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Continuous electrochemical deionization by utilizing the catalytic redox effect of environmentally friendly riboflavin-5'-phosphate sodium
Journal Pre-proof Continuous Electrochemical Deionization by Utilizing the Catalytic Redox Effect of Environmentally Friendly Riboflavin-5’-phosphate Sodium Qi Zhang, Su Htike Aung, Than Zaw Oo, Fuming Chen
PII:
S2352-4928(19)31543-0
DOI:
https://doi.org/10.1016/j.mtcomm.2020.100921
Reference:
MTCOMM 100921
To appear in:
Materials Today Communications
Received Date:
30 November 2019
Accepted Date:
13 January 2020
Please cite this article as: Qi Z, Su HA, Than ZO, Fuming C, Continuous Electrochemical Deionization by Utilizing the Catalytic Redox Effect of Environmentally Friendly Riboflavin-5’-phosphate Sodium, Materials Today Communications (2020), doi: https://doi.org/10.1016/j.mtcomm.2020.100921
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2020 Published by Elsevier.
Continuous Electrochemical Deionization by Utilizing the Catalytic Redox Effect of Environmentally Friendly Riboflavin-5'-phosphate Sodium
Qi Zhanga, Su Htike Aungb*, Than Zaw Oob, Fuming Chena,*
Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South
China Normal University 510006
b
ro of
a
Department of Physics, University of Mandalay, Myanmar, 100103
-p
E-mail: [email protected]; [email protected]
re
Highlights:
The environmentally friendly and non-toxic FMN-Na was used as redox catalysis.
The redox-catalysis deionization can continuously work. The 100ppm water product can be obtained from brackish water with 98.1% removal efficiency.
The active electrode regeneration is not required.
na
lP
ur
Abstract
In electrochemical desalination, an efficient ions transfer between positive and negative is
Jo
electrodes
necessary
and
highly
desirable.
Herein,
a
redox
media,
edible
riboflavin-5'-phosphate sodium salt (FMN-Na), is successfully applied to carry out continuous desalination as flow electrolyte in a desalinated device. The desalination process is achieved by trapping Na+/Cl- at positive/negative steams respectively with help of cation/anion exchange membranes. The removal efficiency can be up to 98.1%. The salt removability and consumption rate are investigated under different current densities and 1 / 10
salt concentrations. The flow rate of electrolyte and cyclic-ability are also examined. This green and pollution-free electro-catalytic technology will offer great potential for the safe and effective seawater desalination.
Jo
ur
na
lP
re
-p
ro of
Keywords: Electrochemical desalination; Catalytic Redox Effect; FMN-Na
2 / 10
1 Introduction With global warming and the climate change, the evolution of land desertification and freshwater shortage has become severe. Growing of population and the development of industrialization undoubtedly speed up the freshwater storage. Nearly 97.5% of the world's total water resource is ocean water, and more than 70% of the world's population lives within 70 km along the coastline. Since 1950s, desalination has been considered as the most practical method of sustainably providing fresh water sources and to remediate the enlarging in demands of fresh water. The desalination technology currently used in large-scale industrial applications includes
ro of
multi-stage flashing, reverse osmosis, capacitive deionization and electrodialysis deionization [1]. Multi-stage flash is thermal treatment process with the advantages of high water quality, safe and
reliable operation. However, acid and a scale inhibitor are required to do the regeneration. The thermal power consumption is large, and corrosion occurs in the system in previous developed
-p
methods [2]. RO is widely used in industry all over the world, however the energy consumption is still considered high[3]. Recently, CDI has been paid much attention as an emerging desalination
re
technology based on the electrical double layer absorption from high-surface-area electrode materials such as carbon [4]. Conventional CDI [5, 6], membrane capacitance deionization (MCDI)
lP
[7, 8], hybrid capacitive deionization (HCDI) [9, 10] and flow-electrode capacitive deionization (FCDI) [11-13] are widely investigated. When electrically applied, cation/anion can be
na
electrostatically absorbed by the negative/positive electrodes respectively, resulting in deionization process [14]. Lots of research works were focused on electrode materials such as improvement on the surface area and conductivity in the last decade. The desalination technology with commercial
ur
potential possesses the embodiment of high salt removal capacity, economic energy consumption, and low maintenance cost. However, the desalination ability of CDI devices is not particularly
Jo
desirable because of the limited capacitance of these carbon materials. In addition, another restriction of the conventional CDI or Faradic CDI is it can only work in intermittent desalination/salination exchanged mode [15]. In the practical application, the continuous process is highly demanded. Therefore, in our latest research work, an electrocatalytic redox desalination technique using TEMPO/TEMPO+ was proposed, which enables continuous desalination by the circulation of redox species between the electrode reservoirs [16]. However, these chemicals are 3 / 10
potentially toxic in some extent (Oral-category 4, skin irritation-category 2, eye irritation-category 2A, specific target organ toxicity-category 3). Therefore, utilizing cheap and nontoxic candidate is necessary to develop desalination technology. FMN-Na has been proposed as a versatile electroactive molecule that catalyze diverse redox reactions in various biological organizations [17, 18], and redox flow battery [17, 19-21]. It serves as a cofactor in many enzymes in tissue and cell. In this current work, as a great importance to be environmentally friendly in desalination process, FMN-Na is utilized as a nontoxic redox mediator to achieve the continuous electrochemical deionization by circulating the electrode material between positive and negative electrodes. The
ro of
salt removal efficiency up to 98.1% can be attained by applying FMN-Na as flow electrolyte. By controlling the current density and salt feed concentrations, the desalination performance is
examined. The cyclability and flow rate are also performed. In addition, energy consumption and
salt feed concentration and other important electrochemical tests are also performed. This study
-p
suggests that pollution-free electro-catalytic technology will be huge significant for the future low
2. Material and Experimental method
re
cost and safe desalination.
lP
The detailed preparation, device structure and desalination setup, electrochemical tests are
na
provided in the supplementary information
3 Results and discussion
Continuous desalination of ED was shown in Figure 1a. FMN-Na at the positive stream gains
ur
electron while the generation of FMN-Na at negative chamber. The sodium ions in stream A transport to positive chamber through CEM while the chloride ions move to stream B, occurring a
Jo
salt removal in stream A. With the acceptance of sodium ions from negative chamber through CEM, the salt content in stream B becomes concentrated. Overall, the salt in stream A is removed to stream B, and the constituents of FMN-Na stream remain unchanged. Hence, FMN-Na redox media acting as catalytic function. The salt concentration is recorded by the conductivity meters.
4 / 10
ro of -p
re
Figure 1 (a) a schematic diagram of the principle; (b) desalination device photo; (c) The three electrode CV of FMN-Na, working electrode: glassy carbon, counter: platinum; reference:
lP
standard calomel electrode; (d) the variation of voltage and salt content in stream A and B during the charge process. 4 mM FMN-Na, 0.48 mA cm-2 current density, 17.4 ml min-1 flow rate, volume
na
of stream A, B, or FMN-Na: 25 ml.
The CV measurement was shown in Figure 1c, the oxidation peak appears at -0.40 V and the
ur
reduction peak is located at -0.55 V. The overlapping of curves indicates the excellent cyclical stability. During the reduction of FMN-Na, the reaction can be described as follows,
Jo
FMN-Na + Na+ + e-
FMN-Na2
During the oxidation process, FMN-Na is recovered below, FMN-Na2
FMN-Na + Na+ +
e-
The desalination performance was demonstrated at Figure 1d. Under 0.48 mA cm-2 current density, the feed with 5150 ppm concentration was desalted down to 100 ppm while the salt content reaches 9436 ppm in stream B with the ion blocking of exchange membranes. The stiff voltage increase is due to the ion depletion in the desalted stream, causing a high resistance. This proves 5 / 10
premier desalination performance based on the edible catalytic redox effect of FMN-Na.
Furthermore, various current densities (0.06-0.96 mA cm-2) were investigated in Figure 2. The raised potential plateau and the fast desalination rate are obtained with high current density. The desalination rate of stream A and B indicates no salt losses, which is consistent with concentration slope in Figure S2. At 0.06 mA cm-2 the removal rate is 0.02 μg cm-2 s-1. When the current density is raised to 0.96 mA cm-2, the removal rate is up to 0.5 μg cm-2 s-1. Therefore, the current density has a significant effect on the salt removal rate. The charge efficiency increases with increase in
ro of
current density due to redox catalysis of FMN-Na in Figure 2c. The energy consumption rate gets pronounced at beginning but slightly rise as the current density from 0.24 mA cm-2 due to the
Jo
ur
na
lP
re
-p
polarization at the large current density.
Figure 2 (a) the desalination performance at various current densities, the corresponding salt removal rate (b), the charge efficiency (c), energy consumption (d).
The stability tests of charge/discharge were carried out in Figure 3. Four-cycle tests were performed, and the first charge time was 3 hours, followed by 1/1 hour discharge/charge process. 6 / 10
The salt removal/release behavior in Figure 3c and Figure S3 proves the excellent cycle repeatability. The salt removal rate in Figure 3d, charge efficiency in Figure 3e, and energy consumption in Figure 3f can be maintained during the cycle tests. The energy consumption was
Jo
ur
na
lP
re
-p
ro of
also ~180 kJ mol-1.
Figure 3 The simplified representation charge (a) and discharge (b) process; (c) the salt removal/ release performance during the charge/discharge process; the curves of salt removal rate (d), charge efficiency (e), and energy consumption (f) during the cycling tests. (Current density: ±0.24 mA cm-2)
Figure S4 shows the effect of different salt feed concentration under 0.24 mA cm-2. The 7 / 10
concentration change is less at the higher salt feed in Figure S4-S5. This may be due to the co-ion expulsion effect in high salt feed. Owing to enough salt in feed, the voltages remained essentially same. The most high removal rate can reach 0.144 μg cm-2 s-1 at 3000 ppm feed. However, the charge efficiency drops with the salt concentration increase in Figure S4c. The low energy consumption, 144 kJ mol-1, was obtained at 3000 ppm salt feed. In addition, the influence of FMN-Na concentration was further explored with 1 mM and 4 mM of FMN-Na in Figure S6. The current density is maintained at 0.48 mA cm-2. The better desalination performance low consumption are obtained at 4mM FMN-Na with the desalination slope of 5.47 ppm min-1,
ro of
compared with 4.66 ppm min-1 in 1mM FMN-Na. This is owing to more reaction sites provided at the higher concentration FMN-Na.
4 Conclusion
-p
The edible FMN-Na is utilized firstly for continuous desalination process in the ED cell that consists of the flow FMN-Na between positive and negative electrodes, two salt feeds, separated
re
by two CEMs and one AEM. The electrochemical catalytic function of FMN-Na achieves an uninterrupted desalination effect, reducing the salt feed from 5200 ppm to 100 ppm drinking water
lP
level. A series of experiments were designed to explore the influence of applied current density, feed concentration, and concentrations of active flow materials, and the removal rate, charging
na
efficiency and energy consumption are further analyzed. The salt removal efficiency can reach 98.1%. This research provides a safe and effective way for future environmentally friendly
ur
electrochemical technology.
Jo
Declaration of interests
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Conflicts of interest The authors declare no conflicts of interest. 8 / 10
Acknowledgments This project was supported by Outstanding Young Scholar Project (8S0256), and the Scientific and Technological Plan of Guangdong Province (2018A050506078), and the Project of Blue Fire Plan (CXZJHZ201709).
References [1] J.A. Dietrich, H. Luckenbach, Opflow, 39 (2013) 20-24.
ro of
[2] A. Mabrouk, M. Koc, A. Abdala, Desalination and Water Treatment, 98 (2017) 1-15. [3] S.F. Anis, R. Hashaikeh, N. Hilal, Desalination, 452 (2019) 159-195. [4] Y. Oren, Desalination, 228 (2008) 10-29.
-p
[5] Z.-H. Huang, Z. Yang, F. Kang, M. Inagaki, Journal of Materials Chemistry A, 5 (2017)
re
470-496.
[6] C. Bales, P. Kovalsky, J. Fletcher, T.D. Waite, Desalination, 453 (2019) 37-53.
lP
[7] R. Zhao, P.M. Biesheuvel, A. van der Wal, Energy & Environmental Science, 5 (2012) 9520.
ur
276-286.
na
[8] C. Tan, C. He, W. Tang, P. Kovalsky, J. Fletcher, T.D. Waite, Water Res, 147 (2018)
[9] Y. Huang, F. Chen, L. Guo, H.Y. Yang, Journal of Materials Chemistry A, 5 (2017)
Jo
18157-18165.
[10] S. Porada, A. Shrivastava, P. Bukowska, P.M. Biesheuvel, K.C. Smith, Electrochimica Acta, 255 (2017) 369-378. [11] G.J. Doornbusch, J.E. Dykstra, P.M. Biesheuvel, M.E. Suss, Journal of Materials Chemistry A, 4 (2016) 3642-3647. 9 / 10
[12] S.-i. Jeon, J.-g. Yeo, S. Yang, J. Choi, D.K. Kim, Journal of Materials Chemistry A, 2 (2014) 6378. [13] J. Ma, C. He, D. He, C. Zhang, T.D. Waite, Water Res, 144 (2018) 296-303. [14] J. Choi, P. Dorji, H.K. Shon, S. Hong, Desalination, 449 (2019) 118-130. [15] S.-Y. Pan, S.W. Snyder, Y.J. Lin, P.-C. Chiang, Environmental Science: Water Research & Technology, 4 (2018) 613-638.
Journal of Materials Chemistry A, 7 (2019) 13941-13947.
ro of
[16] J. Wang, Q. Zhang, F. Chen, X. Hou, Z. Tang, Y. Shi, P. Liang, D.Y.W. Yu, Q. He, L.-J. Li,
[17] A. Orita, M.G. Verde, M. Sakai, Y.S. Meng, Nat Commun, 7 (2016) 13230.
-p
[18] R. Miura, The Chemical Record, 1 (2001) 183-194.
re
[19] K. Lin, R. Gómez-Bombarelli, E.S. Beh, L. Tong, Q. Chen, A. Valle, A. Aspuru-Guzik, M.J. Aziz, R.G. Gordon, Nature Energy, 1 (2016).
lP
[20] J. Hong, M. Lee, B. Lee, D.H. Seo, C.B. Park, K. Kang, Nat Commun, 5 (2014) 5335. [21] M. Lee, J. Hong, D.H. Seo, D.H. Nam, K.T. Nam, K. Kang, C.B. Park, Angew Chem Int Ed
Jo
ur
na
Engl, 52 (2013) 8322-8328.
10 / 10
PII:
S2352-4928(19)31543-0
DOI:
https://doi.org/10.1016/j.mtcomm.2020.100921
Reference:
MTCOMM 100921
To appear in:
Materials Today Communications
Received Date:
30 November 2019
Accepted Date:
13 January 2020
Please cite this article as: Qi Z, Su HA, Than ZO, Fuming C, Continuous Electrochemical Deionization by Utilizing the Catalytic Redox Effect of Environmentally Friendly Riboflavin-5’-phosphate Sodium, Materials Today Communications (2020), doi: https://doi.org/10.1016/j.mtcomm.2020.100921
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2020 Published by Elsevier.
Continuous Electrochemical Deionization by Utilizing the Catalytic Redox Effect of Environmentally Friendly Riboflavin-5'-phosphate Sodium
Qi Zhanga, Su Htike Aungb*, Than Zaw Oob, Fuming Chena,*
Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South
China Normal University 510006
b
ro of
a
Department of Physics, University of Mandalay, Myanmar, 100103
-p
E-mail: [email protected]; [email protected]
re
Highlights:
The environmentally friendly and non-toxic FMN-Na was used as redox catalysis.
The redox-catalysis deionization can continuously work. The 100ppm water product can be obtained from brackish water with 98.1% removal efficiency.
The active electrode regeneration is not required.
na
lP
ur
Abstract
In electrochemical desalination, an efficient ions transfer between positive and negative is
Jo
electrodes
necessary
and
highly
desirable.
Herein,
a
redox
media,
edible
riboflavin-5'-phosphate sodium salt (FMN-Na), is successfully applied to carry out continuous desalination as flow electrolyte in a desalinated device. The desalination process is achieved by trapping Na+/Cl- at positive/negative steams respectively with help of cation/anion exchange membranes. The removal efficiency can be up to 98.1%. The salt removability and consumption rate are investigated under different current densities and 1 / 10
salt concentrations. The flow rate of electrolyte and cyclic-ability are also examined. This green and pollution-free electro-catalytic technology will offer great potential for the safe and effective seawater desalination.
Jo
ur
na
lP
re
-p
ro of
Keywords: Electrochemical desalination; Catalytic Redox Effect; FMN-Na
2 / 10
1 Introduction With global warming and the climate change, the evolution of land desertification and freshwater shortage has become severe. Growing of population and the development of industrialization undoubtedly speed up the freshwater storage. Nearly 97.5% of the world's total water resource is ocean water, and more than 70% of the world's population lives within 70 km along the coastline. Since 1950s, desalination has been considered as the most practical method of sustainably providing fresh water sources and to remediate the enlarging in demands of fresh water. The desalination technology currently used in large-scale industrial applications includes
ro of
multi-stage flashing, reverse osmosis, capacitive deionization and electrodialysis deionization [1]. Multi-stage flash is thermal treatment process with the advantages of high water quality, safe and
reliable operation. However, acid and a scale inhibitor are required to do the regeneration. The thermal power consumption is large, and corrosion occurs in the system in previous developed
-p
methods [2]. RO is widely used in industry all over the world, however the energy consumption is still considered high[3]. Recently, CDI has been paid much attention as an emerging desalination
re
technology based on the electrical double layer absorption from high-surface-area electrode materials such as carbon [4]. Conventional CDI [5, 6], membrane capacitance deionization (MCDI)
lP
[7, 8], hybrid capacitive deionization (HCDI) [9, 10] and flow-electrode capacitive deionization (FCDI) [11-13] are widely investigated. When electrically applied, cation/anion can be
na
electrostatically absorbed by the negative/positive electrodes respectively, resulting in deionization process [14]. Lots of research works were focused on electrode materials such as improvement on the surface area and conductivity in the last decade. The desalination technology with commercial
ur
potential possesses the embodiment of high salt removal capacity, economic energy consumption, and low maintenance cost. However, the desalination ability of CDI devices is not particularly
Jo
desirable because of the limited capacitance of these carbon materials. In addition, another restriction of the conventional CDI or Faradic CDI is it can only work in intermittent desalination/salination exchanged mode [15]. In the practical application, the continuous process is highly demanded. Therefore, in our latest research work, an electrocatalytic redox desalination technique using TEMPO/TEMPO+ was proposed, which enables continuous desalination by the circulation of redox species between the electrode reservoirs [16]. However, these chemicals are 3 / 10
potentially toxic in some extent (Oral-category 4, skin irritation-category 2, eye irritation-category 2A, specific target organ toxicity-category 3). Therefore, utilizing cheap and nontoxic candidate is necessary to develop desalination technology. FMN-Na has been proposed as a versatile electroactive molecule that catalyze diverse redox reactions in various biological organizations [17, 18], and redox flow battery [17, 19-21]. It serves as a cofactor in many enzymes in tissue and cell. In this current work, as a great importance to be environmentally friendly in desalination process, FMN-Na is utilized as a nontoxic redox mediator to achieve the continuous electrochemical deionization by circulating the electrode material between positive and negative electrodes. The
ro of
salt removal efficiency up to 98.1% can be attained by applying FMN-Na as flow electrolyte. By controlling the current density and salt feed concentrations, the desalination performance is
examined. The cyclability and flow rate are also performed. In addition, energy consumption and
salt feed concentration and other important electrochemical tests are also performed. This study
-p
suggests that pollution-free electro-catalytic technology will be huge significant for the future low
2. Material and Experimental method
re
cost and safe desalination.
lP
The detailed preparation, device structure and desalination setup, electrochemical tests are
na
provided in the supplementary information
3 Results and discussion
Continuous desalination of ED was shown in Figure 1a. FMN-Na at the positive stream gains
ur
electron while the generation of FMN-Na at negative chamber. The sodium ions in stream A transport to positive chamber through CEM while the chloride ions move to stream B, occurring a
Jo
salt removal in stream A. With the acceptance of sodium ions from negative chamber through CEM, the salt content in stream B becomes concentrated. Overall, the salt in stream A is removed to stream B, and the constituents of FMN-Na stream remain unchanged. Hence, FMN-Na redox media acting as catalytic function. The salt concentration is recorded by the conductivity meters.
4 / 10
ro of -p
re
Figure 1 (a) a schematic diagram of the principle; (b) desalination device photo; (c) The three electrode CV of FMN-Na, working electrode: glassy carbon, counter: platinum; reference:
lP
standard calomel electrode; (d) the variation of voltage and salt content in stream A and B during the charge process. 4 mM FMN-Na, 0.48 mA cm-2 current density, 17.4 ml min-1 flow rate, volume
na
of stream A, B, or FMN-Na: 25 ml.
The CV measurement was shown in Figure 1c, the oxidation peak appears at -0.40 V and the
ur
reduction peak is located at -0.55 V. The overlapping of curves indicates the excellent cyclical stability. During the reduction of FMN-Na, the reaction can be described as follows,
Jo
FMN-Na + Na+ + e-
FMN-Na2
During the oxidation process, FMN-Na is recovered below, FMN-Na2
FMN-Na + Na+ +
e-
The desalination performance was demonstrated at Figure 1d. Under 0.48 mA cm-2 current density, the feed with 5150 ppm concentration was desalted down to 100 ppm while the salt content reaches 9436 ppm in stream B with the ion blocking of exchange membranes. The stiff voltage increase is due to the ion depletion in the desalted stream, causing a high resistance. This proves 5 / 10
premier desalination performance based on the edible catalytic redox effect of FMN-Na.
Furthermore, various current densities (0.06-0.96 mA cm-2) were investigated in Figure 2. The raised potential plateau and the fast desalination rate are obtained with high current density. The desalination rate of stream A and B indicates no salt losses, which is consistent with concentration slope in Figure S2. At 0.06 mA cm-2 the removal rate is 0.02 μg cm-2 s-1. When the current density is raised to 0.96 mA cm-2, the removal rate is up to 0.5 μg cm-2 s-1. Therefore, the current density has a significant effect on the salt removal rate. The charge efficiency increases with increase in
ro of
current density due to redox catalysis of FMN-Na in Figure 2c. The energy consumption rate gets pronounced at beginning but slightly rise as the current density from 0.24 mA cm-2 due to the
Jo
ur
na
lP
re
-p
polarization at the large current density.
Figure 2 (a) the desalination performance at various current densities, the corresponding salt removal rate (b), the charge efficiency (c), energy consumption (d).
The stability tests of charge/discharge were carried out in Figure 3. Four-cycle tests were performed, and the first charge time was 3 hours, followed by 1/1 hour discharge/charge process. 6 / 10
The salt removal/release behavior in Figure 3c and Figure S3 proves the excellent cycle repeatability. The salt removal rate in Figure 3d, charge efficiency in Figure 3e, and energy consumption in Figure 3f can be maintained during the cycle tests. The energy consumption was
Jo
ur
na
lP
re
-p
ro of
also ~180 kJ mol-1.
Figure 3 The simplified representation charge (a) and discharge (b) process; (c) the salt removal/ release performance during the charge/discharge process; the curves of salt removal rate (d), charge efficiency (e), and energy consumption (f) during the cycling tests. (Current density: ±0.24 mA cm-2)
Figure S4 shows the effect of different salt feed concentration under 0.24 mA cm-2. The 7 / 10
concentration change is less at the higher salt feed in Figure S4-S5. This may be due to the co-ion expulsion effect in high salt feed. Owing to enough salt in feed, the voltages remained essentially same. The most high removal rate can reach 0.144 μg cm-2 s-1 at 3000 ppm feed. However, the charge efficiency drops with the salt concentration increase in Figure S4c. The low energy consumption, 144 kJ mol-1, was obtained at 3000 ppm salt feed. In addition, the influence of FMN-Na concentration was further explored with 1 mM and 4 mM of FMN-Na in Figure S6. The current density is maintained at 0.48 mA cm-2. The better desalination performance low consumption are obtained at 4mM FMN-Na with the desalination slope of 5.47 ppm min-1,
ro of
compared with 4.66 ppm min-1 in 1mM FMN-Na. This is owing to more reaction sites provided at the higher concentration FMN-Na.
4 Conclusion
-p
The edible FMN-Na is utilized firstly for continuous desalination process in the ED cell that consists of the flow FMN-Na between positive and negative electrodes, two salt feeds, separated
re
by two CEMs and one AEM. The electrochemical catalytic function of FMN-Na achieves an uninterrupted desalination effect, reducing the salt feed from 5200 ppm to 100 ppm drinking water
lP
level. A series of experiments were designed to explore the influence of applied current density, feed concentration, and concentrations of active flow materials, and the removal rate, charging
na
efficiency and energy consumption are further analyzed. The salt removal efficiency can reach 98.1%. This research provides a safe and effective way for future environmentally friendly
ur
electrochemical technology.
Jo
Declaration of interests
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Conflicts of interest The authors declare no conflicts of interest. 8 / 10
Acknowledgments This project was supported by Outstanding Young Scholar Project (8S0256), and the Scientific and Technological Plan of Guangdong Province (2018A050506078), and the Project of Blue Fire Plan (CXZJHZ201709).
References [1] J.A. Dietrich, H. Luckenbach, Opflow, 39 (2013) 20-24.
ro of
[2] A. Mabrouk, M. Koc, A. Abdala, Desalination and Water Treatment, 98 (2017) 1-15. [3] S.F. Anis, R. Hashaikeh, N. Hilal, Desalination, 452 (2019) 159-195. [4] Y. Oren, Desalination, 228 (2008) 10-29.
-p
[5] Z.-H. Huang, Z. Yang, F. Kang, M. Inagaki, Journal of Materials Chemistry A, 5 (2017)
re
470-496.
[6] C. Bales, P. Kovalsky, J. Fletcher, T.D. Waite, Desalination, 453 (2019) 37-53.
lP
[7] R. Zhao, P.M. Biesheuvel, A. van der Wal, Energy & Environmental Science, 5 (2012) 9520.
ur
276-286.
na
[8] C. Tan, C. He, W. Tang, P. Kovalsky, J. Fletcher, T.D. Waite, Water Res, 147 (2018)
[9] Y. Huang, F. Chen, L. Guo, H.Y. Yang, Journal of Materials Chemistry A, 5 (2017)
Jo
18157-18165.
[10] S. Porada, A. Shrivastava, P. Bukowska, P.M. Biesheuvel, K.C. Smith, Electrochimica Acta, 255 (2017) 369-378. [11] G.J. Doornbusch, J.E. Dykstra, P.M. Biesheuvel, M.E. Suss, Journal of Materials Chemistry A, 4 (2016) 3642-3647. 9 / 10
[12] S.-i. Jeon, J.-g. Yeo, S. Yang, J. Choi, D.K. Kim, Journal of Materials Chemistry A, 2 (2014) 6378. [13] J. Ma, C. He, D. He, C. Zhang, T.D. Waite, Water Res, 144 (2018) 296-303. [14] J. Choi, P. Dorji, H.K. Shon, S. Hong, Desalination, 449 (2019) 118-130. [15] S.-Y. Pan, S.W. Snyder, Y.J. Lin, P.-C. Chiang, Environmental Science: Water Research & Technology, 4 (2018) 613-638.
Journal of Materials Chemistry A, 7 (2019) 13941-13947.
ro of
[16] J. Wang, Q. Zhang, F. Chen, X. Hou, Z. Tang, Y. Shi, P. Liang, D.Y.W. Yu, Q. He, L.-J. Li,
[17] A. Orita, M.G. Verde, M. Sakai, Y.S. Meng, Nat Commun, 7 (2016) 13230.
-p
[18] R. Miura, The Chemical Record, 1 (2001) 183-194.
re
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