Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences
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Promotion Effect of Carbon Nanotubes-Doped SDS on Methane Hydrate Formation
No full textTo achieve greater performance of a low concentration of sodium dodecyl sulfate (SDS) in methane hydrate formation, SDS solutions were doped with pristine carbon nanotubes (pCNTs) and the oxidized forms (OCNTs). With nanotubes as the predominant accelerant in the mixed promoters, the nucleation stage could be shorten efficiently due to the continuous Brownian motion of more nanoparticles. The mixed promoters exerted more pronounced influence on the methane hydrate growth rate compared to the pure SDS, with the OCNTs-SDS system performing slightly better owing to the high dispersion and stability of the OCNTs in the aqueous SDS solutions. Nevertheless, the promotion effects of highly concentrated pCNTs or OCNTs could be weakened possibly due to the aggregation of nanotubes
Environmental response to long-term mariculture activities in the Weihai coastal area, China
No full textThe environmental impacts of rapid expansion of mariculture have garnered worldwide attention. China is currently one of the largest countries to engage in this practice. In this study, a representative mariculture zone, the Weihai coastal area in China, was explored to determine the temporal variations in regional nutrients, N/P ratio, dissolved oxygen (DO), pH, chlorophyll a (Chl-a), and cellular abundance of diatoms and dinoflagellates in response to the rapid growth in mariculture activities between 2006 and 2014. The temporal variations in inorganic and organic nitrogen concentrations in the surface water presented significantly increasing trends during August, between 2009 and 2014. A marked increase in the ratios of dinoflagellate to diatom abundance, concurrently with ascending N/P ratios, was also observed during August between 2011 and 2014. In addition, dissolved inorganic nitrogen and phosphate variations revealed the highest concentrations during October and lower levels during May and August, which was attributed in part to the seasonal growth characteristics of kelp cultivated in the study area. Moreover, the nutrient concentrations in Sanggou, Rongcheng, Wulei, and Rushan bays were affected significantly by the various cultured organisms in these bays. The intensive mariculture activity in the Weihai coastal area is likely one of the causes of the negative effects on water quality, such as eutrophication and future ocean acidification. The exploration of effective strategies is quite necessary in the future for keeping good quality of coastal environment and sustainable mariculture development. (C) 2017 Elsevier B.V. All rights reserved
Crystalline Medium-Bandgap Light-Harvesting Donor Material Based on beta-Naphthalene Asymmetric-Modified Benzodithiophene Moiety toward Efficient Polymer Solar Cells
No full textIn this paper, we reported a crystalline p-type medium-bandgap conjugated D-A polymer asy-PBDBTN based on a symmetry-breaking-modified BDT moiety to combine the advantages of both one-dimension (1D) and two-dimension (2D) symmetric BDTs. Polymer asy-PBDBTN is a highly efficient light-harvesting donor material. Single BHJ PSCs exhibit PCE of 8.88% with PC71BM as acceptor. Also, PCE values of 10.50% are achieved with the use of ITIC as an acceptor to couple asy-PBDBTN with V-oc of 0.942 V, J(SC) of 16.81 mA cm(-2), and FF of 0.663. It is worth noting that lower energy loss is obtained in fullerene-free-based PSCs, which is essential to overcome the trade-off between Voc and J(SC) and boost these two parameters simultaneously for high photovoltaic performance. The combination process of additive and thermal annealing is critical to enhance and retain the pi-pi stacking behavior of donor and fullerene-free acceptor; as a result, the trap-assisted recombination was greatly suppressed. This work demonstrates a great prospect for the construction of the symmetry-breaking BDT-based D-A conjugated polymers toward high-performance PSCs, especially with fullerene-free acceptor material
Effect of auxiliary blowing agents on properties of rigid polyurethane foams based on liquefied products from peanut shell
No full textThe bio-based rigid polyurethane (PU) foams were successfully prepared based on liquefied products from peanut shell with water as the blowing agent. The influence of reaction parameters on properties of rigid PU foams was investigated. Rigid PU foams showed excellent compressive strength and low shrinkage ratio, whereas their open-cell ratio and water absorption were higher. Therefore, rigid PU foams were synthesized with petroleum ether, diethyl ether, and acetone as auxiliary blowing agents and their inner temperature, shrinkage performance, density, compressive strength, water absorption, and open-cell ratio were determined. The results indicated that above rigid PU foams showed lower compressive strength than the original foam but their water absorption and close-cell ratio were improved. Compared with the original foam, the highest inner temperature of rigid PU foams with petroleum ether, diethyl ether, and acetone as auxiliary blowing agents was reduced by 11, 19, and 23 degrees C, respectively. Typically, foams with petroleum ether as auxiliary blowing agent displayed better water absorption and swelling ratio in water and exhibited obvious improvement in close-cell ratio. These foams were preferable for application in thermal insulation materials because of low thermal conductivity and better corrosion resistance. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45582
Bioinspired catecholic activation of marine chitin for immobilization of Ag nanoparticles as recyclable pollutant nanocatalysts
No full textBeing one type of the most abundant marine polysaccharides in nature, chitin has inert chemical properties and thus prolonged been hindered for high-value utilization. A mussel-inspired catecholic chemistry was found to be able to confer nature-derived mesoporous chitin aerogels with high and tunable surface activities. When further combining with their high porosity, high specific surface area, mechanical toughness and unique nanofibrous architecture, these catechol-activated chitin aerogels could be used as a unique supporting matrix to immobilize Ag nanoparticles. Besides the mild synthesis conditions and the merits inherited from pristine chitin, the resultant chitin-Ag hybrid aerogels further exhibited high catalytic activity, excellent recyclability, super solvent endurance and fast regeneration ability. Their high mechanic properties and porous structures also enabled a convenient membrane process to remove organic dyes from water. (C) 2017 Elsevier Inc. All rights reserved
The Effects of a Mixed Precipitant on the Morphology and Electrochemical Performance of LiNi0.5Mn1.5O4 Cathode Materials
No full textA series of LiNi0.5Mn1.5O4 (LNMO) samples were synthesized by adjusting the molar ratio of (NH4)(2)CO3 to Na2CO3 in a mixed precipitant for evaluating the effects of ammonia from (NH4)(2)CO3 as a complexing agent and Na2CO3 as a precipitant on the morphology and electrochemical performances of LNMO. In this research, a rapid precipitation method followed by hydrothermal treatment was used to prepare the precursors of LNMO, and different molar ratios (0:1, 1:2, 1:1, 2:1, 1:0) of (NH4)(2)CO3 to Na2CO3 were used for mixed precipitants. The test results revealed that the cathode material exhibits the best electrochemical performance when the molar ratio of (NH4)(2)CO3 to Na2CO3 is set at 1:2, displaying a specific discharge capacity of 129.4 mA h g(-1) at 0.5 C and a capacity retention of 82.3% after 200 charge-discharge cycles. In addition, it still shows a high rate performance with a discharge capacity of 112.7 mA h g(-1) at 10 C and 98.8 mA h g(-1) at 20 C, which is attributed to an accurate Ni/Mn ratio, smaller primary particle sizes and a porous spherical morphology
A controlled alkaline treatment of Al-SBA-15: a facile route to adjust the chemical composition and synthesize an ordered mesoporous carbon material, CMK-3, possessing strong pressure resistant capability
No full textThe effect of an alkaline treatment on the mesoporous material Al-SBA-15 was investigated using powder X-ray diffraction (XRD), inductively coupled plasma (ICP) analysis, mid-infrared spectroscopy (IR), N-2 sorption isotherm measurements, transmission electron microscopy (TEM), scanning electron microscopy (SEM), solid state Al-27 MAS NMR analysis, and structural replicating technology. It was observed that elemental Si could be readily extracted from wall structures, and the Al-rich surface that was consequently exposed protected the uniform hexagonal arrays. The extracted substances rapidly accumulate inside the Al-SBA-15 mesopores and continuously dissolve and migrate into the alkaline solution upon a prolonged treatment time. Therefore, alkaline-treated Al-SBA-15 exhibits a larger pore size and a thinner wall than that before treatment. Due to its Al-rich surface and highly-open mesostructure, alkaline-treated Al-SBA-15 exhibits excellent catalytic performance in a low density polyethylene (LDPE) catalytic degradation reaction. The temperature corresponding to the maximum degradation rate was measured to be similar to 10 K lower than that in raw Al-SBA-15. More importantly, the secondary-scale mesopores inside the Al-SBA-15 walls were remarkably expanded, allowing efficient penetration of the carbon precursor. Its structural replica, CMK-3, has a highly ordered mesostructure, which is attributed to the formation of enhanced carbon sticks that connect the primary carbon rods. For the same reason, CMK-3 templated from alkaline-treated Al-SBA-15 exhibits a strong pressure resistant capability. The reduction in the surface area and pore volume after high-pressure treatment were calculated to be as low as 4.5% and 3.0%, respectively
Effects of elevated CO2 and nitrogen supply on the growth and photosynthetic physiology of a marine cyanobacterium, Synechococcus sp PCC7002
No full textOcean acidification due to increasing atmospheric CO2 concentration and coastal eutrophication are growing global threats to affect marine organisms and ecosystem health. However, little is known about their interactive impacts on marine picocyanobacteria which contribute to a large proportion of primary production. In this study, we cultivated the cyanobacterium Synechococcus sp. PCC7002 at ambient (380 ppmv) and high CO2 (1000 ppmv), across a range of nitrogen levels (LN, 10 mu M NO3 (-); MN, 35 mu M NO3 (-); HN, 110 mu M NO3 (-)). In LN media, elevated CO2 significantly decreased cellular chlorophyll a, but insignificantly affected growth rate, photosynthetic efficiency (F (v) /F (m) ) and maximum relative electron transport rate (rETR(max)). Nitrogen (N)-supply positively increased the growth, F (v) /F (m) , dissolved organic carbon (DOC) and cellular carotenoids/Chl a ratios, but decreased the rETR(max) in both ambient and elevated CO2 conditions. The cellular C/N ratios were significantly increased by either elevated CO2 or N-supply, and the cell size was significantly enhanced by elevated CO2, not by N-supply. In addition, we found the N-supply alone had no significant effects on the four main components of chromophoric dissolved organic matter (cDOM) in ambient CO2, while the N-supply interacted with elevated CO2 significantly decreasing the cDOM contents in the cultures. Our results indicated that elevated CO2 and N-supply interacted to alter the physiology and cellular biochemistry of Synechococcus sp. PCC7002, providing useful information for understanding the environmental adaptability of Synechococcus to coastal ocean acidification and eutrophication
The Response Regulator Slr1588 Regulates spsA But Is Not Crucial for Salt Acclimation of Synechocystis sp PCC 6803
No full textCyanobacterial sucrose biosynthesis is stimulated under salt stress, which could be used for biotechnological sugar production. It has been shown that the response regulator Slr1588 negatively regulates the spsA gene encoding sucrose-phosphate synthase and mutation of the slr1588 gene also affected the salt tolerance of Synechocystis (Chen et al., 2014). The latter finding is contrary to earlier observations (Hagemann et al., 1997b). Here, we observed that ectopic expression of slr1588 did not restore the salt tolerance of the slr1588 mutant, making the essential function of this response regulator for salt tolerance questionable. Subsequent experiments showed that deletion of the entire coding sequence of slr1588 compromised the expression of the downstream situated ggpP gene, which encodes glucosylglycerol-phosphate phosphatase for synthesis of the primary osmolyte glucosylglycerol. Mutation of Delta slr1588 by deleting the N-terminal part of this protein (Delta slr1588-F976) did not affect ggpP expression, glucosylglycerol accumulation as well as salt tolerance, while the mutation of ggpP resulted in the previously reported salt-sensitive phenotype. In the Delta slr1588-F976 mutant spsA was up-regulated but sucrose content was lowered due to increased invertase activity. Our results reveal that Slr1588 is acting as a repressor for spsA as previously suggested but it is not crucial for the overall salt acclimation of Synechocystis