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Xu J.,Key Laboratory of Marine Chemistry Theory and Technology | Ruan G.,Institute of Seawater Desalination And Multipurpose Utilization | Zou L.,University of South Australia | Gao C.,Key Laboratory of Marine Chemistry Theory and Technology
Desalination | Year: 2010

Bio-fouling results in deterioration of permeate quality and flux in reverse osmosis (RO) process. Cellulose triacetate hollow fiber membrane used for RO in SWRO has anti-chlorine property that makes technical sense compared to polyamide spiral-wound RO for overcoming bio-fouling. Mode of chlorine injection is the controlling factor of sterilization in SWRO system. This work evaluated the effects of five different modes of chlorine injecting system as well as HCl injection on the performance of HF RO system. In addition, effects of HCl and anti-scalants on anti-scale performance of HF RO system were also investigated, respectively. A brief list of chemical costs under different abovementioned operating conditions was covered in a cost analysis. The results indicated that the injecting mode that employed continuous chlorine with a relatively low concentration of 0.3-0.4 mg/L at pH 5.8-6.2 was preferable in the aspects of total bacterial count (TBC) removal, permeate flow rate, differential pressure, permeability (Pp), performance factor (η) and chemical costs. HCl injection could improve the sterilization and prevent scaling on the membrane surface efficiently. The expense of anti-scalant (MDC220) was higher than HCl. © 2010 Elsevier B.V. All rights reserved. Source

Zhang Y.,Institute of Seawater Desalination And Multipurpose Utilization
Wei sheng wu xue bao = Acta microbiologica Sinica | Year: 2010

OBJECTIVE: To isolate, identify and characterize a fungus with flocculating activity. METHODS: We used gradient dilution, plaque distribution and 18S rDNA analysis to isolate and identify a fungus with flocculating activity. We used high-speed centrifugation, ultrasonication and qualitative test to determine the nature of flocculating active substances. RESULTS: We isolated a flocculating active fungi and identified it as Penicillium purpurogenum. Ultrasonication test confirmed that the flocculating activity was primarily in the fermentation supernatant. We explored the flocculating activity curve and found that 4 days was the optimum fermentation time for accumulating flocculating active substances. The strain flocculating activity remains unchanged when pH varied from 2 to 11 and temperature varied from -70 degrees C to 100 degrees C. We finally identified the flocculating active substances as saccharides. CONCLUSION: We isolated a flocculating active strain P. purpurogenum EL-02, and identified its flocculating active products as saccharides. Source

Han Y.,Tianjin University | Zhang M.,Tianjin University | Zhang M.,Institute of Seawater Desalination And Multipurpose Utilization | Li W.,Tianjin University | Zhang J.,Tianjin University
Physical Chemistry Chemical Physics | Year: 2012

First-principles density functional theory studies have been carried out to investigate the effects of perfect and defective anatase TiO 2 supports on the structural stabilities and electronic properties of Pd mAg n(m + n = 2-5) bimetallic clusters. Our results showed that the structures of supported Pd-Ag bimetallic clusters are distorted compared to their structures in the gas phase, which is caused by the balance of the cluster inner-interaction and the metal-support interfacial interaction. In particular, Pd 1Ag 3 and Pd 1Ag 4 clusters prefer to form three-dimensional structures on both perfect and defective anatase TiO 2 support while their most stable structures in the gas phase are planar. In the most stable structures of supported Pd mAg n bimetallic clusters, Pd atoms always occupy the most active sites of TiO 2(101) surface, which induced Pd enriched at the interface of TiO 2 support and Ag atoms exposed at the surface of the bimetallic cluster. As Ag% increases, the perfect TiO 2 support gets more electrons from the Pd-Ag bimetallic cluster, which reduced the stability of the supported Pd-Ag cluster. The Mulliken population and electron density difference analysis demonstrated that the co-deposition of Ag induced the charge of adsorbed Pd on the perfect TiO 2 support from positive to negative as a result of charge transfer from the half-filled s-orbital of Ag(5s 1) to the d-orbit of Pd, and the negative charges of Pd on the defective TiO 2 support were also increased by Pd-Ag charge polarization. Therefore, the selectivity of acetylene hydrogenation is enhanced by anatase-TiO 2 supported Pd-Ag bimetallic catalyst as it serves as an electron donor. This journal is © the Owner Societies 2012. Source

Li S.-P.,Shandong University | Cui J.-J.,Institute of Seawater Desalination And Multipurpose Utilization | Jiang Y.-Y.,Shandong University | Fang H.-C.,Shandong University
Gaodianya Jishu/High Voltage Engineering | Year: 2011

In order to study the effect of low-temperature plasma on Nitenpyram (NTP) pesticide containing wastewater treatment, employing reactor with a structure of radial flow sedimentation tank and centered fluid inlet, NTP solution was experimentally treated by low-temperature plasma produced by dielectric barrier discharge process. The influences of different dielectric barrier discharge's input power and different external factors, such as Fe2+, butanol, Na2CO3 and H2O2 on nitenpyram degradation, on treatment results were studied. The results show that NTP could be effectively removed from aqueous solution by the low-temperature plasma. Increasing the input power can increase the degradation efficiency. 82.7% of the NTP in 1L NTP solution (initially 100 mg/L) was degraded after 180 min treatment when the input power was 200 W. Low concentrations of Fe2+ and H2O2 could enhance the degradation, however, they hinder the degradation at higher concentrations. The presence of n-butanol as hydroxide radical scavenger and sodium carbonate as buffer in the aqueous solution decreases the removal efficiency of NTP to some extent. Furthermore, the pH of NTP drops with the degradation processing. Source

Feng J.-M.,Tianjin University | Feng J.-M.,Institute of Seawater Desalination And Multipurpose Utilization | Dai Y.-J.,Tianjin University
Nanoscale | Year: 2013

Combining carbon nanotubes (CNTs) with graphene has been proved to be a feasible method for improving the performance of graphene for some practical applications. This paper reports a water-assisted route to grow graphene on CNTs from ferrocene and thiophene dissolved in ethanol by the chemical vapor deposition method in an argon flow. A double injection technique was used to separately inject ethanol solution and water for the preparation of graphene/CNTs. First, CNTs were prepared from ethanol solution and water. The injection of ethanol solution was suspended and water alone was injected into the reactor to etch the CNTs. Thereafter, ethanol solution was injected along with water, which is the key factor in obtaining graphene/CNTs. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and Raman scattering analyses confirmed that the products were the hybrid materials of graphene/CNTs. X-ray photo-electron spectroscopy analysis showed the presence of oxygen rich functional groups on the surface of the graphene/CNTs. Given the activity of the graphene/CNT surface, CdS quantum dots adhered onto it uniformly through simple mechanical mixing. This journal is © 2013 The Royal Society of Chemistry. Source

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