Papers by Keyword: Carbon Source

Abstract: We investigated the phenomenon of non-uniform height distribution within CVD-grown carbon nanotube (CNT) arrays. This phenomenon is related to the activity of the catalyst which is affected by the deposition of the carbon source and the subsequent formation of pyrolysis products on the catalyst. We developed a model that considers the effects of deposition of the carbon source as well as the fact that the pyrolysis products also accumulate at the edges of CNT arrays. This model also illustrates that carbon source deposition results in moderate growth over large areas, whereas the pyrolysis products hinder growth significantly over small areas. Together, the two have a competitive effect on CNT growth and bring about the height distribution feature.

Abstract: In this paper, carbon nanotubes (CNTs) were synthesized by catalytic pyrolysis of CO and CH₄ using flame pyrolysis method. The effects of using the two different carbon sources to the preparation of CNTs with all other conditions being equal were comparatively studied. The results showed that: the morphology of CNTs synthesized from different carbon source gases had certain difference. Higher yield of carbon nanotubes could be synthesized using CH₄ as carbon source than using CO. At the same time, the former had less number of tube walls and the vascular bundles arranged more neatly. Synthetizing CNTs via catalytic decomposition of CH₄ had more advantages than using CO by flame pyrolysis method.

Abstract: The influence of different carbon sources such as glucose, sodium acetate, sodium propionate and ethanol for polyhydroxyalkanoates (PHA) storage were studied in details. It was shown that both the cell content and composition of PHA synthesized by microorganisms in activated sludge were different when different carbon sources were used. PHB (polyhydroxybutyrate) was the main PHA if sodium acetate was used as carbon source, while PHV (polydroxyvalerate) become the main PHA when sodium propionate was used. Sodium acetate and sodium propionate as carbon source had higher PHA production, which reached to 40.89% and 40.96% sludge dry weight, respectively . When ethanol used as carbon source, PHA content was 25.69% sludge dry weight. The minimal PHA storage was 20.14% sludge dry weight when glucose was used.

Abstract: Effects of different carbon source and Fe³⁺ for the growth and lipid accumulation of Monoraphidium sp. FXY-10 cultured mixotrophically was studied in our present work. The final cell density was reached to 2.626 g L^-1 when glucose was the only carbon source, which is 1.43-fold to sodium acetate (1.834 g L^-1), far higher than sucrose (0.251 g L^-1) and xylitol (0.471 g L^-1), but barely grow in other culture condition. Additionally, the highest algae lipid productivity (77.45 mg L^-1 d^-1) was obtained in 10 g L^-1 glucose group, which indicated that glucose was the optimal carbon source for growth and lipid accumulation of Monoraphidium sp. FXY-10. Nevertheless, Monoraphidium sp. FXY-10 was grew slowly in BG-11 culture medium with the absence of Fe³⁺. The biomass was achieved at the top with 50μM Fe³⁺ added. With the increase of Fe³⁺ concentration, it showed no variation in the growth of microalgae. The highest biomass productivity (209.87 mg L^-1 d^-1) was reached when the Fe³⁺ concentration was at 150μM while highest lipid productivity (94.05 mg L^-1 d^-1) reached at 50μM, which indicated that Fe³⁺ was one of the most indispensable trace elements for the growth and lipid accumulation of Monoraphidium sp. FXY-10.

Abstract: The fermentation process utilization to produce lactic acid has been studied from carbohydrate source and another source because of several significant reasons. Above all the production of biotechnology construction is found to be less costly compared to chemical synthesis. The production of biodegradable lactic polymer from lactic acid utilization of raw material can easily be obtained from industrial wastes such as pineapple waste. The process can positively affect the environment by reducing the environmental problems. The aim of this study is to estimate the effects of glucose concentration of pineapple wastewater as the carbon source on the volume of Lactobacillus casei (L. casei) subspecies in producing lactic acid. Five different glucose concentrations as carbon source are used for production of high lactic acid in the fermentation process using L. casei. L. casei could be ingesting the glucose presented within the levels tested and converts all into lactic acid. The result shows efficient yields of 0.09 g lactic acid/g glucose. The highest level of lactic acid is at 125.71 g/l and was obtained from 100 % pineapple waste medium. When the carbon source is at 4 g/l, the level of lactic acid is decreased to 84.22 g/l. The fermentation time increases with the increment of sugars. It is more than double if the medium is composed of 100 % of pineapple waste. Therefore pineapple waste is the best alternative as carbon source for bacteria growth because it is more cost effective.

Abstract: In this paper, effects of carbon source on the biofilm cultivation were investigated by adding or not adding liquid carbon source with corncob used as solid carbon source and biocarriers. By adding or not adding glucose in the culture solution, effects of carbon source on the biofilm cultivation were determined by measuring COD, NO₃^--N, NO₂^--N and pH of culture solution after reaction. Results showed that adding liquid carbon source was beneficial to forming the biofilm with good denitrification performance, however, not adding carbon source could only form biofilm with bad denitrification performance and denitrification reaction only proceeded to the step of NO₂^--N after reaction. Results indicated that it was necessary to add liquid carbon source for the forming biofilm with good denitrification performance on the surface of corncob biocarriers.

Abstract: Cathode material LiFePO₄/C was prepared via optimized solid state reaction and calcinations using different carbon source. The crystalline and morphology of the resultant powder was evaluated by X-Ray diffraction (XRD), scanning electronic microscope (SEM). The electrochemical performance was measured by galvanostatic charge-discharge test at 0.1C and 0.5C. The results demonstrated that the sample with layer-like stacking microstructure had the best capacity retention up to 96% after 50-cycle at 0.5C; the sample with good carbon coating using glucose as carbon source exhibited the lowest flat charge plateau and the highest flat discharge plateau, also the best storage performance at 60 oC temperature. Nevertheless, the sample with spherical-like shape and homogeneous particle size had the most capacity loss, maybe due to the increased internal resistance caused by the big interstices between the particle sizes.

Abstract: This paper aims to study the impact of different carbon sources on phosphorus removal after the (AO)²SBR system was started successfully. Four kinds of carbon resources were used in sequence experiments to observe the impact of different carbon resources on phosphorus release at anaerobic condition, uptake aerobic condition, uptake anoxic condition and phosphorus removal of the (AO)²SBR system. And the carbon sources are sodium acetate, sodium propionate, glucose, sodium acetate + sodium propionate separately. The experiment result shows that the phosphorus release and uptake of active sludge at anaerobic/aerobic/anoxic condition was preferable with sodium acetate as carbon source. And the phosphorus removal rate of (AO)²SBR system and TP concentration in the effluent were 95% and under 0.5mg·L^-1 respectively. The phosphorus removal rate of (AO)²SBR system was only 60% with glucose as carbon resource. This study concluded that it is beneficial for the biological phosphorus removal to choose organics with short carbon chain, such as sodium acetate as carbon source.

Abstract: Biological nitrification and denitrification via nitrite pathway is technically feasible and economically favorable, especially when wastewater with high ammonium concentrations or low C/N ratios is treated. Therefore, it has attracted more and more attention. It is very important to maintain partial nitrification of ammonium to nitrite. In this paper, the factors that influence operation and efficiency of nitrification and denitrification via nitrite are discussed, including DO concentration, carbon source, aeration pattern, PH, temperature and high free ammonia. High ammonia concentration and temperature are prone to accomplish of short-cut nitrification and denitrification, but limit application in practice. Finally, the review discussed the future challenges for application of short-cut nitrification and denitrification.

Abstract: A novel denitrification process with wheat straw as both carbon source and biofilm carrier was developed to simultaneously remove nitrate and pentachlorophenol (PCP) from contaminated drinking water. The experimental results indicated that the reactor packed with wheat straw could be started up readily, and the removal efficiencies of nitrate and PCP reached approximately 98% and 40%, respectively, with 8 h of HRT at 25 °C. A significant increase in PCP removal was observed with prolonged HRT. Approximately 85% of PCP removal efficiency was reached, and 1.61mg/L of chloride ion was released from the contaminated water containing 5 mg/L of PCP with 16 h of HRT. Reductive dechlorination reaction was a major degradation mechanism of PCP under the denitrifying conditions with wheat straw as carbon source.