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61.
《Journal of the European Ceramic Society》2017,37(9):3185-3193
Nanocrystalline TiO2 coated scaffolds offers the possibility to be used in bone tissue regeneration providing not only space for new tissue formation, but also to enhance bioactivity of the implant. In the present study, direct current electrophoretic deposition (EPD) was chosen as simple and low cost technique to coat 3D porous structure of TiO2-x ceramic. Suspension for EPD was prepared suspending nanocrystalline TiO2 particles in isopropanol and adding triethanolamine as dispersant. TiO2 particles were electrophoretically deposited on the surface of TiO2-x scaffolds through varying EPD time and applied voltage. The scaffold pore structure was maintained after applying the coating by EPD. The deposition of nanocrystalline TiO2 coating can be a smart strategy to impart bioactive properties to the 3D scaffold, allowing formation of spherical hydroxyapatite particles on the coated scaffolds after immersion in simulated body fluid. In vitro cell studies does not show cytotoxic effect of nanocrystalline TiO2 coated scaffolds. 相似文献
62.
《International Journal of Hydrogen Energy》2020,45(56):32413-32422
Microbial fuel cells (MFCs) represent a new approach that can simultaneously enhance the treatment of waste streams and generate electricity. Although MFCs represent a promising technology for renewable energy production, they have not been successfully scaled-up mainly due to the relatively-low electricity generation and high cost associated with MFCs operation. Here, we investigated whether graphitic mesoporous carbon (GMC) decoration of carbon felt would improve the conductivity and biocompatibility of carbon felt anodes, leading to higher biomass attachment and electricity generation in MFCs fed with an organic substrate. To test this hypothesis, we applied 3 different GMC loading (i.e., 2, 5, and 10 mg/cm2 of anode surface area) in MFCs compared to control MFCs (with pristine carbon felt electrodes). We observed that the internal resistances of modified anodes with GMC were 1.2–2.3-order of magnitude less than pristine carbon felt anode, leading to maximum power densities of 70.3, 33.3, and 9.8 mW/m2 for 10, 5, and 2 mg/cm2-doped anode, respectively compared to only 3.8 mW/m2 for the untreated carbon felt. High-throughput sequencing revealed that increasing the GMC loading rate was associated with enriching more robust anode-respiring bacteria (ARB) biofilm community. These results demonstrate that 3-D GMC-doped carbon felt anodes could be a potential alternative to other expensive metal-based electrodes for achieving high electric current densities in MFCs fed with organic substrates, such as wastewater. Most importantly, high electron transfer capability, strong chemical stability, low cost, and excellent mechanical strength of 3-D GMC-doped carbon felt open up new opportunities for scaling-up of MFCs using cheap and high-performance anodes. 相似文献
63.
《International Journal of Hydrogen Energy》2020,45(11):6563-6572
It remains urgent to make continuous efforts on well-designed and highly active non-precious metal (NPM) electrocatalysts for the cathodic oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs), thus helping greatly reduce the fuel cell cost. Due to an unsatisfied stability caused by Fenton reaction for Fe-based materials, Co-based materials bear much more expectations as one type of NPM electrocatalysts to be applied in the ORR. Here we report a novel strategy to synthesize a series of mesoporous nitrogen-doped carbon-supported cobalt electrocatalysts (Co-DCD-CA), which takes full advantage of electrostatic interaction between carboxyl in citric acid (CA) and amidogen in dicyandiamide (DCD) as well as chelating interaction between citric acid and cobalt cation. When CA is employed as carbon source, the optimal derivative of the Co-DCD-2-CA-900 electrocatalyst exhibits a higher ORR activity with a half-wave potential at 0.75 V, which is 60 mV higher than that prepared using Ketjenblack EC 300 J (Co-DCD-2-EC-900) as the carbon support. Besides, the effects of pyrolysis temperature as well as DCD to CA ratio on the ORR activity are detailedly investigated. 相似文献
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66.
A novel Cu-Mn-Ce/cordierite honeycomb catalyst was prepared by an incipient wetness method and the catalyst was characterized. The active ingredients were present as various spinel species of Cu, Mn and Ce oxides with different valences and they were unevenly dispersed over the surface of the catalyst. The catalytic oxidation of gaseous toluene was primarily investigated using a fixed bed reactor under microwave heating in the continuous flow mode. Under the optimal conditions of 6.7 wt-% loading of the active component, a bed temperature of 200℃, a flow rate of 0.12 m^3 · h^-1 and an initial concentration of toluene of 1000 mg·m^-3, the removal and mineralization efficiencies of toluene were 98% and 70%, respectively. Thus the use of the microwave effectively improved the oxidation of toluene and this is attributed to dipole polarization and hotspot effects. After four consecutive cycles (a total of 1980 min), the Cu-Mn- Ce/cordierite catalyst still exhibited excellent catalytic activity and structural stability, and the toluene removal was higher than 90%. This work demonstrates the possibility of treating volatile organic compounds in exhaust gases by microwave-assisted catalytic oxidation. 相似文献
67.
Gaojun Wang Qian Li Chaosui Yuwen Kai Gong Li Sheng Yu Li Yao Xing Rong Chen 《International Journal of Hydrogen Energy》2021,46(15):9666-9677
Rapid methanogenesis recovery of an acidified anaerobic digestion (AD) system is a challenging issue in engineering application, due to the unfavorably thermodynamics of volatile fatty acids (VFA) syntrophic oxidation process with hydrogen as electron transfer mediator. To breakthrough this bottleneck, in this study, we developed the strategy with biochar as an additive for rapid methanogenesis recovery of a severely acidified AD system is elucidated. First, with VFA as substrate, it was found that biochar addition shortened lag time and promoted maximum methane production rate, confirming the role of biochar to enhance VFA syntrophic oxidation. Moreover, the addition of biochar to the acidified sludge significantly decreased hydrogen partial pressure, which thermodynamically stimulated VFA oxidation by reducing Gibbs free energy. Microbial community analysis delivered that biochar addition largely altered the dominant microbes. The enrichment of electro-active Syntrophomonas and Methanosarcina suggested the role of biochar as potential redox-active mediator to stimulate potential direct interspecies electron transfer between syntrophic microorganisms, and inhibit hydrogen-based syntrophic pathway simultaneously. Further stable operation confirms that biochar is a promising additive for the rapid methanogenic recovery of acidified AD systems. 相似文献
68.
好氧颗粒污泥处理综合城市污水的中试研究 总被引：1，自引：0，他引：1
采用好氧颗粒污泥技术对水质波动较大、含大量工业废水的城市污水开展了中试研究.研究发现采用该类污水可成功培养出好氧颗粒污泥,占COD总量60%的颗粒态COD是导致所形成的颗粒不规则、结构松散且颗粒化进程较慢的主要原因.运行期间系统对COD,NH4+-N、TP的平均去除率分别为(75.80±16.09)%、(52.85±33.65)%,(66.57±22.36)%.当进水COD浓度较低时,系统的去除效果受到严重的影响.进水氨氮浓度的大幅度变化对颗粒污泥沉速、粒径的影响不明显,但对颗粒污泥密度的影响显著.氨氮冲击负荷是导致颗粒污泥解体的主要原因.因此,建议在好氧颗粒污泥工艺的运行过程中设置厌氧搅拌阶段以加快颗粒化过程及保持颗粒的长期稳定,并应避免氨氮的冲击负荷. 相似文献
69.
为了寻找替代传统铬酸盐转化的处理工艺,采用由NaF,(NH4)2SiF6,(NaPO3)6和钛盐促进剂组成的转化液,在2024铝合金表面制备了一种氟铝酸盐化学转化膜,优化了转化液组分及转化工艺条件。结果表明:最优工艺为5.0 g/L NaF,5.0 g/L(NH4)2SiF6,0.9 g/L(NaPO3)6,0.5 g/L钛盐促进剂,pH值为4.7,室温,20 min;最优工艺所得氟铝酸盐转化膜由排列紧密且形状规则的晶体颗粒组成,表面覆盖有胶状物,膜层连续而致密、呈亚光,组成(质量分数)为7.53%O,48.87%F,19.11%Na,20.78%Al,0.79%Si,1.66%P,1.26%Cu;氟铝酸盐转化膜耐蚀性优良,最优工艺所得转化膜耐盐雾腐蚀达285 h,其使铝合金在3.5%NaCl溶液中的腐蚀电位增加了58 mV,腐蚀电流密度降为钝化前的1/9。 相似文献
70.
Being able to predict the soluble microbial product (SMP) concentration, an important foulant in membrane bioreactors (MBRs), with mathematical models provides the opportunity to use foulant production as an MBR design and optimization parameter. This study examined the ability of three mathematical model structures to describe two distinct mechanisms of SMP production. The production mechanisms evaluated are (1) the erosion or hydrolysis of floc-associated extracellular polymeric substance (EPS) and (2) decay of active cells. The models were compared based on their ability to predict SMP concentrations observed in an MBR system during a period of increased SMP and floc-associated EPS production due to increased predation. Predation was an important contributor to overall biomass decay. Short-term batch experiments were also preformed to examine model assumptions related to the (1) production of SMP due to decay of active cells, (2) production of SMP due to erosion of floc-associated EPS, (3) degradability of SMP present in the MBR mixed liquor during increased predation and (4) degradability of eroded floc-associated EPS. Both erosion of floc-associated EPS and decay of active cells were shown to be important independent mechanisms of SMP production. Therefore, a mathematical model used to predict SMP concentrations should provide the ability to capture both mechanisms independently. SMP produced during increased predation were slowly degradable while eroded floc-associated EPS was rapidly degradable. Model results demonstrate that the slowly biodegradable SMP fraction will dominate the bulk phase SMP concentration. 相似文献