Performance of anaerobic fluidized bed microbial fuel cell with different porous anodes

CJCHE-01576; No of Pages 8 Chinese Journal of Chemical Engineering xxx (xxxx) xxx

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Article

Performance of anaerobic fluidized bed microbial fuel cell with different porous anodes Xiuli Zhang 1,2, Chunhu Li 1,⁎, Qingjie Guo 2,⁎, Kelei Huang 1 1

Key Laboratory of Marine Chemistry Theory and Engineering Technology of Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China Key Laboratory of Clean Chemical Processing of Shandong Province, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, China

2

a r t i c l e

i n f o

Article history: Received 19 March 2019 Received in revised form 25 September 2019 Accepted 10 October 2019 Available online xxxx Keywords: Circulating fluidized bed Multiphase flow Porous anodes Anode modification Electrochemistry

a b s t r a c t Anode materials were used to construct microbial fuel cells (MFCs), and the characteristics of the anodes were important for successful applied performance of the MFCs. Via the cyclic voltammetry (CV) method, the experiments showed that 5 wt% multiwalled carbon nanotubes (MWNTs) were optimal for the PANI/MWNT film anodes prepared using 24 polymerization cycles. The maximum output voltage of the PANI/MWNT film anodes reached 967.7 mV with a power density of 286.63 mW·m−2. Stable output voltages of 860 mV, 850 mV, and 870 mV were achieved when the anaerobic fluidized bed microbial fuel cell (AFBMFC) anodes consisted of carbon cloth with carbon black on one side, copper foam and carbon brushes, respectively. Pretreatment of the anodes before starting the AFBMFC by immersion in a stirred bacterial fluid significantly shortened the AFBMFC startup time. After the AFBMFC was continuously run, the anode surfaces generated active microbial catalytic material. © 2019 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.

1. Introduction Sewage and industrial organic wastewater is produced by biomass sent to a sewage treatment plant. Treatment of sewage and industrial organic wastewater consumes a large amount of energy. Anaerobic treatment technology provides the potential to cut treatment and operating costs [1]. Microbial fuel cells, which are new technologies to process wastewater while simultaneously producing electricity [2–4], can solve these problems. To date, the main challenge is to obtain sufficient power density and a large as possible optimal voltage. However, the maximum voltage hardly exceeds the theoretical open circuit voltage (OCV). The open circuit voltage of the air cathodes used in the MFC with acetate as the substrate is 1.105 V, even when neglecting the internal resistance loss [5]. Anode materials and their characteristics are key factors in determining whether the performance of MFCs will be successful. The successful performance of MFCs has an important influence on bacterial adsorption, electron transfer, matrix oxidation, and so on. A large number of materials have been applied for the preparation of microbial fuel cells. Anode materials are characterized by their high internal resistance which limits power generation. However, increasing the anode surface area may not appreciably affect the power output. Huang et al. [6] utilized different metals as the anodes of a twochamber MFC, suggesting that metals perform better as anodes. Metals, ⁎ Corresponding authors. E-mail addresses: [email protected] (C. Li), [email protected] (Q. Guo).

however, have unsatisfactory stability, especially when corrosive organic sewage is used as the matrix. The current densities obtained using graphite rods, graphite felt or graphite foam as the anode material were thoroughly examined by Chaudhuri et al. [7], who found that the total accessible geometrical (projected) surface area was the primary factor producing the main differences in current density. Huang et al. [8] compared carbon paper, graphite and carbon felt materials and investigated the influence of five different anodes on the power generation performance of MFCs. Li et al. [9] performed a comparison between a conventional carbon cloth anode and a granular activated carbon anode in a dual-chamber MFC. The results of the comparison indicated that a large specific surface area was responsible for a granular activated carbon anode achieving better performance in the MFC. However, the particulate carbon easily filled the anode chamber, leading to plugging and difficulty in cleaning up the MFC. In this paper, a liquid–solid fluidized bed is combined with a singlechamber air cathode MFC reactor to construct an anaerobic fluidized bed microbial fuel cell (AFBMFC). A membrane-less anaerobic fluidized bed microbial fuel cell (AFBMFC), combed with the fluidized bed system with a single-chamber air cathode MFC, is a device that can directly produce electricity from the bacterial oxidation of organic substances. The AFBMFC is characterized by good backmixing, high reaction area, high transfer rate, etc. The flow rate of the AFBMFC was controlled to overcome the susceptibility of the fiber caking. To compare different anode materials in AFBMFC, several anodes with large surface areas were selected to evaluate the performance of the AFBMFC with each of the anodes. The anode materials were prepared with a PANI/MWNT

https://doi.org/10.1016/j.cjche.2019.10.002 1004-9541/© 2019 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.

Please cite this article as: X. Zhang, C. Li, Q. Guo, et al., Performance of anaerobic fluidized bed microbial fuel cell with different porous anodes, Chinese Journal of Chemical Engineering, https://doi.org/10.1016/j.cjche.2019.10.002

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composite film using a cyclic voltammetry (CV) method. Other candidate anode materials included carbon cloth with a coated carbon black layer on one side, copper foam, and a carbon fiber brush.

Table 1 Properties of fresh active carbon particles Average size distribution/mm

Bulk density/mg·m−3

True density/mg·m−3

Porosity

0.45–0.90

566

1150

0.45

2. Materials and Methods 2.1. Experimental apparatus As illustrated in Fig. 1, the AFBMFC was composed of a plexiglass fluidized bed 40 mm in diameter and 600 mm in height. The AFBMFC consisted of a cathode and a porous anode made of a carbon cloth (3.14 cm2, 0.35 mg·cm−2 Pt) and coated with four diffusion layers fixed onto one side of the chamber wall. In this test, fresh active carbon particles (60 g) with the particulate properties listed in Table 1 were used as the carrier medium for the biofilm. The distributor was a porous glass plate with a thickness of 2 mm, a pore size of 2 mm, and a fractional perforated area of 20%. 2.2. MFC inoculation and operation The AFBMFC was inoculated with 150 ml of anaerobic sludge collected from the wastewater treatment plant in Qingdao, China. Mixed microbial cultures were more suitable for complex fuels such as wastewater because single organisms generally metabolized only a limited range of organic compounds. Wastewater, collected from a restaurant at a university, was used as the fluidization liquid and pumped by a peristaltic pump. The pH of the solution in the anode chamber was initially adjusted to approximately 7. Generally, the circulating wastewater was kept at 30 °C by a thermostated water bath tank. AFBMFC experiments were generally performed at 30 °C unless otherwise specified [10]. To run the AFBMFC continuously, the feed solution was replaced when the voltage dropped below 50 mV, representing one complete cycle of operation.

2.3. Preparation of anodes 2.3.1. Pretreatment of the multi walled carbon nanotubes (MWNT) The performance of the commercial MWNTs used in this experiment is shown in Table 2. MWNTs have excellent performance, but acid treatment [11] is necessary to remove the amorphous carbon chopped impurities, connect the corresponding functional groups, and increase dispersal in an acid solution. 2.3.2. Preparation of the anodes by an electrochemical method Prior to each electrochemical synthesis, the working electrode was carefully polished with abrasive paper and then washed with distilled water. The electrode was then scanned and activated in 1 mol·L−1 sulfuric acid solution, with the voltammetric sweep varying between −0.5 V and 1.5 V/SCE, at 50 mV·s−1. The scanning process continued until a stable CV curve was observed. The CV method was utilized with a three electrode systems. During the electrochemical synthesis, hydrochloric acid was used as the proton-bearing acid with a concentration at 1 mol·L−1 in the electrolyte. The aniline concentration was 0.1 mol·L−1. Different scanning laps were used to prepare PANI/ MWNT film anodes. 2.3.3. Preparation of common anodes Carbon cloth with carbon black (NOK Co., Japan) coating on one side, carbon fiber brushes (Anhui Jialiqi Carbon Fiber Co., China) and copper foam (Jilin Zhuoerkeji Co., China) served as anodes. The anode has an area of 15 mm × 60 mm with one side connected using conducting wire. Fig. 2 depicts the microscopic surface structure of the carbon cloth with a carbon black layer. As illustrated in Fig. 2(a), there are numerous interspaces where carbon fibers were intermeshed, and the diameter of the carbon fibers ranged from 7 μm to 10 μm. Fig. 2 (b) indicates that the carbon black layer has fine granularity (approximately 50 nm) and exhibits a granular structure that is round in shape. Table 3 shows the properties of the carbon fibers. The carbon brush has a mass of approximately 1.2 g with a diameter of 40 mm. The copper foam is characterized as having a porosity of 95.11%. 2.4. Calculation method The electronic potential across the resistor was sampled every 2 min using a multimeter with a data acquisition system (USB1608FS, Measurement Computing Co., USA). For each batch experiment, polarization data were collected by changing the external resistance from 30 Ω to 90 kΩ using a variable resistor box. The current, power density, resistance, COD removal rate (national standard: GB11914-89), and Coulomb efficiency were calculated using Eqs. (1), (2), (3), (4), and (5), respectively:

I¼

U R

ð1Þ

Table 2 Properties of multi-walled carbon nanotubes Diameter/nm Length/μm Purity/wt Ash/wt SSA/m2·g−1 Conductivity/S·cm−1 % % Fig. 1. Schematic diagram of the AFB-MFC 1. Fluidized bed 2. Cylinder graphite rod 3. Active carbon/graphite 4. Distribution plate 5. A peristaltic pump 6. Water storage tank 7. Copper wire 8 Resistance 9. Voltage acquisition system 10. A carbon cloth.

8–15

~50

N95

b1.5

N233

N102

Note: Specific surface area (SSA).

Please cite this article as: X. Zhang, C. Li, Q. Guo, et al., Performance of anaerobic fluidized bed microbial fuel cell with different porous anodes, Chinese Journal of Chemical Engineering, https://doi.org/10.1016/j.cjche.2019.10.002

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Fig. 2. SEM images of carbon fiber cloth (a) carbon fiber layer; (b) carbon black layer).

Table 3 Properties of carbon fibers with different specifications Specification

Linear density/mg·m−1

Tensile strength/GPa

Tensile modulus/GPa

Carbon content/%

Resistance/Ω·m−1

1K

66.5

4.00

218

≥93

440

P¼

UI U 2 ¼ RA RA

U ¼ −rI þ U ocv

ð2Þ ð3Þ

3. Results and Discussion 3.1. Electrochemical impedance spectroscopy (EIS) studies

where U is the voltage, P is the power density, R is the external resistance, UOCV is the open-circuit voltage, r is the internal resistance, and A is the geometric surface area of the anode electrode. T is the reaction time, V is the liquid volume in the reactor, △COD is the change in COD, MO 2 is the molecular weight of oxygen, I is the current, Faraday's constant is equal to 96,485 °C·mol−1, and b is the mole number of electrons exchanged per mole of oxygen (4 mol−1) [12,13].

EIS measurements were used to examine the characteristics of charge transfer and ion transport in the PANI/MWNT composite made from different laps. Fig. 3 shows single semicircles over the high frequency range followed by short straight lines in the low-frequency region for all anodes. The equivalent circuit diagram of Fig. 3 was applied to fit the measured EIS results, and the fitting curves are drawn in Fig. 4. Fig. 4 shows that the total resistance of all anodes gradually decreased with the polymerization laps. The electrochemical reaction resistance (Rct) and diffusion resistance (Ws) decreased, whereas the solution resistance (Rs) was nearly invariable. The Rct is primarily responsible for the internal resistance. The interaction between polyaniline (PANI) and MWNT promotes the charge transfer in the PANI/MWNT composite as expected. The MWNTs show an obvious

Fig. 3. EIS of anodes made in different cycles by the CV method (Nyquist plot).

Fig. 4. Scattergram of resistance for every part.

C 0 −C i  100% B¼ C0 CE ¼

R Idt q  100% ¼  100% qth ð F  b  V  ΔCODÞ=MO2

ð4Þ

ð5Þ

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Fig. 6. Polarization curve and power density curve for different AFBMFC anodes. Fig. 5. Voltage curve of AFBMFC for one cycle.

improvement in making the charge transfer rate faster due to the favorable electrical conductivity. The film anodes not only improve the electrode conductivity but also provide increased specific surface area, possibly due to the specific nanostructure of the film anode, which favors the host bacteria and provides an efficient degradation ability for wastewater. The thick film falls off the electrode surface when it is dry. Cycling the prepared anodes for 32 laps could decrease the resistance. Anode preparation should therefore choose the appropriate number of laps ranging from 20 to 30. In the present test, the performance of anodes made in 24 laps was explored in the AFBMFC. 3.2. Voltage variations in one cycle Fig. 5 reveals the voltage curve of the AFBMFC with different anodes in continuous cycles. The PANI/MWNT film anode AFBMFC exhibited excellent performance with regard to voltage stability with an initial stable voltage of approximately 850 mV and a stable voltage of 950 mV for four days after working for 30 h. The maximum output voltage was 967.7 mV. However, as shown in Fig. 5, the output voltage decreased gradually after 150 h. The average voltage in one cycle is approximately 800–900 mV, while the maximum average output voltage is 897.6 mV with the carbon cloth serving as the anode. When the voltage reached a high value, the voltage remained constant for a long time. After 150 h of operation, the rate of voltage reduction increased significantly, while the COD removal rate increased to 79.5%. When the carbon brush anode was used in the AFBMFC, the voltage was stable at 870 mV for the first 120 h. The voltage then decreased significantly while the COD removal efficiency approached 77.2%; this result was possibly due to the decrease in organic matter and the degradation of organic matter in sewage because of the consumption of organic matter by anaerobic bacteria to produce electricity. The stability of the copper foam anode in the AFBMFC is inferior to the stability of both the carbon cloth and carbon brush anodes. The voltage of the copper foam anode was stable at 850 mV for the first 100 h. Then, there was a significant declining trend owing to the increased concentration of Cu2+ over the working time interval, which was the result of corrosion. The Cu2+ restrained the growth of the microorganisms, even poisoning the bacterial cell structure. The output voltage therefore decreased more quickly than the output voltage of the carbon cloth anode in the AFBMFC, and the sustained performance of the copper foam anode was difficult over a long period of time. 3.3. Power density and polarization curve The polarization and power density curves for different AFBMFC anodes are delineated in Fig. 6. The maximum output voltage, power

density, and open circuit voltage of AFBMFC for various anodes were recorded and are shown in Table 4. The open circuit voltages of 1.025 V, 1.026 V and 1.044 V were obtained when the carbon cloth anode, carbon brush anode and copper foam anode were used in AFBMFC. The carbon cloth anode and carbon brush anode were found to have equal open circuit voltage values. However, the copper foam AFBMFC anode had the highest open circuit voltage because of the good electrical conductivity of copper, which enhanced the electron transfer. The open circuit voltage of the three types of AFBMFC anode was approximately 1.105 V. The electrochemical method [14–16] is an effective way to prepare anodes. The PANI/MWNT film anode had a maximum output voltage and power density of 907.4 mV and 222.2 mW·m−2, respectively. Fitting these values to the polarization curve of Eq. (3), the apparent resistance approaches 973.6 Ω. This value of 973.6 Ω is responsible for the low voltage and power output compared with the workable voltage of 3 V. The apparent resistance of MFCs includes three main parts [17–19]: ohm resistance, activation resistance, and concentration differential resistance. The ohm resistance is dominant because the transmission of electrons or ions is hampered by the electrolyte. The activation resistance is caused by the activation reaction on the electrode surface. The concentration differential resistance depends on the low diffusion speed of the reactant to the electrode surface or the low speeding of the reaction products in the solution.

Table 4 Values of maximum voltage and power density for every anode Anodes/project

Maximum voltage/mV

Power density/mW·m−2 anode area

Open-circuit voltage/mV

Carbon cloth on one side is carbon black Copper foam Carbon brush PANI film PANI/MWNT film (CV method, 24 laps) Ammonia treatment of carbon cloth[14] Graphite fiber brush[15] Multiwall carbon nanotubes on carbon cloth[11] Conductive polymers coated with carbon felt [16] Metallic copper[6] Reticulated vitreous carbon [17]

897.6

170.7

1.025

870.6 907.4 735 967.7

115.9 222.2 135 286.63

1.044 1.026 – –

500–560

1970

825

580–600 190

2400 (cathode area) 44–65

800 –

600

27.4

–

380 750

– 170

450 750

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Fig. 7. SEM images of PANI/MWNT film anode (a: before running of AFBMFC; b: after running of AFBMFC).

The AFBMFC fluidized bed combined with the MFC could mix the matrix completely with a high-efficiency mass transfer, reducing the concentration differential resistance. The fluidization particles (coconut shell activated carbon) barely make complete contact with the anodes and could reduce the electronic recovery, leading to a large apparent resistance. AFBMFC is a direct-air cathode single-chamber microbial fuel cell, and Liang et al. [20]found that the air cathode MFCs have a high ohm resistance. A reduction in the ohm resistance and activation resistance can lower the internal resistance of the AFBMFC. The method of increasing the electrode area, which improves the anode shape, enhances the ionic strength, optimizes the operating conditions, and domesticates the highly active microorganisms, can reduce the internal resistance of the AFBMFC. Scanning electron micrograph (SEM) images of the PANI/MWNT film anodes made using the CV method (5 wt% MWNT incorporating 24 laps) are presented in Fig. 7. The PANI/MWNT composite films have a networked rod nanostructure, and the surface of the films has many raised folded shapes to increase the surface area and the specific surface area, providing many growing points for the microorganisms. The surface of the PANI/MWNT film anode forms a membrane-shaped material containing the microorganisms and their metabolites. The transmission of electrons and protons, as well as the improvement of the degradation speed of the organic matter in sewage, is therefore easier. Transmission electron microscopy of the MWNT and PANI/MWNT composite films is shown in Fig. 8. The diameter of the MWNT varies from 8 to 15 nm with a hollow tubular structure. The term “PANI/ MWNT” emphasizes that the outer layer is PANI and the inner layer is

MWNT. The amorphous and lamellate outer PANI layer has a thickness of 80–100 nm. The Π combined key between PANI and MWNT [21] improves the stability of the PANI/MWNT composite films and avoids the poisoning of the microbes of the MWNT. 3.4. SEM analysis of the carbon cloth anode The microscopic structures of the carbon fiber layer and carbon black layer are described in Fig. 9. Fig. 9(a) and (b) delineates the carbon cloth layer, exhibiting materials containing microbes with their metabolites on the surface of the carbon fiber. The materials on the carbon cloth surface combine closely with the carbon fiber to produce electrons, protons, etc., by decomposing organic matter. Electrons were then transferred to the anode directly. Fig. 9(c) and (d) explains the morphology of single bacteria on the carbon black layer. The lengths of the microbes in Figs. 9(c) and (d) are 1.8 μm and 6.5 μm, respectively. A comparison of the four pictures demonstrates that there are mixed bacteria on the anode. Through competitive growth, mixed microbes disintegrate sewage and generate electricity. 3.5. CV curve The cyclic voltammograms of the carbon cloth electrode and the carbon brush electrode immersed in 1 mmol⋅L-1 K4Fe(CN)6/1 mmol⋅L-1 K3Fe(CN)6/0.1 mol⋅L-1 KCl solution [22], as indicated in Figs. 10 and 11, demonstrate the electrocatalytic behavior of the electrode material. The series of CV experiments was conducted at the original value of −1.0 V with a scanning voltage in the range of − 1.0–1.0 V while the

Fig. 8. TEM images of acidulated MWNTs and PANI/MWNT film anode. (a: prepared by the acidized method; b: prepared by the method of CV).

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Fig. 9. SEM images of carbon fiber cloth with biomembrane. (a and b: carbon fiber layer; c and d: carbon black layer).

scanning speed was 25 mV·s−1. Oxidation–reduction peaks emerge if oxidation/reduction reactions are observed in the process of scanning, which determines the oxidation–reduction potential of the redox material [23] as well as giving insight on the microbial electrochemical activity [18,24]. Figs. 10 and 11 show that the unused carbon cloth anode has a very small redox current d-value without any peaks. When the used carbon cloth anode was tested under the same conditions, − 0.1 V, 0.1 V and 0.5 V emerged as obvious oxidation peaks, and 0.1 V and −0.5 V were the two reduction peaks. The electrically active material on the surface of the used anodes was observed consistent with the report of Zou et al. [21]. The carbon fiber brush anode was tested under the same conditions as those for the carbon cloth anode. A distinct increase

in the oxidation peak at 0.5 V and the reduction peak at 0.1 V and 0.5 V was observed. 3.6. COD changing The COD removal efficiencies are summarized in Table 5, which reveals that the PANI/MWNT film anode made from 24 laps with the CV method exhibited better performance and increased the consumption of organic matter. The Coulomb efficiency is not high, approximately 6%–7%. It is therefore imperative to further improve the electronic recovery from wastewater. Electron transport in the MFC is basically dependent on three

Fig. 10. CV curve of carbon fiber cloth anode.

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Fig. 11. CV curve of carbon fiber brush.

presented in Fig. 13, the minimum resistance value of 541 Ω emerged on the fifth day. Given the consumption due to the reaction substrate, the resistance increases from the fifth day, adding enough resistance.

Table 5 Removal of COD and the Coulomb efficiency Project/anode

Carbon anode

Carbon brush

Copper anode

PANI/MWNT film anode

Removal of COD/%

93.17

92.99

92.14

95.29

mechanisms: electron shuttling via self-produced mediators or chemical mediators, nanowires and cytochrome. The MWNT doping in film anodes facilitated the electronic recovery because of the increasing electrode surface area. However, electronic recovery is very low with different anodes in the AFBMFC. Mixed bacteria were used in this experiment, so the ability to produce electrons was reduced because of the oxidation of the organic substrate by methanogenic and thiogenic bacteria, etc. [13]. In particular, the internal resistance is higher. Further study is needed to reduce such internal resistance.

3.7. Relationship of the resistance and power density The resistance and power density were measured every day, and the curve of resistance and power versus time was plotted as presented in Fig. 12. The resistance was high in the beginning, then decreased, and the minimum resistance value of 452 Ω emerged on the fifth day. Because of a shortage of the biomass matrix, the resistance increased from the fifth day. Adequate matrix and increasing operation time are suggested to make the AFBMFC resistance remain at a low level. As

Fig. 12. Resistance and power density of carbon brush anode in the AFBMFC over time.

4. Conclusions In this paper, organic cooking wastewater was used as a substrate to study the electrical properties and wastewater treatment performance of composite membrane anodes directly synthesized by electrochemical methods for an AFBMFC, and several anode materials with large specific surface areas were compared. The composite film anode with 5 wt% MWNT content has the best performance, the maximum voltage reaches 926.5 mV, the maximum power density is 112.3 mW·m-2, and the COD removal rate reaches 95.3% after one cycle. A higher output voltage can be obtained using a porous carbon cloth anode and a large specific surface area carbon brush anode in the AFBMFC. In the experiment, those anodes have stable voltages of approximately 860 mV and 870 mV, respectively. Microbial precoating of the anode before starting can significantly shorten the startup time of the MFC and achieves a higher output voltage within a few hours, which can greatly reduce the cycle time of the treated sewage. With increasing running time, the internal resistance first increases and then decreases, and to ensure an adequate matrix, it may be appropriate to increase the number of days of the operation so the internal resistance of AFBMFC is maintained at a relatively low level. Nomenclature A anode area, m2 B removal of COD b mole number of electrons exchanged per mole of oxygen, 4 mol−1

Fig. 13. Resistance and power density of carbon cloth anode in the AFBMFC over time.

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C CE C0, Ci D F I L M MO2 N P Q q, qth R r t U UOCV V

1 C = electrical quantity consisting of 1.6 ∗ × 1019 electrons Coulomb efficiency chemical oxygen demand of wastewater before and after the operation, g·L−1 diameter of MWNT, nm Faraday's constant, 96,485 °C·mol−1 current, mA length of MWNT, μm amount of substance, mol·L−1 molecular weight of oxygen, 32 g·mol−1 polymerization laps output power density, mW⋅m−2 cathode sedimentary power, C harvestable electric quantity and theoretical maximum electric quantity, C load resistance, Ω internal resistance of MFC, Ω reaction time, s output voltage, mV open-circuit voltage, mV matrix volume, L

Acknowledgments The authors gratefully acknowledge the support from the National Key R&D program (2018YFB06050401), Key R&D program of the Ningxia Hui Autonomous Region (2018BCE01002), National Natural Science Foundation of China (21868025), and the Key Research & Development Program of Shandong Province (2018GGX104013). References [1] H. Liu, B.E. Logan, Electricity generation using an air-cathode single chamber microbial fuel cell in the presence and absence of a proton exchange membrane, Environ Sci Technol. 38 (14) (2004) 4040–4046. [2] P.L. Cloirec, Adsorption onto activated carbon fiber cloth and electrothermal desorption of volatile organic compound (VOCs): A specific review, Chin. J. Chem. Eng. 20 (3) (2002) 461–468. [3] J.R. Rao, G.J. Richter, F. Von Sturm, E. Weidlich, The performance of glucose electrodes and the characteristics of different biofuel cell constructions, Bioelectrochem. Bioenerg. 3 (1976) 139–150. [4] B.E. Logan, J.M. Regan, Microbial fuel cells-challenges and applications, Environ Sci Technol. 40 (17) (2006) 5172–5180. [5] Weifang Kong, Qingjie Guo, Xuyun Wang, Electricity generation from wastewater using an anaerobic fluidized bed microbial fuel cell, Industrial Engineering Chemical Research. 50 (21) (2011) 12225–12232.

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Please cite this article as: X. Zhang, C. Li, Q. Guo, et al., Performance of anaerobic fluidized bed microbial fuel cell with different porous anodes, Chinese Journal of Chemical Engineering, https://doi.org/10.1016/j.cjche.2019.10.002