Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences
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Characterization of fume composition and rheological properties of asphalt with crumb rubber activated by microwave and TOR
No full textThis paper studied asphalt fume chemical composition, rheological properties and microstructure of asphalt with crumb rubber (CR) activated by microwave and trans-polyoctenamer (TOR). To that end, asphalt fume was trapped through laboratory fume generation and capture system, which was subsequently analyzed by Gas Chromatography-Mass Spectrometry system (GC-MS). Moreover, the rheological behavior and microstructure of CR modified asphalt (CRMA) were characterized by dynamic shear rheometer (DSR) and FTIR. The GC-MS results indicated that CR activated by microwave and TOR reduces the contents of PAHs and sulfur compounds, implying the lower toxicological potential of fume. TOR has the greater effect of reduction in the toxicological species. The rheological results indicated that CR activated by TOR significantly improves modulus, zero shear viscosity (ZSV), and recovery ability of CRMA at high temperatures, which cause asphalt binder having the stronger resistance to rutting. The enhancement in thermo-mechanics is due to chemical cross-linking among TOR, rubber, and asphalt, which was verified by FTIR results. On the other hand, microwave treatment on CR affects high temperature performance of CRMA negatively in comparison to the untreated CRMA. However, microwave treatment leads to the faster stress relaxation response of CRMA, indicating the stronger resistance to thermal cracking. (C) 2017 Elsevier Ltd. All rights reserved
High-performance chiral stationary phases based on chitosan derivatives with a branched-chain alkyl urea
No full textIn this study, two series of chitosan 3,6-bis(arylcarbamate)-2-(isobutylurea)s and corresponding coated-type chiral stationary phases (CSPs) were prepared from two kinds of chitosans with different molecular weights. Most of the prepared CSPs demonstrated better enantioseparation performance than the homemade CSP of cellulose tris(3,5-dimethylphenylcarbamate). The CSPs of chitosan 3,6-bis(4-methylphenylcarbamate)-2-(isobutylurea) with higher molecular weight and chitosan 3,6-bis(3-chloro-4-methylphenylcarbamate)-2-(isobutylurea) with lower molecular weight possessed outstanding chiral recognition abilities which were at least as good as that of the commercialized CSP of Chiralcel OD-H towards the tested chiral analytes. Except for the two CSPs derived from chitosan 3,6-bis( 4-methylphenylcarbamate)-2-(isobutylurea) s, the CSPs (the first class) with the chiral selectors of lower molecular weight provided better enantioseparations than the ones (the second class) with the chiral selectors of higher molecular weight. On the other hand, the chiral selectors of the first class CSPs showed higher swelling capacities in organic solvents than the ones of the second class. All prepared CSPs could be analyzed with a wider range of mobile phases, in which some "unusual organic solvents" such as ethyl acetate, chloroform and THF etc. could be used as additives. According to separation performance and tolerance against organic solvents, we concluded that the chitosan derivatives with branched-chain alkyl urea at 2-C of glucosamine residue were preferable to be used as chiral selectors for enantiomeric separation. (C) 2017 Elsevier B.V. All rights reserved
Enhanced paramagnetism of mesoscopic graphdiyne by doping with nitrogen
No full textThe new two-dimensional graphitic material, graphdiyne, has attracted great interest recently due to the superior intrinsic semiconductor properties. Here we investigate the magnetism of pure graphdiyne material and find it demonstrating a remarkable paramagnetic characteristic, which can be attributed to the appearance of special sp-hybridized carbon atoms. On this basis, we further introduce nitrogen with 5.29% N/C ratio into graphdiyne followed by simply annealing in a dopant source and realize a twofold enhancement of saturation moment at 2 K. Associate with the density of states calculation, we investigate the influence of the nitrogen atom doping sites on paramagnetism, and further reveal the important role of doped nitrogen atom on benzene ring in improving local magnetic moment. These results can not only help us deeply understand the intrinsic magnetism of graphdiyne, but also open an efficient way to improve magnetism of graphdiyne by hetero atom doping, like nitrogen doping, which may promote the potential application of graphdiyne in spintronics
Transcriptome analysis of genes involved in secondary cell wall biosynthesis in developing internodes of Miscanthus lutarioriparius
No full textMiscanthus is a promising lignocellulosic bioenergy crop for bioethanol production. To identify candidate genes and regulation networks involved in secondary cell wall (SCW) development in Miscanthus, we performed de novo transcriptome analysis of a developing internode. According to the histological and in-situ histochemical analysis, an elongating internode of M. lutarioriparius can be divided into three distinct segments, the upper internode (UI), middle internode (MI) and basal internode (BI), each representing a different stage of SCW development. The transcriptome analysis generated approximately 300 million clean reads, which were de novo assembled into 79,705 unigenes. Nearly 65% of unigenes was annotated in seven public databases. Comparative profiling among the UI, MI and BI revealed four distinct clusters. Moreover, detailed expression profiling was analyzed for gene families and transcription factors (TFs) involved in SCW biosynthesis, assembly and modification. Based on the co-expression patterns, putative regulatory networks between TFs and SCW-associated genes were constructed. The work provided the first transcriptome analysis of SCW development in M. lutarioriparius. The results obtained provide novel insights into the biosynthesis and regulation of SCW in Miscanthus. In addition, the genes identified represent good candidates for further functional studies to unravel their roles in SCW biosynthesis and modification
Pyrolysis kinetic analysis of the three pseudocomponents of biomass-cellulose, hemicellulose and lignin
No full textThe pyrolysis kinetic analysis of the three pseudocomponents of biomass, namely cellulose, hemicellulose and lignin, were investigated using a thermogravimetric (TG) analyzer. The multi-peaks method was used to fit the Gaussian distribution model of DTG curves. The activation energies of three pseudocomponents pyrolysis were evaluated using sinusoidally modulated temperature method. The results showed that the multi-peaks methods can fit the DTG curves of cellulose, hemicellulose and lignin successfully. There was only one reaction stage for the pyrolysis of cellulose and hemicelluloses. There were two reaction stages for the pyrolysis of lignin. The average E was 112.6, 162.8 and 156.8 kJ mol(-1) for cellulose, hemicellulose and lignin, respectively
A comparative analysis of biomass and lipid content in five Tribonema sp strains at autotrophic, heterotrophic and mixotrophic cultivation
No full textMicroalgae Tribonema sp. is the first reported filamentous strain which has capability to accumulate large amounts of lipid, especially triacylglycerols (TAGs), useful for biodiesel production. In this study, five filamentous strains identified as Tribonema sp. were cultured with different carbon source and nitrogen source in batch cultures, and their biomass and total lipid contents were determined. In terms of high biomass and lipid contents, strains EA903 and EA904 were further cultivated in scale up cultures at photoautotrophic (CO2 as the carbon source), heterotrophic (glucose as the carbon source, NaNO3 and peptone as the nitrogen source, respectively) and mixotrophic (heterotrophic + light) conditions. Results suggested that autotrophic and glucose-treated cultures of Tribonema sp. strains (both EA903 and EA904) showed an evident difference on the biomass concentrations. Moreover, in spite of being characterized by higher biomass concentrations, strains EA903 and EA904 grown in heterotrophic cultivation with addition of peptone yielded lower lipid contents than those in autotrophic and heterotrophic cultivation with addition of NaNO3. The highest lipid productivity was achieved at the mixotrophic cultivation with NaNO3 addition
A Smart Flexible Zinc Battery with Cooling Recovery Ability
No full textFlexible batteries are essential for wearable electronic devices. To meet practical applications, they need to be mechanically robust and stable. However, strong or multiple bending may sever the interfacial contact between electrode and electrolyte, causing capacity fading or even battery failure. Herein we present a new cooling-recovery concept for flexible batteries, which involves a temperature-sensitive sol-gel transition behavior of the thermoreversible polymer hydrogel electrolyte. Once a battery has suffered from strong mechanical stresses, a simple cooling process can refresh the electrode-electrolyte interface. The energy-storage capability can be recovered with a healing efficiency higher than 98%. It is believed that this study not only offers new valuable insights, but also opens up new perspectives to develop functional wearable devices
A Superior Polymer Electrolyte with Rigid Cyclic Carbonate Backbone for Rechargeable Lithium Ion Batteries
No full textThe fabricating process of Well-known Bellcore poly(vinylidene fluoride-hexaflutrropropyleoe) (PVcIF-HFP)-based polyrner, electrolytes is very complicated, tedious, and expensive owing to containing a large amount of fluorine substituents. Herein, a novel kind of poly(vinylene carbonate) (PVCA)-based polymer electrolyte is developed via a facile in situ polymerization method, which possesses the merits of good interfacial compatibility with electrodes. In addition, this polymer electrolyte presents a high ionic conductivity of 5.59 X 10(-4) S Cm-1 and a wide electrochemical stability window exceeding 4.8 V vs Li+/Li at ambient temperature. In addition, the rigid cyclic carbonate backbone of poly(vinylene carbonate) endows polymer electrolyte a superior mechanical property. The LiFe0.2Mn0.8PO4/graphite lithium ion batteries using this polymer electrolyte deliver good rate capability and excellent cyclability at room temperature. The superior performance demonstrates that the PVCA-based electrolyte via in situ polymerization is a potential alternative polymer elettrolyte for high-performance rechargeable lithium ion batteries
Wastewater recycling technology for fermentation in polyunsaturated fatty acid production
No full textTo reduce fermentation-associated wastewater discharge and the cost of wastewater treatment, which further reduces the total cost of DHA and ARA production, this study first analyzed the composition of wastewater from Aurantiochytrium (DHA) and Mortierella alpina (ARA) fermentation, after which wastewater recycling technology for these fermentation processes was developed. No negative effects of DHA and ARA production were observed when the two fermentation wastewater methods were crossrecycled. DHA and ARA yields were significantly inhibited when the wastewater from the fermentation process was directly reused. In 5-L fed-batch fermentation experiments, using this cross-recycle technology, the DHA and ARA yields were 30.4 and 5.13 g L-1, respectively, with no significant changes (P > 0.05) compared to the control group, and the water consumption was reduced by half compared to the traditional process. Therefore, this technology has great potential in industrial fermentation for polyunsaturated fatty acid production. (C) 2017 Elsevier Ltd. All rights reserved
Leaching of Cu, Cd, Pb, and phosphorus and their availability in the phosphate-amended contaminated soils under simulated acid rain
No full textPhosphate amendments have been used to immobilize heavy metal-contaminated soils. However, phosphate amendments contain large amounts of phosphorus, which could leach out to potentially contaminate groundwater and surface water. A laboratory column leaching experiment was designed to study the effects of simulated acid rain (SAR) on the potential release of copper (Cu), lead (Pb), cadmium (Cd), and phosphorus (P), and their availability after immobilizing with hydroxyapatite (HAP) and potassium dihydrogen phosphate (PDP). The application of HAP and PDP enhanced the leachate electrical conductivity, total organic carbon, and pH. Higher P was found in the PDP- (> 4.29 mg L-1) and HAP-treated (> 1.69 mg L-1) columns than that in untreated (< 0.2 mg L-1) columns, and they were both over the class V limit (0.4 mg L-1) mandated by the Chinese National Quality Standards for Surface Waters (GB 3838-2002). PDP application decreased the leachate Cu, Pb, and Cd effectively; however, HAP addition increased leachate Cu and Pb. HAP and PDP applications decreased the soil CaCl2-extractable and exchangeable fraction of Cu, Pb, and Cd, and increased resin P. However, eluviations transformed the heavy metals from inactive to active fractions and reduced soil labile P. These findings showed that HAP and PDP had a potential risk of excessive P-induced eutrophication. Meanwhile, more attention should be paid to the leaching loss of multiple metals because phosphate amendments might promote the leaching of some metals while immobilizing others