Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.1.2.42 (DTA)
 1,693 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To recycle calcium carbide residue effectively, calcium carbide of different crystal form, including global aragonite, calcite and acicular calcium carbide was synthesized. Both the influence of pretreatment in the purity of calcium carbide, and the influence of temperatures of carbonization reaction, release velocity of carbon dioxide in the apparition of calcium carbide of different crystal form were studied with DTA-TG and SEM. The result shows that calcium carbide residue can take place chemistry reaction with ammonia chlorinate straight. Under the condition that pH was above 7, the purity of calcium carbide was above 97%, and the whiteness was above 98. Once provided the different temperatures of carbonization reaction and the proper release velocity of carbon dioxide, global aragonite, calcite and acicular calcium carbide were obtained.
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PMID:[Calcium carbide of different crystal formation synthesized by calcium carbide residue]. 1676 5

Stable alginate microcapsules in dried form containing bis(2,4,4-trimethylpentyl) monothiophosphinic acid (HA) were prepared by coating of fresh alginate microcapsules with chitosan or polyethyleneimine (PEI). The thickness of coatings was estimated by electron probe microanalysis (EPMA), along with electron microscopy (SEM), as well as comparison of uptake percentage of coated and uncoated hollow capsules. Characterization of microcapsules was carried out by Ag(+) uptake experiments, destructive chemical analyses and thermogravimetric methods (TG and DTA). Chemical stability tests in HNO(3) and NaNO(3) media indicated that the coating with 4-double layer chitosan or mono-layer PEI led to an appreciable enhancement of impermeability in the range of pH > 1 or [Na(+)] < 1 M (mol dm(-3)). Unfortunately, multiple coating causes some extractant losses due to effect of physical stress during the coating; however, PEI-coated microcapsules nearly completely hold their extractant content. Stable extractive microcapsules have an appreciable potential for the selective removal of heavy metal ions.
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PMID:Preparation of stable alginate microcapsules coated with chitosan or polyethyleneimine for extraction of heavy metal ions. 1680 Dec 41

The hybrid microspheres with polystyrene core coated by titania nanoparticles were prepared by miniemulsion polymerization, and the as-prepared samples were characterized by SEM, XRD, TG-DTA, XPS, and SPS techniques. TiO2 nanoparticles experienced two processes of phase transition, i.e., amorphous to anatase and anatase to rutile at the calcining temperature range from 400 to 1000 degrees C. The phase transformation temperature of TiO2 hybrid microspheres from anatase to rutile was increased by about 300 degrees C due to the blocking function of calcined polymer remainder. SPS results present that the band-gap of hybrid microspheres is 3.2-3.4 eV, which is larger than that of pure TiO2. The maximum intensity of the SPS signal is about 3 times larger for the hybrid material as compared to the pure TiO2. In addition, the photocatalytic degradation rate of TiO2 hybrid microspheres was 15% faster than that of pure TiO2 in the experiment of the photocatalytic degradation of methyl orange.
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PMID:Crystallization and photovoltaic properties of titania-coated polystyrene hybrid microspheres and their photocatalytic activity. 1685 28

Biochemical sludges of sewage and petrochemistry and surplus sludge were taken as raw materials to prepare adsorbents for flue gas desulfurization by pyrolysis. To compare with active carbon, the abilities of adsorbents made from different sludges were studied by SEM, X-ray diffraction diagram, TG and DTA, pore characteristics and elements analysis, and the adsorption mechanisms of systems of SO2 -O2-N2 and SO2-O2-H2O(g)-N2 were studied by FTIR. Results indicated that the desulfurization performance of adsorbent made from surplus sludge was better, subsequent was petrochemical sludge, and the adsorbent made from biochemical sludge of sewage was worse. The desulfurization efficiency of adsorbent made from surplus sludge was slightly lower than active carbon. In the system of SO2-O2-N2, physical adsorption was primary, but in the condition of water, chemical adsorption was primary, where catalysis and oxidation of SO2 took place in sludge-derived adsorbent. In adsorption process, the adsorption depends on micropore structure.
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PMID:[Preparation of adsorbent made from sewage sludge and its spectrum properties]. 1688 62

Amorphous mesoporous aluminophosphates (AlPO) with P/Al molar ratio in the range 0.8-1.15 are synthesized by using the citric acid (CA) route and are systematically characterized using N(2)-adsorption, XRD, SEM, solid-state CP-MAS NMR, FT-IR, TG-DTA, CO(2)-TPD, and NH(3)-TPD. The characterization studies show that the change in P/Al ratio could affect the structure, texture, thermal stability, and surface acid-base properties of AlPO. Samples with a relatively low P/Al ratio (< or =1.0) exhibit uniform amorphous mesoporous character and high thermal stability (up to 1173 K). Partial crystallization of the AlPO framework easily occurred on the sample with higher P/Al ratio (> or =1.1), thus leading to significant decrease of surface area and formation of particle pile mesopores. Both weak acid and weak base sites are observed over AlPO materials, and the amounts of acid-base sites can be effectively controlled by adjusting the P/Al ratio. The presence of suitable interaction between citric acid and AlPO framework is critical for the formation of mesoporous structures. Both CA and PO(4) units are considered to be ligands to coordinate with aluminum ions, forming relative uniform complexes (such as CA-Al-PO(4)) in the as-synthesized AlPO materials. The mesoporous structure of AlPO materials is obtained after the rapid decomposition of citric acid. Vapor phase selective O-methylation of catechol with methanol reaction is carried out to investigate the catalytic performances of AlPO materials with different P/Al ratios. Among them, AlP(1.1)O shows the highest activity (88.4% conversion of catechol) and the highest yield of guaiacol (74.3%). The presence of suitable weak acid-base pairs may play an important role on the title reaction.
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PMID:Thermally stable amorphous mesoporous aluminophosphates with controllable P/Al ratio: synthesis, characterization, and catalytic performance for selective O-methylation of catechol. 1692 87

This study assesses the phosphate removal capacity and mechanism of precipitation or adsorption from aqueous solutions in batch experiments by an industrial sludge containing gypsum (CaSO(4).2H(2)O) obtained as a by-product from a fuller's earth process. The potential capacity for phosphate removal was tested using various solution concentrations, pH values, reaction times, and amount of sludge. The maximum phosphate adsorption capacity calculated using the Langmuir equation was 2.0 g kg(-1). The pH for the maximum adsorption by the sludge was neutral to alkaline (pH 7-12). Over 99% of phosphate was removed from a phosphate solution of 30 mg L(-1) using 0.15 g of sludge in a 9-h reaction. Sulfate (SO(4)(2-)) concentration increased with increasing initial phosphate concentration, possibly because of dissolution of gypsum and adsorption of both sulfate and phosphate. At high phosphate concentration (>1000 mg L(-1)), relative constant concentration of Ca(2+) was not consistent with adsorption of the most important phosphate removal mechanism. Results suggest that precipitation of calcium phosphate is principally responsible for phosphate removal under its high concentration. Agglomerated precipitate in the reaction sludge was observed by SEM and identified as brushite (CaHPO(4).2H(2)O) by XRD, FT-IR, and DTA. Based on thermodynamic considerations, it is suggested that the brushite will readily transform to more stable phases, such as hydroxyapatite (Ca(5)(PO(4))(3).OH).
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PMID:Phosphate removal using sludge from fuller's earth production. 1703 Apr 13

The synthesis of TiO2 and Fe-TiO2 by sol-gel method is demonstrated and characterized. The characterization of TiO2 and Fe-TiO2 is performed with instruments, including TGA/DTA, FTIR, UV-Vis, N2 adsorption and SEM. Dichloromethane is used for the photocatalytic activity test. From the results of dichloromethane photocatalytic degradation, the calcined temperature of TiO2 and the presence of water vapor influence the photocatalytic activity. The optimum doping amount of iron ions is 0.005 mol%, and this can enhance the photocatalytic activity, while too great an amount will make the iron ions become recombination centers for the electron-hole pairs and reduce the photocatalytic activity. UV-Vis diffuse reflectance spectra of Fe-TiO2 show an increase in absorbency in the visible light region with the increase in iron ions doping concentration The intermediate of dichloromethane photodegradation includes CHCl3, CCl4, CH2Cl2 and COCl2. The presence of iron ions may reduce the adsorption of Cl element on the surface of the photocatalyst.
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PMID:Study on photocatalytic degradation of gaseous dichloromethane using pure and iron ion-doped TiO2 prepared by the sol-gel method. 1709 38

In this paper, surface physiochemical properties of three typical aluminas, gamma-Al(OH)3, gamma-Al2O3, and alpha-Al2O3, were investigated by means of XRD, SEM, TEM, BET surface area, TG/DTA, and potentiometric titration techniques. Based on the titration data, surface protonation and deprotonation constants were determined using the constant capacitance model (CCM). The emphasis of this research was laid on the comparison of the crystal structure, surface hydration/dehydration and acid-base properties of these three typical alumina minerals. The calculation results revealed that the surface acidity of the aluminas is in the order of alpha-Al2O3>gamma-Al(OH)3>gamma-Al2O3 after being hydrated for 1 h. The correlation between the hydration/dehydration mechanisms of alumina and its acid/base properties is discussed.
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PMID:Surface acid-base properties and hydration/dehydration mechanisms of aluminum (hydr)oxides. 1727 18

The synthesis of modified hydrophobic starch nanoparticles using long chain fatty acids was accomplished. Grafting of fatty acid on the starch was done using potassium persulphate as catalyst and the formation of graft polymer was confirmed by FTIR spectra. The thermal properties of the native and grafted starch were investigated using simultaneous TG-DTA and DSC. The graft polymerization was found to be depending on the temperature and the duration of the reaction. The modified starch nanoparticles were cross-linked with sodium tripoly phosphate for better stabilization. Morphology of the grafted starch nanoparticles was studied by SEM and AFM. Drug-loading and the controlled release of the drug from the nanoparticles was studied using indomethacin as model drug.
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PMID:Hydrophobic grafted and cross-linked starch nanoparticles for drug delivery. 1727 45

A combination of pyro and hydrometallurgical process has been proposed to selectively recover molubdenum, cobalt and aluminium from the spent catalyst containing 12.3% Mo; 31.8% Al; 2.38% Co; 9.5% S and 2.9% C. Before a two-stage alkali-acid leaching process to selectively target Mo, Co and Al from the uncrushed sample, the spent catalyst was calcined at different temperatures. Characterization of different calcined samples was carried out by different instrumental analysis like XRD, TG/DTA, IR and SEM in order to understand the structural changes and dissolution behavior of spent catalyst. It was found that calcination at 500 degrees C preferred for spent catalyst roasting since the surface and pore structures obtained by roasting at this temperature facilitated dissolution of calcined spent catalyst in the leachant. Mo was selectively separated and recovered from the leach liquor by carbon adsorption method; whereas, Al and Co were separated by an organo-phosphinic-based extractant, Cyanex 272. In the whole process, 95.9% Mo, 89.6% Co and 39.8% Al was recovered from the spent catalyst. Finally, a complete process flowsheet has been presented.
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PMID:Selective recovery of Mo, Co and Al from spent Co/Mo/gamma-Al2O3 catalyst: effect of calcination temperature. 1736 21


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