Co-reporter:Junjie Wen, Xiaojun Tan, Yongyou Hu, Qian Guo, and Xuesen Hong
Environmental Science & Technology June 6, 2017 Volume 51(Issue 11) pp:6395-6395
Publication Date(Web):May 10, 2017
DOI:10.1021/acs.est.6b06290
The removal and inactivation of waterborne pathogens from drinking water are important for human health. Here, a polyacrylonitrile/polyaniline/silver nanowires-carbon fiber cloth (PAN/PANI/AgNWs-CC) composite nanofiber membrane was fabricated using a simple and rapid coelectrospinning process, and an electrical device was applied with the PAN/PANI/AgNWs-CC filter for water electrochemical disinfection. The effects of voltage, flow rate, and microbial concentration on the filtration and electrochemical disinfection performance of the nanocomposite membrane were investigated. The characterization results show that PAN/PANI/AgNWs with uniform diameters and without beads were successfully fabricated on CC. AgNWs were uniformly distributed in the PAN/PANI/AgNWs. The PAN/PANI/AgNWs-CC filter was an effective sieve for completely removing both Escherichia coli and Staphylococcus aureus in the absence of applied voltage, and the sieved bacteria were completely inactivated by the released silver within 8 h. Over 99.999% inactivation of the sieved bacteria was achieved within a few seconds by concurrent filtration and electrochemical disinfection under a voltage of 3 V. This high performance is enabled by means of an electrical mechanism, and an extremely high electric field induces sharp AgNWs tips to generate electroporated pores in the bacteria. The electrochemical PAN/PANI/AgNWs-CC membrane is an excellent material with potential application value in point-of-use drinking water treatment.
Co-reporter:Feng Deng;Jian Sun;Yongyou Hu;Junfeng Chen;Sizhe Li;Jie Chen;Yaping Zhang
RSC Advances (2011-Present) 2017 vol. 7(Issue 67) pp:42172-42179
Publication Date(Web):2017/08/29
DOI:10.1039/C7RA07956G
To understand how microbial reduction of graphene oxide (mrGO) influenced the biofilm during the in situ preparation of a graphene/exoelectrogen composite biofilm anode in a microbial fuel cell (MFC), an in situ mrGO-modified anode was fabricated, and the evolution and viability of the anodic biofilm were investigated by sampling the biofilm at different stages of the MFC operation. The total protein, thickness and viability of the anodic biofilm in mrGO-added MFCs were generally lower than that in mrGO-free MFC at the first electricity production cycle (EPC) due to the antibacterial activity of the GO flake. However, the three indicators increased dramatically and were much higher in mrGO-added MFC than in mrGO-free MFC after three EPCs, derived from enhanced bacterial adhesion and accelerated biofilm recovery in the presence of mrGO due to its high specific area for increased biomass attachment and high conductivity for enhanced electron transfer between bacteria and anode. The electricity generation performance of the MFC was found to follow the same trend as biofilm evolution. The power density of the mrGO-modified MFC increased sharply after five electricity production cycles, reaching a maximum value of 1140.63 mW m−2, which is 65.20% higher than the blank control. This study gives an insight into the interaction between the exoelectrogens and their induced GO reduction which contribute to the understanding of the essence of the process for high-performance MFC application.
Co-reporter:Cao Yang, Jianhua Cheng, Yuancai Chen, Yongyou Hu
Applied Surface Science 2017 Volume 420(Volume 420) pp:
Publication Date(Web):31 October 2017
DOI:10.1016/j.apsusc.2017.05.102
•A novel CdS/MOF-derived porous carbon (MPC) composite was prepared.•The evenly disperse growth of CdS nanoparticles on the MPC surface was realized.•The CdS/MPC (20 wt%) showed the highest photocatalytic degradation rate.•The MPC as the electron acceptor promoted the separation of charges.The CdS/MOF-derived porous carbon (MPC) composite as an efficient visible-light-driven photocatalyst was prepared through the pyrolysis of ZIF-8 and subsequent growth of CdS. The porous and functionalized MPC enables intimate and discrete growth of CdS nanoparticles. This unique structure not only reduces the bulk recombination owing to nano-size effect of CdS, but also suppresses the surface recombination due to the discrete growth of CdS nanoparticles on MPC polyhedrons, which facilitates electron transfer and charge separation. Moreover, such a composite material possessed good adsorption ability toward the antibiotic pollutants because of the amino-functionalized surface. As a result, the as-prepared CdS/MPC composites showed excellent photocatalytic performance for the antibiotic degradation, significantly improving the photoactivity of CdS. Importantly, the CdS/MPC composite with the CdS loading of 20 wt% exhibited the highest photocatalytic efficiency of approximately 91% and apparent rate constant of 0.024 min−1.Download high-res image (152KB)Download full-size image
Co-reporter:Junfeng Chen, Yongyou Hu, Wantang Huang, Lihua Zhang
International Journal of Hydrogen Energy 2017 Volume 42, Issue 17(Volume 42, Issue 17) pp:
Publication Date(Web):27 April 2017
DOI:10.1016/j.ijhydene.2017.03.012
•GO was reduced by in situ microbial-induced reduction successfully.•Graphene modified biocathode was formed through polarity reversion.•Graphene modified biocathode increased MFC power density and decreased interfacial charge transfer resistance.•Typical exoelectrogens in graphene modified biocathode were enriched.A simple effective and environmentally friendly pathway to form graphene modified biocathode was induced by polarity reversion of graphene modified bioanode, which was made by in situ microbial-induced reduction of graphene oxide (GO). Graphene assembled by microbes showed that D/G intensity increased from 0.84 to 0.91 and C/O atomic ratio added from 2.13 to 4.45, indicating GO was reduced largely. The graphene modified biocathode exhibited crumples that grown on the lamellar and glossy surface and was capable of improving catalytic reduction of oxygen. Microbial fuel cell (MFC) fabricated with graphene modified biocathode obtained 1.22 times in maximum power density, 0.21 times in interfacial charge transfer resistance, and recorded an obvious redox peaks at −0.50 V (vs. SCE) than control biocathode MFC. Geobacter, Clostridium, Pseudomonas, Geothrix and Hydrogenophaga belonged to exoelectrogens occupied 17.53% in graphene modified biocathode, 2.07% in control biocathode in genus level. This study provided a new insight into the feasibility to make microbes self-assembled graphene to improve electrochemical performance of biocathode MFC.Download high-res image (256KB)Download full-size image
Co-reporter:Junfeng Chen, Lihua Zhang, Yongyou Hu, Wantang Huang, Zhuyu Niu, Jian Sun
Bioresource Technology 2017 Volume 241(Volume 241) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.biortech.2017.05.123
•GM-BE was prepared by microbial self-assembly graphene and polarity reversion.•Bacterial community shift of GM-BE in MFC was illustrated.•Firmicutes and Proteobacteria were dominant bacteria in GM-BA/GM-BC respectively.•MFC performance separately composed by GM-BA and GM-BC were improved.In this work, bacterial community shift and incurred performance of graphene modified bioelectrode (GM-BE) in microbial fuel cell (MFC) were illustrated by high throughput sequencing technology and electrochemical analysis. The results showed that Firmicutes occupied 48.75% in graphene modified bioanode (GM-BA), while Proteobacteria occupied 62.99% in graphene modified biocathode (GM-BC), both were dominant bacteria in phylum level respectively. Typical exoelectrogens, including Geobacter, Clostridium, Pseudomonas, Geothrix and Hydrogenophaga, were counted 26.66% and 17.53% in GM-BA and GM-BC. GM-BE was tended to decrease the bacterial diversity and enrich the dominant species. Because of the enrichment of exoelectrogens and excellent electrical conductivity of graphene, the maximum power density of MFC with GM-BA and GM-BC increased 33.1% and 21.6% respectively, and the transfer resistance decreased 83.8% and 73.6% compared with blank bioelectrode. This study aimed to enrich the microbial study in MFC and broaden the development and application for bioelectrode.Download high-res image (92KB)Download full-size image
Co-reporter:Ping Tan, Yongyou Hu
Journal of Molecular Liquids 2017 Volume 242(Volume 242) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.molliq.2017.07.010
•GNS/β-CD was prepared by an improved method.•The synergistic adsorption of each component in GNS/β-CD was achieved.•GNS/β-CD exhibited high adsorption ability for dyes.•GNS/β-CD exhibited good reusability after repeated uses.Graphene/beta-cyclodextrin (GNS/β-CD) composite was prepared by an improved method, and its adsorption performance for phenolphthalein was investigated. This improved method could enhance the stability of GNS/β-CD due to the covalent bond link between β-CD and GNS, and achieve the synergistic adsorption of organic dye compound on β-CD and GNS in GNS/β-CD composite because of the remove of some oxygen-containing groups on the surface of GO in GNS/β-CD. The adsorption of Php on GNS/β-CD was hardly influenced by ionic strength. The adsorption equilibrium was achieved within 20 min. The adsorption kinetics followed the pseudo-second-order model and the adsorption isotherms were well fitted by the Langmuir model. Thermodynamic analysis suggested that the adsorption of Php on GNS/β-CD was spontaneous and exothermic. The GNS/β-CD composite could be regenerated several times based on its adsorption/desorption cycles, with a slight loss in its adsorption. For the actual dyes, the saturated adsorption capacities of methyl blue, methyl orange and basic fuchsin on GNS/β-CD were 580.4, 328.2 and 425.8 mg/g, respectively, higher than many currently reported. The obtained results indicated that GNS/β-CD could be rapid and high effective adsorbent to remove dyes from water.
Co-reporter:Junfeng Chen, Yongyou Hu, Lihua Zhang, Wantang Huang, Jian Sun
Bioresource Technology 2017 Volume 238(Volume 238) pp:
Publication Date(Web):1 August 2017
DOI:10.1016/j.biortech.2017.04.044
•D-GM-BE was prepared by microbial-induced reduction of GO and polarity reversion.•Proteobacteria and Firmicutes were the dominant bacteria in GM-BE.•Typical exoelectrogens in GM-BE shared much higher proportion.•The maximum power density obtained by D-GM-BE MFC was 2.34 times than C-BE-MFC.Dual graphene modified bioelectrode (D-GM-BE) was prepared by in situ microbial-induced reduction of graphene oxide (GO) and polarity reversion in microbial fuel cell (MFC). Next Generation Sequencing technology was used to elucidate bacterial community shift in response to improved performance in D-GM-BE MFC. The results indicated an increase in the relative ratio of Proteobacteria, but a decrease of Firmicutes was observed in graphene modified bioanode (GM-BA); increase of Proteobacteria and Firmicutes were observed in graphene modified biocathode (GM-BC). Genus analysis demonstrated that GM-BE was beneficial to enrich electrogens. Typical exoelectrogens were accounted for 13.02% and 8.83% in GM-BA and GM-BC. Morphology showed that both GM-BA and GM-BC formed 3D-like graphene/biofilm architectures and revealed that the biofilm viability and thickness would decrease to some extent when GM-BE was formed. D-GM-BE MFC obtained the maximum power density by 124.58 ± 6.32 mW m−2, which was 2.34 times over C-BE MFC.Download high-res image (258KB)Download full-size image
Co-reporter:Cao Yang, Jianhua Cheng, Yuancai Chen, Yongyou Hu
Journal of Colloid and Interface Science 2017 Volume 504(Volume 504) pp:
Publication Date(Web):15 October 2017
DOI:10.1016/j.jcis.2017.05.020
A MoS2 nanosheet-coated chromium terephthalate MIL-101 octahedron hybrid (denoted as MoS2/MIL-101) was prepared via a simple hydrothermal reaction. The obtained MoS2/MIL-101 hybrid exhibited a significantly enhanced adsorption ability toward rhodamine B (RhB) as compared with pure MoS2, MIL-101, and the physical mixture of the two. The results demonstrate that the MoS2/MIL-101 hybrid had a high uptake capacity (Qm ≈ 344.8 mg g–1) and fast adsorption rate for the removal of aqueous RhB. The excellent adsorption performance is likely related to the synergism of hydrogen bonding, π-π stacking interactions, and direct coordination between the MIL-101 substrate and RhB, as well as electrostatic interactions between MoS2 nanosheets and RhB. In particular, the uniform distribution of MoS2 nanosheets along with the negative charges on MIL-101 could have a strong interaction with the positively charged RhB, thus leading to an improvement in adsorption performance as observed for the MoS2/MIL-101 hybrid. Furthermore, MoS2/MIL-101 displayed good regenerability and reusability, making it attractive for the adsorption removal of aqueous RhB.Download high-res image (177KB)Download full-size image
Co-reporter:Zheng Fang, Yongyou Hu, Weiwen Zhang, Xian Ruan
Chemical Engineering Journal 2017 Volume 316(Volume 316) pp:
Publication Date(Web):15 May 2017
DOI:10.1016/j.cej.2017.01.072
•An feasible method for shell-free three-dimensional graphene-based monoliths was proposed.•The shell-free Vc‘Na-GBM exhibited a higher BET surface area and recovered more.•sp2-hybridized domains.•The strong electrostatic repulsion induced by Vc‘Na promoted the removal of the shell of GBMs.Three-dimensional graphene-based monoliths (GBM) are promising materials for pollutant adsorption in aqueous solution. However, the compact shell of GBM blocks mass transfer, reduces the specific surface area and adsorption sites, and reduces overall adsorption performance. To improve the properties of these materials, we used sodium ascorbate (Vc‘Na) to reduce graphene oxide (GO) to prepare shell-free GBM. The microstructures and properties of the produced Vc‘Na-GBM were characterized. Hydrophilic methylene blue (MB) and hydrophobic Bisphenol A (BPA) were used as adsorbates to investigate the adsorption performance of the prepared Vc‘Na-GBM. The shell-free Vc‘Na-GBM, compared with un-modified Vc-GBM, exhibited a higher BET surface area of 248.3 m2/g for an increase of 21.4%, recovered 43.3% of sp2-hybridized domains for an increase of 24.4%, showed higher mass transfer efficiency with 1.60 and 2.47-fold increases in the kinetic constants for MB and BPA respectively, and possessed higher saturated adsorption capacities of 154 mg/g and 204 mg/g, for MB and BPA respectively, for an increase of 1.34 and 1.20-fold. We propose that the strong electrostatic repulsion induced by Vc‘Na promoted the removal of the shell of GBM. This study provides the theoretical basis for the facile and low-cost preparation of high-performance GBM adsorbents.Download high-res image (203KB)Download full-size image
Co-reporter:Junfeng Chen, Yongyou Hu, Xiaojun Tan, Lihua Zhang, Wantang Huang, Jian Sun
Bioresource Technology 2017 Volume 241(Volume 241) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.biortech.2017.06.020
•A three-step method was built to prepare dual graphene modified bioelectrode.•3D graphene/biofilm architectures were formed in graphene modified bioelectrode.•The viability/thickness of microbial biofilm decreased in graphene bioelectrode.•Electrochemical performance of graphene modified MFC was significantly enhanced.•Mechanisms of EET process and implication of graphene modified MFC were proposed.This study proposed a three-step method to prepare dual graphene modified bioelectrode (D-GM-BE) by in situ microbial-induced reduction of GO and polarity reversion in microbial fuel cell (MFC). Both graphene modified bioanode (GM-BA) and biocathode (GM-BC) were of 3D graphene/biofilm architectures; the viability and thickness of microbial biofilm decreased compared with control bioelectrode (C-BE). The coulombic efficiency (CE) of GM-BA was 2.1 times of the control bioanode (C-BA), which demonstrated higher rate of substrates oxidation; the relationship between peak current and scan rates data meant that GM-BC was of higher efficiency of catalyzing oxygen reduction than the control biocathode (C-BC). The maximum power density obtained in D-GM-BE MFC was 122.4 ± 6.9 mW m−2, the interfacial charge transfer resistance of GM-BA and GM-BC were decreased by 79% and 75.7%. The excellent electrochemical performance of D-GM-BE MFC was attributed to the enhanced extracellular electron transfer (EET) process and catalyzing oxygen reduction.Download high-res image (173KB)Download full-size image
Co-reporter:Yuancai Lv, Zhuyu Niu, Yuancai Chen and Yongyou Hu
RSC Advances 2016 vol. 6(Issue 24) pp:20357-20365
Publication Date(Web):15 Feb 2016
DOI:10.1039/C5RA22388A
Polybrominated diphenyl ethers (PBDEs) are emerging persistent organic pollutants and the degradation of PBDEs is still a significant challenge owing to their extreme persistence and toxicity. In this study, the remediation of 2,2′,4,4′-tetrabromodiphenyl ether (BDE47) was investigated by employing a nano-biological combined system with SiO2-coated zero-valent iron/palladium bimetallic nanoparticles (SiO2-nZVI/Pd) as a reductant and Pseudomonas putida as a biocatalyst. The SiO2-nZVI/Pd exhibited much lower toxicity to the P. putida strain and higher reactivity in debromination than nZVI/Pd. The strain could grow well when the dosage was up to 1.0 g L−1. During the combined process, BDE47 (5 mg L−1) was completely debrominated to diphenyl ether (DE) within 2 h by SiO2-nZVI/Pd (1.0 g L−1) and then DE was completely degraded by P. putida after 4 days in sequential aerobic biodegradation. All the possible intermediates in the whole process were identified by ultra performance liquid chromatography (UPLC) and gas chromatography-mass spectrometer (GC-MS) analyses. The detection of BDE17, BDE7, BDE1 and DE indicated that rapidly stepwise debromination preferentially occurred at para positions in the anaerobic stage. Moreover, during aerobic biodegradation by P. putida, a number of phenolic compounds, such as phenol, catechol and hydroquinone were generated via ring opening by dioxygenation and further mineralized through the tricarboxylic acid cycle (TCA). Importantly, this combined process achieved rapid mineralization of PBDEs and avoided the generation of some highly toxic products like bromophenols and HO–PBDEs, which might have promising application prospects in the remediation of halogenated POPs.
Co-reporter:Ping Tan, Junjie Wen, Yongyou Hu and Xiaojun Tan
RSC Advances 2016 vol. 6(Issue 83) pp:79641-79650
Publication Date(Web):16 Aug 2016
DOI:10.1039/C6RA18052C
Novel poly(vinyl alcohol)/graphene oxide (PVA/GO) nanofibers were fabricated by electrospinning and applied to remove Cu2+ and Cd2+ from aqueous solution. The adsorption performances of the PVA/GO nanofibers were investigated by removing Cu2+ and Cd2+. The results showed that the adsorption of Cu2+ and Cd2+ onto PVA/GO nanofibers increased as the pH was increasing, but only slightly reduced with the increasing of ionic strength. The adsorption could reach equilibrium within 25 min and the experimental kinetic data followed the pseudo-second-order kinetic model. The equilibrium adsorption data can be well fitted with the Langmuir model. The thermodynamic parameters calculated from adsorption isotherms at four different temperatures indicated that the adsorption processes were endothermic and spontaneous. The PVA/GO nanofibers have good regeneration ability and can be recycled 8 times with a small amount of loss in adsorption efficiency. FTIR and XPS results indicated that the carboxyl and the carbonyl groups of GO on the surface of the nanofibers mainly participated in the adsorption of Cu2+ and Cd2+.
Co-reporter:Ping Tan, Yongyou Hu, Qi Bi
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2016 Volume 509() pp:56-64
Publication Date(Web):20 November 2016
DOI:10.1016/j.colsurfa.2016.08.081
•A novel GOM was prepared by induced directional flow.•The difference in HSAB of metal ions caused the competitive adsorption of metal ions on GOM.•The GOM indicated a good selectivity toward Cu2+ over Cd2+ and Ni2+.•The early adsorbed Cd2+ or Ni2+ on GOM was displaced by later adsorbed Cu2+.A novel graphene oxide membrane (GOM) was prepared using the vacuum filtration-induced directional flow method. The properties of GOM were characterized by scanning electron microscope, X-ray diffraction instrument, transmission electron microscope, and Fourier transform infrared spectroscopy apparatus. The adsorptive properties of Cu2+, Cd2+ and Ni2+ onto GOM were systematically investigated in single, binary and ternary solutions by batch experiments. In a single system, the maximum adsorption capacities of Cu2+, Cd2+ and Ni2+ obtained by the Langmuir model were 1.21, 0.81 and 1.08 mmol/g, respectively. The isotherms results for Cu2+ indicated that GOM exhibited good selectivity in the adsorption of Cu2+ over Cd2+ and Ni2+. The adsorption capacity followed the order of Cu2+ > Ni2+ > Cd2+ in binary systems. For ternary system, the order of the adsorption capacity was Cu2+ > Cd2+ > Ni2+. Previously adsorbed metal ions on GOM could be displaced by subsequently adsorbed metal ions from the solution. The difference in hard and soft acids and bases of Cu2+, Cd2+ and Ni2+ solutions was identified as the main reason for GOM to be able to selectively adsorb favorable metal ions during competitive adsorption in binary systems. This interaction mechanism between the favorable component and other metal ions could be the primary cause of direct displacement.
Co-reporter:Wanjun Li, Jian Sun, Yongyou Hu, Yaping Zhang, Feng Deng, Jie Chen
Journal of Power Sources 2014 Volume 268() pp:287-293
Publication Date(Web):5 December 2014
DOI:10.1016/j.jpowsour.2014.06.047
Co-reporter:Yaping Zhang, Jian Sun, Yongyou Hu, Zhaoyi Wang, Sizhe Li
International Journal of Hydrogen Energy 2014 Volume 39(Issue 15) pp:8048-8054
Publication Date(Web):15 May 2014
DOI:10.1016/j.ijhydene.2014.03.110
•MFCs could be successfully adapted for use under day–night temperature difference.•MFCs at 18/30 °C produced the highest power density of 2169 ± 82 mW m−2 at 30 °C.•MFCs at 6/18 °C obtained a coulombic efficiency of 94.6 ± 5.2%.•The anodic biofilm could keep electrochemical activity under day–night temperature.Practical applications of microbial fuel cells (MFCs) for wastewater treatment are usually operated over a wide range of temperature, especially day–night temperature difference. Here, MFCs at alternating temperatures were compared with those at constant temperatures. MFCs at 6/18 °C reached a steady-state voltage of 0.41 ± 0.05 V at 6 °C and 0.36 ± 0.04 V at 18 °C, which were lower than that of MFCs at 18/30 °C (0.42 ± 0.01 V at 18 °C and 0.47 ± 0.02 V at 30 °C). MFCs at 18/30 °C produced the highest power density of 2169 ± 82 mW m−2 at 30 °C, even higher than that of MFCs at constant temperature 30 °C. Moreover, MFCs at 6/18 °C and 18/30 °C obtained a comparable coulombic efficiencies (94.6 ± 5.2%, 83.2 ± 4.1%, respectively) compared with MFCs at constant temperatures (86.3 ± 7.3% at 18 °C and 84.1 ± 5.5% at 30 °C). These results demonstrate that MFCs could be successfully adapted for use under day–night temperature difference conditions.
Co-reporter:Yan-Ping Guo, Yong-You Hu
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2014 Volume 445() pp:12-20
Publication Date(Web):20 March 2014
DOI:10.1016/j.colsurfa.2013.12.076
•Mono- and di-rhamnolipids both increased EE2 aqueous solubility.•Dirhamnolipid exhibited higher solubilization capability but slower mass transfer rate.•DLS, TEM, and UV-spectra measurements confirmed solubilization behavior.•Rhamnolipidic type was important factor for micellar solubilization.Rhamnolipids are typically produced as multicomponent mixtures of homologues and are notably promising for environmental remediation. Because different mixtures exhibit dissimilar surface-active and micellization properties, which may affect their functional behaviors, the individual contribution of each rhamnolipidic homologue to the solubilization has largely been unexplored. In this study, enhanced solubilization of moderately hydrophobic 17α-ethinylestradiol (EE2) by two independent rhamnolipidic fractions (i.e., RL-F1 and RL-F2, which are mono- and di-rhamnolipids, respectively) was investigated. The results of the solubilization experiments indicated that RL-F2 exhibited a higher maximum dissolving capability of EE2 compared to RL-F1. However, a higher mass transfer rate was observed for RL-F1. To confirm the results of the solubilization experiments, dynamic light scattering, transmission electron microscopy, and UV-spectral analysis were performed. The type of rhamnolipid and the aggregate morphology strongly influenced the incorporation of solubilizate into the surfactant aggregates. The results of this study may be used to understand the rhamnolipid-facilitated transport of contaminants in aquatic environments, as well as the selection of rhamnolipids, with high specificity for practical applications.The morphologies of mono- and di-rhamnolipidic aggregates solubilized with or without EE2 solute were reported.
Co-reporter:Yaping Zhang, Jian Sun, Yongyou Hu, Sizhe Li, Qian Xu
Journal of Power Sources 2013 Volume 239() pp:169-174
Publication Date(Web):1 October 2013
DOI:10.1016/j.jpowsour.2013.03.115
•CNT-coated stainless steel mesh (CNT-SSM) was fabricated by a simple, scalable process.•The CNT-SSM showed a three-dimensional network structure.•The CNT-SSM biocathode performed better catalytic activity toward oxygen reduction.•The electrochemical capability of cathodic biofilms was characterized by CV.•The CNT-SSM biocathode can meet the required shape for different MFC application systems.A novel carbon nanotubes (CNTs) coated stainless steel mesh (SSM) electrode has been fabricated by a simple and scalable process and is used as biocathode in microbial fuel cell (MFC) for performance improvement. Examination by scanning electron microscope shows that CNTs are uniformly distributed over the surface of the SSM, thus forming a three-dimensional network structure. The MFC with CNT-SSM biocathode achieves higher maximum power density (147 mW m−2), which is 49 times larger than that (3 mW m−2) produced from the MFC with bare SSM biocathode. Moreover, cyclic voltammetry shows that the microorganisms on the CNTs-SSM biocathode play a major role in oxygen reduction reaction (ORR), and the CNT-SSM biocathode performes better catalytic activity toward ORR than that of SSM biocathode. Additionally, the MFC with CNTs-SSM biocathode has higher Coulombic Efficiency than that of MFC with bare SSM biocathode. In this study, we demonstrate that the use of CNTs-SSM offers an effective mean to enhance the electricity of biocathode MFCs.
Co-reporter:Yang Yang, Yongyou Hu, Xuhua Xiong and Yanzhe Qin
RSC Advances 2013 vol. 3(Issue 22) pp:8431-8436
Publication Date(Web):26 Mar 2013
DOI:10.1039/C3RA00117B
The microwave-assisted method is rapid in synthesizing silver nanowires. However, a by-product of silver particles is often simultaneously produced. For better utilization of microwaves to produce silver nanowires, the effect of microwave power on the morphologies of silver nanostructures was studied. The synthesis was conducted at various single microwave powers, 80, 160, 320, 560 and 800 W and with a combination of 800 W and 320 W with different sequences and time assignments. The results showed that 320 W produced silver nanowires of 6–8 μm, while when a lower power was used, silver nanowires were shortened to 2–4 μm. At higher microwave power, vast silver particles dominated the product with short nanowires of about 3–4 μm. In addition, the combination of 800 W × 0.5 min + 320 W × 2.5 min ideally resulted in mainly uniform silver nanowires up to 10 μm in length, with a small quantity of silver particles. However, prolonged treatment at 800 W during the first heating phase and the reversed combination of 320 W + 800 W led to a high yield of silver particles. We believe that different microwave powers lead to products of various morphologies by impacting on the reduction rate and seed growth. Generally, this study highlights the microwave power dependent effects on silver nanostructures and a better utilization of microwave power combination to synthesize silver nanowires.
Co-reporter:Sizhe Li, Yongyou Hu, Qian Xu, Jian Sun, Bin Hou, Yaping Zhang
Journal of Power Sources 2012 Volume 213() pp:265-269
Publication Date(Web):1 September 2012
DOI:10.1016/j.jpowsour.2012.04.002
In this work, iron- and nitrogen-functionalized graphene (Fe–N–G) as a non-precious metal catalyst is synthesized via a facile method of thermal treatment of a mixture of Fe salt, graphitic carbon nitride (g-C3N4) and chemically reduced graphene. The electrocatalytic activity of the prepared catalysts toward oxygen reduction reaction (ORR) evaluated by using linear sweep voltammetry tests shows that the Fe–N–G catalyst has more positive onset potential and increased reduction current densities as compared to the pristine graphene (P–G) catalyst, indicating an enhanced ORR activity of the Fe–N–G catalyst. More importantly, the Fe–N–G-MFC achieves the highest power density of 1149.8 mW m−2, which is ∼2.1 times of that generated with the Pt/C-MFC (561.1 mW m−2) and much higher than that of the P–G-MFC (109 mW m−2). These results demonstrate that the Fe–N–G catalyst can hold the promise of being an excellent alternative to the costly Pt catalyst for practical MFC applications.Highlights► It is the first time to use Fe–N functionalized graphene as a cost-effective catalyst in microbial fuel cells. ► Fe–N–G exhibited excellent electrocatalytic activity toward oxygen reduction in neutral medium. ► Fe–N–G significantly enhanced the performance of MFC as compared to that of Pt/C cathode. ► Fe–N–G is a promising alternative to costly Pt catalyst for practical MFC application.
Co-reporter:Yaping Zhang, Jian Sun, Yongyou Hu, Sizhe Li, Qian Xu
International Journal of Hydrogen Energy 2012 Volume 37(Issue 22) pp:16935-16942
Publication Date(Web):November 2012
DOI:10.1016/j.ijhydene.2012.08.064
The choice of the cathode material is crucial for every bio-cathode microbial fuel cell (MFC) setup. The commonly used biocathode materials, Graphite felt (GF), carbon paper (CP) and stainless steel mesh (SSM) were compared and evaluated in terms of current density, power density, and polarization. The maximum current density and power density of the MFC with GF-biocathode achieved 350 mA m−2 and 109.5 mW m−2, which were higher than that of the MFC with CP-biocathode (210 mA m−2 and 32.7 mW m−2) and the MFC with SSM-biocathode (18 mA m−2 and 3.1 mW m−2). The polarization indicated that the biocathode was the limiting factor for the three MFC reactors. Moreover, cyclic voltammetry (CV) showed that the microorganisms on the biocathode played a major role in oxygen reduction reaction (ORR) for GF- and CP-biocathode but SSM-biocathode. Electrochemical impedance spectroscopy suggested that GF biocathode performed better catalytic activity toward ORR than that of CP- and SSM-biocathode, also supported by CV test. Additionally, the MFC with GF-biocathode had the highest Coulombic Efficiency. The results of this study demonstrated GF was the most suitable biocathode for MFCs application among the three types of materials when using anaerobic sludge as inoculums.Highlights► Systematical comparison on the biocathode materials was studied in MFCs. ► The electrochemical capability of cathodic biofilms was characterized by CV. ► The electrochemical impedance behavior of bio-cathodes was characterized by EIS. ► Graphite felt was the most suitable biocathode for MFCs. ► Biocathode was the main limiting factor in MFCs.
Co-reporter:Yaping Zhang, Jian Sun, Bin Hou, Yongyou Hu
Journal of Power Sources 2011 Volume 196(Issue 18) pp:7458-7464
Publication Date(Web):15 September 2011
DOI:10.1016/j.jpowsour.2011.05.004
A novel mesoporous carbon (MC) modified carbon paper has been constructed using layer-by-layer self-assembly method and is used as anode in an air-cathode single-chamber microbial fuel cell (MFC) for performance improvement. Using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), we have demonstrated that the MC modified electrode exhibits a more favorable and stable electrochemical behavior, such as increased active surface area and enhanced electron-transfer rate, than that of the bare carbon paper. The MFC equipped with MC modified carbon paper anode achieves considerably better performance than the one equipped with bare carbon paper anode: the maximum power density is 81% higher and the startup time is 68% shorter. CV and EIS analysis confirm that the MC layer coated on the carbon paper promotes the electrochemical activity of the anodic biofilm and decreases the charge transfer resistance from 300 to 99 Ω. In addition, the anode and cathode polarization curves reveal negligible difference in cathode potentials but significant difference in anode potentials, indicating that the MC modified anode other than the cathode was responsible for the performance improvement of MFC. In this paper, we have demonstrated the utilization of MC modified carbon paper to enhance the performance of MFC.Highlights► Mesoporous carbon modified electrode exhibits a favorable and stable electrochemical behavior. ► The electrochemical activity of the anodic biofilm is promoted by mesoporous carbon. ► Mesoporous carbon anode significantly enhances the performance of microbial fuel cells. ► Mesoporous carbon is promising in application of microbial fuel cells.
Co-reporter:Yaping Zhang, Yongyou Hu, Sizhe Li, Jian Sun, Bin Hou
Journal of Power Sources 2011 Volume 196(Issue 22) pp:9284-9289
Publication Date(Web):15 November 2011
DOI:10.1016/j.jpowsour.2011.07.069
To develop an efficient and cost-effective cathodic electrocatalyst for microbial fuel cells (MFCs), carbon nanotubes (CNTs) coated with manganese dioxide using an in situ hydrothermal method (in situ MnO2/CNTs) have been investigated for electrochemical oxygen reduction reaction (ORR). Examination by transmission electron microscopy shows that MnO2 is sufficiently and uniformly dispersed over the surfaces of the CNTs. Using linear sweep voltammetry, we determine that the in situ MnO2/CNTs are a better catalyst for the ORR than CNTs that are simply mechanically mixed with MnO2 powder, suggesting that the surface coating of MnO2 onto CNTs enhances their catalytic activity. Additionally, a maximum power density of 210 mW m−2 produced from the MFC with in situ MnO2/CNTs cathode is 2.3 times of that produced from the MFC using mechanically mixed MnO2/CNTs (93 mW m−2), and comparable to that of the MFC with a conventional Pt/C cathode (229 mW m−2). Electrochemical impedance spectroscopy analysis indicates that the uniform surface dispersion of MnO2 on the CNTs enhanced electron transfer of the ORR, resulting in higher MFC power output. The results of this study demonstrate that CNTs are an ideal catalyst support for MnO2 and that in situ MnO2/CNTs offer a good alternative to Pt/C for practical MFC applications.Highlights► Carbon nanotubes (CNTs) enhance the activity of MnO2 toward oxygen reduction reaction (ORR). ► The in situ MnO2/CNTs significantly enhances the performance of microbial fuel cell (MFC). ► The sufficient dispersion of MnO2 over the surface of CNTs facilitates electron transfer for ORR in MFC. ► The in situ MnO2/CNTs offer a good alternative to Pt/C in practical MFCs applications.
Co-reporter:Jian Sun, Yong-you Hu, Bin Hou
Electrochimica Acta 2011 Volume 56(Issue 19) pp:6874-6879
Publication Date(Web):30 July 2011
DOI:10.1016/j.electacta.2011.05.111
To achieve high power output based on simultaneously azo dye decolorization using microbial fuel cell (MFC), the bioanode responses during decolorization of a representative azo dye, Congo red, were investigated in an air-cathode single chambered MFC using representative electrochemical techniques. It has been found that the maximum stable voltage output was delayed due to slowly developed anode potential during Congo red decolorization, indicating that the electrons recovered from co-substrate are preferentially transferred to Congo red rather than the bioanode of the MFC and Congo red decolorization is prior to electricity generation. Addition of Congo red had a negligible effect on the Ohmic resistance (Rohm) of the bioanode, but the charge-transfer resistance (Rc) and the diffusion resistance (Rd) were significantly influenced. The Rc and Rd firstly decreased then increased with increase of Congo red concentration, probably due to the fact that the Congo red and its decolorization products can act as electron shuttle for conveniently electrons transfer from bacteria to the anode at low concentration, but result in accelerated consumption of electrons at high concentration. Cyclic voltammetry results suggested that Congo red was a more favorable electron acceptor than the bioanode of the MFC. Congo red decolorization did not result in a noticeable decrease in peak catalytic current until Congo red concentration up to 900 mg l−1. Long-term decolorization of Congo red resulted in change in catalytic active site of anode biofilm.
Co-reporter:Feng Ju, Yongyou Hu
Separation and Purification Technology 2011 Volume 78(Issue 1) pp:33-41
Publication Date(Web):24 March 2011
DOI:10.1016/j.seppur.2011.01.014
The efficient removal of EDTA-chelated copper from aqueous solution was achieved using waste iron scraps in interior microelectrolysis. The experimental results show that the appropriate ranges for the cast iron scrap (CIS) dosage and the Fe/C mass ratio are 20–40 g/L and 2:1–4:1, respectively. This method proved effective over a wide range of pH, from 2.0 to 10.0, and copper removal efficiency decreased unevenly as pH increased. Copper removal accelerated as dissolved oxygen (DO) was increased from 0.15 mg/L to 5.25 mg/L, but it decelerated as DO was further increased from 5.25 mg/L to 9.0 mg/L. Additionally, the Taguchi method was used for a L9 (34) orthogonal array design to determine the optimum microelectrolytic conditions for copper removal, and it was found that 98.2% of copper and 32.3% of EDTA (in terms of TOC) were removed under the following optimum microelectrolytic conditions: a pH of 3.0, a CIS dosage of 40 g/L, 40 min of reaction time and a Fe/C mass ratio of 2/1. The results of the Fourier transform infrared (FT-IR) and UV–Visible spectra confirmed the existence of Fe2+-based replacement-precipitation and electrocoagulation during interior microelectrolysis, and these processes contributed to the removal of EDTA-chelated copper from aqueous solution. Economic analysis indicated that interior microelectrolysis was cost-effective and had great potential for practical application in the pretreatment of EDTA-chelated copper in wastewater.Research highlights► Interior microelectrolysis effectively removes EDTA-chelated copper. ► Copper removal is mainly influenced by solution pH, DO and Fe/C mass ratio. ► Optimum conditions are determined by orthogonal array L9(34) using Taguchi method. ► Fe2+-based effects attribute to copper removal from EDTA-chelated solution. ► Interior microelectrolysis is efficient and cost-effective.
Co-reporter:Yunqing Cao, Yongyou Hu, Jian Sun, Bin Hou
Bioelectrochemistry 2010 Volume 79(Issue 1) pp:71-76
Publication Date(Web):August 2010
DOI:10.1016/j.bioelechem.2009.12.001
Microbial fuel cell (MFC) holds a great promise to harvest electricity directly from a wide range of ready degradable organic matters and enhance degradation of some recalcitrant contaminants. Glucose, acetate sodium and ethanol were separately examined as co-substrates for simultaneous bioelectricity generation and Congo red degradation in a proton exchange membrane (PEM) air-cathode single-chamber MFC. The batch test results showed that more than 98% decolorization at the dye concentration of 300 mg/L were achieved within 36 h for all tested co-substrates during electricity generation. The decolorization rate was different with the co-substrates used. The fastest decolorization rate was achieved with glucose followed by ethanol and sodium acetate. Accumulated intermediates were observed during Congo red degradation which was demonstrated by UV–Visible spectra and high performance liquid chromatography (HPLC). Electricity generation was sustained and not significantly affected by the Congo red degradation. Glucose, acetate sodium and ethanol produced maximum power densities of 103 mW/m2, 85.9 mW/m2 and 63.2 mW/m2, respectively, and the maximum voltage output decreased by only 7% to 15%. Our results demonstrated the feasibility of using various co-substrates for simultaneous decolorization of Congo red and bioelectricity generation in the MFC and showed that glucose was the preferred co-substrate.
Co-reporter:Jian Sun, Yongyou Hu, Zhe Bi, Yunqing Cao
Journal of Power Sources 2009 Volume 187(Issue 2) pp:471-479
Publication Date(Web):15 February 2009
DOI:10.1016/j.jpowsour.2008.11.022
Substantial optimization and cost reduction are required before microbial fuel cells (MFCs) can be practically applied. We show here the performance improvement of an air-cathode single-chamber MFC by using a microfiltration membrane (MFM) on the water-facing side of the cathode and using multiple aerobic sludge (AES), anaerobic sludge (ANS), and wetland sediment (WLS) as anodic inoculums. Batch test results show that the MFC with an MFM resulted in an approximately two-fold increase in maximum power density compared to the MFC with a proton exchange membrane (PEM). The Coulombic efficiency increased from 4.17% to 5.16% in comparison with the membrane-less MFC, without a significant negative effect on power generation and internal resistance. Overall performance of the MFC was also improved by using multiple sludge inoculums in the anode. The MFC inoculated with ANS + WLS produced the greatest maximal power density of 373 mW m−2 with a substantially low internal resistance of 38 Ω. Higher power density with a decreased internal resistance was also achieved in MFC inoculated with ANS + AES and ANS + AES + WLS in comparison with those inoculated with only one sludge. The MFCs inoculated with AES + ANS achieved the highest Coulombic efficiency. Over 92% COD was removed from confectionery wastewater in all tested MFCs, regardless of the membrane or inoculum used.
Co-reporter:Yan-Ping Guo, Yong-You Hu, Roy R. Gu, Hui Lin
Journal of Colloid and Interface Science 2009 Volume 331(Issue 2) pp:356-363
Publication Date(Web):15 March 2009
DOI:10.1016/j.jcis.2008.11.039
Two representative rhamnolipidic fractions, RL-F1 and RL-F2, produced by the P. aeruginosa mutant strain MIG-N146, were separated and chemically characterized by TLC, HPLC-MS, and FTIR. The RL-F1 fraction is predominantly mono-rhamnolipid homologues with a high content of one or two fatty acid moieties. The RL-F2 fraction is mainly composed of di-rhamnosyl moieties with two hydrophobic tails. Micellization behavior was investigated to assess the physicochemical properties of the surfactants, RL-F1, RL-F2, and crude rhamnolipidic extracts. The variations in morphology of micelle formation and growth were examined by dynamic light scattering measurements as a function of surfactant concentration. Critical micelle concentration (CMC), average minimal surface tension (γCMCγCMC), saturated surface excess (ΓmΓm), mean surface area per molecule (S), and adsorption efficiency (pC20) were determined from the surface tension profiles and compared for the three surfactant systems. It was found that micelle growth was significantly enhanced by increasing rhamnolipid bulk concentration, which was most probably accompanied with an aggregate shape transition. Well-separated multi- or bi-modal distributions of particle size were observed in RL-F2 and the crude extracts solutions. The results of this study demonstrate that molecular architecture of different surfactant compositions profoundly influences the performance of rhamnolipidic surfactants.Changes in particle size for rhamnolipidic fractions and crude extracts as a function of concentration.
Co-reporter:Xiao Ling;Chun-De Wu;Gui-Ping Hu
Journal of Chemical Technology and Biotechnology 2006 Volume 81(Issue 2) pp:128-135
Publication Date(Web):23 SEP 2005
DOI:10.1002/jctb.1366
The performance of the hydrolyzation film bed and biological aerated filter (HFB–BAF) combined system in pilot scale (with a daily treatment quantity of 600–1300 m3 d−1), operated for 234 days, for low-strength domestic sewage was assessed using different amounts of aeration, reflux ratios and hydraulic loading rates (HLR). In steady state it was found that the average removal efficiency of chemical oxygen demand (COD) and biological oxygen demand at 5 days (BOD5) were 82.0% and 82.2% and the average effluent concentrations were 15.8 mg L−1 and 9.4 mg L−1 respectively as the HFB was running at an HLR of 1.25–1.77 m3 m−2 h−1 and the BAF was running at an HLR of 1.56–2.21 m3 m−2 h−1. In general, the removal efficiency of total nitrogen (TN) fluctuated with the HLR, gas–water ratio and reflux ratio, so the ratio of gas to water should be controlled from 2:1 to 3:1 and the reflux ratio should be as high as possible. The effluent concentration of TN was 10.4 mg L−1 and the TN removal averaged 34.3% when the gas–water ratio was greater than 3:1 and the reflux ratio was 0.5. The effluent concentration and removal efficiency of NH4+-N averaged respectively 2.3 mg L−1 and 78.5%. The overall reduction of total phosphorus (TP) was 30% and the average effluent concentration was 0.95 mg L−1. The removal efficiency of linear alkylbenzene sulfonates (LAS) reached 83.8% and the average effluent concentration was almost 0.9 mg L−1. The effluent concentration and removal efficiency of polychlorinated biphenyls (PCBs) were 0.0654 µ g L−1 and 37.05% respectively when the influent concentration was 0.1039 µ g L−1. The excess sludge containing water (volume 15 m3) was discharged once every 3 months. The power consumption of aeration was 0.06–0.09 kWh of sewage treated. The results show that the HFB–BAF combined technology is suitable for the treatment of low-concentration municipal sewage in south China. Copyright © 2005 Society of Chemical Industry
Co-reporter:Yurong Yin, Yongyou Hu, Fen Xiong
International Biodeterioration & Biodegradation (October 2011) Volume 65(Issue 7) pp:1012-1018
Publication Date(Web):1 October 2011
DOI:10.1016/j.ibiod.2011.08.001
Sorption of Cu(II) and Cd(II) onto the extracellular polymeric substances (EPS) produced by Aspergillus fumigatus was investigated for the initial pH of the solution, EPS concentrations, contact time, NaCl concentration, initial metal ion concentration and the presence of other ions in the solution. The results showed that the adsorption of metal ions was significantly affected by pH, EPS concentrations, initial metal concentration, NaCl concentration and co-ions. The sorption of Cu(II) and Cd(II) increased with increasing pH and initial metal ion concentration but decreased with an increase in the NaCl concentration. The maximum sorption capacities of A. fumigatus EPS calculated from the Langmuir model were 40 mg g−1 EPS and 85.5 mg g−1 EPS for Cu(II) and Cd(II), respectively. The binary metal sorption experiments showed a selective metal binding affinity in the order of Cu(II) > Pb(II) > Cd(II). Both the Freundlich and Langmuir adsorption models described the sorption of Cu(II) and Cd(II) by the EPS of A. fumigatus adequately. Fourier transform infrared spectroscopy (FTIR) analysis revealed that carboxyl, amide and hydroxyl functional groups were mainly correlated with the sorption of Cu(II) and Cd(II). Energy dispersive X-ray (EDX) system analysis revealed that the ion-exchange was an important mechanism involved in the Cu(II) and Cd(II) sorption process taking place on EPS.Highlights► Extracellular polymeric substances (EPS) produced by A. fumigatus as biosorbents. ► High pH is favourable for the sorption of Cu(II) and Cd(II). ► Both the Freundlich and Langmuir models described the sorption adequately. ► Sorption of Cu(II) and Cd(II) involves carboxyl, amide and hydroxyl groups.
Co-reporter:Junfeng Chen, Shinian Liu, Jia Yan, Junjie Wen, Yongyou Hu, Weiwen Zhang
Ecological Engineering (April 2017) Volume 101() pp:75-83
Publication Date(Web):1 April 2017
DOI:10.1016/j.ecoleng.2016.11.029
•OFBR-MBR system was studied for intensive carbon and ammonium removal of municipal tail water.•The optimum ozone dosage concentration and HRT of OFBR-MBR system were 70 mg L−1 and 25 h, respectively.•Bacterial community composition in both OFBR and MBR were analyzed before and after ozone addition.•Potential application of OFBR-MBR (protection for RO membrane system) was discussed.Residual carbon and ammonium in municipal wastewater treatment plant (WWTP) tail water lead to membrane fouling, and prejudice the operation and life time of reverse osmosis (RO) membrane. In this study, a new combined treatment system of ozone oyster shells fix-bed bioreactor (OFBR)-membrane bioreactor (MBR) was developed and pilot scale was tested for 110 days to intensify the removal of residual carbon and ammonium in WWTP tail water. This results showed that the mean maximum COD, ammonium and TP removal efficiencies were achieved by 73%, 99% and 43%, under the optimum ozone dosage of 70 mg L−1 and HRT of 25 h. The single contribution of OFBR and MBR was 62% and 38% to COD removal, 94% and 6% to ammonium removal, 63% and 37% to TP removal, respectively. High throughput sequencing data showed that there were rich bacterial populations (>2800 species), and Deinococcus-Thermus, Firmicutes, Actinobacteria and Planctomyctes were dominant in both reactors. After addition of ozone, Deinococcus-Thermus and Planctomyctes species bacteria increased significantly in OFBR, and Firmicutes, Actinobacteria and Planctomyctes species bacteria increased remarkably in MBR, which might mainly contribute to carbon removal in OFBR and MBR, respectively. Aerobic ammonia-oxidizing bacteria, nitrite-oxidizing bacteria, and denitrifying bacteria were all existed in both reactors, which might be the main reasons for high removal efficiency of ammonium in OFBR-MBR system.
Co-reporter:Jian Sun, Yongyou Hu, Wanjun Li, Yaping Zhang, Jie Chen, Feng Deng
Journal of Hazardous Materials (30 May 2015) Volume 289() pp:108-117
Publication Date(Web):30 May 2015
DOI:10.1016/j.jhazmat.2015.02.010
•Novel PBES was explored for azo dye wastewater treatment and electricity generation.•Two-stage azo dye treatment in single chamber was achieved by polarity reversion.•Polarity reversion reduced buffer requirements and improved electrodes performance.•Synergy between alga and bacteria responsible for successful operation of the PBES.•Enhanced azo dye treatment, high net power and buffer minimization were achieved.A novel photobioelectrochemical system (PBES) was developed by acclimating algal-bacterial biofilm in both anode and cathode using Chlorella vulgaris and indigenous wastewater bacteria as inoculums. The PBES was operated in polarity reversion mode depend on dark/light alternate reaction to achieve simultaneous pH self-neutralization, azo dye degradation (Congo red) and bioelectricity generation. The anodic accumulated acidity and cathodic accumulated alkalinity were self-neutralized after polarity reversion and hence eliminate the membrane pH gradient. The Congo red was first decolored in the dark anode and the resultant decolorization liquid was subsequently mineralized after the dark anode changing to the photo-biocathode. The presence of C. vulgaris significantly enhanced the two-stage degradation of Congo red, with 93% increases in decolorization rates and 8% increases in mineralization compared to the algae-free BES. The PBES continuously generated stable voltage output over four months under repeatedly reversion of polarity. The maximum power density produced before and after polarity reversion was 78 and 61 mW/m2, respectively. The synergy between C. vulgaris and mixed bacteria was responsible for the successful operation of the PBES which can be potentially applied to treat wastewater containing azo dye with benefits of enhanced azo dye degradation, high net power output and buffer minimization.Download full-size image
Co-reporter:Wantang Huang, Junfeng Chen, Yongyou Hu, Jie Chen, Jian Sun, Lihua Zhang
International Journal of Hydrogen Energy (26 January 2017) Volume 42(Issue 4) pp:2349-2359
Publication Date(Web):26 January 2017
DOI:10.1016/j.ijhydene.2016.09.216
Co-reporter:Bao-e WANG, Yong-you HU
Journal of Environmental Sciences (2007) Volume 19(Issue 4) pp:451-457
Publication Date(Web):1 January 2007
DOI:10.1016/S1001-0742(07)60075-8
Four materials sodium carboxymethylcellulose (Na-CMC) sodium alginate (SA) polyvinyl alcohol (PVA) and chitosan (CTS) were prepared as supports for entrapping fungus Aspergillus fumigatus. The adsorption of synthetic dyes Reactive Brilliant Blue KNR and Reactive Brilliant Red K-2BP by these immobilized gel beads and plain gel beads was evaluated. The adsorption efficiencies of Reactive Brilliant Red K-2BP and Reactive Brilliant Blue KN-R by CTS immobilized beads were 89.1% and 93.5% in 12 h respectively. The adsorption efficiency by Na-CMC immobilized beads was slightly lower than that of mycelial pellets. But the dye culture mediums were almost completely decolorized in 48 h using the above-mentioned two immobilized beads (exceeding 95%). The adsorption efficiency by SA immobilized beads exceeded 92% in 48 h. PVA-SA immobilized beads showed the lowest adsorption efficiency which was 79.8% for Reactive Brilliant Red K-2BP and 92.5% for Reactive Brilliant Blue KN-R in 48 h. Comparing the adsorption efficiency by plain gel beads Na-CMC plain gel beads ranked next to CTS ones. SA and PVA-SA plain gel beads hardly had the ability of adsorbing dyes. Subsequently the growth of mycelia in Na-CMC and SA immobilized beads were evaluated. The biomass increased continuously in 72 h. The adsorption capacity of Reactive Brilliant Red K-2BP and Reactive Brilliant Blue KN-R by Na-CMC immobilized beads was 78.0 and 86.7 mg/g respectively. The SEM micrographs show that the surface structure of Na-CMC immobilized bead is loose and finely porous which facilitates diffusion of the dyes.
Co-reporter:Yuancai Lv, Zhuyu Niu, Yuancai Chen, Yongyou Hu
Water Research (15 May 2017) Volume 115() pp:297-308
Publication Date(Web):15 May 2017
DOI:10.1016/j.watres.2017.03.012
•Bactericidal effects of nZVI/Pd nanoparticles on Pseudomonas putida were evaluated.•Flow Cytometry was employed to analyze the change of cell structure by nZVI/Pd.•Physical disruption was the dominant inactivation mechanism (anaerobic).•Inactivation involved both the physical disruption and oxidative stress (aerobic).•nZVI/Pd caused a severe change of peptides and polysaccharides on cell surface.With the introduction of nano zero valent iron (nZVI) technology into our environment, its potential environmental risk to environmental microorganisms has attracted considerable attention. In this study, Pseudomonas putida was chosen as a typical strain to study the bacterial toxicity of nZVI/Pd. The CFU assay results indicated that nZVI/Pd was toxic to P. putida cells but the toxicity decreased with an increase in DO. The experiments isolated by dialysis bag and flow cytometry analysis suggested that both membrane disruption caused by direct contact and oxidative stress were the main bactericidal mechanisms under the aerobic condition, while membrane disruption resulting from direct contact was the primary bactericidal mechanism in the anaerobic system. Furthermore, according to TEM, SEM, EDS, XRD, FTIR and XPS, it was indicated that in the aerobic system, the reactive oxygen species (ROS) generated by nZVI/Pd could oxidize the amide and hydroxyl groups into carboxyl groups, resulting in a decline in peptides and increase in polysaccharides. In addition, the ROS also accumulated inside the cell and caused cell inactivation via oxidative stress. In the anaerobic system, the adhered nZVI/Pd particles would attack the functional groups such as carboxyl, ester and amide, leading to the decline in proteins and polysaccharides and subsequent damage of the membrane. The findings provide a significant guide for the application of nano-bio combined technology.Download high-res image (346KB)Download full-size image
