Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences
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Methane Hydrate Formation Promoted by -SO3--coated Graphene Oxide Nanosheets
No full textSodium dodecyl sulfate (SDS) has been reported as the most efficient kinetic promoter for hydrate-based natural gas storage and transportation; however, the foam generation during hydrate dissociation is a serious problem. In this work, we grafted the -SO3- group (similar as the hydrophilic group of SDS) on nanosheets of graphene oxide (GO) to prepare -SO3--coated GO nanosheets (sulfonate graphene oxide, SGO), which were then used to promote methane hydrate formation. For comparison, graphene (GP) and GO were also prepared and used as kinetic promoters for methane hydrate formation. Among SGO, GP, and GO, SGO produced the best promotion, which at concentrations of 0.25, 0.5, 0.75 g/L resulted in methane hydrate formation finished within 208.7 +/- 26.6, 242.3 +/- 97.6, and 312 +/- 135.5 min, respectively, with storage capacities reaching 139.7 +/- 4.7, 143.3 +/- 6.1, and 143.9 +/- 7.2 v/v, respectively. Furthermore, -SO3--coated nanosheets of SGO even produced better promotion to methane hydrate formation compared with SDS and avoided foam generation during hydrate dissociation, which has great: potential in hydrate-based natural gas storage and transportation
Efficient polymer solar cells based on poly(thieno[2,3-f]benzofuran-co-thienopyrroledione) with a high open circuit voltage exceeding 1 V
No full textA new donor-acceptor type conjugated polymer (PTBFTPD) based on two-dimensional (2D) conjugated alkylthienyl substituted thieno[2,3-f]benzofuran (TBF) and thienopyrroledione (TPD) unit, was synthesized and applied as donor material for bulk heterojunction polymer solar cells. As a comparison, its counterpart conjugated polymer (PBDTTPD) based on allcylthienyl substituted thieno[2,3-f]benzothiophene (BDT) and TPD unit, was also synthesized. The thermal properties, optical and electrochemical properties, energy levels, molecular chain orientation stacking behavior and photovoltaic properties of two polymers were intensively investigated. Both polymers showed similar optical properties. Compared with PBDTTPD, PTBFTPD shown the similar absorption properties in solution and in a thin film. PTBFTPD had a slightly narrow bandgap of 1.83 eV while that of 1.85 eV for PBDTTPD. PTBFTPD displayed a deeper highest occupied molecular orbital (HOMO) energy level of (-5.64 eV), which was 0.1 eV lower than that for PBDTTPD. The XRD study showed that PTBFTPD possessed a closer pi-pi stacking than PBDTTPD. The photovoltaic properties were investigated under various conditions, the optimized power conversion efficiency (PCE) of 433% with an open-circuit voltage (V-oc) of as high as 1.09 V were obtained, which resulted in a 32% improvement in comparison with PBDTTPD/PC71BM-based device under the same conditions. (C) 2017 Elsevier Ltd. All rights reserved
Strong anion receptor-assisted boron-based Mg electrolyte with wide electrochemical window and non-nucleophilic characteristic
No full textHerein we present a strong anion receptor-assisted Mg-ion electrolyte, which is synthesized from tris(2H-hexafluoroisopropyl) borate (THFPB) and MgO in 1,2-dimethoxyethane (DME). The as-prepared borate magnesium oxide complex (BMOC) electrolyte delivers exceptional electrochemical performances, including extremely high anodic stability (up to 4.2 V vs. Mg), non-corrosivity to stainless steel and aluminium foils, and reasonable ionic conductivity of 1.74 x 10(-4) S cm(-1). In addition, by virtue of the non-nucleophilic characteristic of the BMOC electrolyte, S|| BMOC|| Mg cells have been assembled, which show a high stable discharge capacity of 1030 mAh g(-1) for 15 cycles and one well-defined voltage plateau of approximate to 1.1 V vs. Mg, yielding a desirable energy density beyond 1100 Wh kg(-1) based on the weight of sulfur in cathodes
Elimination of methane in exhaust gas from biogas upgrading process by immobilized methane-oxidizing bacteria
No full textBiogas upgrading is essential for the comprehensive utilization of biogas as substitute of natural gas. However, the methane in the biogas can be fully recovered during the upgrading process of biogas, and the exhaust gas produced during biogas upgrading may contain a very low concentration of methane. If the exhaust gas with low concentration methane releases to atmosphere, it will be harmful to environment. In addition, the utilization of large amounts of digestate produced from biogas plant is another important issue for the development of biogas industry. In this study, solid digestate was used to produce active carbon, which was subsequently used as immobilized material for methane-oxidizing bacteria ( MOB) in biofilter. Biofilter with MOB immobilized on active carbon was used to eliminate the methane in exhaust gas from biogas upgrading process. Results showed porous active carbon was successfully made from solid digestate. The final methane elimination capacity of immobilized MOB reached about 13 mol h(-1) m(-3), which was more 4 times higher than that of MOB without immobilization. (C) 2017 Elsevier Ltd. All rights reserved
Poly(ethyl alpha-cyanoacrylate)-Based Artificial Solid Electrolyte Interphase Layer for Enhanced Interface Stability of Li Metal Anodes
No full textThe inhomogeneous deposition/dissolution of Li metal and an unstable SEI layer are still tough issues for lithium metal batteries, causing severe safety problems and low Coulombic efficiency. In this paper, we design an artificial SEI layer based on in situ polymerization of ethyl a-cyanoacrylate precursor with LiNO3 additive. The CN- and NO3- groups can react with lithium metal during cycling to form a nitrogenous interface inorganic layer, facilitating ions conduction and blocking further undesirable interface reaction. The poly(ethyl a-cyanoacrylate) with excellent mechanical property presents as the dominate organic species in the artificial SEI layer to offer a uniform and firm protective outer layer. A lithium metal battery with this artificial SEI film exhibits a capacity retention of 93% even after 500 cycles at a rate of 2C. A smooth surface morphology of the lithium metal anode is obtained without any cracks and dendrites
Catecholic Coating and Silver Hybridization of Chitin Nanocrystals for Ultrafiltration Membrane with Continuous Flow Catalysis and Gold Recovery
No full textDespite great advantages of chitin for water purification, current researches have lacked the intensive study for the utilization of chitin in high-flux filters. To tackle this, we proposed, for the first time, a facile method for the construction of multifunctional nanoporous chitin ultrafiltration membranes derived from renewable marine resources (shells of shrimp and crab). Chitin nanocrystals with average diameter and length of 43.3 and 446.1 nm were prepared by H2SO4 hydrolysis, and a simple vacuum-filtration method was utilized to convert these uniform dispersed nanocrystals to nanoporous membranes. To greatly improve the permeation flux and functionality of the filtration membranes, a bioinspired dopamine coating procedure was adopted to intercalate high content silver nanoparticles (57.2 wt %) into the chitin nanocrystal matrix, which might construct interfacial regions and foster low-resistance channels for enhancing solvent permeability. The resulting hybrid chitin membranes possessed numerous interconnected nanopores and its thickness could be easily tuned from 100 to 4000 nm by the volume of filtered nanocrystal suspensions. They allow fast permeation of water during vacuum assisted filtration. Typically, the flux of 100 nm thick hybrid filtration membranes with similar to 4 nm cutoff was up to 13400 L m(-2) h(-1) bar(-1), which was nearly 3 orders of magnitude higher than that of commercial filtration membranes. More importantly, the hybridization of Ag nanoparticles also offered the membranes with continuous flow properties, for example, super catalytic activity and substitution reactivity in decomposing toxic organic pollutants and recycling noble Au ions in water
Structural dependence on the property of chiral stationary phases derived from chitosan bis(arylcarbamate)-(amide)s
No full textThe goal of present study was to investigate the structural dependence of chitosan derivatives on enantioseparation and mobile phase tolerance of the corresponding chiral packing materials for liquid chromatography. Hence, a series of chitosan bis(arylcarbamate)-(n-pentyl amide)s and the related chiral stationary phases (CSPs) were prepared from chitosans with different molecular weights. Because of the H-bond formed via CH3-pi interaction, the CSP bearing methyl substituent exhibited high tolerance than the ones bearing dichloro substituents. The CSP derived from the chitosan bis(3,5-dichlorophenylcarbamate)-(n-pentyl amide) with a higher molecular weight possessed high tolerance to mobile phases, whereas the enantioseparation capability of this CSP was not as good as that of the one prepared from the chitosan derivative with a lower molecular weight. Therefore, enantioseparation capability and mobile phase tolerance have to be counterbalanced in designing chiral selectors for the CSPs derived from chitosan bis(arylcarbamate)-(amide)s. (C) 2017 Elsevier Ltd. All rights reserved
Toward Fast Pyrolysis-Based Biorefinery: Selective Production of Platform Chemicals from Biomass by Organosolv Fractionation Coupled with Fast Pyrolysis
No full textThe heterogeneous structure of biomass causes the complex compositions of bio-oil, thereby posing huge challenges for the extraction of value-added chemicals from bio-oil and the catalytic upgrading of bio-oil in existing petroleum-refining infrastructures. In order to overcome these challenges, a new advanced biorefinery based on organosolv fractionation coupled with fast pyrolysis is first proposed. The experimental results showed that biomass can be effectively divided into cellulose-rich fractions, organosolv lignins, and xylose by organosolv fractionation, thus improving the relative yields of platform chemicals (levoglucosan (LG) and phenols) in subsequent fast pyrolysis. The relative LG yields from eucalyptus, pine, and bagasse increased from 4.8, 3.5, and 2.1 wt % to 42.1, 22.7, and 59.8 wt %, respectively. These findings provide a simple and efficient integrated process to selective production of platform chemicals, which is different from the existing processes, e.g. catalytic fast pyrolysis and postpyrolysis separation. In addition, the fast pyrolysis of acid-passivated cellulose-rich fractions with varying cellulose contents revealed that the LG yields were linearly related to the cellulose contents of feedstocks, and the gap between actual and theoretical yields of LG decreased with increasing cellulose contents of feedstocks, suggesting that the interactions between cellulose and other components (lignin and hemicellulose) were the main controlling factor of LG yields from pyrolysis of acid-passivated cellulose-rich fractions
Synthesis of Chlorine-Substituted Graphdiyne and Applications for Lithium-Ion Storage
No full textChlorine-substituted graphdiyne (Cl-GDY) is prepared through a Glaser-Hay coupling reaction on the copper foil. Cl-GDY is endowed with a unique pi-conjugated carbon skeleton with expanded pore size in two dimensions, having graphdiyne-like sp- and sp(2)- hybridized carbon atoms. As a result, the transfer tunnels for lithium (Li) ions in the perpendicular direction of the molecular plane are enlarged. Moreover, benefiting from the bottom-to-up fabrication procedure of graphdiyne and the strong chemical tailorability of the alkinyl-contained monomer, the amount of substitutional chlorine atoms with appropriate electronegativity and atom size is high and evenly distributed on the as-prepared carbon framework, which will synergistically stabilize the Li intercalated in the Cl-GDY framework, and thus generate more Li storage sites. Profiting from the above unique structure, Cl-GDY shows remarkable electrochemical properties in lithium ion half-cells
Enzymatic hydrogelation of self-assembling peptide I4K2 and its antibacterial and drug sustained-release activities
No full textHydrogels provide great potential for biomedical applications. For clinical use, hydrogels could be used as scaffold materials for cell culture, regenerative medicine and drugs release with bactericidal properties. The amphiphilic peptide I4K2 is designed to inhibit bacterial growth through membrane permeation mechanisms. I4K2 is found to be able to self-assemble into nanofibers and form hydrogels in the presence of an enzyme (plasma amine oxidase, PAO). HPLC and MALDI-TOF-MS data show that PAO promoted the oxidation of the 3-amine of the lysine side chain. The cross-linking of I4K2 molecules catalyzed by PAO leads to a decrease in the amount of the positive charge of the system, which enhances the interaction between the self-assembled nanofibers and contributes to the formation of hydrogels. This self-supported hydrogel showed antibacterial activity against both G(+) and G(-) bacteria and has low cytotoxicity, which enable it be consequently used as an antimicrobial agent or biological engineering scaffold material. The hydrogel also possesses good drug sustained-release activities. These advantages result in the great potential of this enzymatic I4K2 hydrogel for biomedical applications