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Two-phase Flow Patterns in a Square Mini-channel

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Journal of Thermal Science 2004年第2期13卷 174-178页

作者： jianfu zhao Gang Liu Bin Li Chinese Acad Sci Inst Mech Natl Micrograv Lab Beijing 100080 Peoples R China

This paper presents a new set of experimental data of air-water flow patterns in a channel with a cross-section of 1×1 mm2. The ranges of the gas and liquid superficial velocities are 0.1-10 m/s and 0.2~7 m/s, respectively. Bubble, bubble-slug, slug, and frothy flows are observed. The present data are compared with other data in mini-channels reported in literature, and also compared with those in normal channel at microgravity, in which the Bond number has the same order of magnitude. The slug-frothy boundary is in consistent with each other, but for the bubble-slug transition, a much smaller value for the transition quality in the drift-flux model is obtained in the present study than those predicted by the empirical relations for the case of microgravity. It’s shown that the mini-scale modeling may not be an effective way to anticipate the bubble-slug transition of two-phase flow at microgravity.

关键词： two-phase flow flow pattern mini-channel microgravity

Removal of lead from aqueous solution by hydroxyapatite/ manganese dioxide composite

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Frontiers of Environmental Science & Engineering 2016年第1期10卷 28-36页

作者： Lijing DONG Zhiliang ZHU Yanling QIU jianfu zhao Key Laboratory of Yangtze River Water Environment Ministry of Education Shanghai 200092 China Environmental Monitoring Centre of Changzhou Changzhou 213000 China State Key Laboratory of Pollution Control and Resource Reuse Tongji University Shanghai 200092 China

A novel composite adsorbent, hydroxyapatite/ manganese dioxide （HAp/MnO2）, has been developed for the purpose of removing lead ions from aqueous solutions. The combination of HAp with MnO2 is meant to increase its adsorption capacity. Various factors that may affect the adsorption efficiency, including solution pH, coexistent substances such as humic acid and competing cations （Ca2＋, Mg2＋）, initial solute concentration, and the duration of the reaction, have been investigated. Using this composite adsorbent, solution pH and coexistent calcium or magnesium cations were found to have no significant influence on the removal of lead ions under the experi- mental conditions. The adsorption equilibrium was described well by the Langmuir isotherm model, and the calculated maximum adsorption capacity was 769 mg. gl. The sorption processes obeyed the pseudo-second-order kinetics model. The experimental results indicate that HAp/MnO2 composite may be an effective adsorbent for the removal of lead ions from aqueous solutions.

关键词： manganese dioxide hydroxyapatite lead,adsorption composite materials

Effect of ferric and bromide ions on the formation and speciation of disinfection byproducts during chlorination

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Journal of Environmental Sciences 2011年第5期23卷 765-772页

作者： Shaogang Liu Zhiliang Zhu Yanling Qiu jianfu zhao State Key Laboratory of Pollution Control and Resource Reuse Tongji University Shanghai 200092 China. E-mail:zzl@*** Department of Chemical and Ecological Engineering Guangxi University for Nationalities Nanning 536000 China

The effects of ferric ion, pH, and bromide on the formation and distribution of disinfection byproducts （DBPs） during chlorination were studied. Two raw water samples from Huangpu River and Yangtze River, two typical drinking water sources of Shanghai, were used for the investigation. Compared with the samples from Huangpu River, the raw water samples from Yangtze River had lower content of total organic carbon （TOC） and ferric ions, but higher bromide concentrations. Under controlled chlorination conditions, four trihalomethanes （THMs）, nine haloacetic acids （HAAs）, total organic halogen （TOX） and its halogen species fractions, including total organic chlorine （TOC1） and total organic bromide （TOBr）, were determined. The results showed that co-existent ferric and bromide ions significantly promoted the formation of total THMs and HAAs for both raw water samples. Higher concentration of bromide ions significantly changed the speciation of the formed THMs and HAAs. There was an obvious shift to brominated species, which might result in a more adverse influence on the safety of drinking water. The results also indicated that high levels of bromide ions in raw water samples produced higher percentages of unknown TOBr.

关键词： disinfection byproducts total organic halogen chlorination ferric ion bromide ion

Synthesis of mesoporous Cu/Mg/Fe layered double hydroxide and its adsorption performance for arsenate in aqueous solutions

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Journal of Environmental Sciences 2013年第5期25卷 944-953页

作者： Yanwei Guo Zhiliang Zhu Yanling Qiu jianfu zhao State Key Laboratory of Pollution Control and Resource Reuse Tongji University Key Laboratory of Yangtze River Water Environment Ministry of EducationTongji University

The mesoporous Cu/Mg/Fe layered double hydroxide（Cu/Mg/Fe-LDH） with carbonate intercalation was synthesized and used for the removal of arsenate from aqueous *** Cu/Mg/Fe-LDH was characterized by Fourier transform infrared spectrometry,X-ray diffraction crystallography,scanning electron microscopy,X-ray photoelectron spectroscopy and *** of various physico-chemical parameters such as pH,adsorbent dosage,contact time and initial arsenate concentration on the adsorption of arsenate onto Cu/Mg/Fe-LDH were *** showed that it was efficient for the removal of arsenate,and the removal efficiency of arsenate increased with the increment of the adsorbent dosage,while the arsenate adsorption capacity decreased with increase of initial pH from 3 to *** adsorption isotherms can be well described by the Langmuir model with R 2 〉 *** adsorption kinetics followed the pseudo second-order kinetic *** ions such as HPO42-,CO32-,SO42and NO3could compete with arsenate for adsorption sites on the Cu/Mg/*** adsorption of arsenate on the adsorbent can be mainly attributed to the ion exchange *** was found that the synthesized Cu/Mg/Fe-LDH can reduce the arsenate concentration down to a final level of 〈 10 μg/L under the experimental conditions,and makes it a potential material for the decontamination of arsenate polluted water.

关键词： arsenate adsorption mesoporous layered double hydroxide anion exchange

Study on membrane fouling of submerged membrane bioreactor in treating bathing wastewater

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Journal of Environmental Sciences 2008年第10期20卷 1158-1167页

作者： GUO Jifeng XIA Siqing WANG Rongchang zhao jianfu State Key Laboratory of Pollution Control and Resource Reuse School of Environmental Science and Engineering Tongji University Shanghai 200092 China

A pilot-scale submerged membrane bioreactor (MBR) was used to treat the bathing wastewater for more than 90 d. Several factors a?ecting membrane fouling were studied, including the variation in transmembrane pressure (TMP), changes in extracellular polymeric substance (EPS), and distribution of membrane resistance (R). The relationships between R and EPS concentration were found to be R = 0.00008(EPSS)2.915 in the mixed liquor (EPSS) and R = 0.2853(EPSm) – 0.824 on the membrane surface (EPSm). The constant ...

关键词： MBR membrane fouling extracellular polymeric substance (EPS) PCR-DGGE fluorescent in situ hybridization (FISH)

Changes of Cu, Zn, and Ni chemical speciation in sewage sludge co-composted with sodium sulfide and lime

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Journal of Environmental Sciences 2008年第2期20卷 156-160页

作者： WANG Xuejiang CHEN Ling XIA Siqing zhao jianfu State Key Laboratory of Pollution Control and Resources Reuse College of Environmental Science and Engineering Tongji University Shanghai 200092 China

A batch composting study was performed to evaluate the feasibility of co-composting sewage sludge with sodium sulfide and lime （SSL） mixture （Na2S/CaO= 1：1）, aiming at reducing the availability of heavy metals in the sludge compost. Sewage sludge with sawdust as a bulking agent was amended with SSL at 3% （w/w, dw）, and composted for 15 d in laboratory batch reactors. The four stages of the Tessier sequential extraction method was employed to investigate changes in heavy metal fractions of Cu, Zn, and Ni in sewage sludge composted with SSL. For all the three metals, the mobile fractions, such as, exchangeable and carbonate bound were mainly transformed into low availability fractions （organic matter and sulfide, Fe-Mn oxides bound and residual forms）, and the addition of SSL enhanced this transformation. Therefore, SSL is a suitable material to co-compost with sewage sludge to reduce the availability of heavy metals. According to the cabbage seed germination test, a SSL amendment of ≤3% （w/w, dw） is recommended to co-compost with sewage sludge.

关键词： sewage sludge co-composting heavy metals sequential extraction

Construction and application of the Synechocystis ***6803-ftnA in microbial contamination control in a coupled cultivation and wastewater treatment

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Journal of Environmental Sciences 2016年第8期28卷 174-181页

作者： Yalei Zhang Chunmin Zhang Xuefei Zhou Zheng Shen Fangchao zhao jianfu zhao State Key Laboratory of Pollution Control and Resource Reuse Key Laboratory of Yangtze Water Environment of Ministry of EducationTongji University Water Conservancy Development Research Center Taihu Basin Authority of Ministry of Water Resources

Inspired by iron fertilization experiments in HNLC（high-nitrate, low-chlorophyll） sea areas,we proposed the use of iron-rich engineered microalgae for microbial contaminant control in iron-free culture media. Based on the genome sequence and natural transformation system of Synechocystis sp. PCC6803, ftn A（encoding ferritin） was selected as our target gene and was cloned into wild-type Synechocystis sp. PCC6803. Tests at the molecular level confirmed the successful construction of the engineered Synechocystis sp. PCC6803-ftn A. After Fe3＋-EDTA pulsing, the intracellular iron content of Synechocystis sp. PCC6803-ftn A was significantly enhanced, and the algae was used in the microbial contamination control system. In the coupled Synechocystis sp. PCC6803-ftn A production and municipal wastewater（MW, including Scenedesmus obliquus and Bacillus） treatment, Synechocystis sp. PCC6803-ftn A accounted for all of the microbial activity and significantly increased from 70% of the microbial community to 95%.These results revealed that while the stored iron in the Synechocystis sp. PCC6803-ftn A cells was used for growth and reproduction of this microalga in the MW, the growth of other microbes was inhibited because of the iron limitation, and these results provide a new method for microbial contamination control during a coupling process.

关键词： Synechocystis PCC6803-ftnA Municipal wastewater treatment Microbial contaminants

Study of 4-t-octylphenol degradation and microbial community in granular sludge

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Journal of Environmental Sciences 2008年第2期20卷 167-171页

作者： LIU Yi WANG Feng XIA Siqing zhao jianfu State Key Laboratory of Pollution Control and Resource Reuse Key Laboratory Yangtze River Water Environment Ministry of Education School of Environmental Science and Engineering Tongji University Shanghai 200092 China

In this study, the authors have investigated the effects of various factors on both aerobic and anaerobic degradation of 4-t-octylphenol （4-t-OP） in granular sludge. In comparison, the aerobic degradation rate was much higher than that of anaerobic degradation. The optimal pH values for 4-t-OP degradation in granular sludge were 9 and 7 under aerobic and anaerobic conditions, respectively. And the degradation rate decreased with an increase in the initial 4-t-OP concentration. Addition of yeast extract or homologous compounds such as phenol also enhanced the 4-t-OP degradation, especially under the aerobic condition. To investigate the bacterial community in this study, the denaturing gradient gel electrophoresis （DGGE） method was applied, based on the primers, for the 16S rDNA V3 region of bacteria, γ-proteobacteria and bacillus were identified as the major species of sludge.

关键词： aerobic degradation anaerobic degradation 4-t-octylphenol (4-t-OP) granular sludge DGGE

Removal of humic acid from aqueous solution by cetylpyridinium bromide modified zeolite

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Journal of Environmental Sciences 2010年第9期22卷 1327-1334页

作者： Yanhui Zhan Zhiliang Zhu Jianwei Lin Yanling Qiu jianfu zhao State Key Laboratory of Pollution Control and Resource Reuse Tongji University Shanghai 200092 China College of Marine Science Shanghai Ocean University Shanghai 201306 China

Natural zeolite was modified by loading cetylpyridinium bromide （CPB） to create more efficient sites for humic acid （HA） adsorption. The natural and CPB modified zeolites were characterized with X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy and elemental analysis. The effects of various experimental parameters such as contact time, initial HA concentration, solution pH and coexistent Ca^2＋, upon HA adsorption onto CPB modified zeolites were evaluated. The results showed that natural zeolite had negligible affinity for HA in aqueous solutions, but CPB modified zeolites exhibited high adsorption efficiency for HA. A higher CPB loading on natural zeolites exhibited a larger HA adsorption capacity. Acidic pH and coexistent Ca^2＋ were proved to be favorable for HA adsorption onto CPB modified zeolite. The kinetic process was well described by pseudo second-order model. The experimental isotherm data fitted well to Langmuir and Sips models. The maximum monolayer adsorption capacity of CPB modified zeolite with surfactant bilayer coverage was found to be 92.0 mg/g.

关键词： modified zeolite cetylpyridinium bromide humic acid