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Zhang X.,Tianjin University of Science and Technology | Zhang X.,Tianjin Key Laboratory of Marine Resources and Chemistry | Kan J.,Stroud Water Research Center | Wang J.,Tianjin University of Science and Technology | And 5 more authors.
Ecotoxicology | Year: 2015

Nannochloropsis is an ubiquitous genus, found in diverse aquatic environments including open ocean as well as fresh and brackish water. Recently, large-scale blooms occurred frequently along eutrophic coastal zone from the Bohai Sea to the northern Yellow Sea in China. The cell density reached 109 to 1010cells per liter during a bloom near Qinhuangdao, Hebei Province. The bloom forming species, a yellow–green microalgae was successfully isolated and cultivated in the laboratory. Microscopic observation indicated that the cells contained simple morphological characteristics with a diameter about 2 μm. Pigment analyses confirmed that the pigment composition of the newly isolated strain BDH02 was similar to that of Nannochloropsis granulata. Phylogenetic analyses of 18S rRNA gene, ITS, and rbcL gene indicated that the strain was closely related to N. granulata. This is the first record of a bloom caused by N. granulata in China. © 2015 Springer Science+Business Media New York


Sun J.,Tianjin University of Science and Technology | Sun J.,Tianjin Key Laboratory of Marine Resources and Chemistry | Feng Y.,Tianjin University of Science and Technology | Feng Y.,Tianjin Key Laboratory of Marine Resources and Chemistry | And 6 more authors.
Deep-Sea Research Part II: Topical Studies in Oceanography | Year: 2013

The source and significance of three nutrients - nitrogen, phosphorous and silicon - were investigated by a modified dilution method performed on seawater samples from the Central Yellow Sea (CYS), in spring blooming period of 2007. This modified dilution method accounted for the phytoplankton growth rate, microzooplankton grazing mortality rate, the internal and external nutrient pools, as well as nutrients supplied through remineralization by microzooplankton grazing. The results indicate that phytoplankton growth during the bloom is mostly contributed by internal nutrient pools (KI=0.062-1.730). The external nutrient pools (KE=<0-0.362) are also of importance for phytoplankton growth during the bloom at some sampling sites. Furthermore, the contribution of the recycled-nutrient pool by remineralization (KR=<0-0.751) is significant when microzooplankton grazing rate was higher than 0.5d-1 during the spring phytoplankton blooms in the Central Yellow Sea. Compared with internal phosphorus, internal nitrogen and silicon contribute more to the phytoplankton production at most sampling stations. © 2013 Elsevier Ltd.


Sun J.,Tianjin University of Science and Technology | Sun J.,Tianjin Key Laboratory of Marine Resources and Chemistry | Feng Y.,Tianjin University of Science and Technology | Feng Y.,Tianjin Key Laboratory of Marine Resources and Chemistry | And 5 more authors.
Deep-Sea Research Part II: Topical Studies in Oceanography | Year: 2013

Phytoplankton growth and microzooplankton grazing were studied during the 2007 spring bloom in Central Yellow Sea. The surveyed stations were divided to pre-bloom phase (Chl a concentration less than 2μgL-1), and bloom phase (Chl a concentration greater than 2μgL-1). Shipboard dilution incubation experiments were carried out at 19 stations to determine the phytoplankton specific growth rates and the specific grazing rates of microzooplankton on phytoplankton. Diatoms dominated in the phytoplankton community in surface waters at most stations. For microzooplankton, Myrionecta rubra and tintinnids were dominant, and heterotrophic dinoflagellate was also important in the community. Phytoplankton-specific growth rates, with an average of 0.60±0.19d-1, were higher at pre-bloom stations (average 0.62±0.17d-1), and lower at the bloom stations (average 0.59±0.21d-1), but the difference of growth rates between bloom and pre-bloom stations was not statistically significant (t test, p=0.77). The phytoplankton mortality rate by microzooplankton grazing averaged 0.41±0.23d-1 at pre-bloom stations, and 0.58±0.31d-1 during the blooms. In contrast to the growth rates, the statistic difference of grazing rates between bloom and pre-bloom stations was significant (after removal of outliers, t test, p=0.04), indicating the importance of the top-down control in the phytoplankton bloom processes. Average potential grazing efficiency on primary productivity was 66% at pre-bloom stations and 98% at bloom stations, respectively. Based on our results, the biomass maximum phase (bloom phase) was not the maximum growth rate phase. Both phytoplankton specific growth rate and net growth rate were higher in the pre-bloom phase than during the bloom phase. Microzooplankton grazing mortality rate was positively correlated with phytoplankton growth rate during both phases, but growth and grazing were highly coupled during the booming phase. There was no correlation between phytoplankton growth rate and cell size during the blooms, but they were positive correlated during the pre-bloom phase. Our results indicate that microzooplankton grazing is an important process controlling the growth of phytoplankton in spring bloom period in the Central Yellow Sea, particularly in the "blooming" phase. © 2013 Elsevier Ltd.


Tang N.,Tianjin University of Science and Technology | Tang N.,Tianjin Key Laboratory of Marine Resources and Chemistry | Jia Q.,Tianjin University of Science and Technology | Jia Q.,Tianjin Key Laboratory of Marine Resources and Chemistry | And 6 more authors.
Desalination | Year: 2010

Isotactic polypropylene (iPP) hydrophobic microporous flat sheet membranes were developed via thermally induced phase separation for vacuum membrane distillation (VMD). The synthesized membranes were characterized by contact angle measurements, poremeter and scanning electron microscopy. The membranes had an asymmetric cross-sectional structure with cellular pores on the skin layer and dendritic pores on the non-skin layers. Pure water and 0.5molL-1 aqueous NaCl solution VMD performance was developed with the resultant membranes. The factors of iPP concentration, iPP melt index and nucleating agent concentration affect pore morphology and performance of the membranes significantly. The formation of the membrane is not very sensitive to quench bath temperature, although temperature has a small effect on porosity. It was found that the diluent agent has a strong effect on the morphology and performance of the membranes; soybean oil is a good diluent agent for preparation of narrow pore size iPP hydrophobic membranes with pore size distribution of about 0.02-0.2-m. © 2010 Elsevier B.V.


Xu Y.,Tianjin University of Science and Technology | Xu Y.,Tianjin Key Laboratory of Marine Resources and Chemistry | Yu T.,Tianjin University of Science and Technology | Zhong Y.,Tianjin University of Science and Technology | Wang X.,Tianjin University of Science and Technology
Lecture Notes in Electrical Engineering | Year: 2014

The water in Bohai Bay has become more and more eutrophic, causing a frequent red tide bloom. How to decrease eutrophication of this sea area is a pressing problem. The seawater often enters the estuary by flood tide, so the estuary may be a good place to remove eutrophic compounds from the seawater. This paper reported apocynum venetum seedlings growth status in water from Beitang estuary and its effects on nutrient removal. The results showed that apocynum venetum seedlings could grow both in flood tide water and in ebb tide water from Beitang estuarine, and the content of nitrogen and phosphorus in the water was significantly decreased by apocynum venetum seedlings, and the decrease level was largest for nitrite nitrogen in flood tide water. These results indicated that the eutrophic water in Bohai Bay was probably purified by apocynum venetum growing in ecological floating boat at estuarine. © Springer-Verlag Berlin Heidelberg 2014.


Jia Z.Y.,Tianjin University of Science and Technology | Jia Z.Y.,Tianjin Key Laboratory of Marine Resources and Chemistry | Zhang L.,Tianjin University of Science and Technology | Zhang L.,Tianjin Key Laboratory of Marine Resources and Chemistry | And 4 more authors.
Advanced Materials Research | Year: 2014

The marine oil and gas transmission pipelines should be washed by phosphoric acid solution before they were used. The washing wastewater, containing high level of phosphorus, was treated by calcium chloride. The response surface method (RSM) based on Box-Behnken was adopted to consider the impact of n(Ca):n(P), pH and reaction temperature on total phosphorus (TP) removal rate. In this work, the Design-Expert 8.0.6 was employed to design and analyze the results. Then, a quadratic polynomial model was built with TP removal rate as the response value. It was shown that the n(Ca):n(P) and pH have a significant effect on TP removal rate. The interaction of pH and temperature is significant. The optimum conditions were X1=3.40, X2=10.97, X3=38.12. In this condition, the predicted value of TP removal rate is 99.9242% while the average removal rate of verification is 99.9365%, which was shown that the predicted value was identical with experiment value. © (2014) Trans Tech Publications, Switzerland.


Wang S.,Tianjin University of Science and Technology | Wang S.,Tianjin Key Laboratory of Marine Resources and Chemistry | Han X.,Tianjin University of Science and Technology | Jing Y.,Tianjin University of Science and Technology | And 5 more authors.
Journal of Chemical and Engineering Data | Year: 2016

The solubilities and physicochemical properties, including density, refractive index, and pH, of the ternary system (LiCl + Li2SO4 + H2O) at T = (288.15 and 308.15) K and p = 0.1 MPa were determined with the isothermal dissolution equilibrium method. The phase diagram in the ternary system at 288.15 K consists of one invariant point, two univariant solubility curves, and two crystallization regions corresponding to Li2SO4·H2O and LiCl·H2O. A similar structure can be found in this system at 308.15 K. This ternary system belongs to hydrate type I at two temperatures, and neither double salts nor solid solutions were formed at the investigated temperatures. The crystallized area of LiCl·H2O decreases with increasing temperature, while that of Li2SO4·H2O increases obviously. The solution density, refractive index, and pH value of the ternary system (LiCl + Li2SO4 + H2O) at the two temperatures change regularly with the mass fraction of lithium. The Pitzer-Harvie-Weare thermodynamic model of aqueous electrolyte solutions was chosen to simulate the solubility of (LiCl + Li2SO4 + H2O) at (288.15 and 308.15) K. Reasonable agreement between the predicted solubilities and experimental data was found. © 2016 American Chemical Society.


Tang N.,Tianjin University of Science and Technology | Tang N.,Tianjin Key Laboratory of Marine Resources and Chemistry | Zhang H.,Tianjin University of Science and Technology | Zhang H.,Tianjin Key Laboratory of Marine Resources and Chemistry | And 2 more authors.
Desalination | Year: 2011

Vacuum membrane distillation (VMD) was considered as the multiphase flow (liquid and gas phase) process inside the porous media, and the membrane module was simplified to the two-dimensional structure with a single membrane silk. The simulation has studied the mass transformation and heat transformation of VMD process in the porous media, in which aqueous NaCl solution was seemed as an incompressible and steady fluid. In the processes of mass transfer, heat transfer and phase transition, all particles were supposed in local thermodynamic balance. By means of FLUENT, one of the softwares about computational fluid dynamics (CFD), the numerical simulation of the two-dimensional model of VMD for aqueous NaCl solution was established under the steady state. The paper also calculated and analyzed the volume rate of vapor with different feed temperatures. © 2011 Elsevier B.V.


Tang N.,Tianjin University of Science and Technology | Tang N.,Tianjin Key Laboratory of Marine Resources and Chemistry | Yin J.,Tianjin University of Science and Technology | Yin J.,Tianjin Key Laboratory of Marine Resources and Chemistry
Shiyou Xuebao, Shiyou Jiagong/Acta Petrolei Sinica (Petroleum Processing Section) | Year: 2011

Residual alkali, sulfides, phenols and naphthenic are contained in refinery alkaline residue, which can be removed by carbonization method. The effects of carbonization factors on the removal ratio of sulfides and phenols, and the rate of COD change from the alkaline residue were investigated. Orthogonal test design was adopted to obtain the optimal conditions in refinery alkaline residue treatment. The results showed that the optimized conditions of carbonization were temperature of 95°C, time of 150 min and the CO2 volume fraction of 80%. CuO was used as a desulphurization agent to remove the sulfur from refinery alkaline residue, and removal ratio of sulfides could reach 98%.


Wang S.,Tianjin University of Science and Technology | Wang S.,Tianjin Key Laboratory of Marine Resources and Chemistry | Guo Y.,Tianjin University of Science and Technology | Guo Y.,Tianjin Key Laboratory of Marine Resources and Chemistry | And 3 more authors.
Journal of Solution Chemistry | Year: 2015

The solubilities and physicochemical properties, including density and pH, in the ternary system (LiBO2 + CaB2O4 + H2O) at (288.15 and 298.15) K were investigated using the isothermal dissolution equilibrium method. According to the experimental results of the ternary system at (288.15 and 298.15) K, the stable phase diagrams and the diagrams of physicochemical properties were plotted versus composition. In the phase diagrams of the ternary system at (288.15 and 298.15) K, there is one invariant point (LiBO2·8H2O + CaB2O4·6H2O), two univariant isotherm dissolution curves, and two crystallization regions corresponding to lithium metaborate octahydrate (LiBO2·8H2O) and calcium metaborate hexahydrate (CaB2O4·6H2O), respectively. This system at both temperatures belongs to hydrate type I classification and neither double salt nor solid solution were found. A comparison of the phase diagrams for the ternary system at (288.15 and 298.15) K shows that the numbers of solid phase and the minerals present are the same; the crystallized area of CaB2O4·6H2O increased at the higher temperature, while that of LiBO2·8H2O decreased. The physicochemical properties (density and pH values) of the ternary system at the two temperatures change regularly with increasing lithium metaborate concentration. The calculated values of density using empirical equations of the ternary system are in good agreement with the experimental values. © 2015 Springer Science+Business Media New York.

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