Effect of External Aeration on Cr (VI) Reduction in the Leersia hexandra Swartz Constructed Wetland-Microbial Fuel Cell System
Abstract
:1. Introduction
2. Materials and Methods
2.1. Construction of the CW-MFC System
2.2. Sludge Inoculation and Wastewater Composition
2.3. Water Quality and Electrochemical Analysis Index
2.4. Scanning Electron Microscopy
2.5. Sample Collection and Determination of Chromium
2.6. Chemical Speciation Analysis of Cr in Plants
2.7. Chemical Speciation Analysis of Cr in the Substrate
- (1)
- Weak acid extraction: 40 mL 0.1 mol·L−1 CH3COOH;
- (2)
- Reducible state: 40 mL 0.5 mol·L−1 hydroxylamine hydrochloride (NH2OH·HCl) (pH 2);
- (3)
- Oxidizable state: 10 mL 30% H2O2 (pH 2), then 10 mL 30% H2O2 (pH 2)—cool, and add 50 mL 1 mol·L−1 NH4OAc (pH 2);
- (4)
- Residue state: The oxidizable extract residue was dried, filtered through a 100-mesh soil sample sieve, and digested with the substrate Cr total determination method.
2.8. Microbial Analysis Methods
2.9. Quality Control
3. Results
3.1. Scanning Electron Microscopy Measurement before and after System Stabilization
3.2. Effects of Different DO Concentration on Pollutant Removal and Electricity Generation
3.3. Effect of Different DO Concentrations on Cr Content in the L. hexandra CW-MFC System
3.3.1. Effect of Different DO Concentrations on Cr Content in the Substrate
3.3.2. Effect of Different DO Concentrations on Cr Content in L. hexandra
3.4. Chemical Speciation Analysis of Cr in the L. hexandra CW-MFC System under Different DO Concentrations
3.4.1. Chemical Speciation Analysis of Cr in the Substrate
3.4.2. Chemical Speciation Analysis of Cr in L. hexandra
3.5. Microbial Community Structure Analysis
3.5.1. Community Diversity Analysis
3.5.2. Analysis of System Community Composition
4. Discussion
4.1. Effect of Cathode DO Concentration on System Performance
4.2. Effect of Cathode DO Concentration on the Migration and Distribution of Cr
4.3. The Effect of Cathode DO Concentration on the Valence Change and Morphological Characteristics of Cr
4.4. Changes to the Microbial Community in the CW-MFC System under Aeration
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
- Li, M.; Zhou, S.; Xu, Y.; Liu, Z.; Ma, F.; Zhi, L.; Zhou, X. Simultaneous Cr(VI) reduction and bioelectricity generation in a dual chamber microbial fuel cell. Chem. Eng. J. 2018, 334, 1621–1629. [Google Scholar] [CrossRef]
- Liu, X.; Chen, X.; Zhang, X.; Guo, H.; Zhang, C.; Zang, X.; Li, B. Quantifying the influence of soil factors on the migration of chromium (VI). Process Saf. Environ. Prot. 2021, 155, 32–40. [Google Scholar] [CrossRef]
- Qin, N.; Zhang, Y.; Zhou, H.; Geng, Z.; Liu, G.; Zhang, Y.; Zhao, H.; Wang, G. Enhanced removal of trace Cr(VI) from neutral and alkaline aqueous solution by FeCo bimetallic nanoparticles. J. Colloid Interface Sci. 2016, 472, 8–15. [Google Scholar] [CrossRef] [PubMed]
- Khosravi, R.; Moussavi, G.; Ghaneian, M.T.; Ehrampoush, M.H.; Barikbin, B.; Ebrahimi, A.A.; Sharifzadeh, G. Chromium adsorption from aqueous solution using novel green nanocomposite: Adsorbent characterization, isotherm, kinetic and thermodynamic investigation. J. Mol. Liq. 2018, 256, 163–174. [Google Scholar] [CrossRef]
- Li, Y.; Jin, Z.; Li, T.; Xiu, Z. One-step synthesis and characterization of core–shell Fe@SiO2 nanocomposite for Cr (VI) reduction. Sci. Total Environ. 2012, 421–422, 260–266. [Google Scholar] [CrossRef]
- Dermou, E.; Velissariou, A.; Xenos, D.; Vayenas, D.V. Biological chromium(VI) reduction using a trickling filter. J. Hazard. Mater. 2005, 126, 78–85. [Google Scholar] [CrossRef]
- Dharnaik, A.S.; Ghosh, P.K. Hexavalent chromium [Cr(VI)] removal by the electrochemical ion-exchange process. Environ. Technol. 2014, 35, 2272–2279. [Google Scholar] [CrossRef]
- Sinha, V.; Manikandan, N.A.; Pakshirajan, K.; Chaturvedi, R. Continuous removal of Cr(VI) from wastewater by phytoextraction using Tradescantia pallida plant based vertical subsurface flow constructed wetland system. Int. Biodeterior. Biodegrad. 2017, 119, 96–103. [Google Scholar] [CrossRef]
- Zheng, Q.; Na, S.; Li, X.; Li, N.; Hai, R.; Wang, X. Acute effects of hexavalent chromium on the performance and microbial community of activated sludge in aerobiotic reactors. Environ. Technol. 2019, 40, 1871–1880. [Google Scholar] [CrossRef] [PubMed]
- Gong, Y.; Gai, L.; Tang, J.; Fu, J.; Wang, Q.; Zeng, E.Y. Reduction of Cr(VI) in simulated groundwater by FeS-coated iron magnetic nanoparticles. Sci. Total Environ. 2017, 595, 743–751. [Google Scholar] [CrossRef]
- Chaudhry, S.A.; Khan, T.A.; Ali, I. Equilibrium, kinetic and thermodynamic studies of Cr(VI) adsorption from aqueous solution onto manganese oxide coated sand grain (MOCSG). J. Mol. Liq. 2017, 236, 320–330. [Google Scholar] [CrossRef]
- Wang, W.; Zhang, Y.; Li, M.; Wei, X.; Wang, Y.; Liu, L.; Wang, H.; Shen, S. Operation mechanism of constructed wetland-microbial fuel cells for wastewater treatment and electricity generation: A review. Bioresour. Technol. 2020, 314, 123808. [Google Scholar] [CrossRef]
- Kong, F.; Zhang, Y.; Wang, H.; Tang, J.; Li, Y.; Wang, S. Removal of Cr(VI) from wastewater by artificial zeolite spheres loaded with nano Fe–Al bimetallic oxide in constructed wetland. Chemosphere 2020, 257, 127224. [Google Scholar] [CrossRef]
- Liu, J.; Zhang, X.-h.; You, S.-h.; Wu, Q.-x.; Chen, S.-m.; Zhou, K.-n. Cr(VI) removal and detoxification in constructed wetlands planted with Leersia hexandra Swartz. Ecol. Eng. 2014, 71, 36–40. [Google Scholar] [CrossRef]
- Tandukar, M.; Huber, S.J.; Onodera, T.; Pavlostathis, S.G. Biological Chromium(VI) Reduction in the Cathode of a Microbial Fuel Cell. Environ. Sci. Technol. 2009, 43, 8159–8165. [Google Scholar] [CrossRef]
- Wang, G.; Huang, L.; Zhang, Y. Cathodic reduction of hexavalent chromium [Cr(VI)] coupled with electricity generation in microbial fuel cells. Biotechnol. Lett. 2008, 30, 1959–1966. [Google Scholar] [CrossRef]
- Yadav, A.K.; Dash, P.; Mohanty, A.; Abbassi, R.; Mishra, B.K. Performance assessment of innovative constructed wetland-microbial fuel cell for electricity production and dye removal. Ecol. Eng. 2012, 47, 126–131. [Google Scholar] [CrossRef]
- Wang, L.; Xu, D.; Zhang, Q.; Liu, T.; Tao, Z. Simultaneous removal of heavy metals and bioelectricity generation in microbial fuel cell coupled with constructed wetland: An optimization study on substrate and plant types. Environ. Sci. Pollut. Res. 2022, 29, 768–778. [Google Scholar] [CrossRef]
- Zhao, C.; Shang, D.; Zou, Y.; Du, Y.; Wang, Q.; Xu, F.; Ren, L.; Kong, Q. Changes in electricity production and microbial community evolution in constructed wetland-microbial fuel cell exposed to wastewater containing Pb(II). Sci. Total Environ. 2020, 732, 139127. [Google Scholar] [CrossRef]
- Srivastava, P.; Abbassi, R.; Garaniya, V.; Lewis, T.; Yadav, A.K. Performance of pilot-scale horizontal subsurface flow constructed wetland coupled with a microbial fuel cell for treating wastewater. J. Water Process Eng. 2020, 33, 100994. [Google Scholar] [CrossRef]
- Mu, C.; Wang, L.; Wang, L. Performance of lab-scale microbial fuel cell coupled with unplanted constructed wetland for hexavalent chromium removal and electricity production. Environ. Sci. Pollut. Res. 2020, 27, 25140–25148. [Google Scholar] [CrossRef]
- Srivastava, P.; Dwivedi, S.; Kumar, N.; Abbassi, R.; Garaniya, V.; Yadav, A.K. Performance assessment of aeration and radial oxygen loss assisted cathode based integrated constructed wetland-microbial fuel cell systems. Bioresour. Technol. 2017, 244, 1178–1182. [Google Scholar] [CrossRef]
- Yang, Y.; Zhao, Y.; Tang, C.; Xu, L.; Morgan, D.; Liu, R. Role of macrophyte species in constructed wetland-microbial fuel cell for simultaneous wastewater treatment and bioenergy generation. Chem. Eng. J. 2020, 392, 123708. [Google Scholar] [CrossRef]
- Li, J.; Wen, Y.; Zhou, Q.; Xingjie, Z.; Li, X.; Yang, S.; Lin, T. Influence of vegetation and substrate on the removal and transformation of dissolved organic matter in horizontal subsurface-flow constructed wetlands. Bioresour. Technol. 2008, 99, 4990–4996. [Google Scholar] [CrossRef] [PubMed]
- Torresi, E.; Escolà Casas, M.; Polesel, F.; Plósz, B.G.; Christensson, M.; Bester, K. Impact of external carbon dose on the removal of micropollutants using methanol and ethanol in post-denitrifying Moving Bed Biofilm Reactors. Water Res. 2017, 108, 95–105. [Google Scholar] [CrossRef] [Green Version]
- Ge, X.; Cao, X.; Song, X.; Wang, Y.; Si, Z.; Zhao, Y.; Wang, W.; Tesfahunegn, A.A. Bioenergy generation and simultaneous nitrate and phosphorus removal in a pyrite-based constructed wetland-microbial fuel cell. Bioresour. Technol. 2020, 296, 122350. [Google Scholar] [CrossRef]
- Wen, H.; Zhu, H.; Xu, Y.; Yan, B.; Shutes, B.; Bañuelos, G.; Wang, X. Removal of sulfamethoxazole and tetracycline in constructed wetlands integrated with microbial fuel cells influenced by influent and operational conditions. Environ. Pollut. 2021, 272, 115988. [Google Scholar] [CrossRef]
- Teoh, T.-P.; Ong, S.-A.; Ho, L.-N.; Wong, Y.-S.; Oon, Y.-L.; Oon, Y.-S.; Tan, S.-M.; Thung, W.-E. Up-flow constructed wetland-microbial fuel cell: Influence of floating plant, aeration and circuit connection on wastewater treatment performance and bioelectricity generation. J. Water Process Eng. 2020, 36, 101371. [Google Scholar] [CrossRef]
- Gupta, S.; Srivastava, P.; Patil, S.A.; Yadav, A.K. A comprehensive review on emerging constructed wetland coupled microbial fuel cell technology: Potential applications and challenges. Bioresour. Technol. 2021, 320, 124376. [Google Scholar] [CrossRef]
- Xu, W.; Yang, B.; Wang, H.; Wang, S.; Jiao, K.; Zhang, C.; Li, F.; Wang, H. Improving the removal efficiency of nitrogen and organics in vertical-flow constructed wetlands: The correlation of substrate, aeration and microbial activity. Environ. Sci. Pollut. Res. 2022, 30, 21683–21693. [Google Scholar] [CrossRef]
- Liu, S.; Qiu, D.; Lu, F.; Wang, Y.; Wang, Z.; Feng, X.; Pyo, S.-H. Acorus calamus L. constructed wetland-microbial fuel cell for Cr(VI)-containing wastewater treatment and bioelectricity production. J. Environ. Chem. Eng. 2022, 10, 107801. [Google Scholar] [CrossRef]
- Zhang, X.-H.; Liu, J.; Huang, H.-T.; Chen, J.; Zhu, Y.-N.; Wang, D.-Q. Chromium accumulation by the hyperaccumulator plant Leersia hexandra Swartz. Chemosphere 2007, 67, 1138–1143. [Google Scholar] [CrossRef] [PubMed]
- Kartal, Ş.; Aydın, Z.; Tokalıoğlu, Ş. Fractionation of metals in street sediment samples by using the BCR sequential extraction procedure and multivariate statistical elucidation of the data. J. Hazard. Mater. 2006, 132, 80–89. [Google Scholar] [CrossRef]
- Quevauviller, P.; Rauret, G.; Griepink, B. Single and Sequential Extraction in Sediments and Soils. Int. J. Environ. Anal. Chem. 1993, 51, 231–235. [Google Scholar] [CrossRef]
- Gul, P.; Ahmad, K.S.; Ali, D. Activated carbon processed from Citrus sinensis: Synthesis, characterization and application for adsorption-based separation of toxic pesticides from soils. Sep. Sci. Technol. 2021, 56, 2026–2035. [Google Scholar] [CrossRef]
- Hanumantu, J.R. Characterization Studies on Adsorption of Lead and Cadmium Using Activated Carbon Prepared from Waste Tyres. Nat. Environ. Pollut. Technol. 2021, 20, 561–568. [Google Scholar] [CrossRef]
- Oon, Y.-L.; Ong, S.-A.; Ho, L.-N.; Wong, Y.-S.; Dahalan, F.A.; Oon, Y.-S.; Lehl, H.K.; Thung, W.-E.; Nordin, N. Role of macrophyte and effect of supplementary aeration in up-flow constructed wetland-microbial fuel cell for simultaneous wastewater treatment and energy recovery. Bioresour. Technol. 2017, 224, 265–275. [Google Scholar] [CrossRef] [PubMed]
- Zhao, Y.; Collum, S.; Phelan, M.; Goodbody, T.; Doherty, L.; Hu, Y. Preliminary investigation of constructed wetland incorporating microbial fuel cell: Batch and continuous flow trials. Chem. Eng. J. 2013, 229, 364–370. [Google Scholar] [CrossRef] [Green Version]
- Srikanth, S.; Venkata Mohan, S. Change in electrogenic activity of the microbial fuel cell (MFC) with the function of biocathode microenvironment as terminal electron accepting condition: Influence on overpotentials and bio-electro kinetics. Bioresour. Technol. 2012, 119, 241–251. [Google Scholar] [CrossRef]
- Dordio, A.V.; Carvalho, A.J.P. Organic xenobiotics removal in constructed wetlands, with emphasis on the importance of the support matrix. J. Hazard. Mater. 2013, 252–253, 272–292. [Google Scholar] [CrossRef] [Green Version]
- Tao, Z.; Jing, Z.; Tao, M.; Chen, R. Recycled utilization of ryegrass litter in constructed wetland coupled microbial fuel cell for carbon-limited wastewater treatment. Chemosphere 2022, 302, 134882. [Google Scholar] [CrossRef]
- Yadav, A.K.; Kumar, N.; Sreekrishnan, T.R.; Satya, S.; Bishnoi, N.R. Removal of chromium and nickel from aqueous solution in constructed wetland: Mass balance, adsorption–desorption and FTIR study. Chem. Eng. J. 2010, 160, 122–128. [Google Scholar] [CrossRef]
- Ye, Z.H.; Lin, Z.Q.; Whiting, S.N.; de Souza, M.P.; Terry, N. Possible use of constructed wetland to remove selenocyanate, arsenic, and boron from electric utility wastewater. Chemosphere 2003, 52, 1571–1579. [Google Scholar] [CrossRef] [PubMed]
- Srivastava, P.; Yadav, A.K.; Mishra, B.K. The effects of microbial fuel cell integration into constructed wetland on the performance of constructed wetland. Bioresour. Technol. 2015, 195, 223–230. [Google Scholar] [CrossRef] [PubMed]
- Wu, Z.; Chen, Z.; Tang, J.; Zhou, Z.; Chen, L.; Fang, Y.; Hu, X.; Lv, J. Efficient adsorption and reduction of Cr(VI) in water using one-step H3PO4-assisted prepared Leersia hexandra Swartz hydrochar. Mater. Today Sustain. 2023, 21, 100260. [Google Scholar] [CrossRef]
- Wang, Y.; Zhang, X.; Xiao, L.; Lin, H. The in-depth revelation of the mechanism by which a downflow Leersia hexandra Swartz constructed wetland-microbial fuel cell synchronously removes Cr(VI) and p-chlorophenol and generates electricity. Environ. Res. 2023, 216, 114451. [Google Scholar] [CrossRef] [PubMed]
- Liu, S.; Lu, F.; Qiu, D.; Feng, X. Wetland plants selection and electrode optimization for constructed wetland-microbial fuel cell treatment of Cr(VI)-containing wastewater. J. Water Process Eng. 2022, 49, 103040. [Google Scholar] [CrossRef]
- Liang, Y.; Zhu, H.; Bañuelos, G.; Shutes, B.; Yan, B.; Cheng, X. Removal of sulfamethoxazole from salt-laden wastewater in constructed wetlands affected by plant species, salinity levels and co-existing contaminants. Chem. Eng. J. 2018, 341, 462–470. [Google Scholar] [CrossRef]
- Wang, J.; Song, X.; Wang, Y.; Bai, J.; Li, M.; Dong, G.; Lin, F.; Lv, Y.; Yan, D. Bioenergy generation and rhizodegradation as affected by microbial community distribution in a coupled constructed wetland-microbial fuel cell system associated with three macrophytes. Sci. Total Environ. 2017, 607–608, 53–62. [Google Scholar] [CrossRef] [PubMed]
- Choi, C.; Cui, Y. Recovery of silver from wastewater coupled with power generation using a microbial fuel cell. Bioresour. Technol. 2012, 107, 522–525. [Google Scholar] [CrossRef]
- Singh, S.; Modi, A.; Verma, N. Enhanced power generation using a novel polymer-coated nanoparticles dispersed-carbon micro-nanofibers-based air-cathode in a membrane-less single chamber microbial fuel cell. Int. J. Hydrog. Energy 2016, 41, 1237–1247. [Google Scholar] [CrossRef]
- Amin, A.Z.; Hamed, B.; Khaled, S.R.; Razieh, K. Performance Evaluation of Continuous Aeration Process in Wastewater Treatment Contaminated with Chrome Heavy Metal in Pilot Scale. Orient. J. Chem. 2017, 33, 3086. [Google Scholar] [CrossRef]
- Yang, X.; Nguyen, V.B.; Zhao, Z.; Wu, Y.; Lei, Z.; Zhang, Z.; Le, X.S.; Lu, H. Changes of distribution and chemical speciation of metals in hexavalent chromium loaded algal-bacterial aerobic granular sludge before and after hydrothermal treatment. Bioresour. Technol. 2022, 355, 127229. [Google Scholar] [CrossRef]
- Scattolin, M.; Peuble, S.; Pereira, F.; Paran, F.; Moutte, J.; Menad, N.; Faure, O. Aided-phytostabilization of steel slag dumps: The key-role of pH adjustment in decreasing chromium toxicity and improving manganese, phosphorus and zinc phytoavailability. J. Hazard. Mater. 2021, 405, 124225. [Google Scholar] [CrossRef] [PubMed]
- Li, L.-X.; Li, Q.; Tang, Y.-J.; Li, S.-L.; Cheng, X.-R.; Li, Z.-W.; Wang, X.-L.; Li, Z.-G. Effects of different nutritional conditions on accumulation and distribution of Cr in Coix lacryma-jobi L. in Cr6+-contaminated constructed wetland. Ecotoxicol. Environ. Saf. 2021, 225, 112763. [Google Scholar] [CrossRef]
- Rauser, W.E. Structure and function of metal chelators produced by plants. Cell Biochem. Biophys. 1999, 31, 19–48. [Google Scholar] [CrossRef]
- Brune, A.; Urbach, W.; Dietz, K.J. Compartmentation and transport of zinc in barley primary leaves as basic mechanisms involved in zinc tolerance. Plant Cell Environ. 1994, 17, 153–162. [Google Scholar] [CrossRef]
- Fang, Z.; Cao, X.; Li, X.; Wang, H.; Li, X. Electrode and azo dye decolorization performance in microbial-fuel-cell-coupled constructed wetlands with different electrode size during long-term wastewater treatment. Bioresour. Technol. 2017, 238, 450–460. [Google Scholar] [CrossRef] [Green Version]
- Li, H.; Cai, Y.; Gu, Z.; Yang, Y.-L.; Zhang, S.; Yang, X.-L.; Song, H.-L. Accumulation of sulfonamide resistance genes and bacterial community function prediction in microbial fuel cell-constructed wetland treating pharmaceutical wastewater. Chemosphere 2020, 248, 126014. [Google Scholar] [CrossRef]
- Li, J.; Li, H.; Zheng, J.; Zhang, L.; Fu, Q.; Zhu, X.; Liao, Q. Response of anodic biofilm and the performance of microbial fuel cells to different discharging current densities. Bioresour. Technol. 2017, 233, 1–6. [Google Scholar] [CrossRef]
- Hidayat, A.R.P.; Widyanto, A.R.; Asranudin, A.; Ediati, R.; Sulistiono, D.O.; Putro, H.S.; Sugiarso, D.; Prasetyoko, D.; Purnomo, A.S.; Bahruji, H.; et al. Recent development of double chamber microbial fuel cell for hexavalent chromium waste removal. J. Environ. Chem. Eng. 2022, 10, 107505. [Google Scholar] [CrossRef]
- Di, L.; Li, Y.; Nie, L.; Wang, S.; Kong, F. Influence of plant radial oxygen loss in constructed wetland combined with microbial fuel cell on nitrobenzene removal from aqueous solution. J. Hazard. Mater. 2020, 394, 122542. [Google Scholar] [CrossRef]
- Wen, H.; Zhu, H.; Yan, B.; Xu, Y.; Shutes, B. Treatment of typical antibiotics in constructed wetlands integrated with microbial fuel cells: Roles of plant and circuit operation mode. Chemosphere 2020, 250, 126252. [Google Scholar] [CrossRef] [PubMed]
- Oon, Y.-L.; Ong, S.-A.; Ho, L.-N.; Wong, Y.-S.; Oon, Y.-S.; Lehl, H.K.; Thung, W.-E. Hybrid system up-flow constructed wetland integrated with microbial fuel cell for simultaneous wastewater treatment and electricity generation. Bioresour. Technol. 2015, 186, 270–275. [Google Scholar] [CrossRef] [PubMed]
- Ouellet-Plamondon, C.; Chazarenc, F.; Comeau, Y.; Brisson, J. Artificial aeration to increase pollutant removal efficiency of constructed wetlands in cold climate. Ecol. Eng. 2006, 27, 258–264. [Google Scholar] [CrossRef]
- Feng, L.; He, S.; Zhao, W.; Ding, J.; Liu, J.; Zhao, Q.; Wei, L. Can biochar addition improve the sustainability of intermittent aerated constructed wetlands for treating wastewater containing heavy metals? Chem. Eng. J. 2022, 444, 136636. [Google Scholar] [CrossRef]
- Logan, B.E.; Regan, J.M. Electricity-producing bacterial communities in microbial fuel cells. Trends Microbiol. 2006, 14, 512–518. [Google Scholar] [CrossRef]
DO Concentration (mg·L−1) | Total Chromium (mg·kg−1) | Cr (VI) (mg·kg−1) | Cr (III) (mg·kg−1) | |||
---|---|---|---|---|---|---|
Anode | Cathode | Anode | Cathode | Anode | Cathode | |
3.0 | 7988.54 | 8386.46 | 572.50 | 448.33 | 7416.04 | 7938.13 |
3.5 | 8295.83 | 8517.71 | 487.50 | 416.25 | 7808.33 | 8101.46 |
4.0 | 9045.83 | 9525.00 | 453.75 | 246.25 | 8592.08 | 9278.75 |
4.5 | 14,945.83 | 16,350.00 | 357.92 | 204.17 | 14,587.92 | 16,145.83 |
5.0 | 10,132.29 | 12,778.13 | 422.08 | 241.67 | 9710.21 | 12,536.46 |
DO Concentration (mg·L−1) | Total Chromium (mg·kg−1) | Cr (VI) (mg·kg−1) | Cr (III) (mg·kg−1) | ||||||
---|---|---|---|---|---|---|---|---|---|
Root | Stem | Leaf | Root | Stem | Leaf | Root | Stem | Leaf | |
3.0 | 8428.13 | 1428.13 | 1191.67 | 1927.08 | 635.42 | 483.33 | 6501.04 | 792.71 | 708.33 |
3.5 | 9913.54 | 1851.04 | 1365.63 | 1616.67 | 495.83 | 472.92 | 8296.88 | 1355.21 | 892.71 |
4.0 | 13,070.83 | 2402.08 | 1913.54 | 1104.17 | 481.25 | 450.00 | 11,966.67 | 1920.83 | 1463.54 |
4.5 | 18,869.79 | 3642.71 | 3070.83 | 641.67 | 418.75 | 385.42 | 18,228.13 | 3223.96 | 2685.42 |
5.0 | 14,313.54 | 2588.54 | 2187.50 | 1081.25 | 441.67 | 414.58 | 13,232.29 | 2146.88 | 1772.92 |
Sample | Shannon | Chao | Ace | Simpson | Shannoneven |
---|---|---|---|---|---|
A1 * | 3.73 | 514.44 | 499.83 | 0.04 | 0.60 |
A2 * | 4.77 | 515.52 | 515.37 | 0.02 | 0.77 |
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Shi, Y.; Tang, G.; You, S.; Jiang, P. Effect of External Aeration on Cr (VI) Reduction in the Leersia hexandra Swartz Constructed Wetland-Microbial Fuel Cell System. Appl. Sci. 2023, 13, 3309. https://doi.org/10.3390/app13053309
Shi Y, Tang G, You S, Jiang P. Effect of External Aeration on Cr (VI) Reduction in the Leersia hexandra Swartz Constructed Wetland-Microbial Fuel Cell System. Applied Sciences. 2023; 13(5):3309. https://doi.org/10.3390/app13053309
Chicago/Turabian StyleShi, Yucui, Gang Tang, Shaohong You, and Pingping Jiang. 2023. "Effect of External Aeration on Cr (VI) Reduction in the Leersia hexandra Swartz Constructed Wetland-Microbial Fuel Cell System" Applied Sciences 13, no. 5: 3309. https://doi.org/10.3390/app13053309
APA StyleShi, Y., Tang, G., You, S., & Jiang, P. (2023). Effect of External Aeration on Cr (VI) Reduction in the Leersia hexandra Swartz Constructed Wetland-Microbial Fuel Cell System. Applied Sciences, 13(5), 3309. https://doi.org/10.3390/app13053309