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Seasonal shifts in the solute ion ratios of vadose zone rock moisture from the Eel River Critical Zone Observatory
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作者 Jennifer L.Druhan Nicole Fernandez +2 位作者 Jia Wang William E.Dietrich Daniella Rempe 《Acta Geochimica》 EI CAS CSCD 2017年第3期385-388,共4页
One of the greatest challenges in critical zone studies is to document the moisture dynamics, water flux,and solute chemistry of the unsaturated, fractured and weathered bedrock that lies between the soil and groundwa... One of the greatest challenges in critical zone studies is to document the moisture dynamics, water flux,and solute chemistry of the unsaturated, fractured and weathered bedrock that lies between the soil and groundwater table. The central impediment to quantifying this component of the subsurface is the difficulty associated with direct observations. Here, we report solute chemistry as a function of depth collected over a full year across the shale-derived vadose zone of the Eel River Critical Zone Observatory using a set of novel sub-horizontal wellbores,referred to as the vadose zone monitoring system. The results of this first geochemical glimpse into the deep vadose zone indicate a dynamic temporal and depth-resolved structure. Major cation concentrations reflect seasonal changes in precipitation and water saturation, and normalized ratios span the full range of values reported for the world's largest rivers. 展开更多
关键词 Vadose zone solute ion ratios Critical Zone OBSERVATORY Seasonal solute dynamics
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Adsorption of Hg(Ⅱ) from aqueous solution using thiourea functionalized chelating fiber 被引量:3
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作者 Xiaoxia Yao Huicai Wang +3 位作者 Zhenhua Ma Mingqiang Liu Xiuqing Zhao Dai Jia 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第10期1344-1352,共9页
A fast and selective adsorbent for Hg(ll) from aqueous solutions using thiourea (TU) functionalized polypropylene fiber grafted acrylic acid (PP-g-AA), PP-g-AA-TU fibers, was characterized by Fourier transform i... A fast and selective adsorbent for Hg(ll) from aqueous solutions using thiourea (TU) functionalized polypropylene fiber grafted acrylic acid (PP-g-AA), PP-g-AA-TU fibers, was characterized by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The adsorption behavior of the functionalized chelating fibers for Hg(Ⅱ) was investigated by static adsorption experiments, and the effects of some essential factors on adsorption of Hg(Ⅱ) were examined, such as pH, initial concentration, adsorption time, coexisting cations, and temperature, The results showed that the adsorptive equilibrium could be achieved in 10 min, and the equilibrium adsorption quantity of PP-g-AA-TU fibers was 20 times that of PP-g-AA fibers. The PP-g-AA-TU fibers showed a very high adsorption rate and a good selectivity for Hg(Ⅱ) over a wide range of pH. The adsorption isotherm can be well described with Langmuir model, with the maximum adsorption capacity for Hg(Ⅱ) up to 52.04 mg.g-1 and the removal of Hg(Ⅱ) more than 97%. The kinetic data indicate that the adsorption process is best-fitted into the pseudo-second-order model. 展开更多
关键词 Thiourea Chelating fiber Adsorption Mercury ions Aqueous solution
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Lattice Boltzmann model for simulation on leaching process of weathered elution-deposited rare earth ore 被引量:5
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作者 邱廷省 朱冬梅 +1 位作者 吴承优 王利民 《Journal of Rare Earths》 SCIE EI CAS CSCD 2017年第10期1014-1021,共8页
The lattice Boltzmann model with coupled chemical reaction was proposed to simulate the ion exchange process of rare earth leaching and verified by comparison with both empirical correlation of mass transfer coefficie... The lattice Boltzmann model with coupled chemical reaction was proposed to simulate the ion exchange process of rare earth leaching and verified by comparison with both empirical correlation of mass transfer coefficient and unreacted-core shrinking model. By simulation, the zonation phenomenon of leaching reagent in the leaching column was presented, and the breakthrough curve of leaching reagent was obtained. When t=50 s, there existed the saturated and exchange zones, and the leaching reagent concentration decreased gradually from 20 to 9.3 g/L. In accordance with the breakthrough curve, the breakthrough capacity of ion-type rare earth ore and the adsorbed ion concentration of leaching reagent were derived, the time of t=25 s was the breakthrough point of ammonium ion in leaching reagent and the breakthrough capacity of the rare earth ore was 125 g/L. Besides, the chemical kinetics parameters used for the solute transfer process of rare earth leaching were obtained by the simulation and then were used to determine the rate-limiting steps of rare earth leaching process. 展开更多
关键词 lattice Boltzmann model rare earth leaching ion exchange simulation solute transfer
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Simulation Experiment of Loading Influence to Reinforcement Corrosion Affected by Stray Current and Salt Solution
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作者 TENG H W YANG S M +2 位作者 SHU Z C HUANG Y HUO D 《武汉理工大学学报》 CAS CSCD 北大核心 2010年第17期147-151,共5页
According to the service environment of subway structure,experiment is carried out to simulate influence of different loading levels to reinforcement corrosion of R.C element affected by stray current and chlorine sal... According to the service environment of subway structure,experiment is carried out to simulate influence of different loading levels to reinforcement corrosion of R.C element affected by stray current and chlorine salt solution. The current density of the corrosion is measured with the linear polarization resistance method,together with the qualitative analysis and quantitative calculation. Experiment shows that rebar corrosion current density increase accordingly with the increase of loading level. The quantitative relations and the time of rust corrosion of reinforcement are obtained. 展开更多
关键词 reinforcement corrosion stray current chloride ion solution loading level simulation experiment
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Hydrogen bonding mediated ion pairs of some aprotic ionic liquids and their structural transition in aqueous solution
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作者 Huiyong Wang Miao Liu +3 位作者 Yuling Zhao Xiaopeng Xuan Yang Zhao Jianji Wang 《Science China Chemistry》 SCIE EI CAS CSCD 2017年第7期970-978,共9页
Ion pair speciation of ionic liquids(ILs) has an important effect on the physical and chemical properties of ILs and recognition of the structure of ion pairs in solution is essential. It has been reported that ion pa... Ion pair speciation of ionic liquids(ILs) has an important effect on the physical and chemical properties of ILs and recognition of the structure of ion pairs in solution is essential. It has been reported that ion pairs of some ILs can be formed by hydrogen bonding interactions between cations and anions of them. Considering the fact that far-IR(FIR) spectroscopy is a powerful tool in indicating the intermolecular and intramolecular hydrogen bonding, in this work, this spectroscopic technique has been combined with molecular dynamic(MD) simulation and nuclear magnetic resonance hydrogen spectroscopy(~1H NMR) to investigate ion pairs of aprotic ILs [Bmim][NO_3], [BuPy][NO_3], [Pyr_(14)][NO_3], [PP_(14)][NO_3] and [Bu-choline][NO_3] in aqueous IL mixtures. The FIR spectra have been assigned with the aid of density functional theory(DFT) calculations, and the results are used to understand the effect of cationic nature on the structure of ion pairs. It is found that contact ion pairs formed in the neat aprotic ILs by hydrogen bonding interactions between cation and anion, were still maintained in aqueous solutions up to high water mole fraction(say 0.80 for [BuPy][NO3]). When water content was increased to a critical mole fraction of water(say 0.83 for [BuPy][NO3]), the contact ion pairs could be transformed into solvent-separated ion pairs due to the formation of the hydrogen bonding between ions and water. With the further dilution of the aqueous ILs solution, the solvent-separated ion pairs was finally turned into free cations and free anions(fully hydrated cations or anions). The concentrations of the ILs at which the contact ion pairs were transformed into solvent-separated ion pairs and solvent-separated ion pairs were transformed into free ions(fully hydrated ion) were dependent on the cationic structures. These information provides direct spectral evidence for ion pair structures of the aprotic ILs in aqueous solution. MD simulation and ~1H NMR results support the conclusion drawn from FIR spectra investigations. 展开更多
关键词 ionic liquids ion pair hydrogen bonding far infrared spectroscopy solution
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