Advanced Materials Research Vols. 236-238

Abstract: Pyrolysis of dried sewage sludge samples treated with the additives silica zeolite, calcium oxide, dolomite, ammonium sulphate or diammonium sulphate were conducted by thermal gravimetric anaysis (TGA). The pyrolysis of the untreated sewage sludge showed four regions in which differential thermal gravimetry (DTG) peaks was observed. These peaks were identified as being due to: dehydration of the physically bound water in the sludge; chemical dehydration of carbohydrates in the sludge; decomposition of hemicellulose, cellulose and proteins in the sludge, and; decomposition of lignin and plastics in the sludge. Addition of chemical additives changed the mass-loss due to chemical dehydration, with the dolomite additive reducing the mass-loss and AS or DAP increasing the mass-loss. AS and DAP also changed the mass-loss kinetics of the decomposition of hemicellulose and cellulose. At temperatures greater than 750°C, the proportion of sludge converted to char was unaffected by the type of additive used. The observed mass-loss data was modelled with a three or four step kinetic mechanism; the calculated kinetic parameters are reported.

Abstract: The removal of dyes from synthetic wastewater by sunflower husk was studied in batch and dynamics removal. The extent of adsorption was studied in batch as a function of burning temperature, chemical treatment, adsorbents size, pH and solution temperature. Methylene blue and Mexican red in aqueous solution was used as synthetic wastewater. Dynamic removal of methylene blue and Mexican red by sunflower husk was also studied in packed bed column. In batch, both dyes were removed with the maximum adsorption by unburned adsorbents. Removal of methylene blue was increased when the adsorbents treated with NaOH whereas treated with HCl for Mexican red. The optimum pH for removal of methylene blue solution was between 4 and 10 and the maximum value for Mexican red was pH 2. The adsorption of methylene blue and Mexican red follows Langmuir adsorption model. In packed bed column, values of column parameter were investigated as a function of flow rate and bed height. Dynamic of adsorption process was modeled by bed depth service time (BDST) and the experimental data were fitted very well to the BDST model

Abstract: Chemical mechanical polishing (CMP) of Cu pattern wafer based alkaline slurry in GLSI with R(NH₂)_n as complexing agent was investigated. In Cu CMP procedure, it is necessary to minimize the surface dishing and erosion while maintaining good planarity. This requirements are met through the complexing agents. Based on the reaction mechanism analysis of Cu in alkaline slurry with R(NH₂)_n as complexing agent in CMP, the performance of Cu dishing and erosion were discussed. The results showed that the slurry stability can be improved obviously by the addition of R(NH₂)_n as complexing agent, both Cu1 and Cu2 have good dishing and erosion performance. Furthermore, the dishing condition of Cu2 (180-230nm) is better than that of Cu1 (280-370nm), and the erosion condition of Cu2 (230-260nm) is also better than that of Cu1 (450-500nm).

Abstract: The report presents the effects of the thickness on the TiO₂ thin films prepared by the GLAD technique with incline spinning substrate on rotating holder (ISSRH) by using the electron beam evaporation. The prepared films were heated at 500 °C for 2 hr in air. The microstructure of films was investigated by UV- visible photometer, X-ray diffraction, XRD and field emission scanning electron microscope, FE-SEM. The results showed the thickness of 10, 50, 100 and 300 nm films exhibited continuity distribution of the crystalline. The crystalline structure evidenced the dominant peak at the 300 nm thickness. GLAD TiO₂ films exhibited the columnar growth and porosity. The TiO₂ nanostructures showed rutile phase.

Abstract: The Eu²⁺ and Dy³⁺ codoped Ba₂MgSi₂O₇ phosphor is synthesized via high temperature solid state reaction. The phase identification shows that the calcining temperature of this material is 1250°C. The photoluminescence analysis presents that the emission of this phosphors shifts from 440nm to 500nm as the phase become purity monocline Ba₂MgSi₂O₇. The decay curve and the TL illustrates that this materials shows a weak afterglow with a short duration owing to the deep trap. This deep trap has a strong ability to store the trapped carriers. So the application of this materials can be extended.

Abstract: In this paper we study the predictive capacity of three methods to compute biodiesel viscosity and their behavior in different ranges of temperature (those able to be measured in laboratory and those of interest in the study of atomization and combustion) and we compare the results with the viscosity data obtained in our laboratory for three biodiesel from different feedstock. We also compare our experimental viscosity values with literature data in the same range of temperature to analyze differences in the tendency of evolution of this property with temperature.

Abstract: A series of 13-cis-retinoate aryl derivatives were synthesized from 13-cis-retinoic acid and phenols or arylalcohol with dicyclohexylcarbodiimide (DCC) as reagent and 4-dimethylaminopyridine (DMAP) as catalyst. Their structures were characterized by ¹H, ¹³C NMR, IR and MS. The crystal of 3a has been determined by single crystal X-ray diffraction analysis and its molecular structure has been confirmed. Compound 3a belongs to monoclinic system with space group P2 (1)/c, a = 22.235 (3) Å, b = 7.4117 (10) Å, c = 15.990 (2) Å, β = 109.253 (3) °, V = 2487.7 (6) Å3, Z = 4, R = 0.0613, ωR = 0.01437.

Abstract: Fe(II)-Zn-based double metal cyanide complex catalysts modified with rare earth metal or transition metal promoters(lanthanum, cerium, zirconium, manganese) for the production of biodiesel were prepared, and the effect of the addition of different metal promoters on the characteristics of the catalyst was studied by using X-ray diffraction (XRD), BET, ICP and Infrared techniques .The experiment results show that the Fe(II)-Zn-based catalyst promoted with 1 wt.% of La(NO₃)₃·nH₂O exhibits the highest catalytic activity for the reaction, being as high as 99.3% of the yield of fatty acid methyl esters (FAME). Fe(II)-Zn-based catalysts have a tentative molecular formula: K₂Zn₃ [Fe(CN)₆]₂·xH₂O· (t-BuOH), where x=3-9 determined by using elemental analysis and ICP. It has been shown that the molecular formula of Fe(II)-Zn-based double metal cyanide complex catalysts did not change by adding 1 wt.% of rare earth metal or transition metal promoters. X-ray diffraction and BET results showed that Fe(II)-Zn-based catalysts with 1 wt.% of metal promoters salts exhibit smaller particle size, higher surface area than the Fe(II)-Zn catalyst ,which may be related to the higher activity of the catalysts.

Abstract: Carbon-supported gold catalysts Au/C were prepared by an impregnation-reduction method and modified by AgNO₃ to obtain bi-metallic catalysts Au-Ag/C, which were characterized by X-ray-diffraction (XRD) and Transmission Electron Microscope (TEM). Their catalytic performance was tested in the oxidation of cyclohexene in an autoclave without any solvent. The results showed that Ag doping can significantly enhance the catalytic performance of carbon-supported gold catalyst. Au(1.0 wt.%)-Ag(1.0 wt.%)/C has been found to be an efficient catalyst for the cyclohexene oxidation with a conversion of 27.6% at 80 °C and 0.4 MPa for 12 h while selectivity for ∑C₆ products (including cyclohexene oxide, 2-cyclohexene-1-ol, 2-cyclohexene-1-one and cyclohexane-1,2-diol) exceeding 88.9%, especially the selectivity of cyclohexane-1,2-diol up to 47.6%. Moreover, the effects of Au, Ag content on catalytic performance were also reported.

Abstract: Young’s modulus of monolayer graphene with carbon-circles is considered based on least-energy principle (LEP) and finite displacement theory (FDT). The relationships between the Young’s modulus and the numbers of carbon-circles of graphene are obtained. The results suggest that the Young’s modulus of graphene increases with the increasing number of carbon-circles in y-direction, but reduces with the increasing number in x-direction, and gradually comes to the constant .