly mixed. In the invention, the concentration of the humic acid suspension is preferably 20-30 g/L, and the soluble Fe is treated by the method3+The concentration and the dosage of the salt water solution are not specially limited, and the humic acid-Fe (III) complex can ensure that humic acid and Fe in the humic acid-Fe (III) complex3+Is preferably 1: 1.5 to 2.5, more preferably 1: 2, the product is obtained.
In the present invention, the pH is preferably 6.5, and the pH of the regulator for adjusting the pH to 6 to 7 is not particularly limited.
After obtaining the electrode matrix and the suspension, the invention takes the electrode matrix as an anode, the platinum electrode as a cathode and the suspension as dispersion liquid to carry out electrophoretic deposition to obtain the humic acid-Fe composite modified anode.
In the invention, the electrode distance of the electrophoretic deposition is preferably 2-4 cm, the direct current voltage is preferably 5-30V, more preferably 15-20V, and the time is preferably 1-2 h.
In the invention, after the electrophoretic deposition, the obtained electrophoretic deposition product is preferably washed and soaked by water in sequence, and then dried. In the present invention, the soaking time is preferably 24 hours, the drying temperature is preferably 90 ℃, and the drying time is not particularly limited, and the moisture can be completely removed.
After obtaining the suspension, the invention brushes the suspension on the surface of the electrode matrix, and after drying, the humic acid-Fe composite modified anode is obtained. The present invention is not particularly limited to the specific operation of the brushing and drying.
The invention also provides the application of the humic acid-Fe composite modified anode in the technical scheme or the humic acid-Fe composite modified anode prepared by the preparation method in the technical scheme in a submarine microbial fuel cell.
The invention also provides a submarine microbial fuel cell, which comprises the humic acid-Fe composite modified anode in the technical scheme or the humic acid-Fe composite modified anode prepared by the preparation method in the technical scheme, wherein the humic acid-Fe composite modified anode is placed in submarine sediments, the cathode is placed in seawater, and the interface of the submarine sediments and the seawater is used as a natural proton exchange membrane.
In the invention, the humic acid-Fe composite modified anode and the cathode are preferably connected with a load through an external circuit.
In order to further illustrate the invention, the humic acid-Fe composite modified anode, the preparation method and the application thereof, and the marine microbial fuel cell provided by the invention are described in detail by combining the examples below, but the invention is not to be construed as limiting the scope of the invention.
Example 1
1. The preparation method of the electrode comprises the following steps:
(1) processing carbon felt and humic acid, cutting the carbon felt into 3cm × 3cm squares, respectively immersing the squares in acetone and ethanol for 30min, washing the squares with deionized water for multiple times, drying the squares at 90 ℃, immersing the dried carbon felt in concentrated nitric acid, oscillating the squares for 2h in a water bath at 90 ℃, washing the squares to be neutral with the deionized water, drying the squares at 90 ℃ to obtain Blank anodes (Blank), weighing 2.5g of humic acid, dissolving the humic acid in 500mL of NaOH solution, adjusting the pH value to be 12, and obtaining the humic acid with the concentration of 5 g.L-1The humic acid alkali solution.
(2) And preparing the HA modified anode by an electrophoretic deposition method. 500mL of 5 g.L-1The humic acid alkali solution is used as a dispersion liquid, the pretreated carbon felt is used as an anode, the platinum electrode is used as a cathode, the distance is 2cm, the direct current voltage is applied for 20V, and the time is 1 h. After electrophoresis, washing and soaking the membrane for 24 hours by using deionized water, and drying the membrane at 90 ℃ to obtain the HA modified anode, wherein HA is successfully loaded on the carbon feltSurface, HA loading 60 wt.%.
(3) Preparing the HA-Fe composite modified anode by an electrophoretic deposition method. 2.5g humic acid is weighed and suspended in 100mL deionized water, 100mL Fe is added2(SO4)3Solution (humic acid and Fe)3+In a molar ratio of 1: 2). Adjusting the pH value to 6.5 at room temperature under the condition of continuous stirring, adding deionized water until the final volume is 500mL, stirring for 1h to obtain the humic acid-iron complex, ultrasonically dispersing to uniform suspension to obtain a dispersion liquid, using a pretreated carbon felt as an anode, using a platinum electrode as a cathode, keeping the distance between the electrodes at 2cm, and applying 20V direct current voltage for 1 h. And after electrophoresis, washing and soaking the anode by using deionized water for 24 hours, and drying the anode at 90 ℃ to obtain the HA-Fe composite modified anode. HA and Fe3+The HA-Fe complex is successfully loaded on the surface of the carbon felt, and the loading amount of the HA-Fe is 60 wt.%.
2. Battery assembly
600g of sea mud was weighed into a 500mL beaker, and the prepared anode was inserted into the sediment, overlaid with 200mL of 3.5% NaCl solution. After standing for about two weeks until the anode potential stabilized, the electrochemical properties were measured. Each group of anodes is respectively provided with 3 parallel groups for testing. The anode is connected with the cathode with enough surface area through a salt bridge, and a circuit load is a 1k omega constant value resistor to form the battery.
3. Anode surface characterization and analysis
Surface microstructure
Fig. 1 to 3 show the surface topography of different anodes, wherein fig. 1 shows the surface topography of a blank carbon felt, fig. 2 shows the surface topography of an HA modified anode, and fig. 3 shows the surface topography of an HA-Fe composite modified anode, as can be seen from fig. 1, the surface of the blank carbon felt is relatively smooth, after HA modification, sheet-shaped and granular HA is grafted or attached to the surface of the carbon felt, and part of the HA is agglomerated (fig. 2), and a large amount of film-shaped and granular HA-Fe complexes are attached to the surface of the HA-Fe composite modified anode and are distributed uniformly (fig. 3). This indicates that HA and HA-Fe modified anodes were successfully prepared by electrophoretic deposition.
Surface functional group analysis
The infrared spectra of different anodes are shown in FIG. 4, and after nitric acid oxidation, the blank carbon felt is obtainedAnd the modified carbon felt is 1720cm-1Characteristic absorption peaks of carboxylic acid C ═ O appear on the left and right, and the carbon felt peak intensity of the HA modified anode is the greatest. The modified carbon felts are all at 3470cm-1The wide peak of nuO-H appears around the filter, and is 1600-1400 cm-1Characteristic bands of benzene ring skeleton vibration appear on the left and right, and the characteristic bands are HA infrared spectrum absorption bands. HA-Fe composite modified anode at 1720cm-1The absorption peak intensity of the carboxylic acid C ═ O is weakened, which proves that HA-Fe complex is generated on the surface of the carbon felt.
Surface wettability analysis
The electrode surface contact angle test results are shown in fig. 5-7, wherein fig. 5 is a surface contact angle test chart of a blank anode, fig. 6 is a surface contact angle test chart of an HA modified anode, fig. 7 is a surface contact angle test chart of an HA-Fe composite modified anode, the contact angles of the blank anode and the HA-Fe composite modified anode are 119.5 ° and 78.12 °, respectively, and the contact angle of the HA modified anode is too small to be measured. A decrease in contact angle means an increase in electrode wettability, favoring microbial attachment. Since the HA surface contains a large number of hydrophilic groups such as-OH, -COOH, the contact angle of the modified electrode is significantly reduced. When the HA-Fe complex is formed, a part of hydrophilic groups are complexed, and thus wettability is slightly reduced.
Microorganism count characterization
The fluorescence photographs and the number statistics of the microbes on the surfaces of the anodes are shown in fig. 8-10 and table 1, the scales of fig. 8-10 are all 50 micrometers, fig. 8 is the fluorescence photograph of the microbes on the surfaces of the blank anodes, fig. 9 is the fluorescence photograph of the microbes on the surfaces of the HA modified anodes, fig. 10 is the fluorescence photograph of the microbes on the surfaces of the HA-Fe composite modified anodes, and the gray bright spots in the photographs are the microbes. After software treatment, the number of the microorganisms on the surface of the HA-Fe composite modified anode is 27445 cfu.m-2Respectively, a blank anode (15304 cfu. m)-2) And HA modified Anode (23724 cfu. m)-2) 1.80 times and 1.16 times. This shows that the anode after HA modification HAs enhanced hydrophilicity and is easier for microorganism attachment and growth, and the presence of Fe ions may attract more attachment of metal reducing bacteria, so that the number of microorganisms on the surface of the HA-Fe composite modified anode is significantly increased.
TABLE 1 statistics of microbial counts on different anode surfaces
Electrochemical performance
Cyclic voltammogram
Cyclic voltammograms and parameters of the blank anode, HA-modified anode and HA-Fe composite modified anode are shown in fig. 11 and table 2. The HA modified anode and the HA-Fe composite modified anode both have two oxidation peaks. All anodes have oxidation peaks around 0.70V, which shows that microorganisms attached to the surfaces of the anodes can catalyze and oxidize organic matters in sediments. And the oxidation peak of the HA modified anode and the HA-Fe composite modified anode at 0.80V is caused by the oxidation-reduction reaction of the quinone group in HA. The maximum oxidation peak current density of the HA-Fe composite modified anode is 0.61 A.m-2And the oxidation-reduction electrochemical activity of the HA-Fe composite modified anode is the highest as 6.1 times that of a blank anode.
The CV curves were integrated and the capacitances of the different anodes were calculated according to equation (1) and the results are reported in table 2. The capacitance characteristic of the modified anode is obviously improved, and the sequence is CHA-Fe＞CHA＞CBlankThe capacity characteristic of the HA-Fe composite modified anode is 4.2 times that of the unmodified anode, which indicates that the anode HAs the best performance.
C＝S/2νΔU (1)
Wherein S is the integral area of CV, ν is the sweep rate, and Δ U is the potential sweep range.
TABLE 2 different parameters of the cyclic voltammogram of the anode
Tafel curve
The Tafel curves and parameters of the blank anode, the HA modified anode and the HA-Fe composite modified anode are shown in fig. 12 and table 3, and it can be seen from fig. 12 that the current density at the initial stage increases rapidly with the increase of the overpotential and then changes linearly, according to the Tafel formula η ═ a + b ═ log | i |, the blank, the HA modified anode and the HA-Fe composite modified anode are calculated by linear fittingThe anode exchange current density is respectively 4.8mA · m-2、21.0mA·m-2、62.9mA·m-2. The exchange current density of the HA-Fe composite modified anode is the maximum and is respectively 13.1 times and 3 times of that of the blank anode and the HA anode, which shows that the electron transfer kinetic activity of the HA-Fe composite modified anode is the highest.
TABLE 3 different anode Tafel Curve parameters
Electrochemical impedance
Electrochemical impedance fitting curves and equivalent circuits of the blank anode, the HA modified anode and the HA-Fe composite modified anode are respectively shown in fig. 13 and 14, and fitting parameters are shown in table 4. The ohmic resistance Rs of different anodes is not greatly different, and the modified anode Rs is slightly smaller than that of a blank anode, which shows that the ohmic resistance of the material is not increased by HA modification and HA-Fe composite modification. However, the charge transfer resistance Rct of the HA modified anode and the HA-Fe composite modified anode was significantly less than that of the blank anode, 0.33 times and 0.28 times, respectively, because HA reduced the charge transfer resistance of the anode as an electron transfer mediator, resulting in a significant increase in the anode exchange current density, which is consistent with the Tafel test results (table 3 and fig. 12).
The electric double layer capacitance CPE-1 of the modified anode does not change obviously, but the biological membrane capacitance CPE-2 is increased obviously. This is due to the increased number of microorganisms on the surface of the modified anode. The resistance of the biological membrane of the HA-Fe composite modified anode is the largest, which indicates that the number of microorganisms attached to the surface of the HA-Fe composite modified anode is the largest, and the result is consistent with the fluorescence detection result (figure 10).
TABLE 4 electrochemical impedance fitting parameters
Polarization curve
Polarization curves of the blank anode, the HA modified anode and the HA-Fe composite modified anode are shown in fig. 15. The slope of the polarization curve is related to the polarization resistance of the anode, and the greater the slope, the poorer the polarization resistance. As can be seen from the figure, the order of resistance to polarization is: the HA-Fe composite modified anode is larger than the HA modified anode and is larger than the blank anode. The HA-modified anode and the HA-Fe composite modified anode were polarized to-320 mV and-339 mV when the blank anode potential was polarized to 0mV (at which time the current was 0.141mA), respectively, and the current was about 0.853mA, which was about 6 times that of the blank electrode, when the HA-Fe composite modified anode potential was polarized to 0 mV. Therefore, the HA-Fe composite modified anode HAs the best polarization resistance and the highest electrochemical activity.
Battery power density curve
The cell power density curves and parameters for the blank anode, the HA modified anode and the HA-Fe composite modified anode are shown in fig. 16 and table 5. The maximum power densities of MSMFCs constructed by the blank anode, the HA modified anode and the HA-Fe composite modified anode are respectively 25.4 mW.m-2、84.9mW·m-2、165.3mW·m-2Wherein the maximum power density of the HA-Fe composite modified anode battery is 6.5 times that of a blank anode battery and 1.95 times that of the HA modified anode battery respectively. This shows that the HA-Fe composite modified anode significantly improves the output power of MSMFCs, and the battery performance is optimal.
TABLE 5 maximum Power Density of different batteries
MSFCs constructed by using HA-Fe composite modified anode stably operate for more than 3 months, and battery power is kept at 150 mW.m-2Left and right.
HA/HA-Fe modified anode mechanism analysis
The reasons why the electrochemical performance of MSMFCs can be improved by the HA-modified anode are as follows: (1) the HA surface contains a large number of hydrophilic groups such as-OH and-COOH, so that the hydrophilicity of the anode is improved, and the attachment of microorganisms is facilitated; (2) the HA quinone group can be used as an electron transfer mediator (as shown in fig. 17), and the quinone-phenol conversion can not only improve the electron transfer rate, but also reduce the charge transfer resistance and increase the capacitance performance.
The action mechanism of the HA-Fe composite modified anode is shown in figure 18. On one hand, the HA-Fe composite modified anode attracts the attachment of metal reducing bacteria by iron ions, so that the types of microorganisms are increased, and the quantity of generated electrons is increased; on the other hand, iron ions are converted by Fe (II) and Fe (III) ions, and electron transfer is accelerated. However, the modified HA layer and the large amount of surface microorganisms can increase the resistance of the anode and affect the electron transfer rate. The HA-Fe composite modified anode HAs optimal performance by integrating the synergistic effect of humic acid and iron ions.
Example 2
1. The preparation method of the electrode comprises the following steps:
(1) processing carbon felt and humic acid, cutting the carbon felt into 3cm × 3cm squares, respectively immersing the squares in acetone and ethanol for 30min, washing the squares with deionized water for multiple times, drying the squares at 90 ℃, immersing the dried carbon felt in concentrated nitric acid, oscillating the squares for 2h in a water bath at 90 ℃, washing the squares to be neutral with the deionized water, drying the squares at 90 ℃ to obtain Blank anodes (Blank), weighing 3g humic acid, dissolving the humic acid in 500mL NaOH solution, adjusting the pH value to 12 to obtain the humic acid with the concentration of 6 g.L-1The humic acid alkali solution.
(2) And preparing the HA modified anode by an electrophoretic deposition method. 500mL of 6 g.L-1The humic acid aqueous alkali is used as a dispersion liquid, the pretreated carbon felt is used as an anode, a platinum electrode is used as a cathode, the distance is 2cm, the direct current voltage is applied for 30V, and the time is 2 h. And after electrophoresis, washing and soaking the carbon felt by deionized water for 24 hours, and drying the carbon felt at 90 ℃ to obtain the HA modified anode, wherein HA is successfully loaded on the surface of the carbon felt, and the loading amount of the HA is 80 wt.%.
(3) And brushing to prepare the HA-Fe composite modified anode. 3g humic acid is weighed and suspended in 100mL deionized water, 100mL Fe is added2(SO4)3Solution (humic acid and Fe)3+In a molar ratio of 1: 2). Adjusting the pH value to 7 at room temperature under the condition of continuous stirring, adding deionized water until the final volume is 500mL, stirring for 3h to obtain a humic acid-iron complex, performing ultrasonic dispersion to obtain uniform suspension to be used as dispersion liquid, coating the dispersion liquid on the surface of a pretreated carbon felt, and drying at 90 ℃ to obtain the HA-Fe composite modified anode. HA and Fe3+The HA-Fe complex is successfully loaded on the surface of the carbon felt, and the loading amount of the HA-Fe is 80 wt.%.
2. Battery assembly
600g of sea mud was weighed into a 500mL beaker, and the prepared anode was inserted into the sediment, which was covered with 200mL of 3.5% NaCl solution (artificial seawater). After standing for about two weeks until the anode potential stabilized, the electrochemical properties were measured. Each group of anodes is respectively provided with 3 parallel groups for testing. The anode is connected with the cathode with enough surface area through a salt bridge, and a circuit load is a 1k omega constant value resistor to form the battery. The test results were similar to example 1.
Example 3
The same as example 1, except that HA and Fe were contained in the obtained HA-Fe composite modified anode3+The HA-Fe complex was successfully loaded on the surface of the carbon felt, with the HA-Fe loading amount being 10 wt.%, and the performance of the HA-Fe composite modified anode obtained in this example was tested, with the following results:
surface wettability analysis: the surface contact angle of the HA-Fe composite modified anode obtained in this example was 102.6 °.
And (3) microorganism quantity characterization: the microbial count on the surface of the HA-Fe composite modified anode obtained in the example is 19756cfu m-2The relative multiple was 1.29.
Electrochemical performance: the HA-Fe composite modified anode obtained in the example HAs the maximum oxidation peak current density of 0.15 A.m-21.5 times that of the blank anode, 1.7 times that of the unmodified anode, and 9.79mA · m of exchange current density-2The maximum power density is 31.1 mW.m-2。
Example 4
The same as example 1, except that HA and Fe were contained in the obtained HA-Fe composite modified anode3+The HA-Fe complex was successfully loaded on the surface of the carbon felt, with the HA-Fe loading amount being 30 wt.%, and the performance of the HA-Fe composite modified anode obtained in this example was tested, and the results are as follows:
surface wettability analysis: the surface contact angle of the HA-Fe composite modified anode obtained in the embodiment is 89.03 degrees.
And (3) microorganism quantity characterization: the number of microorganisms on the surface of the HA-Fe composite modified anode obtained in this example was 22003cfu · m-2The relative multiple was 1.43.
Electrochemical performance: the HA-Fe composite modified anode obtained in the example HAs the maximum oxidation peak current density of 0.29 A.m-22.9 times that of the blank anode, the capacitance characteristic of the anode is 3.1 times that of the anode without modification, and the exchange current density is 28.6mA · m-2Maximum power density of 78.2 mW.m-2。
The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be construed as the protection scope of the present invention.
Claims (10)
1. The humic acid-Fe composite modified anode is characterized by comprising an electrode substrate and a humic acid-Fe (III) complex loaded on the surface of the electrode substrate.
2. The humic acid-Fe composite modified anode of claim 1, wherein the loading amount of the humic acid-Fe (III) complex in the humic acid-Fe composite modified anode is 10 wt.% to 80 wt.%.
3. The humic acid-Fe composite modified anode according to claim 1 or 2, wherein humic acid and Fe in the humic acid-Fe (III) complex3+In a molar ratio of 1: 1.5 to 2.5.
4. The preparation method of the humic acid-Fe composite modified anode as claimed in any one of claims 1 to 3, which is characterized by comprising the following steps:
pretreating the electrode to obtain an electrode matrix;
mixing humic acid and soluble Fe3+Mixing salt and water, adjusting the pH value to 6-7, and performing a complexing reaction to obtain a suspension;
carrying out electrophoretic deposition by taking the electrode substrate as an anode, a platinum electrode as a cathode and the suspension as dispersion liquid to obtain the humic acid-Fe composite modified anode;
or
And brushing the turbid liquid on the surface of the electrode substrate, and drying to obtain the humic acid-Fe composite modified anode.
5. The production method according to claim 4, wherein the pretreatment comprises acetone ultrasonic cleaning, ethanol ultrasonic cleaning, first water washing, first drying, nitric acid soaking, second water washing, and second drying, which are performed in this order.
6. The preparation method according to claim 4, wherein the time of the complexation reaction is 1-3 h.
7. The preparation method according to claim 4, wherein the electrode spacing of the electrophoretic deposition is 2-4 cm, the DC voltage is 5-30V, and the time is 1-2 h.
8. The method according to claim 4 or 7, wherein after the electrophoretic deposition, the electrophoretic deposition product is sequentially washed and soaked with water and then dried.
9. Use of the humic acid-Fe composite modified anode of any one of claims 1 to 3 or the humic acid-Fe composite modified anode prepared by the preparation method of any one of claims 4 to 8 in a submarine microbial fuel cell.
10. A seabed microbial fuel cell, which is characterized by comprising the humic acid-Fe composite modified anode of any one of claims 1 to 3 or the humic acid-Fe composite modified anode prepared by the preparation method of any one of claims 4 to 8, wherein the humic acid-Fe composite modified anode is placed in seabed sediments, a cathode is placed in seawater, and the interface between the seabed sediments and the seawater is used as a natural proton exchange membrane.
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080221314A1 (en) * | 2007-03-07 | 2008-09-11 | Timac Agro Espana, S.A. | Heteromolecular metal-humic (chelate) complexes |
| US20100227203A1 (en) * | 2006-02-14 | 2010-09-09 | Magneto Special Anodes B.V. | Device Comprising a New Cathode and Method for Generating Electrical Energy with Use Thereof |
| WO2011025021A1 (en) * | 2009-08-31 | 2011-03-03 | 独立行政法人科学技術振興機構 | Electrode for microbial fuel cell, and microbial fuel cell using same |
| CN102509809A (en) * | 2011-12-27 | 2012-06-20 | 中国海洋大学 | Method for constructing ocean sediment microbial fuel battery with high output voltage and high output power |
| WO2015016238A1 (en) * | 2013-07-31 | 2015-02-05 | 国立大学法人名古屋大学 | Electron transfer system and application for same |
| CN104766981A (en) * | 2015-05-05 | 2015-07-08 | 合肥工业大学 | Fuel cell operation technology for improving regeneration rate and electricity generating efficiency of complex iron in desulfuration process |
| CN105489908A (en) * | 2016-01-13 | 2016-04-13 | 中国科学院广州能源研究所 | Application of humic acid composite biochar in microbial fuel cell and preparation method of humic acid composite biochar |
| CN108328718A (en) * | 2018-04-24 | 2018-07-27 | 南京林业大学 | A kind of generating means of fulvic acid chelated iron ion |
| CN110247091A (en) * | 2019-06-28 | 2019-09-17 | 昆明理工大学 | A method of accelerate electroactive microorganism to carry out extracellular electron transfer process |
| CN110877952A (en) * | 2018-09-06 | 2020-03-13 | 中国石化扬子石油化工有限公司 | Composite system for assisting in strengthening anaerobic sludge digestion by microbial fuel cell |
-
2020
- 2020-06-24 CN CN202010589363.9A patent/CN111682229B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100227203A1 (en) * | 2006-02-14 | 2010-09-09 | Magneto Special Anodes B.V. | Device Comprising a New Cathode and Method for Generating Electrical Energy with Use Thereof |
| US20080221314A1 (en) * | 2007-03-07 | 2008-09-11 | Timac Agro Espana, S.A. | Heteromolecular metal-humic (chelate) complexes |
| WO2011025021A1 (en) * | 2009-08-31 | 2011-03-03 | 独立行政法人科学技術振興機構 | Electrode for microbial fuel cell, and microbial fuel cell using same |
| CN102509809A (en) * | 2011-12-27 | 2012-06-20 | 中国海洋大学 | Method for constructing ocean sediment microbial fuel battery with high output voltage and high output power |
| WO2015016238A1 (en) * | 2013-07-31 | 2015-02-05 | 国立大学法人名古屋大学 | Electron transfer system and application for same |
| CN104766981A (en) * | 2015-05-05 | 2015-07-08 | 合肥工业大学 | Fuel cell operation technology for improving regeneration rate and electricity generating efficiency of complex iron in desulfuration process |
| CN105489908A (en) * | 2016-01-13 | 2016-04-13 | 中国科学院广州能源研究所 | Application of humic acid composite biochar in microbial fuel cell and preparation method of humic acid composite biochar |
| CN108328718A (en) * | 2018-04-24 | 2018-07-27 | 南京林业大学 | A kind of generating means of fulvic acid chelated iron ion |
| CN110877952A (en) * | 2018-09-06 | 2020-03-13 | 中国石化扬子石油化工有限公司 | Composite system for assisting in strengthening anaerobic sludge digestion by microbial fuel cell |
| CN110247091A (en) * | 2019-06-28 | 2019-09-17 | 昆明理工大学 | A method of accelerate electroactive microorganism to carry out extracellular electron transfer process |
Non-Patent Citations (1)
| Title |
|---|
| SHUNGUI ZHOU ET AL: "Influence of Humic Acid Complexation with Metal Ions on Extracellular Electron Transfer Activity", 《SCIENTIFIC REPORTS》 * |
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