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Ar-calcined NCS-CoPt shows a robust HER activity owing to its highly active CoPt3 sites and pyridinic N enriched carbon nanosheets.

Rational design of low-cost and efficient electrocatalyst for the anodic oxygen evolution reaction (OER) to replace noble-metal-based catalysts is greatly desired for the large-scale application of water electrocatalysis. And compared with the conventional powdery catalysts, the freestanding electrode architecture is more attractive owing to the enhanced kinetics and stability. In this work, we report an electrospinning-carbonization-post oxidation strategy to develop the freestanding N-doped carbon nanofibers anchored with Ni/NiO nanoparticles (denoted as Ni/NiO-NCNFs) as efficient OER electrocatalyst. In the synthesized Ni/NiO-NCNFs, the conductive ultrathin carbon layer could promote electron transfer and thus improve the electrocatalytic activity. Meanwhile, the ratio between Ni and NiO could be regulated by tuning the oxidation duration, so as to optimize the adsorption energy of intermediates and improve the OER activity. The Ni/NiO-NCNFs prepared with the oxidation time of 3 h exhibit a promising OER activity and long-term operation durability in 0.1 M KOH solution, requiring an overpotential as small as 153 mV to achieve a current density of 10 mA cm

The cerebral ischemic stroke is a major type of stroke characterized by brain injury, neurological deficits, and cognitive impairments, which accounts for increased disability and mortality worldwide. The present study focusses to investigate the therapeutic efficacy of ononin against the ischemic stroke induced by ischemia–reperfusion (I/R) injury via suppression of I/R injury stimulated neuroinflammation in rat model. Animals were separated into four groups as Sham, I/R induced, I/R + ononin pretreated (10 mg/kg body weight), and I/R + ononin pretreated (20 mg/kg body weight). The ischemic stroke was stimulated in animals by middle artery occlusion method as described previously. The infarct volume, brain edema, and neurological deficits were studied by standard methods. The oxidative stress markers like SOD, CAT, GSH, GSH-Px, Cu/Zn-SOD, Mn-SOD, MDA, and acetylcholinesterase were assessed by previously described methods. The contents of TNF-α, IL-1β, and IL-6 were assessed using assay kits. The in vitro studies were performed using SH-SY5Y neuroblastoma cells. The level of Ononin given at 10 and 20 mg/kg body weight resulted in increase in water content, reduced volume of infarct, improved neurological deficit score, and exerted its antioxidant, anti-inflammatory and neuroprotective efficacy against cerebral I/R injury-induced rats. Increase in proinflammatory cytokine expression was observed in cerebral I/R injury-stimulated rats. Oxygen glucose deprivation/ reoxygenation (OGD/R) injury showed reduction in cell viability of SH-SY5Y cells which was attenuated following treatment with ononin at varying concentrations. Ononin has reduced proinflammatory cytokine expression in vitro. Thus, ononin has successfully attenuated I/R injury-induced neuroinflammation in rats and thus minimized neuronal injury. Therefore, all the findings of the study depicts that ononin can thus be used as a beneficiary move toward treatment of cerebral I/R injury.

Ischemic heart disease (IHD) is one of the leading causes of mortality worldwide. Moreover, the effects of air pollution have been associated with several cardiovascular diseases (CVDs). The relationship between sandstorm weather and IHD is unknown. The Hexi Corridor is located in northwestern China and is a typical desert region comprising a large area of desert with a high incidence of sandstorms. This study aimed to explore the association between sandstorm weather and IHD-related mortality in this area. We acquired meteorological data of sandstorm weather from 2006 to 2015 from the Gansu Meteorological Bureau, and data regarding deaths due to IHD in five cities within the Hexi Corridor were collected from the death registration system of the Center for Disease Control of Gansu during the same period. Two other cities with few sandstorm events were selected as control regions. The time series method of the generalized additive model (GAM) was used to assess the association between sandstorm weather and IHD-related mortality in the Hexi Corridor. The results showed that the frequency of sandstorms in the Hexi Corridor was higher than that in the control regions (5.48% vs 1.64%, P

Asymmetric carbon molecular sieve (CMS) membranes prepared from cellulose hollow fiber precursors were investigated for H2/CO2 separation in this work. The prepared carbon membrane shows excellent separation performance with H2 permeance of 111 GPU and an H2/CO2 selectivity of 36.9 at 10 bar and 110 °C dry mixed gas. This membrane demonstrates high stability under a humidified gas condition at 90 °C and the pressure of up to 14 bar. A two-stage carbon membrane system was evaluated to be techno-economically feasible to produce high-purity H2 (>99.5 vol%) by HYSYS simulation, and the minimum specific H2 purification cost of 0.012 $/Nm3 H2 produced was achieved under the optimal operating condition. Sensitivity analysis on the H2 loss and H2 purity indicates that such membrane is still less cost-effective to achieve ultrapure hydrogen (e.g., >99.8 vol%) unless the higher operating temperatures for carbon membrane systems are applied.

Carbon molecular sieve (CMS) membranes with rigid and uniform pore structures are ideal candidates for high temperature- and pressure-demanded separations, such as hydrogen purification from the steam methane reforming process. Here, we report a facile and scalable method for the fabrication of cellulose-based asymmetric carbon hollow fiber membranes (CHFMs) with ultramicropores of 3–4 Å for superior H2 separation. The membrane fabrication process does not require complex pretreatments to avoid pore collapse before the carbonization of cellulose precursors. A H2/CO2 selectivity of 83.9 at 130 °C (H2/N2 selectivity of >800, H2/CH4 selectivity of >5700) demonstrates that the membrane provides a precise cutoff to discriminate between small gas molecules (H2) and larger gas molecules. In addition, the membrane exhibits superior mixed gas separation performances combined with water vapor- and high pressure-resistant stability. The present approach for the fabrication of high-performance CMS membranes derived from cellulose precursors opens a new avenue for H2-related separations., Energy-efficient hydrogen purification technologies are needed for the hydrogen economy. Here the authors report facile and scalable fabrication of asymmetric carbon molecular sieve membranes for the separation of hydrogen and carbon dioxide.

This chapter describes the gas separation performances of different types of carbon membranes such as self-supported hollow fibers, supported flat sheets, and those supported on ceramic tubes. Unsupported flat-sheet carbon membranes have been widely studied to investigate material properties. It is, however, difficult to upscale their production because of the fragility of the carbon membranes. Thus, the development of high-performance supported tubular carbon membranes and self-standing carbon hollow fiber membranes is crucial to meet industrial needs. Self-supported hollow fibers potentially have a lower cost and are applicable for larger gas volumes, whereas the supported carbon membranes, which have a lower packing density, will probably be a good choice for medium to small gas volumes. Asymmetric carbon hollow fiber membranes produced without complex pretreatment have great potential if the problem of continuous production can be solved.

Carbon hollow fiber membranes (CHFMs) were fabricated based on cellulose hollow fiber precursors spun from a cellulose/ionic liquid system. By a thermal treatment on the precursors using a preheating process before carbonization, the micropores of the prepared CHFMs were tightened and thus resulting in highly selective carbon molecular sieve (CMS) membranes. By increasing the drying temperature from RT to 140 °C, the cellulose hollow fiber precursors show a substantial shrinkage, which results in a reduction of average pore size of the derived CHFMs from 6 to 4.9 Å. Although the narrowed micropore size causes the decrease of gas diffusion coefficient, stronger resistance to the larger gas molecules, such as CH4, eventually results in an ultra-high CO2/CH4 ideal selectivity of 917 tested at 2 bar for CHFM-140C due to the simultaneously enhanced diffusion and sorption selectivity. The CHFM-140C was further tested with a 10 mol%CO2/90 mol%CH4 mixed gas at 60 °C and feed pressure ranging from 10 to 50 bar. The obtained remarkable CO2/CH4 separation factor of 131 at 50 bar and good stability make these carbon membranes great potential candidates for CO2 removal from high-pressure natural gas. https://doi.org/10.1016/j.memsci.2020.118529. 0376-7388/© 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license http://creativecommons.org/licenses/by/4.0/

Carbonized cellulose -based hollow fiber membranes were prepared by dry-wet spinning phase inversion method, followed by carbonization and evaluated in terms of gas separation performance for CO2/N2 and CO2/CH4 mixtures, under flow conditions. Permeability and real selectivity were measured for both mentioned mixtures, in a temperature range of 25 °C to 60 °C, a differential pressure range of 8 bar(a) to 20 bar(a) and a CO2 concentration range from 5% v/v to 15% v/v. The highest yielding mixture selectivity values were 42 for CO2/N2 at 10% v/v CO2, 25 °C & 8 bar(a) and around 150 for CO2/CH4 at the same conditions, whereas the respective CO2 permeabilities were 110 and 45 Barrer. Additionally, experiments of varying head pressure, while maintaining differential pressure, transmembrane pressure, at 8 bar(a), have revealed that CO2/N2 separation factor can be further enhanced with real selectivity being raised to 55 and permeability to 180 at 20 bar head pressure. The same approach had negligible effect on CO2/CH4 separation. This is an important finding by taking into consideration that natural gas treatment, i.e. sweetening and purification processes, is energetically and economically convenient if it takes place under the conditions, where the NG stream is extracted from the wells, or after a decompression. Moreover, Process simulation indicates that a two-stage system using the developed carbon membranes is technologically feasible to produce 96% methane with a low methane loss of

CO2 removal from gas streams using energy-efficient and environmentally friendly separation technologies can contribute to achieving a low-carbon energy future. Carbon membrane systems for hydrogen purification, post-combustion CO2 capture, and natural gas (NG) sweetening are considered as green processes because of their low energy consumption and negligible environmental impact. Much effort has been devoted to enhancing gas permeance and/or selectivity of carbon membranes by tailoring micropore structures to accomplish different CO2 removal processes. In this review, the status of tuning microstructure and fabrication of the ultrathin selective layer of carbon membranes, as well as membrane module upscaling was analyzed. The precursors made from a clean process using the solvent of ionic liquids have a particular interest, and high-performance asymmetric carbon hollow fiber membranes (CHFMs) without complex pre-treatment were highlighted towards technology advances of carbon membrane development. Energy-efficient processes of carbon membranes for CO2 removal in oil/gas/chemical industries and power plants were discussed for decreasing production costs, environmental impact, energy consumption, and improving process flexibility. Future perspectives on advanced carbon membrane material development based on renewable precursors and simple carbonization processes, as well as module design and process optimization, were proposed. This is an open access article distributed under the terms of the Creative Commons CC-BY license, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Graphene oxide (GO) membranes have shown great promise in pervaporation dehydration of biofuels, expected to satisfy the demand of lower energy consumption. However, the swelling of interlayer spacing between GO nanosheets in aqueous environment, usually leads to deteriorated membrane separation performance and limited stability. Here, we report ultra-permeable sulfonated carbon quantum dots (SCDs)/GO composite membranes that are designed through strategically introducing the functional quasi-spherical nanoparticles - SCDs as water transport promoters and crosslinker into GO laminates. Well self-assembly stacked manner between SCDs and GO nanosheets created highly hydrophilic two-dimensional sub-nanometer confinement interlayer channels for fast water transport, while the crosslinking effect between SCDs and GO nanosheets producing a stable microstructure to maintain GO interlayer spacing against swelling. Furthermore, the SCDs occupied the vacancies around the ordered edges of GO nanosheets also resulted in an enhancement of water selective permeation. The microstructure evolution was confirmed by low-field nuclear magnetic resonance spectra. The prepared SCDs/GO membrane on polyethersulfone (PES) substrate with ∼150 nm selective layer exhibited a total flux of 5.88 kg m−2 h−1 and water/butanol separation factor of ∼4407 at 343 K, which outperforms the performance of state-of-the-art membranes reported to date. Meanwhile, the thin composite membrane showed long-term operation stability for 130 h when fed with 90 wt% butanol/water solution. This research provides a promising method for the selective water separation of high-performance GO membranes.

Biohydrogen production from biomass through dark fermentation provides a great potential to achieve a green hydrogen economy for sustainable energy development. However, the purification of fermentative biohydrogen usually contains 30–40 vol% CO2 at small-scale plants requires advanced separation technologies. Carbon molecular sieving membranes are considered as an alternative solution in this application. This work focuses on the techno-economic feasibility analysis of H2-selective carbon membrane systems for biohydrogen enrichment by investigation of process design, optimization of operating parameters, and the selection of membrane materials. High vacuum operation on the permeate is favorable to reduce the specific cost as the membrane-related capital cost is dominating the total cost. While the operation with feed gas compression provides better separation performance, and the minimum specific cost of $ 0.026/Nm3 at 6 bar was identified to achieve the hydrogen recovery of 90%. A two-stage carbon membrane system is technically feasible to reach the biohydrogen purity of >99.5 vol% with the specific cost of $ 0.06/Nm3, which is lower than pressure swing adsorption. The sensitivity analysis indicates that the carbon membrane system is scalable and flexible in responding to the variation of plant capacity with the feed flow ranges from 500 to 2500 Nm3/h without significant changes in production cost. Compared to the enhancement of membrane selectivity, improving hydrogen permeance by developing submicrometer asymmetric carbon membranes is urgently needed to increase its competitiveness for biohydrogen purification.

Ordered nanostructured cathodes based on controlled vertically aligned Pt nanotubes are fabricated via combining sacrificial template method and in-situ galvanic replacement for ultra-low Pt loading passive direct methanol fuel cells (DMFCs). The Pt nanotubes are composed of highly dispersed Pt nanoparticles shell with an average thickness of ca. 15 nm. Employed as the oxygen reduction reaction (ORR) electrocatalyst, it exhibits similar activity but better durability than that of the commercial Pt black. Serving as the cathode for passive DMFC, a high electrochemical specific area of 77.48 m 2 g −1 (Pt) is obtained by the ordered nanostructured cathode, which is 3 times higher than that of the conventional Pt/C based cathode (19.46 m 2 g −1 (Pt) ), indicating a significant improvement in the Pt catalyst utilization. Impressively, the Pt loading at the cathode side can be reduced to approximately 1/7 (0.12 mgcm −2 ) of the conventional MEA without sacrificing cell performance by using the vertically aligned Pt nanotubes catalytic layer. This method may provide a new way to fabricate ordered nanostructured cathode for ultra-low Pt loadings fuel cells.

Background: The mortality rate of coronary heart disease (CHD) in China is different from region to region, and there are sex, age and urban-rural differences. This study described trend and distribution of CHD in Hexi corridor of Gansu province from 2006 to 2015. Method: The death data of CHD were obtained using the Death Reporting System of Gansu CDC for 2006-2015. The trend of the death cases of CHD by year, month and its distribution by sex, age and region were studied, and the changing characteristics of epidemiology was analyzed. Results: Overall, The mortality rate of CHD in Hexi corridor showed a decline trend from 2006 to 2015, a tendency that higher in winter and spring, and lowest in summer. The relative mortality of males was higher than that of females ( P < 0.05), increased with age ( P < 0.05), and that of rural areas was higher than that of urban areas ( P < 0.05). The trend analysis of death rate for ten-year showed a marked decline in females, an increase in 18-39 years old, a small change in 40-59 years old, a decrease in over 60 years old, and a downward tendency of urban areas. Further analysis showed that the mortality rate of males were higher than that of females in 18-39 years old and 40-59 years old group and also in urban areas group ( P < 0.05), while no sex difference in over 60 years old group and rural areas group ( P > 0.05). Conclusion: The mortality of CHD in Hexi corridor of Gansu province in China was lower than the national average from 2006 to 2015, but increased gradually in specified population such as in males, young and middle-age, rural areas groups. The prevention and control measures should be strengthened in these special populations.

Novel carbon hollow fiber membranes (CHFMs) have been, for the first time, prepared from cellulose precursors directly spun with a cellulose/(1-ethyl-3-methylimidazolium acetate (EmimAc) + dimethyl sulfoxide (DMSO)) system. The spinning parameters such as air gap, dope and bore flow, bore fluid composition, and take-up speed are investigated by a factorial design method to screen hollow fiber precursors. All the precursors were carbonized using the same controlled protocol, and the prepared CHFMs show good performance that are above the Robeson upper bounds of CO2/CH4 and O2/N2. The best obtained CHFMs shows a CO2 permeability of 239 barrer and a CO2/CH4 selectivity of 186 from single gas permeation measurement. The CHFM shows attractive CO2/CH4 selectivities of 75 and 50 from 10% CO2/90% CH4 permeation tests at 25 °C with a feed pressure of 28 bar, and at 60 °C with 8 bar, respectively. Thus, the developed cellulose-based CHFMs show potential for gas separation.

Hollow fiber membranes show a great potential in natural gas sweetening by removing CO2 to meet gas grid specifications. A membrane model with high prediction accuracy is developed to model multicomponent gas transport through hollow fiber modules. The influences of hollow fiber diameter and length, and packing density on module efficiency related to pressure drops in both sides were systematically investigated based on the developed model. The total pressure drop along the length is less than 1% if the inner diameter of hollow fibers (0.6 m length) is larger than 200 μm. Moreover, the highest module packing density was found to be dependent on hollow fiber dimension, and too high packing density will cause extreme high pressure drops. Both feed CO2 concentration and pressure were found to significantly influence membrane module performance related to the required specific membrane area and hydrocarbon loss based on process parametric study of CO2 removal from natural gas. Larger pressure drops along fiber length was found for the more-permeable polyimide membranes compared to the less-permeable cellulose acetate and carbon membranes. The developed model can be used for guiding the design of efficient hollow fiber membrane modules and potentially process simulation of membrane gas separation. © 2019 The Author(s). Published by Elsevier B.V.on behalf of Institution of Chemical Engineers. This is an open access article under the CCBY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Utilization of the low concentration methane from coal-mining ventilation air is challenging but can significantly contribute to the mitigation of methane emissions to the atmosphere. This work focuses on the techno-economic feasibility analysis of N2-selective membrane systems for the enrichment of ventilation air methane (VAM). The feed methane concentration and gas permeance are found to significantly influence the specific methane enrichment cost, while feed pressure has the lest effect. For a stand-alone membrane system, the optimal methane recovery of ca. 70% is identified to achieve a higher methane purity at the same cost, which may gain an economic benefit when it is operated at high plant capacity. Although the SAPO-34 membrane system is technologically feasible for the enrichment of 1.5 vol% VAM, novel membranes with a higher N2/CH4 selectivity of greater than 25 is required to reduce the membrane stages for the pre-concentration of a very diluted VAM of

Compared with commercial polymeric membranes for natural gas (NG) sweetening, the facilitated transport (FT) membranes present a great potential to reduce methane loss with the improved CO2/CH4 selectivity at high pressure operation. Different types of FT membranes together with their advantages and challenges have been reviewed. The carbon nanotube–reinforced polyvinylamine-based fixed-site-carrier membranes were identified as one of the most promising materials in this application. This chapter also provided a clear overview on the process parameter influences on the membrane separation performance for CO2 removal from NG. The technology feasibility was also discussed from the process simulation point of view. Finally, the future perspective on the membrane material and process development for NG sweetening was described.