Volume 15, No. 3 (2014)
Articles
CATALYTIC COMBUSTION OF METHANE OVER Pt/γ-Al2O3 IN MICRO-COMBUSTOR WITH DETAILED CHEMICAL KINETIC MECHANISMS
JUNJIE CHEN(*), XUHUI GAO
Micro-scale catalytic combustion characteristics and heat transfer processes of preheated methane-air mixtures (φ = 0.4) in the plane channel were investigated numerically with detailed chemical kinetic mechanisms. The plane channel of length L = 10.0 mm, height H =1.0 mm and wall thickness δ = 0.1 mm, which inner horizontal surfaces contained Pt/γ-Al2O3 catalyst washcoat. The computational results indicate that the presence of the gas phase reactions extends mildly the micro-combustion stability limits at low and moderate inlet velocities due to the strong flames establishment, and have a more profound effect on extending the high-velocity blowout limits by allowing for additional heat release originating mainly from the incomplete CH4 gas phase oxidation in the plane channel. When the same mass flow rate (ρin × Vin) is considered, the micro-combustion stability limits at p: 0.1 MPa are much narrower than at p: 0.6 MPa due to both gas phase and catalytic reaction activities decline with decreasing pressure. Catalytic micro-combustor can achieve stable combustion at low solid thermal conductivity ks < 0.1 W∙m-1•K-1, while the micro-combustion extinction limits reach their larger extent for the higher thermal conductivity ks = 20.0-100.0 W∙m-1•K-1. The existence of surface radiation heat transfers significantly effects on the micro-combustion stability limits and micro-combustors energy balance. Finally, gas phase combustion in catalytic micro-combustors can be sustained at the sub-millimeter scale (plane channel height of 0.25 mm).
SYNTHESIS AND CRYSTAL STRUCTURE OF A Ni(II) COMPLEX WITH 1,5-NAPHTHALENEDISULFONATE
WANG LI-HUA(*)
A new Ni(II) complex, [Ni(H2O)6]•(L) (L=1,5-naphthalenedisulfonate) has been obtained by the reaction of Ni(OAc)2•4H2O with sodium 1,5-naphthalenedisulfonate in the CH3CH2OH/H2O (V:V=1:1) solution. The complex was characterized by elemental analysis, IR and X-ray single crystal diffraction analysis. The results showed that the local geometry around central Ni(II) ion can be described as distorted octahedral environment which connected by six coordinated water molecules. The complex molecules formed one dimensional chained structure by hydrogen bonds and π-π stacking.
TREATMENT OF TEXTILE WASTEWATER USING A CONTINUOUS FLOW ACTIVATED SLUDGE SYSTEM AT PILOT-SCALE </br> TRAITEMENT DES EAUX USEES DE L’INDUSTRIE TEXTILE PAR UN SYSTEME A BOUES ACTIVEES EN ALIMENTATION CONTINUE A L’ECHELLE PILOTE
M.A. ABOULHASSAN(1*), S. SOUABI(2), H. EL OUARGHI(1), M.A. BAHLAOUI(2)
Textile industry wastewaters contain high concentrations of organic matter, toxic substances and dyes and pigments, and are harmful to receiving environment. Activated sludge system at pilot scale with continuous feeding, was used for the treatment of a dyeing unit effluent. The results showed that treatment allows a removal rate of 40-56 % of chemical oxygen demand (COD), and 13 to 30 % of color. The adsorption on sludge appears to be the main process responsible for the color removal of wastewater generated by textile industry.
TECHNOLOGICAL PROPERTIES OF RAW CLAY BASED CERAMIC TILES: INFLUENCE OF TALC </br> PROPRIETES TECHNOLOGIQUES DE CARREAUX CERAMIQUES A BASE D’ARGILES : INFLUENCE D’UN TALC NATUREL
MOUSTAPHA SAWADOGO, LAMINE ZERBO, MOHAMED SEYNOU(*), BRAHIMA SORGHO, RAGUILNABA OUEDRAOGO
Local clay from Burkina Faso has been used as a basic raw material in the formulation of ceramic tile with a natural talc (0 - 4% wt) as a flux. The used sintering temperatures are between 950 and 1100 °C with one hour as hold at heating rate of 5 °C∙min-1. The different technological properties (shrinkage, water absorption and mechanical strength) are improved when the sintering temperature exceeds 1000 °C. The mixture with 4% wt of talc provides better properties than the other grades. The tiles obtained at 1050 °C with 4% wt of talc have similar characteristics to those obtained at 1100 °C without talc. An energy gain with a difference of temperature of 50 °C could be made with the use of talc as the adjuvant.
SYNTHESIS AND INFRARED STUDY OF SOME SULFATO TRIORGANOTIN DERIVATIVES AND ADDUCTS
DAOUDA NDOYE, LIBASSE DIOP(*)
On allowing ethylenediammonium sulfate or Me4NSO4H to react with SnPh3Cl or SnBu2Cl2 in ethanolic media in specific ratios the three sulfato complexes were obtained and their infrared study carried out. The molecular structures of these compounds have been proposed on the basis of the infrared data. Discrete structures are suggested: the sulfate anion is tetradentate in two of them and monodentate in the other, the tin center being in a trigonal bipyramidal environment in all the structures. When the ethylenediammonium ion is involved through hydrogen bonds, dimeric structures may be obtained.
THE INFLUENCE OF THERMAL REGIME ON STABILIZATION PROCESS OF YOUNG WINES INFLUENCE DU RÉGIME THERMIQUE SUR LE PROCESSUS DE STABILISATION TARTRIQUE DES VINS JEUNES
RODICA STURZA, ECATERINA COVACI(*)
The excess of tartaric salts determines in certain conditions the formation of characteristic crystals that fall in the form of sediment. The aim of the study is to search the optimal process of tartaric stabilization conditions of young wines. We examined the tartaric stabilization of young wines by decreasing their content in tartaric salts by conventional cold stabilization and contact seeding with three thermal regimes (-5 °C, 0 °C and 5 °C). The study results showed a reduction with 23÷40 % of chromatic intensity, with 16.45÷24 % of the content of potassium and a titratable acidity between 0.73 and 1.04 g∙L-1. The recommendations of optimum regime of the stabilization of young wines, based on experimental results, included: cooling of wine at -5 °C or 0 °C, followed by the administration of cream of tartar in a doses 4÷8 g∙L-1, maintaining in these conditions until the stabilization and isothermal filtration before bottling. The described process generates a healthy and balanced product, good nutritional value and organoleptic quality.
(Cation)2C2O4∙nSnPh2C2O4(n=1, 2; cation=Pr2NH2, MeNH3) AND SOME OF THEIR ADDUCTS: SYNTHESIS, INFRARED AND MOSSBAUER STUDIES
YAYA SOW(*), LIBASSE DIOP
Three [SnPh2(C2O4)2]2- containing new adducts have been synthesized and characterized by elemental analyses, infrared and Mossbauer spectroscopy, the suggested structures being discrete, the SnPh2 residues octahedral cis or trans coordinated. A trans [SnPh2(C2O4)2]2- complex- anion has been evidenced by spectroscopic methods for the first time in this work. The new complex-anion [SnPh2Cl(C2O4)2]3- with a seven coordinated tin centre has been reported in this paper and a two metallic components structure containing a tetranuclear and a mononuclear components with octahedral environments around the tin centers interacting with cations and involving OH groups leading to a supramolecular architecture has also been reported. The anion behaves as a mono- or a bichelating ligand.
SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF A NOVEL Mg(II) COMPLEX WITH 1,2-PHENYLENEDIOXYDIACETIC ACID
XI-SHI TAI(1*), JIE YIN(2), YUAN-YUAN LIU(1)
A novel Mg(II) complex, [Mg(HL)2•(H2O)4]•4H2O•HCl (HL = 1,2-phenylenedioxydiacetato), has been synthesized by the reaction of 1,2-phenylenedioxydiacetic acid, NaOH and MgCl2•6H2O in one-pot. The compound was characterized by X-ray single crystal diffraction analysis. The crystal of the title complex belongs to monoclinic, space group Pn with a = 10.772(2) Å, b = 9.7145(19) Å, c = 13.996(3) Å, β = 104.32(3)º, V = 1419.1(5) Å3, Z = 2, Dc = 1.498 μg•m-3, μ = 0.245 mm-1, F(000) = 658 and final R1 = 0.0653, ωR2 = 0.1913. The molecules are connected by π-π stacking to form three dimensional network structures.
SOME SULFATO ADDUCTS AND DERIVATIVE: SYNTHESIS AND SPECTROSCOPIC STUDY
MOUHAMADOU BIRAME DIOP, LIBASSE DIOP(*)
Three new adducts and derivative have been synthesized and studied by infrared and NMR spectroscopies. The suggested structures are discrete with a sulfate behaving as a monochelating, bichelating or monodentate ligand, the environments around the tin centre being octahedral or pentagonal bipyramidal. In all the studied compounds, proposed supramolecular architectures may be obtained when intermolecular hydrogen bonds are considered.
Cy2NH2NO3SnBu2Cl2•H2O AND Cy2NH2NO3SnPh2Cl2•2H2O: SYNTHESIS AND INFRARED STUDY
ABDOU MBAYE, CHEIKH ABDOUL KHADIR DIOP(*), LIBASSE DIOP
On allowing Cy2NH2NO3 to react with SnBu2Cl2 and SnPh2Cl2, the two studied adducts were obtained. While considering the complex-anions [SnBu2Cl2NO3.H2O]- and [NO3.SnPh2Cl2 H2O]-, discrete structures were suggested with monocoordinating nitrate and octahedral environment around the tin centre. When the cation is involved through N-H----O or N-H----Cl hydrogen bonds, suppramolecular architectures are obtained.