Fragmentation and Intracluster Reactions of Hydrated Aluminum Cations Al+(H2O)n,n= 3−50

1996 ◽  
Vol 118 (31) ◽  
pp. 7386-7389 ◽  
Author(s):  
Martin Beyer ◽  
Christian Berg ◽  
Hans W. Görlitzer ◽  
Thomas Schindler ◽  
Uwe Achatz ◽  
...  
Keyword(s):  
Hydrated Aluminum ◽  
Intracluster Reactions

minutes retention depending on the oil processed. Then, Synthetic silica hydrogels: Described in the immediately the oil is heated to 70°C, (158°F) to assist "breaking" the preceding section. emulsion and the mixture is passed through a primary (first) centrifuge. The general dosage of acid-activated bleaching earths is 0.3-0.6%, depending on the quality of the oil and bleach-In contrast, the short-mix process, developed in Europe, ing earth. Bleaching earths provide catalytic sites for de-is conducted at 90°C (84°F), uses a more highly concen-composition of oxidation products. Peroxide values (mea-trated caustic, and a mixing time and primary centrifuging sure of aldehydes) and p-anisidine values (precursors for time of less than 1 minute [135]. Less heat damage to the oxidative degradation) first rise and then decrease during oil and higher refining yield are claimed by advocates of bleaching. Bleaching processes used include atmospheric the long mix process. batch, vacuum batch, and continuous vacuum. Vacuum 4. Silica Absorption bleaching has the advantage of excluding air, partially by In traditional refining, oil from the primary centrifuge is vaporization of water in the earth, and is recommended. A washed with warm soft water to remove residual soap and typical vacuum bleaching process is 20-30 minimum at passed through a (secondary) centrifuge. The washed oil 100-110°C (212-230°F) and 50 mmHg absolute [135]. then is dried under vacuum. However, disposal of wash The reactions catalyzed during bleaching continue into water is increasingly becoming a problem, and the indus-the filter bed and are known as the "press bleaching ef-try is shifting to a modified caustic "waterless" refining fect." The reactive components of oil remain in the bleach-process. Soaps poison the adsorption sites of clays in later ing bed. Care should be taken to "blow" the filter press as bleaching operations and are removed by silica hydrogels. free of oil as possible and to wet the filter cake (which can The oil may be degummed with use of chelating acids, be very dusty) to prevent spontaneous combustion [137]. caustic neutralized, passed through a primary centrifuge, At this point, the product is RB ("refined, bleached") and may be partially vacuum-dried. Synthetic silica hy-oil. If the intended product is an oil, it can be sent to the de-drogels, effective in removing 7-25 times more phos-odorizer and become RBD. If solids are desired, the solids-phatides and soaps than clay on a solids basis, and for re-temperature profile of the oil may be modified by hydro-moving phosphorus and the major metal ions, is added genation, interesterification, or chill fractionation, alone or and mixed with the oil. By absorbing these contaminants in combination. first, the bleaching clay is spared for adsorbing chloro-6. Hydrogenation phyll and the oxidation-degradation products of oil Hydrogenation is the process of adding hydrogen to satu-[136-138]. rate carbon-to-carbon double bonds. It is used to raise try-5. Bleaching glyceride melting points and to increase stability as by jective of bleaching is to remove various contami-converting linolenic acid to linoleic in soybean oil [141]. A The ob lighter, "brush" hydrogenation is used for the latter pur-nants, pigments, metals, and oxidation products before the pose. oil is sent to the deodorizer. Removal of sulfur is especial-Most of the catalysts that assist hydrogenation are nick-ly important before hydrogenation of canola and rapeseed el-based, but a variety is available for special applications. oils. Flavor of the oil also is improved. As mentioned in the "Selectivity" refers to ability of the catalyst and process to preceding section, silica hydrogels will adsorb many of sequentially saturate fatty acids on the triglycerides in the these contaminants and spare the bleaching earth. Howev-order of most unsaturated to the fully saturated. For row er, earths are still used for these purposes in installations crop oils, perfect selectivity would be: that have not adopted hydrated silicas. Types of bleaching materials available include [136,139,140]: C18:3 C18:2 C18:1 Linolenic acid Linoleic acid Oleic acid Neutral earths: Basically hydrated aluminum silicates, sometimes called "natural clays" or "earths," and C18:0 fuller's earth, which vary in ability to absorb pigments. Stearic acid Acid-activated earths: Bentonites or montmorillonites, Although typical hydrogenation is not selective, it can be treated with hydrochloric or sulfuric acid to improve favored to a limited degree by selection of catalyst and by their absorption of pigments and other undesirable temperature and pressure of the process. Efficient hydro-components, are most commonly used. genation requires the cleanest possible feed stock (without Activated carbon: Expensive, more difficult to use, but of soaps, phosphatides, sulfur compounds, carbon monoxide, special interest for adsorbing polyaromatic hydrocar-nitrogen compounds, or oxygen-containing compounds) bons from coconut and fish oils. and the purest, driest hydrogen gas possible [140].

2000 ◽  
pp. 361-373
Keyword(s):  
Linolenic Acid ◽  
Bleaching Earth ◽  
Filter Press ◽  
Hydrogen Gas ◽  
Oxidation Products ◽  
Preceding Section ◽  
Silica Hydrogels ◽  
Acid Acid ◽  
Hydrated Aluminum ◽  
Fuller’S Earth

scholarly journals In Situ Synthesis of Structural Hierarchy Flowerlike Zeolite and Its Application for Fluoride Removal in Aqueous Solution

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Zhihan Tian ◽  
Yiqun Gan
Keyword(s):  
Ph Value ◽  
Three Dimensional ◽  
Adsorption Properties ◽  
Aluminum Silicate ◽  
Fluoride Removal ◽  
Fluoride Ions ◽  
Structural Hierarchy ◽  
Hydrated Aluminum ◽  
Pseudo Second Order ◽  
Ft Ir

A three-dimensional hierarchically structured flowerlike zeolite was synthesized using naturally occurring nanohalloysite (HNT) by hydrothermal methods. Halloysite a hydrated aluminum silicate with nanohollow morphology, microporosity, and environmentally friendly properties was chosen to be the sole precursor. The morphology and structure of the composite that was prepared was characterized using XRD, FT-IR, BET, TG, SEM, HRTEM, and NMR. SEM and HRTEM images indicated that the synthesized zeolite has a flowerlike hierarchical structure, with well-defined edges and uniform pore channels. FT-IR and NMR spectra indicated that different species of silicon and aluminum were present in the synthesized zeolite. The zeolite was applied in fluoride (F-) removal from aqueous solutions. Single-factor studies, including the initial concentration of F-, initial adsorbent concentration, and the effect of pH value on the adsorption properties, were investigated to evaluate the removal behavior of F- by the zeolite. The zeolite exhibited strong adsorption properties for fluoride ions (F-), with an adsorption capacity up to 161 mg g-1. The pseudo-second-order kinetics and Freundlich models were the best fit to the kinetics and isotherm experimental data, respectively.

Photoionization-Induced Intracluster Reactions of Chlorobenzene/Ammonia Mixed Complexes

1994 ◽  
Vol 98 (31) ◽  
pp. 7479-7487 ◽  
Author(s):  
J. R. Grover ◽  
B.-M. Cheng ◽  
W. J. Herron ◽  
M. T. Coolbaugh ◽  
W. R. Peifer ◽  
...  
Keyword(s):  
Mixed Complexes ◽  
Intracluster Reactions

The Preparation and Characteristics of MMT Nanosheets

2013 ◽  
Vol 544 ◽  
pp. 152-155
Author(s):  
Cheng Chen ◽  
Hao Wu ◽  
Qiang Li
Keyword(s):  
Crystal Structure ◽  
Chemical Method ◽  
Ph Value ◽  
Luminescent Properties ◽  
Rare Earth Ions ◽  
Aluminum Silicate ◽  
Practical Applications ◽  
The Status ◽  
Hydrated Aluminum ◽  
The Impact

Montmorillonite (MMT) mainly consist of hydrated aluminum silicate. Montmorillonite has particular properties and many practical applications, because of their special crystal structure. Here, mechano-chemical method was used to prepare MMT nanosheets by controlling the pH value. MMT nanosheets were obtained by ballmilling, and the impact of pH value on the nanosheets preparing was studied. TEM was employed to emamine the microstructure of MMT nanosheets. The size are analyzed to study the status of MMT nanosheets. Different rare earth ions as a fluorescence center were assembled on nanosheets，and composites were obtained. The luminescent properties of composite materials were studied.

Molecular Spectroscopic Study of River Nile Sediment in the Greater Cairo Region

2008 ◽  
Vol 62 (3) ◽  
pp. 306-311 ◽  
Author(s):  
Medhat Ibrahim ◽  
Ali Jameel Hameed ◽  
Abraham Jalbout
Keyword(s):  
Molecular Structure ◽  
Density Functional ◽  
River Sediment ◽  
Nile River ◽  
Functional Theory ◽  
Grain Sizes ◽  
Hydrated Aluminum ◽  
Greater Cairo ◽  
Ft Ir ◽  
Greater Cairo Region

The greater Cairo region is the most populated area in Egypt. The aquatic environment of the Nile River in this area is being affected by industrial activities. The study of the molecular structure of sediment may provide a good trace for such changes. Both Fourier transform infrared spectroscopy (FT-IR) and density functional theory (DFT) were used to study the effect of industrial waste disposal south of Cairo on the molecular structure of Nile River sediment. Four seasonal samples were collected from six sites covering 75 km along the Nile River. Grain sizes of 200 μm, 125 μm, 65 μm, and 32 μm, respectively, were examined. The results indicate that hydrated aluminum hydroxide controls the distribution of organic matter in the different grain sizes. Furthermore, the hydration of phenol may take place in grain sizes lower than 200 μm, which is indicated by the OH stretching at 3550 cm−1 and verified by the obtained model. The formation of metal carboxylate bonds at 1638 cm−1 (asymmetric) and 1382 cm−1 (symmetric) indicate the possible interaction between heavy metals and other organic structures, mainly humic substances.

Photoionization of gas‐phase bromotrifluoromethane and its complexes with methanol: State dependence of intracluster reactions

1994 ◽  
Vol 101 (3) ◽  
pp. 2069-2080 ◽  
Author(s):  
J. T. Clay ◽  
E. A. Walters ◽  
J. R. Grover ◽  
M. V. Willcox
Keyword(s):  
Gas Phase ◽  
State Dependence ◽  
Intracluster Reactions
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