Reverse osmosis （RO） is proved to be the most reliable, cost effective, and energy efficient in producing fresh water compared to other desalination technologies. It is the fastest-growing desalination technology wi...Reverse osmosis （RO） is proved to be the most reliable, cost effective, and energy efficient in producing fresh water compared to other desalination technologies. It is the fastest-growing desalination technology with a greater number of installations around the world. The economic and technical performance of a medium-capacity RO desalination plant （2,000 m^3/day） proposed to be installed in Umm Qasr city south of Basra, Iraq is analyzed using DEEP-3.2 software created by the International Atomic Energy Agency （IAEA）. This port city is located on the Gulf shore and does not have any fresh water resources. The analysis shows that the cost of fresh water produced by this plant is US$0.986/m^3 with a good quality of fresh water （279 ppm）, which is a reasonable price for this remote area. The analysis also shows an increase in water production cost of about 12% at increased electricity price from 0.06 to 0.1 US$/kWh, 53% when the seawater salinity increased from 35,000 to 45,000 ppm, 2.5% when the seawater temperature decreased from 33 ℃ to 20 ℃, and 0.71% when the interest rate increased from 0% to 5%. Pumping fresh water from the Basra purification plant （located 175 km north of Umm Qasr） is 22.16 times the cost and 236.7% poorer quality than the fresh water produced by the RO plant.展开更多
[ Objective] The aim was to find optimum reaction conditions for synthetic process of Vitamin C. [ Method] Vitamin C sodium was used as raw material to prepare vitamin C through acidification, separation, desalination...[ Objective] The aim was to find optimum reaction conditions for synthetic process of Vitamin C. [ Method] Vitamin C sodium was used as raw material to prepare vitamin C through acidification, separation, desalination, recovery and purification. The impact of reaction time, tempera-ture, feedstock molar ratio and water content on the yield of vitamin C were investigated in the experiment. [Result] The optimum reaction condi- tions for synthetic process of Vitamin C were as follows： in the acidification test, reaction time 120 min, temperature 20 -30 ℃, the molar ratio be-tween hydrochloric acid and Vitamin C sodium 1 ： 1 and water content 41.0%. Under the above condition, the purity and yield of vitamin C reach 99.80% and 94.74% respectively. [Conclusion] The process can decrease consumption, enhance quality and recover of the product, improve the environmental pollution, shorten processing periods and reduce production cost. Thus, the process is suitable for industrialization. Key words Vitamin C; Vitamin C sodium; Acidification; China展开更多
In this study, we compared the transcriptomes of Nannochloropsis oceanica cultured in f/2 medium prepared with seawater and freshwater, respectively, aiming to understand the acclimation mechanism of this alga to fres...In this study, we compared the transcriptomes of Nannochloropsis oceanica cultured in f/2 medium prepared with seawater and freshwater, respectively, aiming to understand the acclimation mechanism of this alga to freshwater. Differentially expressed genes were mainly assigned to the degradation of cell components, ion transportation, and ribosomal biogenesis. These find- ings indicate that the algal cells degrade its components （mainly amino acids and fatty acids） to yield excessive energy （ATP） to maintain cellular ion （mainly K＋ and Ca〉） homeostasis, while the depletion of amino acids and ATP, and the reduction of ribosomes attenuate the protein translation and finally slow down the cell growth.展开更多
This study aimed to characterize constituents of phosphorus （P） fractionation as wel as reciprocities among factors in sediments of a freshwater shal ow lake. [Method] Surface sediment was discretely sampled at 24 s...This study aimed to characterize constituents of phosphorus （P） fractionation as wel as reciprocities among factors in sediments of a freshwater shal ow lake. [Method] Surface sediment was discretely sampled at 24 sites through Van Veen grabs. Based on a modified sequential extraction scheme, P fractionation was determined as Fe/Al bound P （Fe/Al-P）, Ca bound P （Ca-P）, solute and re-ductive P （S/R-P） and organic P （OP）. Curve estimation and Pearson product-mo-ment correlation were employed for statistical analysis. [Result] Total P （TP） content ranged from 443 to 774 mg/kg. Inorganic P （IP） was the major component of TP, of which Ca-P was dominated with an average of 51%±9.7%. Average contents of P fractionation were in the fol owing order： Ca-P（51%） 〉 OP（29%） 〉 S/R-P（8%） 〉Fe/Al-P（7%）. The molar ratio of Fe to P was 11 - 20, close to the threshold value of P leaching. [Conclusion] In freshwater shal ow lakes, IP and Ca-P were prone to be relatively high, whereas Fe/Al-P was low compared with deep lakes. Occurrence of spatial y monotonic gradient indicated the primary causation of anthropogenic sources. Imminent sediment P liberation was also expected. Close associations a-mong TP, Fe/Al-P and Ca-P, implying that anthropogenic P was mainly bound to metals in particulates. Significant correlations of TOC and P fractionation highlighted endogenous mechanism and authigenic origin in sediments.展开更多
This article classifies the seawater desalination technology into four types of hot method, membrane method, electric field method and solvent method. Electric field method and solvent method still remain experimental...This article classifies the seawater desalination technology into four types of hot method, membrane method, electric field method and solvent method. Electric field method and solvent method still remain experimental stage, while hot method and membrane method have been realized in commercialization but are difficult to be promoted. The problem lies in high water-producing cost. It is difficult for membrane method seawater desalination technology to reduce the water-producing cost. The heat utilization efficiency is not high for the current hot method seawater desalination technology and there is large amount of heat lost with the emission of concentrated seawater. The new hot method seawater desalination technology and new solar-powered seawater desalination technology can divide the seawater into fresh water and solid salt without any emission of concentrated seawater so that the heat utilization efficiency can reach theoretical limit to multiply reduce the water-producing cost. They will become the mainstream technology for seawater desalination and can totally eliminate the global water crisis.展开更多
The solidification of a binary mixture causes allowed thermosolutal convection. Under certain conditions, the separation of its components gives rise to a preferential movement of migration of solutes. The quantity an...The solidification of a binary mixture causes allowed thermosolutal convection. Under certain conditions, the separation of its components gives rise to a preferential movement of migration of solutes. The quantity and the concentration of the obtained products depend on the mechanisms of sepa＇,ration which depend on different parameters and the applied boundary conditions. In this way, the freezing of H20-NaC1 mixture makes it possible to obtain a liquid phase which is charged in solute and is called brine and a solid phase which is composed of ice being able to become fresh water, and so it can works as a desalination process. In this paper, a series of experiments of seawater freezing on cold surface is carried out at the laboratory under different operating conditions. During these experiments, the role of each parameter （temperature of crystallization, duration of crystallizat on...） which is able to impact the final composition is focused on. After a preliminary series of experiment, the yield is： improved to reach rates of salt and make it possible to regard the water produced as drinkable according to the standards of WHO （World Health Organization）.展开更多
文摘Reverse osmosis （RO） is proved to be the most reliable, cost effective, and energy efficient in producing fresh water compared to other desalination technologies. It is the fastest-growing desalination technology with a greater number of installations around the world. The economic and technical performance of a medium-capacity RO desalination plant （2,000 m^3/day） proposed to be installed in Umm Qasr city south of Basra, Iraq is analyzed using DEEP-3.2 software created by the International Atomic Energy Agency （IAEA）. This port city is located on the Gulf shore and does not have any fresh water resources. The analysis shows that the cost of fresh water produced by this plant is US$0.986/m^3 with a good quality of fresh water （279 ppm）, which is a reasonable price for this remote area. The analysis also shows an increase in water production cost of about 12% at increased electricity price from 0.06 to 0.1 US$/kWh, 53% when the seawater salinity increased from 35,000 to 45,000 ppm, 2.5% when the seawater temperature decreased from 33 ℃ to 20 ℃, and 0.71% when the interest rate increased from 0% to 5%. Pumping fresh water from the Basra purification plant （located 175 km north of Umm Qasr） is 22.16 times the cost and 236.7% poorer quality than the fresh water produced by the RO plant.
文摘[ Objective] The aim was to find optimum reaction conditions for synthetic process of Vitamin C. [ Method] Vitamin C sodium was used as raw material to prepare vitamin C through acidification, separation, desalination, recovery and purification. The impact of reaction time, tempera-ture, feedstock molar ratio and water content on the yield of vitamin C were investigated in the experiment. [Result] The optimum reaction condi- tions for synthetic process of Vitamin C were as follows： in the acidification test, reaction time 120 min, temperature 20 -30 ℃, the molar ratio be-tween hydrochloric acid and Vitamin C sodium 1 ： 1 and water content 41.0%. Under the above condition, the purity and yield of vitamin C reach 99.80% and 94.74% respectively. [Conclusion] The process can decrease consumption, enhance quality and recover of the product, improve the environmental pollution, shorten processing periods and reduce production cost. Thus, the process is suitable for industrialization. Key words Vitamin C; Vitamin C sodium; Acidification; China
基金financially supported by the National Natural Science Foundation of China(31270408)National High Technology Research and Development Program(863 Program)of China(2014AA022001)
文摘In this study, we compared the transcriptomes of Nannochloropsis oceanica cultured in f/2 medium prepared with seawater and freshwater, respectively, aiming to understand the acclimation mechanism of this alga to freshwater. Differentially expressed genes were mainly assigned to the degradation of cell components, ion transportation, and ribosomal biogenesis. These find- ings indicate that the algal cells degrade its components （mainly amino acids and fatty acids） to yield excessive energy （ATP） to maintain cellular ion （mainly K＋ and Ca〉） homeostasis, while the depletion of amino acids and ATP, and the reduction of ribosomes attenuate the protein translation and finally slow down the cell growth.
基金Supported by the National Natural Science Foundation of China(grant No.41171384,41271414 and 41301529)
文摘This study aimed to characterize constituents of phosphorus （P） fractionation as wel as reciprocities among factors in sediments of a freshwater shal ow lake. [Method] Surface sediment was discretely sampled at 24 sites through Van Veen grabs. Based on a modified sequential extraction scheme, P fractionation was determined as Fe/Al bound P （Fe/Al-P）, Ca bound P （Ca-P）, solute and re-ductive P （S/R-P） and organic P （OP）. Curve estimation and Pearson product-mo-ment correlation were employed for statistical analysis. [Result] Total P （TP） content ranged from 443 to 774 mg/kg. Inorganic P （IP） was the major component of TP, of which Ca-P was dominated with an average of 51%±9.7%. Average contents of P fractionation were in the fol owing order： Ca-P（51%） 〉 OP（29%） 〉 S/R-P（8%） 〉Fe/Al-P（7%）. The molar ratio of Fe to P was 11 - 20, close to the threshold value of P leaching. [Conclusion] In freshwater shal ow lakes, IP and Ca-P were prone to be relatively high, whereas Fe/Al-P was low compared with deep lakes. Occurrence of spatial y monotonic gradient indicated the primary causation of anthropogenic sources. Imminent sediment P liberation was also expected. Close associations a-mong TP, Fe/Al-P and Ca-P, implying that anthropogenic P was mainly bound to metals in particulates. Significant correlations of TOC and P fractionation highlighted endogenous mechanism and authigenic origin in sediments.
文摘This article classifies the seawater desalination technology into four types of hot method, membrane method, electric field method and solvent method. Electric field method and solvent method still remain experimental stage, while hot method and membrane method have been realized in commercialization but are difficult to be promoted. The problem lies in high water-producing cost. It is difficult for membrane method seawater desalination technology to reduce the water-producing cost. The heat utilization efficiency is not high for the current hot method seawater desalination technology and there is large amount of heat lost with the emission of concentrated seawater. The new hot method seawater desalination technology and new solar-powered seawater desalination technology can divide the seawater into fresh water and solid salt without any emission of concentrated seawater so that the heat utilization efficiency can reach theoretical limit to multiply reduce the water-producing cost. They will become the mainstream technology for seawater desalination and can totally eliminate the global water crisis.
文摘The solidification of a binary mixture causes allowed thermosolutal convection. Under certain conditions, the separation of its components gives rise to a preferential movement of migration of solutes. The quantity and the concentration of the obtained products depend on the mechanisms of sepa＇,ration which depend on different parameters and the applied boundary conditions. In this way, the freezing of H20-NaC1 mixture makes it possible to obtain a liquid phase which is charged in solute and is called brine and a solid phase which is composed of ice being able to become fresh water, and so it can works as a desalination process. In this paper, a series of experiments of seawater freezing on cold surface is carried out at the laboratory under different operating conditions. During these experiments, the role of each parameter （temperature of crystallization, duration of crystallizat on...） which is able to impact the final composition is focused on. After a preliminary series of experiment, the yield is： improved to reach rates of salt and make it possible to regard the water produced as drinkable according to the standards of WHO （World Health Organization）.
