نتایج جستجو برای: zirconia sulfuric acid zrsa
تعداد نتایج: 754020 فیلتر نتایج به سال:
Nanosized sulfated zirconia with Brønsted acidic sites has been prepared by a simple calcination in the absence of any solvent. XRD patterns reveal that the sulfated zirconia mainly consists of tetragonal crystalline zirconia with average size of about 7 nm, which is further confirmed by TEM images. N2 adsorption data show that the nanosized sulfated zirconia has high surface area (165-193 m2/g...
Zirconia ceramics with porous structure have been prepared by solid-state reaction using yttria-stabilized zirconia and stearic acid powders. Analysis of its microstructure and phase composition revealed that a pure zirconia phase can be obtained. Our results indicated that its porosity and pore size as well as the mechanical characteristics can be tuned by changing the content of stearic acid ...
in order to find the most effective method to overcome seed dormancy in teucrium chamaedrys l. medicinal plant species the effect of some chemical and physical breaking methods including: cold stratification (5 °c), scarification with sandpaper, stratification with needle, concentrated sulfuric acid, gibberellic acid and combination of these methods were investigated. treated seeds along with ...
Ferric Species Standard ferric sulfate solutions were prepared by dissolving spectrographically pure iron rod (Johnson Matthey) in sulfuric acid and oxidizing with hydrogen peroxide. The decadic molar extinction coefficient of ferric ion in 0.8 N sulfuric acid at 24.9?C was found to be 2199 ? 4 liters mole-' cm-l at 304 m,/. The effect of a decrease of acidity and of added ferrous and cupric su...
Sulfuric acid is widely recognized as a very important substance driving atmospheric aerosol nucleation. Based on quantum chemical calculations it has been suggested that the quantitative detection of gas phase sulfuric acid (H2SO4) by use of Chemical Ionization Mass Spectrometry (CIMS) could be biased in the presence of gas phase amines such as dimethylamine (DMA). An experiment (CLOUD7 campai...
Formaldehyde in small quantities is commonly analyzed by spectrophotometric methods. One of the most-commonly used spectrophotometric techniques for this purpose is based on the reaction with chromotropic acid. Because of its simplicity, sensitivity, selectivity and its low cost, it is still widely used. Investigations for replacing the concentrated sulfuric acid with other acids or using more ...
The atmosphere is an inhomogeneous system of vapors, and liquid as well as solid particles. The nucleation process is an important source of particles, observed at most sites where particle measurements have been carried out. Sulfuric acid plays an important role in the first steps of particle formation, but a complete picture of process, after several years of research, is still unclear. Compu...
Neat chlorosulfonic acid reacts with anhydrous sodium tungstate to give tungstate sulfuric acid (TSA), a new dibasic inorganic solid acid in which two sulfuric acid molecules connect to a tungstate moiety via a covalent bond. A variety of oximes were oxidized to their parent carbonyl compounds under mild conditions with excellent yields in short times by a heterogeneous wet TSA/KMnO4 in dichlor...
In this paper we develop a policy model for pollution control investment and operational decisions in the copper industry. The system consists of (i) a nonlinear integer model to optimize smelter operations, including the investment decisions relating to smelting capacity and pollution control plants that complies with environmental regulations, and (ii) a network flow model to describe the eco...
The effect of specimen aging on the recovery of mercury from urine samples was investigated. It was found that in some aged specimens the addition of concentrated sulfuric acid to the urine without cooling resulted in a large loss of mercury. This phenomenon is presumed to be due to enhanced volatility of the mercury caused by bacterial action. This loss can be avoided by adding a suitable pres...
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