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F. Baßmann J.-M. Sèquaris H.-D. Narres M.J. Schwuger 《Journal of Dispersion Science and Technology》2013,34(1-2):607-620
Adsorption isotherms of nonionic polyvinylpyrrolidone (PVP) and anionic ionized polyacrylic acid (PAA) polymers on single Na-montmorillonite clay and γ-alumina adsorbents in 0.01M NaCl and pH 5.6 are reported and compared to results obtained with aqueous adsorbent mixtures. Microeiectrophoretic behaviours of adsorbents are also observed. It can be shown that antagonistic effects due to interactions between oppositely charged adsorbent surfaces largely limit the nonionic PVP adsorption. 相似文献
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The shape asymmetry of gaussian models of linear and circular macromolecules hasbeen numerically invesigated in terms of asphericity and prolateness parameters. Theseparameters are found to decrease with increasing length for the macromolecule eitherconfined to a plane or in three dimensions. The effect of dimensionality on theseparameters is visible only for low dimensions and is generally weak. As dimensionality goesto infinity, it is found that asphericity and prolateness for both chains and rings approachslowly yet descendingly values of corresponding asphericity and prolateness factors, withthe exception of the chain which shows a minimum value of asphericity when theembedding space has a dimensionality of four. 相似文献
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王思恩 《中国科学B辑(英文版)》1989,(5)
Conchostracans, with a laterally compressed body enclosed between two symmetric valves, live swimming in fresh or brackish water. The carapace valve has a number of growth bands with various sculptures. The general trend of sculptural evolution is from smooth to punctate-minute polygon-medium reticulation-large reticulation, while these punctate, polygonal and various reticulate patterns may separately develop into various radial ridges. The development of sculpture can be well explained by mechanical principle. Functional morphology of carapace is discussed in the light of mechanics in this paper. 相似文献
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This paper investigated the influences of butadiene rubber (BR) and dicumylperoxide (DCP) on thermal and rheological behaviour, morphology and mechanical proper-ties of PS/LLDPE/SBS blend. Addition of DCP alone was found to decrease the mechanicalproperties of PS/LLDPE/SBS blend due to the decomposition of PS. When BR was addedtogether with DCP, it is found that the co-crosslinking of BR, SBS and PE takes place,and the decomposition of PS is reduced simultaneously because of the consumption of thefree radicals in the crosslinking process. Synergism was thus realised which resulted in theimprovement of the ductility of blend. 相似文献
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Based on some typical examples, this paper systematically reviews the formation mechanism, geological implications and methodology of organic inclusions as well as their relations with oils and gases.Organic inclusions present a direct mark of primary and secondary migration of oils and gases. The authors put forward the methods and results of investigation and recognition of organic inclusions in this paper. In our research work, the following instruments and techniques were mainly used: polarizing microscope, fluorescent microscope, micro-heating-cooling stage and component analysis. By means of polarizing microscope, the characteristics of organic inclusions, such as their shape, size, distribution, colour and refrigeration, can be known, and furthermore we can divide organic inclusions into two classes. A fluorescent microscope can be used to make ultraviolet scanning on a single inclusion, measure its wavelength and draw a fluorescence spectrum. Heating and cooling experiments show that the measurement of homogenization temperatures is complex and the homogenization temperatures of organic inclusions are 10-20℃lower than those of inorganic salt solution inclusions for the same period. In the cooling process, organic inclusions hardly freeze and such phenomena as deformation of organic inclusions and pulsation stopping of gaseous bubbles can be observed. In component analysis, we can realize the proportion of gas components in each soluble organic constituent in the total extract.In gas and oil exploration, a knowledge of organic inclusions is vital to expanding the application of organic geochemical indices, understanding the geological time and direction of oil and gas migration, confirming the formation stages of oil and gas pools, ascertaining the properties, origin and evolution stages of oil-field waters, and directly guiding the exploration of oil and gas pools. 相似文献
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Situated in the Taihu plain between the mouth of the Changjiang River and theHangzhou Bay, the Taihu Lake is a large shallow-water lake in China with a surface area of 2427.8 km~2.The lake bottom mainly consists of loess-like sediment. Some buried and silted up channels and residual depressions can be found at the bottom and a lot of Neolithic cultural relics on the loess-like sediment. This indicated that the Taihu Lake was formed on the alluvial plain charaterized by widely deposited loess-like sediment because of siltation and stagnancy of water, instead of by development from lagoons as reported in the past.Recent deposition including influent-effluent current accumulation, wind-driven current and storm deposition in this lake occurred mainly in the south, the west shore and the midst of the lake.The sedimentary rate in the east Taihu Lake is about 1.7-1.8 mm/a, whereas in the west Taihu Lake it is about 0.41 ram/a, only 23% of that of the former. 相似文献
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This paper deals with the determination of one male-sterile plant found in Chinese wheatcultivar (T. aestuvum L.). It is the first time in the world that a spontaneous mutant is dis-eovered in wheat. This dominant male-sterile gene is assigned as Ta 1. This determinationfirmly confirms the existence of the genic male-sterility and provides once again the scien-tific evidence to solve the argument of this problem. On the other hand, a breeding programof using this gene, especially in recurrent selection, is herewith proposed. 相似文献
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XIE Lanying ZHONG Kejun LIU Qi Technical Center of Changde Cigarette Factory Hunan China 《Chinese Journal of Reactive Polymers》2005,(Z1)
1. INTRODUCTION Tobacco smoking ranks as a major public health problem whose negative impacts have been well established since the report of “smoking and health” published by the royal medicine academy of English in 1954. Besides nicotine, the major inducer of tobacco dependence, cigarette smoke also contains various toxic compounds, notably N-nitrosamines. Nitrosamines are formed by the nitrosation(addition of an N=O group, from the nitroso ramifications NO2, N2O3,N2O4) of secondary… 相似文献
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LI Xiaotao Pan Bingcai Pan Bingjun Zhang Weimin Meng Fanwei Chen Jinlong Zhang Quanxing . State Key Laboratory of Pollution Control Resources Reuse School of the Environment Nanjing University Nanjing China . Department of Science Technology State Environmental Protection Agency Beijing China 《Chinese Journal of Reactive Polymers》2005,(Z1)
1. INTRODUCTION Phenolic compounds are pollutants encountered frequently in water system. Some of them, such as phenol and p-nitrophenol, have been listed as priority pollutants in many countries. How to remove them completely from the polluted water is of significant concern to environmental scientists. Up to now many technologies such as biodegradation, oxidation and adsorption are available to remove phenolic compounds from the receiving water [1~4]. In the past two decadesphenol sorpt… 相似文献
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Isotherm analysis of phenol adsorption on polymeric adsorbents from nonaqueous solution 总被引:1,自引:0,他引:1
Macroporous poly(methyl methacrylate-co-divinylbenzene) (PMMA), interpenetrating polymer adsorbent based on poly(styrene-co-divinylbenzene) (PS) and poly(methyl methacrylate-co-divinylbenzene) (PMMA/PS), and macroporous cross-linked poly(N-p-vinylbenzyl acetylamide) (PVBA) were prepared for the adsorption of phenol from cyclohexane. The sorption isotherms of phenol on the three polymeric adsorbents were measured and fitted to Langmuir and Freundlich isotherms. It is shown that the Langmuir isotherm, which is based on a homogeneous surface model, is unsuitable to describe the sorption of phenol on the adsorbents from nonaqueous solution and the Freundlich equation fits the tested three adsorption systems well. The isosteric enthalpy was quantitatively correlated with the fractional loading for the sorption of phenol onto the three polymeric adsorbents. The surface energetic heterogeneity patterns of the adsorbents were described with functions of isosteric enthalpy. The results showed that the tested three polymeric adsorbents exhibited different surface energetic heterogeneity patterns. The initial isosteric enthalpy of phenol sorption on polymeric adsorbent has to do with the surface chemical composition and is free from the pore structure of the polymeric adsorbent matrix. Forming hydrogen bonds between phenol molecules and adsorbent is the main driving force of phenol sorption onto PVBA and PMMA adsorbent from nonaqueous solution. When phenol is adsorbed on PMMA/PS, pi-pi interaction resulting from the stacking of the benzene rings of the adsorbed phenol molecules and the pendant benzene ring of adsorbent is involved. 相似文献
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Mechanism of sorption of phenols from aqueous solutions onto surfactant-modified montmorillonite 总被引:6,自引:0,他引:6
Equilibrium and kinetic studies on the sorption of phenol, m-nitrophenol (m-NP), and o-cresol from water onto montmorillonite modified with cetyltrimethylammounium bromide (CTAB) were conducted. Experiments were carried out as a function of solution pH, sorbate concentration, and temperature (25-55 degrees C). It was shown that the sorption capacity decreased in the order phenol>o-cresol>m-NP. The Langmuir, dual-mode sorption, and Redlich-Peterson models were tested to fit the sorption isotherms of single-solute systems, whereas the Langmuir competitive model was used to describe bisolute sorption equilibria. Thermodynamic parameters (DeltaH degrees and DeltaS degrees ) and the mean free energy (E) for the sorption of phenols were determined from the temperature dependence of the distribution constant and the Dubinin-Radushkevick equation, respectively. A simplified kinetic model was proposed to confirm the sorption mechanism. 相似文献
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LI Aimin Zhang Quanxing Liu Fuqiang Fei Zhenghao Zhang Gencheng Chen Jinlong State Key Laboratory of Pollution Control Resources Reuse School of the Environment Nanjing University Nanjing P. R. China Institute of Applied Chemis 《Chinese Journal of Reactive Polymers》2001,(2)
1. INTRUDUCTION As most phenolic compounds are extremely toxic at the concentrations discharged into accepting effluents, the removal or destruction of phenolic compounds from such streams has become a significant environmental task [1]. Increasing concern for public health and environmental quality has led to the establishment of limits on the acceptable environmental levels of specific pollutants [2]. Consequently there has been a growing interest in developing and implementing various … 相似文献
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Kinetics and thermodynamics of sorption of nitroaromatic compounds to as-grown and oxidized multiwalled carbon nanotubes 总被引:1,自引:0,他引:1
The sorption kinetics and thermodynamics of 1,3-dinitrobenzene (DNB), m-nitrotoluene (mNT), p-nitrophenol (pNP), and nitrobenzene (NB) on as-grown and nitric acid-oxidized multiwalled carbon nanotubes (MWCNTs) were investigated. The sorption kinetics was well described by a pseudo-second-order rate model, while both Langmuir and Freundlich models described the sorption isotherms well and the sorption thermodynamic parameters of equilibrium constant (K(0)), standard free energy (DeltaG), standard enthalpy (DeltaH), and standard entropy changes (DeltaS) were measured. The values of DeltaH and DeltaG suggested that the sorption of nitroaromatics (NACs) onto MWCNTs was exothermic and spontaneous. The structure, number, and position of nitro groups of NACs were the main factors affecting the sorption rate and capacity. Treatment of the MWCNTs with nitric acid increased both the surface area and the pore volume and introduced oxygen-containing functional groups to the MWCNTs, which depressed the sorption of NACs onto MWCNTs. 相似文献
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XU Maneai ZENG Ying . SHI Zuoqing XU Mingcheng LI Haitao YU Shanxin FAN Yunge HE Binglin 《Chinese Journal of Reactive Polymers》2000,(1)
I INTRODUCTIONIn our previous work, three series of macroporous hydrogen-bonding adsorbents have beenstudied, which were adsorbents with hydrogen donator, adsorbents with hydrogen acceptor, andadsorbents with both hydrogen donator and acceptor if-31. If a gel-type resin with hydrogendonator and/or acceptor contacts with a compound with hydrogen acceptor and/Or donatof, canthe gel-type resin sorb the compound based on of hydrogen bonding? Here we report the sorptionof phenol onto gel-type … 相似文献
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Spherical crosslinked polystyrene-isocyanuric acid resin was synthesized by reaction of chloromethylated polystryene with isocyanuric acid.The sorption isotherms of phenol from aqueous solution and cyclohexane solution onto the resin were measured.It is of interest to notice that the resin sorbed phenol efficiently though its specific surface area was 0 and did not swell in water,and the sorption capactity from aqueous solution was close to that of phenol onto XAD-4 at the same equilibrium concentration.Sorption enthalpies calculated from the isotherms according to the Clausius-Clapeyron equation were -21-25kJ/mol and -39-41kJ/mol respectively.These values impled that the sorption processes were based on hydrogen bonding.In addition.the details of the hydrogen bonding between the active sites of the resin and phenol were suggested. 相似文献