固体碱对油品中有机硫化物的脱除性能及分析

预碱洗（电精制）是轻质油品精制中的重要环节，通过氢氧化钠水溶液预碱洗可除去油品中的硫化氢、低分子硫醇等酸性物质，但大量含硫废碱液的排放给环保造成很大压力。以固体碱代替液体碱预碱洗，是减少甚至消除废碱液产生和排放的最有效措施。近十几年来，许多学者致力于固体碱对轻质油品中硫醇、硫化氢的脱除研究。     

Complexometric determination of magnesium in nodular cast iron and alloyed cast iron roll samples

A complexometric method for the determination of magnesium in nodular cast iron, alloyed cast iron and roll samples has been developed. The bulk of the iron is removed by ether extraction and the phosphate as zirconium phosphate. The other elements are removed by extraction with dithiocarbamate into chloroform. Magnesium is then titrated with EDTA at pH 10, with Eriochrome Black T as indicator. Calcium interferes, but is very rarely present in such cast iron samples.     

Decontamination of radioactive waste fission products by treated natural clays

The removal of carrier free long living fission products as iodine-131, strontium-90 and cesium-137 by treated local clays is successfully achieved with large capacity. Iodine-131 which is difficultly adsorbed has been removed completely by silver treated phosphate clay. Strontium-90 and cesium-137 by adequately heat treating the clays have been almost removed. Results of column experiments agree well with our batch experiments.     

Removal of Safranine from Aqueous Solution by Using Adsorptive Bubble Separation Techniques

Safranine, a cationic dye, was removed from synthetic wastewater by ion flotation. Over 98% of safranine was removed from the solution in 10 min. A stoichiometric amount of surfactant (1 mol of surfactant to 1 mol of dye) was found to be most effective for safranine removal. The separation efficiency of safranine decreased with increasing concentration of NaNO3. Safranine was also removed by adsorbing colloid flotation technique using Fe(OH)3 as the coagulant. Sodium lauryl sulfate was used as the collector, and over 97% of safranine was removed in 5 min. The separation efficiency decreased with increasing ionic strength of the solution. The deleterious effect of neutral salt was compensated somewhat with the aid of Al^3 as the activator. Both ion flotation and adsorbing colloid flotation may be applicable in the removal of safranine from wastewater.     

Determination of submicrogram quantities of ruthenium by catalysis of the cerium(iv)-arsenic(iii) reaction

Ruthenium in amounts of 0 005–0 1 μg (and less if need be) can be determined by its catalysis of the slow reaction between cerium(IV) and arsenic(III) in sulfuric acid solution The rate of the catalyzed reaction is obtained by measuring the concentration of cerium(lV) spectrophotometrically as a function of the time Ruthenium is first separated by carbon tetrachloride extraction of the tetroxide, following argentic oxide oxidation Osmium tetroxide is removed by prior extraction with carbon tetrachloride after differential oxidation with nitric acid Osmium can also be removed by boiling an acid solution with hydrogen peroxide, ruthenium being left in solution     

Ion and Adsorbing Colloid Flotation of Auramine

Auramine, a cationic dye, was removed from synthetic wastewater by ion flotation of auramine‐sodium lauryl sulfate complex. Over 98% of auramine was removed from the solution in 15 min. A stoichiometric amount of surfactant (1 mol of surfactant to 1 mol of dye) was found to be most effective for auramine removal. The rate of separation and ultimate removal of auramine increased with increasing the rate of air flow and decreased with increasing concentration of NaNO₃. Auramine was also removed by adsorbing colloid flotation technique using ferric hydroxide as the coagulant. Sodium lauryl sulfate was used as the collector, and over 95% of auramine was removed in 10 min. The separation efficiency decreased with increasing ionic strength of the solution. The deleterious effect of neutral salt was compensated somewhat with the aid of aluminum ions as the activator. Both ion flotation and adsorbing colloid flotation are promising approaches for the removal of cationic dye from wastewater.     

Effect of Templates on the Structure and Stability of Ti-TMS

Mesoporousmaterialsareofgreatinteresttocatalysisbecauseoftheirlargeanduniformporesize(20~100A),whichallowstereo-hinderedmoleculesfacilediffusiontointernalactivesites.Althoughrecenteffectshavesuggestedthatitshouldbepossibletosynthesizemesoporousmateri...     

A method for removal of chloride interference in determination of aluminium by atomic-absorption spectrometry with a graphite furnace

Methods for removal of the chloride interferences in determination of aluminium by atomic-absorption spectrometry with a graphite furnace have been investigated. Two mechanisms of chloride interference have been established. The first arises from co-ordination of the chloride to aluminium. This interference can be removed by preventing the co-ordination. The other is due to co-existing chloride salts remaining until the atomization step. This interference can be removed by volatilizing the chloride or by converting it and/or aluminium chloride into another substance such as the oxides before the atomization step. The tetra-ammonium salt of EDTA is very suitable as an additive to overcome chloride interference because of its ability to co-ordinate aluminium and other cations, and also its effect when heated.     

A Study of Thin Liquid Films as Related to the Stability of Crude Oil Emulsions

In this paper, we report the influence of surface-active compounds on the stability of crude oil emulsions using the apparatus designed for bilayer lipid membrane studies. The results obtained show that natural surface-active materials in crude oil, such as petroleum acids and asphaltenes, play a pivotal role. The ionized acids formed by the reaction between the petroleum acids and the alkali can decrease the interfacial tension and accelerate the thinning as well as the breakdown of the thin liquid film. The asphaltenes can adsorb onto the interface and improve the stability of the film. The order of the stability of the films between crude oil and alkaline solutions is found to be as follows: crude oil with asphaltenes removed (ii) 相似文献   

Milking of 234Th from uranium by the combined use of adsorption on active charcoal and anion exchange

A rapid and simple procedure for the preparation of carrier-free 234Th for use as a tracer has been devised. A 0.01 mol X dm-3 HCl solution (120 cm3) of uranium (1.6 mol X dm-3) is kept contact with active charcoal. After the bulk uranium solution is removed, 234Th adsorbed on the charcoal is eluted with a 6 mol X dm-3 HCl solution (120 cm3). A small amount of uranium remaining in the solution of 234Th is completely removed by passing the solution through anion-exchange column.     

Foam Separation of Stannous Ion from Aqueous Solution

Sn(II) was removed from solution using various foam separation techniques. It was found that Sn(II) could be effectively removed by adsorbing colloid flotation using either Fe(OH)₃ or Al(OH)₃ as the adsorbing colloid. Over 99% of the Sn(II) was removed from a solution initially containing 50 ppm Sn(II).     

Direct electroplating of copper on tantalum from ionic liquids in high vacuum: origin of the tantalum oxide layer

In this paper, it is shown that high vacuum conditions are not sufficient to completely remove water and oxygen from the ionic liquid 1-ethyl-3-methylimidazolium chloride. Complete removal of water demands heating above 150 °C under reduced pressure, as proven by Nuclear Reaction Analysis (NRA). Dissolved oxygen gas can only be removed by the use of an oxygen scavenger such as hydroquinone, despite the fact that calculations show that oxygen should be removed completely by the applied vacuum conditions. After applying a strict drying procedure and scavenging of molecular oxygen, it was possible to deposit copper directly on tantalum without the presence of an intervening oxide layer.     

Excited levels of iron,nickel and cobalt obtained by activation of metal carbonyls at 11.8 ev

When direct or sensitized photolysis of gaseous Fe(CO)₅, Ni(CO)₄ and CoNO(CO)₃ is carried out with 11.6 and 11.8 cV phoions, all the ligands are removed in a single step; excess energy is removed by the metal atom as electronic excitation. Compared with UV multiphotonic and collision-induced dissociation, the direct pne-phonon photolysis appears to be the most selective excitation method.     

On the Anti-forcing Number of Benzenoids

The anti-forcing number is introduced as the smallest number of edges that have to be removed that any benzenoid remains with a single Kekulé structure. Similarly, the anti- Kekulé number is discussed as the smallest number of edges that have to be removed that any benzenoid remains connected but without any Kekulé structure. These concepts have been exemplified on damaged benzenoid parallelograms.     

Hydrothermal process of synthetic gibbsite and the characteristics of Na in gibbsite crystal

The presence of Na in synthetic gibbsite was studied by several modern testing methods such as X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and inductively coupled plasma. Results show that Na is located between gibbsite crystals and is not present as sodium aluminosilicate hydrate in synthetic gibbsite. Synthetic gibbsite crystal can be transformed into boehmite under the hydrothermal condition of 210 °C for 60 min. During the reaction process, synthetic gibbsite crystal particles break up into small fragments and form boehmite. During the process, impurities are released and the Na can be removed by washing. Over 90% of Na can be removed during the hydrothermal transformation process. This technology can be applied in the production process of high-purity alumina.     

水热法制备稳定的发光CdTe材料

采用水热合成技术将表面修饰有羧基的纳米CdTe微粒与表面活性剂和硅源进行自组装,得到了一种与氧化硅复合的稳定的CdTe发光材料.通过一系列表征手段(如TG-DTA,EDX,TEM,荧光光谱和N₂吸附)证实了CdTe微粒复合在氧化硅中.进一步通过烧结的方法除去表面活性剂,用稀酸除去金属氧化物,即得到多孔的氧化硅材料.     

Aqueous Wittig reactions of semi-stabilized ylides. A straightforward synthesis of 1,3-dienes and 1,3,5-trienes

A direct synthesis of 1,3-dienes and 1,3,5-trienes from the reaction of semi-stabilized ylides and a range of saturated and unsaturated aldehydes is reported in water as solvent, employing sodium hydroxide as base. The water-soluble phosphine oxide side product is removed simply by aqueous partitioning of the organic products.     

Effect of chloroform on the structure and gas-separation properties of poly(ether imides)

The FTIR spectra of poly(ether imide) films prepared from their chloroform solutions were recorded in a wide temperature interval. The cast films were shown to contain residual solvent. This residual solvent existed in films as unbound chloroform that may be removed by heating to 60–70°C and as bound chloroform that is involved in complex formation with polymers and may be removed by heating at temperatures close to their glass transition temperatures (180°C). Quantum-chemical calculations were performed for structures that model fragments and monomer units of poly(ether imides), as well as their complexes with chloroform. Chloroform was shown to be capable of preferential binding with an oxygen atom in a Ph-O-Ph′ fragment via hydrogen bonds. In this case, the conformational set of poly(ether imide) chains is changed. The above evidence is invoked to explain changes in transport characteristics with time for poly(ether imide) films cast from chloroform solutions.     

Investigations of reactions involved in electrothermal atomic absorption procedures: Part 11. A theoretical and experimental investigation of factors influencing the determination of tin

Factors of importance for the determination of tin by graphite-furnace atomic absorption spectrometry have been investigated. Losses of tin during the drying and ashing stages were monitored by use of radioactivity measurements. It was found that tin could be lost at 100°C when ordinary graphite or glassy carbon surfaces were used. However, if the sample was dispensed into a droplet of ammonia, no losses occurred until 800°C, independent of the graphite surface, because tin is stabilized as SnO₂ (s,l) and chloride is removed as ammonium chloride. High-temperature equilibrium calculations indicate that tin forms volatile oxides, halides and sulphides which are stable up to relatively high temperatures. As is shown experimentally with commercial non-isothermal atomizers, these molecules might be removed from the system before their decomposition temperature is reached. A recently developed constant-temperature furnace was used to vaporize the sample into an environment of high and constant temperature, in which interference effects from chlorine and sulphur were minimized, as predicted by theory.     

The use of continuous extraction for the removal of interfering elements in the determination of calcium and magnesium

Solvent extraction with a continuous extractor has been used to separate Al, Be, Bi, Cd, Ce, Cr, Co, Cu, Ga, In, Fe, Pb, Hg, Mo, Ni, Tl, Th, Sn, Ti, W, U, V, Zn and Zr, from calcium and magnesium, before titration of the latter with ethanediaminotetraacetic acid. Most of these elements arc extracted at ca, pH 5.0 as their chelates with 8-hydroxyquinoline using chloroform. Be, Ce and Cr are not extracted under these conditions and are converted into their acetylacetonates, before extraction with chloroform. Manganese is not quantitatively removed by any of these processes and is precipitated as its hydrated dioxide by boiling the extracted solution with sodium chlorite. Phosphate, arsenate and selenate can be removed by precipitating them in acid solution with excess zirconium nitrate, and removing the latter with 8-hydroxyquinoline.