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Li F.,Tianjin University | Zheng J.,Tianjin University | Zheng J.,Tianjin Key Laboratory of Aquatic Science and Technology | Jia Z.,Tianjin University | And 2 more authors.
Chinese Journal of Environmental Engineering | Year: 2017

Simulative tests were conducted in order to study four typical coexisting algae (Microcystis aeruginosa, Chlorella vulgaris, Oocystis sp., and Phormidium.), the response of growth law and the kinetics under different nitrogen and phosphorus nutrient conditions. The Haihe River in Tianjin was considered as the research object. The results showed that (1) a N/P ratio within 10-40 allowed faster algal growth that was particularly vigorous once the N/P ratio equaled 10; (2) the algal growth-rate increased with the increase in N or P concentrations (CN 2.0-15 mg·L-1 and CP 0.2-1.5 mg·L-1), and it reached an optimal value when the abundance of N and P reached 15 and 1.5 mg·L-1 respectively; (3) Oocystis sp. was the dominant species; (4) Monod kinetic analysis revealed that the maximal increment rate was 0.0508 and the semi saturation-constant was 0.157, indicating a confining role of phosphorus on algal growth in the target river. © 2017, Science Press. All right reserved.


Ma X.,Tianjin University | Zhang X.,Tianjin Chengjian University | Zhang X.,Tianjin Key Laboratory of Aquatic Science and Technology | Wang B.,Tianjin University | And 4 more authors.
Evolutionary Applications | Year: 2014

Evolution has resulted in thousands of species possessing similar metabolic enzymes with identical functions that are, however, regulated by different mechanisms. It is thus difficult to select optimal gene to engineer novel or manipulated metabolic pathways. Here, we tested the ability of molecular evolutionary analysis to identify appropriate genes from various species. We calculated the fraction of synonymous substitution and the effective number of codons (ENC) for nine genes stemming from glycolysis. Our research indicated that an enzyme gene with a stronger selective constraint in synonymous sites would mainly regulate corresponding reaction flux through altering the concentration of the protein, whereas those with a more relaxed selective constraint would primarily affect corresponding reaction flux by changing kinetic properties of the enzyme. Further, molecular evolutionary analysis was investigated for three types of genes involved in succinate precursor supply by catalysis of pyruvate. In this model, overexpression of Corynebacterium glutamicum pyc should result in greater conversion of pyruvate. Succinate yields in two Escherichia coli strains that overexpressed each of the three types of genes supported the molecular evolutionary analysis. This approach may thus provide an alternative strategy for selecting genes from different species for metabolic engineering and synthetic biology. © 2014 The Authors.


Fan X.,Tianjin Institute of Urban Construction | Fan X.,Tianjin Key Laboratory of Aquatic Science and Technology | Zhang X.,Tianjin Institute of Urban Construction | Zhang X.,Tianjin University
Applied Mechanics and Materials | Year: 2013

The simultaneous removal of SO2 and NO was investigated with the activated carbon from sewage sludge (referred as ACS) modified by chitosan (referred as CS).The effects of CS loading and operating conditions on the simultaneous removal of SO2 and NO were analyzed. The results indicate that compared with the ACS, impregnating CS results in significant increase in SO2 or NO removal. Relative humidity enhances SO2 adsorption capacities, but not for NO. The SO2 adsorption capacities of the CS / ACS show no obvious decrease at small amount of NO in the feed. However, higher amounts of NO reduce the SO2 adsorption capacities. The opposite phenomenon appears for NO when a small amount of SO2. So a competitive sorption consists between NO and SO2. Simultaneous adsorptions for NO and SO2 is due to more active sites from CS. © (2013) Trans Tech Publications, Switzerland.


Wang Y.,Tianjin Key Laboratory of Aquatic Science and Technology | Xiong Z.-H.,Tianjin Key Laboratory of Aquatic Science and Technology | Zhou J.-G.,Tianjin Institute of Urban Construction
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2012

The calyx[4]arene was synthesized and connected to Amberlite XAD-4 resin covalently through a diazotization bound. The structure of Amberlite XAD-4 resin base on calyx[4]arene was characterized using FT-IR, SEM and TG/DTA. The sorption results showed that Amberlite XAD-4 resin base on calyx[4]arene had much better removal to the diclofenac in aqueous solutions than Amberlite XAD-4 resin and calyx[4]arene which were presence alone in aqueous solutions. The removal rate of diclofenac increased rapidly with the calyx[4]arene modified Amberlite XAD-4 resin dosage. In the condition of DCF concentration was 20 mg/L, when the Amberlite XAD-4 resin base on calyx[4]arene dosage came up to 80 mg/L, the removal rate of diclofenac was 92.8% and reached equilibrium, the corresponding amount adsorbed was 34.02 mg/g. Kinetic analyses were conducted using pseudo first-order and second-order models. The linear correlation coefficients and standard deviations of Langmuir and Freundlich isotherms were determined, and the results revealed that Langmuir and Freundlich isotherm were fitted the experimental data well. The thermodynamic parameters calculated indicated, ΔH and ΔG were negative, which predicated adsorption process of diclofenac on f Amberlite XAD-4 resin base on calyx[4]arene resin was exothermic and spontaneous.


Fan X.,Tianjin Institute of Urban Construction | Fan X.,Tianjin Key Laboratory of Aquatic Science and Technology | Zhang X.,Tianjin Institute of Urban Construction | Zhang X.,Tianjin University
Advanced Materials Research | Year: 2013

Heavy metal leaching limits activated carbon from sewage sludge (referred as ACS) to be used for wastewater treatment. Cr and Cd leaching from ACS exceed the permitted values. The leaching content of Cr and Cd decrease much with depositing ACS with chitosan (CS),below the permitted values. This is mainly due to the bind of Cr and Cd with the much group -NH2 of CS. The effects of initial dye concentration, pH and contact time had been studied. The dye adsorbed can act as a supple complexion agent with increasing initial dye concentration, increase the affinity for Cr and Cd. For Cd, the amount leaching of CS/ACS or ACS remains content with pH.The amount leaching of Cr decreases when the pH from 1 to 5 and then increases above the pH of 6.0. The contact time has no important influence on the leaching contents of Cr or Cd. © (2013) Trans Tech Publications, Switzerland.


Jian Y.,Tianjin Institute of Urban Construction | Jian Y.,Tianjin Key Laboratory of Aquatic Science and Technology | Man L.,Tianjin Institute of Urban Construction | Man L.,Tianjin Key Laboratory of Aquatic Science and Technology | And 4 more authors.
Hydraulic Engineering - Proceedings of the 2012 SREE Conference on Hydraulic Engineering, CHE 2012 and 2nd SREE Workshop on Environment and Safety Engineering, WESE 2012 | Year: 2013

Because of characteristic of the viscosity, small size of water quality particle, less pollutant content and hard to be degraded, low temperature and low turbidity micro-polluted water has continuously been the problem of drinking water treatment. With the water quality index of turbidity, UV254, CODMn and THMFP, the experiment has a study on the effect of enhanced direct filtration by ozone pre-oxidation in low temperature and low turbidity micro-polluted water treatment. The result shows, ozone dosage is 1.5 mg/L, pre-oxidation time is 10 min, effluent turbidity can drop to 0.3 NTU. The best of CODMn removal rate can reach to 59% and the best of CODMn removal rate can reach to 57%. The ozonation has a better removal efficiency of trihalomethane precursors, and the best removal rate can reach to 79%. © 2013 Taylor & Francis Group.


Fan X.,Tianjin Institute of Urban Construction | Fan X.,Tianjin Key Laboratory of Aquatic Science and Technology | Zhang X.,Tianjin Institute of Urban Construction | Zhang X.,Tianjin University | Xu T.,Tianjin University
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2012

The activated carbon from sewage sludge (ACS) was modified with the chitosan (CS). The desulfurization and denitrification properties of the modified ACS with CS (referred as CS/ACS) were investigated experimentally. The structure and the surface groups of produced CS/ACS were analyzed by BET surface area measurement, scanning electron microscopy (SEM), x-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The effects of modification conditions on the desulfurization and denitrification properties of CS/ACS were investigated to explain the mechanism for SO 2 and NO removal. The results indicated that the pore diameters of CS/ACS were smaller compared with ACS. The binding between ACS and CS in the CS/ACS was good by the chemical bond. Both the modification temperature and the time were able to change the BET surface areas and pore volume of the CS/ACS, with the effect of temperature more significantly. The BET surface area, total pore volume and mesopore volume of the optimum pore structure of A3 were 168.76 m 2·g -1, 0.084 cm 3·g -1 and 0.041 cm 3·g -1, respectively. Compared with the ACS, the desulfurization and denitrification properties of the CS/ACS were greatly improved. This was because of the nitrogen and oxygen containing functional groups of -NH 2 and -O which were formed on the surfaces of ACS and increased the amount and types of the functional groups for the chemical adsorption of SO 2 and NO. The physical adsorption was also improved by controlling modification conditions to obtain optimum BET surface area and mesopore volume, upgrading the desulfurization and denitrification properties.


Zhang X.-B.,Tianjin Chengjian University | Zhang X.-B.,Tianjin Key Laboratory of Aquatic Science and Technology | Ma X.-M.,Kailuan General Hospital | Wang B.-Y.,Tianjin University | And 2 more authors.
Journal of Systematics and Evolution | Year: 2015

The evolutionary suppression of synonymous codon sites is a controversial topic. Although some studies have indicated that synonymous substitution is under positive selection, most of these studies relied on comparison of homologous genes and/or a limited number of sequences. In the present work, we compared the selection strength at synonymous sites for two types of protein-encoding genes: genes encoding enzymes and protein genes encoding non-enzymes. Our method does not require assumptions concerning, for example, evolutionary equilibrium or population size. We compared∼ 70 000 genes from the fully sequenced mammalian Homo sapiens, Pan troglodytes, Mus musculus, and Rattus norvegicus genomes and found that the percentage of C and G in the third position of a codon positively correlates with the percentage of the G/C content within ± 20 000 nucleotides of the gene. More interestingly, we found that synonymous sites in mammalian genes encoding enzymes have undergone stronger selection than did such sites in genes encoding proteins that are not enzymes. © 2014 Institute of Botany, Chinese Academy of Sciences.


Fan X.D.,Tianjin University | Fan X.D.,Tianjin Key Laboratory of Aquatic Science and Technology | Zhang X.K.,Tianjin University
Environmental Protection and Sustainable Ecological Development - Proceedings of the Environmental Protection and Sustainable Ecological Development, EPSED 2014 | Year: 2015

Norfloxacin (Nor) as a common representative of antibiotics was examined for its degradation by Biological Activated Carbon (BAC). The objectives of this study are to show the performance of BAC process treating Nor from aqueous solutions. The adsorption and biodegradation in BAC reactor (BAC column A) and the other reactor with new carbon, not inoculated (BAC column B) were carried out. The results showed that immediate breakthrough of norfloxacin (Nor) is observed in the effluent of BAC column B. The Nor removal efficiencies increase with hydraulic retention time in BAC column A. When hydraulic retention time is 2 h, Nor removal efficiency reached 77.26%. FTIR results indicate that the benzene ligand of Nor has been destructed and produced free-OH group, the stretch of O-H and N-H decrease with the peaks at 3000–3500 cm−1 shifting to 3500–3600 cm−1. Biodegradation can play the leading pole for Nor removal in BAC reactors. © 2015 Taylor & Francis Group, London.


Fan X.D.,Tianjin University | Fan X.D.,Tianjin Key Laboratory of Aquatic Science and Technology | Zhang X.K.,Tianjin University
Journal of Residuals Science and Technology | Year: 2015

Food waste residue is an intractable problem worldwide. The current study discussed the potential of adsorbents prepared from food waste residue (AFWR) for heavy metal removal from wastewater. The microstructure of AFWR was characterized, and kinetic studies on the simultaneous adsorption of Pb2+, Cu2+, Zn2+ and Cd2+ ions from aqueous solutions by AFWR were carried out. It was found that the adsorption of all heavy metals followed a pseudo-second-order kinetics, so that there was a competitive adsorption for Pb2+, Cu2+, Zn2+ and Cd2+. According to the experimental results, the adsorption in competition beads with the heavy metals presented an order of Cu2+ > Pb2+ > Zn2+ > Cd2+. © 2015 DEStech Publications, Inc.

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