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    Investigation of adsorption isotherms used for wool dyeing by aqueous extraction of cehri fruit (Fructus Rhamni Petiolari) and dyeing of wool and silk accompanied by various mordants
    (Scientific Technical Research Council Turkey, 1996) Aydin, AH; Guzel, F; Tez, Z
    In this study, adsorption isotherms were obtained by processing wool with dyestuff solutions of different concentrations extracted from cehri fruit with water. These isotherms follow the Nernst equation; the Nernst constant was determined and interpreted. In addition, wool and silk fibres were dyed with the same dyestuff solution and various mordants. Colours having a high fastness which could be used on an industrial scale were produced.
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    Öğe
    Preparation and characterization of polyoxometallates of molybdenum, tungsten and their salts
    (Marcel Dekker Inc, 1997) Akba, O; Guzel, F; Yurdakoc, K; Gumgum, B; Tez, Z
    In this work, confirmation of the molecular formula and investigation of the structural stability of the prepared various types of heteropoly acids and their salts by TGA are reported. Specific surface areas of the samples were determined by the BET-single point N-2 adsorption method. Scanning electron microscopy (SEM) was used for the of surface topography of the samples in the sense of crystalline and amorphous states and the acidities of these solid samples were determined based on the color changes of suitable indicator solutions by the way of a butylamine titration method. Impurities, weight ratios and bonding states of the characteristic elements of the samples were determined from XRD, EDX and FTIR studies.
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    Öğe
    Removal of heavy metal ions by modified sawdust of walnut
    (Parlar Scientific Publications (P S P), 2003) Bulut, Y; Tez, Z
    Modified walnut sawdust was found to be effective in removing Ni(II), Cd(II) and Pb(II) from aqueous solution. The extent of removal depends on the contact time, concentration and temperature of the solution. The equilibrium time was found to be about 60 min. The adsorption rate constants were calculated by kinetics which fit a pseudo first-order and second-order laws. Experiments were carried out at three different temperatures, expressed as both Freundlich and Langmuir isotherms, and Freundlich and Langmuir constants as well as the thermodynamic parameters DeltaG, DeltaH and DeltaS were calculated. A possible explanation for the adsorption of metal ions by the sawdust may be attributed to the exchange between metal ions and acidic protons in sawdust matter.
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    Öğe
    Thermal decomposition kinetics of poly(acrylic acid-styrene oxide) copolymer using thermogravimetric analysis
    (Marcel Dekker Inc, 2003) Çolak, N; Yagan, A; Tez, Z
    Kinetic parameters for the thermal decomposition of poly(acrylic acid-styrene oxide) copolymer were investigated with the use of a dynamic thermogravimetric analysis (TGA) technique. In this study, nine samples were synthesized in different conditions. TGA thermograms of the samples were recorded in the flow of nitrogen (20 mL.min(-1)) at four heating rates 2, 5, 10, and 20degreesK.min(-1). The activation energies (E), pre-exponential factors (A), and reaction order (n) were obtained from the thermograms. The activation energies changed from 161.86 kJ.mol(-1) to 285.74 kJ.mol(-1), the pre-exponential factors are also in the range of 1.38 x 10(14) to 1.99 X 10(29) min(-1) and reaction order n is 3 for the whole samples.