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Al(III) speciation distribution and transformation in high concentration PACl solutions

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Journal of Environmental Sciences 2006年第5期18卷 872-879页

作者： HUANG Li TANG Hong-xiao wang dong-sheng wang Shui-feng DENG Zai-jun State Key Lab of Environmental Aqueous Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Analytical and Testing Center Beijing Normal University Beijing 100875 China

Effects of Al（Ⅲ） concentration and pH on the speciation of Al（Ⅲ） in polyaluminum chloride （PACl） solutions especially on the Al13 fraction were investigated. A series of PACl samples were prepared over the range of Al（Ⅲ） concentration from 0.01 to 2.0 mol/L with the B （OH/Al ratio） value from 1.0 to 2.5 by forced hydrolysis of AICl3. The samples were characterized by ferron assay, pH and 27^Al NMR. It was shown that the Al（Ⅲ） concentration had a dramatic effect on the hydrolysis processes and the species distribution of PACl was in relate to the decrease of pH. The fraction of Al species, Alb （or Al13） decreased and Al0 increased with increase of total Al（Ⅲ） concentration. Under the condition of Al（Ⅲ） 2.0 reel/L, B = 2.5, the pH value was 2.73 and no Al13 could be detected. During diluting and aging, the species distribution evoIved. The Al13 could then be detected again and the amounts increased with time. If the diluted samples were concentrated by freeze dry at -35℃ or heating at 80℃, the pH value and Al13 content would decrease with the increased concentration. It demonstrated that the key factor for formation of Al13 in concentrated PACl was pH value.

关键词： PACl Al13 B value pH speciation

Effects of pre-ozonation on organic matter removal by coagulation with IPF-PACl

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Journal of Environmental Sciences 2006年第3期18卷 453-458页

作者： LIU Hai-long wang dong-sheng SHI Bao-you wang Min TANG Hong-xiao State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China School of Environmental Science and Resources Shanxi University Taiyuan 030002 China School of Water Resources and Environmental Sciences China University of Geosciences Beijing 100083 China

Ozone plays an important role as a disinfectant and oxidant in potable water treatment practice and is increasingly being used as a pre-oxidant before coagulation. The purpose of this study is to obtain insight into the mechanisms that are operative in pre-ozonized coagulation. Effects ofpre-ozonation on organic matter removal during coagulation with IPF-PAC1 were investigated by using PDA （photometric disperse analysis）, apparent molecular weight distribution and chemical fractionation. The dynamic formation of flocs during coagulation process was detected. Changes of aquatic organic matter （AOM） structure resulted from the influence of pre-ozonation were evaluated. Results show that dosage of O3 and characteristics of AOM are two of the major factors influencing the performance of O3 on coagulation. No significant coagulation-aid effect of O3 was observed for all experiments using either A1C13 or PAC1. On the contrary, with the application of pre-ozonation, the coagulation efficiency of A1C13 was significantly deteriorated, reflected by the retardation of floc formation, and the removal decreases of turbidity, DOC, and UV254. However, if PACl was used instead of AlCl3, the adverse effects of pre-ozonation were mitigated obviously, particularly when the O3 dosage was less than 0.69 （mg O3/mg TOC）. The difference between removals of UV254, and DOC indicated that pre-ozonation greatly changed the molecular structure of AOM, but its capability of mineralization was not remarkable. Only 5% or so DOC was removed by pre-ozonation at 0.6--0.8 mg/L alone. Fractionation results showed that the organic products of pre-ozonation exhibited lower molecular weight and more hydrophilicity, which impaired the removal of DOC in the following coagulation process.

关键词： natural organic matter (NOM) fractionation pre-ozonation PACl coagulation

A device for fluorescence temperature measurement based on fast fourier transform

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Optoelectronics Letters 2008年第2期4卷 147-149页

作者： wang dong-sheng wang Gui-mei PAN Wei-wei wang Yu-tian Hebei Engineering University Hebei 056001 China Yanshan University Qinhuangdao 066004 China

A sapphire fiber thermal probe with Cr^3＋ ion-doped end was grown using the laser heated pedestal method. The fluorescence thermal probe offers advantages of compact structure, high performance and the ability to sustain high temperature from the room temperature to 450℃. Based on the fast fourier transform （FFT）, the fluorescence lifetime is obtained from the tangent function of the phase angle of the first non-zeroth item of FFT result. Compared with other traditional fitting methods, our method has advantages such as fast speed, high accuracy and being free from the influence of the base signal. The standard deviation of FFT method is about half of that method. In addition, since the FFT method is immunity to analysis can be skipped. of the Prony method and close to the one of the Marquardt the background noise of the signal, the background noise

关键词：傅立叶转移器件荧光温度测量方法

Comparative study on the removal technologies of 2-methylisoborneol(MIB) in drinking water

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Journal of Environmental Sciences 2006年第1期18卷 47-51页

作者： LIANG Cun-zhen wang dong-sheng GE Xiao-peng YANG Min SUN Wei State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Beijing 100085 China Department of Environmental Engineering Beijing Institute of Petrochemical Technology Beijing 102617 China

Removal of 2-methylisoborneol （MIB） in drinking water by ozone, powdered activated carbon （PAC）, potassium permanganate and potassium ferrate was investigated. The adsorption kinetics of MIB by both wood-based and coat-based PACs show that main removal of MIB occurs within contact time of 1 h. Compared with the wood-based PAC, the coat-based PAC evidently improved the removal efficiency of MIB. The removal percentage of trace MIB at any given time for a particular carbon dosage was irrelative to the initial concentration of MIB. A series of experiments were performed to determine the effect of pH on the ozonation of MIB. The results show that pH has a significant effect on the ozonation of MIB. It is conclusive that potassium permanganate and potassium ferrate are ineffective in removing the MIB in drinking water.

关键词： odor MIB ozonation powdered activated carbon potassium permanganate potassium ferrate

Removal of natural organic matter in a typical south-China source water during enhanced coagulation with IPF-PACl

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Journal of Environmental Sciences 2005年第6期17卷 1014-1017页

作者： LIU Hai-long wang dong-sheng XIA Zhong-huan TANG Hong-xiao ZHANG Jin- song State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Institute of Environment and Resource Shanxi University Taiyuan 030002 China Shenzhen Water Group Co. Ltd. Shenzhen 518031 China

Systematic investigation on enhancing removal of natural organic matter （NOM） using inorganic polymer flocculant （IPF）, polyaluminum chloride（PACI） and polyacrylamide（PAM） was performed in a typical south-China source water. Enhanced coagulation and applying polymer flocculant-aid were compared through jar tests and pilot tests. Raw water and settled water were characterized and fractionated by resin adsorption. The results show that DOC composes major part of TOC. The DOC distribution keeps relatively stable all around the year with typical high amounts of the hydrophilic matter around 50%. The distribution between HoB, HoA and HoN varies and undergoes fluctuation with the year round. During the summer season, the HoN becomes gradually the major part in hydrophobic parts. PACI with the species being tailor-made shows little pH effect during coagulation. The enhanced coagulation dosage for PACI could be 4.5 mg/L for the typical source water. The highest TOC removal achieved 31%. To be economically, 3 mg/L dose is the optimum dosage. Although hydrophilic fractions of NOM of both treatment strategies are removed about 30%, NOM causing UV254 absorbance were well removed（about 90%）. Hydrophobic bases and acids fractions are much more removed under enhanced conditions. The hydrophilic fraction could be better removed using PAM, the polymer coagulant aid.

关键词： enhanced coagulation PACI PAM NOM fractionation

Transformations of particles, metal elements and natural organic matter in different water treatment processes

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Journal of Environmental Sciences 2007年第3期19卷 271-277页

作者： YAN Ming-quan wang dong-sheng SHI Bao-you WEI Qun-shan QU Jiu-hui TANG Hong-xiao State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

Characterizing natural organic matter （NOM）, particles and elements in different water treatment processes can give a useful information to optimize water treatment operations. In this article, transformations of particles, metal elements and NOM in a pilot-scale water treatment plant were investigated by laser light granularity system, particle counter, glass-fiber membrane filtration, inductively coupled plasma-optical emission spectroscopy, ultra filtration and resin absorbents fractionation. The results showed that particles, NOM and trihalomethane formation precursors were removed synergistically by sequential treatment of different processes. Preozonation markedly changed the polarity and molecular weight of NOM, and it could be conducive to the following coagulation process through destabilizing particles and colloids; mid-ozonation enhanced the subsequent granular activated carbon （GAC） filtration process by decreasing molecular weight of organic matters. Coagulation-flotation and GAC were more efficient in removing fixed suspended solids and larger particles; while sand-filtration was more efficient in removing volatile suspended solids and smaller particles. Flotation performed better than sedimentation in terms of particle and NOM removal. The type of coagulant could greatly affect the performance of coagulation-flotation. Pre-hydrolyzed composite coagulant （HPAC） was superior to FeCl3 concerning the removals of hydrophobic dissolved organic carbon and volatile suspended solids. The leakages of flocs from sand-filtration and microorganisms from GAC should be mitigated to ensure the reliability of the whole treatment system.

关键词： flotation fixed suspended solid trihalomethane formation potential ultra filtration resin absorbent fractionation

Second Harmonic Generation in Scanning Probe Microscopy for Edge Localization

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Chinese Physics Letters 2011年第4期28卷 91-93页

作者： HU Xiao-Gen LI Yu-He LIN Hao-Shan wang dong-sheng QI Xin State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision Instruments and MechanologyTsinghua UniversityBeijing 100084

We present an approach of second harmonic generation for edge localization of nano-scale defects measurement,based on the impact of the oscillating tip on the sample that induces higher harmonics of the excitation *** harmonic signals of tip motion are measured by the heterodyne *** edge amplitude ratio for the edge characterization can be calculated by a mechanics model and the threshold of edge localization is experimentally determined by second harmonic *** approach has been successfully utilized to measure the pitch of a standard *** results show that the second harmonic is sensitive to locating the edge of nano-scale defects with high accuracy.

关键词： harmonic Probe harmonics

Disk-shaped Symmetric Hexa-substituted Triphenylene Derivatives： Synthesis, Physical Properties and Self-assembly

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Chemical Research in Chinese Universities 2013年第3期29卷 495-499页

作者： wang dong MI Yong-sheng TANG Jian-kai LIANG Peng-xia JIN Zhao-kui YANG Zhou YANG Huai Department of Materials Physics and Chemistry School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 P R. China

A series of triphenylene derivatives with six symmetric substituents was synthesized from hexabromotriphenylene. The synthesis was conducted by six-fold palladium-catalyzed Hagihara-Sonogashira crosscoupling reactions to yield the hexa-alkynyl substituted triphenylene derivatives of HTPI, HTP2, HTP3 and HTP4. The six symmetric substituents can not only endow the triphenylene the longer π-conjugated range, but also increase the solubility of the compounds. Their photophysical, electrochemical, thermal properties were investigated respectively. With the comparison of their properties, the structure-property relationships were established which demonstrated the influences of different substituents on the electronic nature and the mesomorphic phase of these disk-shaped molecules. In addition, with the scanning electron microscopy（SEM） and polarized optical microscopy（POM） characterization, the self-assembly behaviors of the compounds were also investigated.

关键词： Triphenylene π-Conjugated range Photophysical property Electrochemical property Self-assembly

Ultra-large Scale Molecular Dynamics Simulation for Nano-engineering

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Chemical Research in Chinese Universities 2008年第3期24卷 367-370页

作者： ZHAO Jian-wei YIN Xing LIANG Shuai LIU Yun-hong wang dong-xu DENG sheng-yuan HOU Jie School of Chemistry and Chemical Engineering Nanjing University Nanjing 210093 P. R. China

In light of the special need of nano-engineering, an ultra-large scale and high-performance molecular dynamics（MD） simulation program was implemented. In many nano-engineering processes, the free boundary condition should be adopted. To meet this particular requirement, a pointer link and dynamic array data structures were employed so that both reliability and accuracy of simulation could be ensured. Using this method, one could realize the MD simulation of the nano-engineering system consisting of several million atoms per single CPU.

关键词： Molecular dynamics Nano-engineering Dynamic array Verlet table Cell list