Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences
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Ionic Liquid Confined in Mesoporous Polymer Membrane with Improved Stability for CO2/N2 Separation
No full textSupported ionic liquid membranes (SILMs) have a promising prospect of application in
flue gas separation, owing to its high permeability and selectivity of CO2. However, existing SILMs
have the disadvantage of poor stability due to the loss of ionic liquid from the large pores of the
macroporous support. In this study, a novel SILM with high stability was developed by confining ionic
liquid in a mesoporous polymer membrane. First, a mesoporous polymer membrane derived from a
soluble, low-molecular-weight phenolic resin precursor was deposited on a porous Al2O3 support,
and then 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF4]) was immobilized inside
mesopores of phenolic resin, forming the SILM under vacuum. Effects of trans-membrane pressure
difference on the SILM separation performance were investigated by measuring the permeances of
CO2 and N2. The SILM exhibits a high ideal CO2/N2 selectivity of 40, and an actual selectivity of
approximately 25 in a mixed gas (50% CO2 and 50% N2) at a trans-membrane pressure difference
of 2.5 bar. Compared to [emim][BF4] supported by polyethersulfone membrane with a pore size of
around 0.45 m, the [emim][BF4] confined in a mesoporous polymer membrane exhibits an improved
stability, and its separation performance remained stable for 40 h under a trans-membrane pressure
difference of 1.5 bar in a mixed gas before the measurement was intentionally stopped
Estimating primary production of picophytoplankton using the carbon-based ocean productivity model: a preliminary study
No full textPicophytoplankton are acknowledged to contribute significantly to primary production
(PP) in the ocean while now the method to measure PP of picophytoplankton (PPPico)
at large scales is not yet well established. Although the traditional 14C method and
new technologies based on the use of stable isotopes (e.g., 13C) can be employed to
accurately measure in situ PPPico, the time-consuming and labor-intensive shortage of
these methods constrain their application in a survey on large spatiotemporal scales.
To overcome this shortage, a modified carbon-based ocean productivity model (CbPM)
is proposed for estimating the PPPico whose principle is based on the group-specific
abundance, cellular carbon conversion factor (CCF), and temperature-derived growth
rate of picophytoplankton. Comparative analysis showed that the estimated PPPico
using CbPM method is significantly and positively related (r2 D 0.53, P < 0.001, n D 171)
to the measured 14C uptake. This significant relationship suggests that CbPM has the
potential to estimate the PPPico over large spatial and temporal scales. Currently this
model application may be limited by the use of invariant cellular CCF and the relatively
small data sets to validate the model which may introduce some uncertainties and
biases. Model performance will be improved by the use of variable conversion factors
and the larger data sets representing diverse growth conditions. Finally, we apply the
CbPM-based model on the collected data during four cruises in the Bohai Sea in 2005.
Model-estimated PPPico ranged from 0.1 to 11.9, 29.9 to 432.8, 5.5 to 214.9, and 2.4
to 65.8 mg C m−2 d−1 during March, June, September, and December, respectively.
This study shed light on the estimation of global PPPico using carbon-based production
model
Mass spectral chemical fingerprints reveal the molecular dependence of exhaust particulate matters on engine speeds
No full textConstruction of Vibronic Diabatic Hamiltonian for Excited-State Electron and Energy Transfer Processes
No full textPhotoinduced excited-state electron and energy transfer processes are crucial in biological photoharvesting systems and organic photovoltaic devices. We discuss the construction of a diabatic vibronic Hamiltonian for the proper treatment of these processes involving the projection approach acting on both electronic wave functions and vibrational modes. In the electronic part, the wave function projection approach is used to construct the diabatic Hamiltonian in which both local excited states and charge-transfer states are included on the same footing. For the vibrational degrees of freedom, the vibronic couplings in the diabatic Hamiltonian are obtained in the basis of the pseudonormal modes localized on each monomer site by applying delocalized-to-localized mode projection. This systematic approach allows us to construct the vibronic diabatic Hamiltonian in molecular aggregates
Production of D-lactate from glucose using Klebsiella pneumoniae mutants.
No full textBackground: d-Lactate is a valued chemical which can be produced by some bacteria including Klebsiella pneumoniae. However, only a few studies have focused on K. pneumoniae for d-lactate production with a signifcant amount of
by-products, which complicated the purifcation process and decreased the yield of d-lactate.
Results: Based on the redirection of carbon towards by-product formation, the efects of single-gene and multiplegene deletions in K. pneumoniae on d-lactate production from glucose via acetolactate synthase (budB), acetate
kinase (ackA), and alcohol dehydrogenase (adhE) were tested. Klebsiella pneumoniae mutants had diferent production
behaviours. The accumulation of the main by-products was decreased in the mutants. The triple mutant strain had
the most powerful ability to produce optically pure d-lactate from glucose, and was tested with xylose and arabinose
as carbon sources. Fed-batch fermentation was also carried out under various aeration rates, and the strain accumulated 125.1 g/L d-lactate with a yield of 0.91 g/g glucose at 2.5 vvm.
Conclusions: Knocking out by-product synthesis genes had a remarkable infuence on the production and yield of
d-lactate. This study demonstrated, for the frst time, that K. pneumoniae has great potential to convert monosaccharides into d-lactate. The results provide new insights for industrial production of d-lactate by K. pneumoniae
An insight into intrinsic interfacial properties between Li metals and Li10GeP2S12 solid electrolytes
No full text材料工程
No full textOrganic-inorganic hybrid perovskite solar cells (PVSCs) as a new generation solar cells, have received considerable attention from research institutes and industry since 2009 and gained rapid development. At present, the power conversion efficiency (PCE) of the state-of-the-art PVSCs in the laboratory stage has reached 22.1%, close to the level of the silicon solar cells. PVSCs show great commercial potential and broad application prospects by virtue of cheap raw materials, simple fabrication technology and the continuous improvement of PCE and stability.
This thesis mainly focus on the film morphology and crystalline control of planar heterojunction PVSCs, and the development of new cheap and efficient interface transport layer material. Concrete was carried out by:
“By using additive to control perovskite film crystallization morphology; to develop new efficient hole-transport materials and to improve the PCE of PVSCs by double hole-transport layer interface engineering” three aspects. The research content is as follows:
1) The PCE and device stability of PVSCs are decided directly by the perovskite film morphology. It is crucial for high-efficiency and stable PVSCs to form a dense, crackles and full coverage film. Here, we adopt mixed solvent gamma-butyrolactone (GBL) : dimethyl sulfoxide (DMSO) (v/v%=7:3) to fabricate perovskite film by spin-coating method. For the first time, N - methyl pyrrolidone (NMP, 5 v/v %) with high boiling point was added as additive. The introduction of the NMP can significantly control the perovskite crystal grain growth process, improve the crystallization morphology of perovskite films. Then perovskite film was formed by annealing as a mirror shine, root mean square of the particle size was only about 2.39 nm. The PCE of correspondent device was 11.77% from 9.94%, fill factor (FF) increased from 0.74 to 0.81.
2) It is an important way to improve PCE of PVSCs by using the energy level matching, stronger conductive ability interface transport materials. Herein, we utilized rich lignin as the main materials, through further chemical modification to prepare sulfonated-acetone-formaldehyde-lignin (abbreviated to GSL). PEDOT:GSL was made by doped GSL to PEDOT, which has the hole mobility of 2.27 x 10-6 cm2 V - 1 s – 1 measured via the space charge limited current method. The PCE with PEDOT:GSL as hole transport layer was 14.9% increased by 18.3% with higher open circuit voltage (Voc), short circuit current (Jsc) and the fill factor (FF) compared with that of PEDOT:PSS.
3) On the basis of the above work, we further used PEDOT:PSS and PEDOT:GSL as double hole transport layer to fabricate PVSCs. The PCE of 17.8% was obtained by modifying the energy level, enhancing the incident light trasmittance, passivating the interface increased by 32.6% compared with the single PEDOT:PSS (13.4%). Our methods provides a good guidance for further improving the PCE of PVSCs.
Key words: Perovskite, Additive, Morphological control, PEDOT:PSS, Interface engineering中文;英
