Tianjin Hydraulic Science Research Institute

Tianjin, China

Tianjin Hydraulic Science Research Institute

Tianjin, China

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Liu Y.,Nankai University | Liu Y.,Tianjin Hydraulic Science Research Institute | Yu H.,Nankai University | Cai M.,Nankai University | Sun J.,Nankai University
Catalysis Communications | Year: 2012

Visible-light-active Ag 2CrO 4 photocatalysts were first synthesized by a microwave hydrothermal (MH) method, which is highly efficient (180°C for only 1 h). The products were characterized by XRD, SEM, Zeta potential and UV-vis diffuse reflectance spectroscopy. The photocatalytic activity of Ag 2CrO 4 was evaluated by the degradation of PCP-Na aqueous solution under visible light irradiation. The reduction of total organic carbon (TOC) (about 98.2% after 5 h of irradiation) showed that the mineralization of PCP-Na over Ag 2CrO 4 photocatalysts was realized. Additionally, the possible photocatalytic mechanism of the Ag 2CrO 4 was proposed to elucidate its superior photocatalytic activity. Crown Copyright © 2012 Published by Elsevier B.V. All rights reserved.


Liu Y.,Tianjin Hydraulic Science Research Institute | Liu Y.,Nankai University | Yang H.,Tianjin Hydraulic Science Research Institute | Yu H.,Nankai University | And 3 more authors.
Chinese Journal of Environmental Engineering | Year: 2013

Magnetic monodisperse pompon-like magnetite/chitosan (Fe3O4/CS) nanocomposites were synthesized by a solvent-thermal method. Then the Fe3O4/CS nanocomposites were used as a magnetic adsorbent for removal of toxic sodium pentachlorophenate (PCP-Na) from aqueous media. Adsorption studies showed that the adsorption equilibrium was achieved within 30 min. And for the PCP-Na solution with initial concentration of 100 mg/L, the prominent removal of PCP-Na (91.5%) was obtained at 25°C and pH 6.5. Adsorption isotherms and adsorption kinetics showed that the adsorption behavior of PCP-Na on Fe3O4/CS was an exothermic adsorption process, obeyed the Langmuir isotherm and fitted the pseudo-second-order kinetics model. Furthermore, after the adsorption process, the Fe3O4/CS can be easily separated from water with magnets for recycle and reuse, which showed that the magnetic adsorbents have great potential and superiority to be used for treating wastewater in practice.


Liu Y.,China Institute of Water Resources and Hydropower Research | Liu Y.,Nankai University | Liu Y.,Tianjin Hydraulic Science Research Institute | Yu H.,Nankai University | And 4 more authors.
Water Science and Technology | Year: 2013

Novel monodispersed pompon-like magnetite/chitosan (Fe3O 4/CS) composite nanoparticles were synthesized by a solvothermal method and used as adsorbents for the removal of toxic sodium pentachlorophenate (PCP-Na) from aqueous media. The adsorption behavior of PCP-Na on Fe 3O4/CS obeyed the Langmuir isotherm and fitted the pseudo-second-order kinetics model. Thermodynamic parameters showed that the adsorption process was exothermic and spontaneous. Moreover, the adsorption was strongly pH-dependent. The results of XPS, thermodynamics, pH-dependent and desorption studies suggested that electrostatic attraction, hydrogen bonding and π-π interactions were all believed to play a role in PCP-Na adsorption on Fe3O4/CS. Having a saturation magnetization of 22.2 emu·g-1, the Fe3O4/CS can be easily separated from water with magnets within 2 min. The adsorption equilibrium was achieved quite rapidly (within 30 min) and the maximum removal of PCP-Na (91.5%) was obtained at 25°C and pH 6.5. The Fe3O4/CS investigated can be used to remove PCP-Na and other contaminants from wastewater. © IWA Publishing 2013.


Chang C.,Tianjin University | Feng P.,Tianjin University | Sun D.-M.,Tianjin University | Zhang K.,Tianjin Hydraulic Science Research Institute
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2015

The stepwise cluster analysis (SCA) was employed to predict the chlorophyll-a content of alga in Yuqiao Reservoir. A SCA model was firstly developed based on 56 data sets of 7factors related to water quality and meteorology from 1999 to 2006, which was used to predict the chlorophyll-a content from 2007 to 2010.The predicted values matched the measured values well with the average absolute error of -0.0007 and the average relative error of 21.66%, and the correlation coefficient is 0.94.It showed that SCA was effective to predict the chlorophyll-a content in Yuqiao Reservoir. The sensitivity analysis were also performed, the results showed that pH value, total phosphorus content and dissolved oxygen had more significant impacts on the alga growth in Yuqiao Reservoir. Therefore, it is an important way to prevent algal blooms by controlling the above 3 factors. ©, 2015, Chinese Society for Environmental Sciences. All right reserved.


Liu X.,Nankai University | Huang S.,Nankai University | Tang T.,Nankai University | Liu X.,Tianjin Hydraulic Science Research Institute | Scholz M.,University of Salford
Ecological Engineering | Year: 2012

Three species of plants, Phragmites australis, Sparganium stoloniferum and Typha orientalis Presl., were selected to assess their growth characteristics and their capability to remove and accumulate nutrients such as nitrogen and phosphorous in pilot-scale-size subsurface vertical flow constructed wetland systems. During the experimental period, the growth situation of each plant was comprehensively evaluated. The rank order of the total influence value was as follows: P. australis (62.5)>T. orientalis Presl. (52)>S. stoloniferum (46). Both the maximum root length and root volume of the three species of plants had significant differences. S. stoloniferum reached maximum individual plant height (1.32m) at the end of July, while P. australis and T. orientalis Presl. did not reach a maximum individual plant height (2.08m and 1.58m, respectively) until the middle of September. Before cultivation, the total biomass of P. australis, S. stoloniferum and T. orientalis Presl. were 0.33, 0.69 and 0.71kgm-2, respectively. After 5 months' growth, total biomass of the three species had become 3.81, 2.86 and 4.22kgm-2, respectively; about 11.5, 4.1 and 5.9 times that the amount before cultivation. The total nitrogen (TN) ranked distributions in all three plants' tissues could be summarized as leaf>root>stem before cultivation and root>leaf> stem at the end of the experiment. P. australis, S. stoloniferum and T. orientalis Presl. mainly accumulated TN and total phosphorus (TP) in their roots, the ratio of belowground and aboveground TN and TP accumulation were 1.58 and 1.59, 2.47 and 3.61, and 2.74 and 5.18, respectively. The chemical oxygen demand (COD), TN, ammonia-nitrogen (NH4-N) and TP removal rates of planted units were significantly higher than those of the unplanted control unit (p<0.05); but no significant differences were found between the different planted units (p>0.05). © 2012 Elsevier B.V.


Li Y.,Tianjin Hydraulic Science Research Institute | Liu Y.,Tianjin Hydraulic Science Research Institute | Li C.,Benxi Land Service of Liaoning Province
Chinese Journal of Environmental Engineering | Year: 2016

Based on the typical geology and the pollution of Cr(VI) in Tianjin, three aquifer mediums of fine sand, medium sand, and coarse sand were chosen as research materials to study their adsorption kinetics and isothermal adsorption of Cr(VI). The results showed that the adsorptions of the three aquifer mediums to Cr(VI) included fast and slow adsorption stages. Adsorption equilibrium was achieved after 2 h and conformed to Elovich adsorption kinetics. The adsorption isothermal model of the aquifer mediums to Cr(VI) obeyed the Freundlich model, which indicated that the adsorption process was mainly uneven. The adsorption capacity of fine sand to Cr(VI) was the highest. However, when the initial concentration of Cr(VI) solution was 0.1 mg/L and the aquifer medium was 10 g of fine sand, the maximum adsorption rate was only 22.67%, which showed that it was difficult for the three aquifer mediums to adsorb Cr(VI). This means that Cr(VI) can be intercepted by an aquifer medium after it has entered the groundwater, but flows in the groundwater can cause long distance pollution. © 2016, Science Press. All right reserved.


PubMed | Nankai University, Tianjin Hydraulic Science Research Institute and China Institute of Water Resources and Hydropower Research
Type: Journal Article | Journal: Water science and technology : a journal of the International Association on Water Pollution Research | Year: 2013

Novel monodispersed pompon-like magnetite/chitosan (Fe3O4/CS) composite nanoparticles were synthesized by a solvothermal method and used as adsorbents for the removal of toxic sodium pentachlorophenate (PCP-Na) from aqueous media. The adsorption behavior of PCP-Na on Fe3O4/CS obeyed the Langmuir isotherm and fitted the pseudo-second-order kinetics model. Thermodynamic parameters showed that the adsorption process was exothermic and spontaneous. Moreover, the adsorption was strongly pH-dependent. The results of XPS, thermodynamics, pH-dependent and desorption studies suggested that electrostatic attraction, hydrogen bonding and - interactions were all believed to play a role in PCP-Na adsorption on Fe3O4/CS. Having a saturation magnetization of 22.2 emu g(-1), the Fe3O4/CS can be easily separated from water with magnets within 2 min. The adsorption equilibrium was achieved quite rapidly (within 30 min) and the maximum removal of PCP-Na (91.5%) was obtained at 25 C and pH 6.5. The Fe3O4/CS investigated can be used to remove PCP-Na and other contaminants from wastewater.

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