نشریه علوم و فناوری رنگ
سال هفتم شماره 3 (پیاپی 25، پاییز 1392)

The Electro-Fenton process with applied H2O2 and electro-generated ferrous ion was investigated for treatment of real textile wastewater. The effects of various factors such as current density, H2O2 dosage and reaction time on color and COD removal from real textile wastewater were evaluated. Likewise, the amounts of energy consumption and generation of ferrous ion were calculated. The results indicated that the application of 11.25mA/cm2 current density with 73mM H2O2 provided 67.9% decolorisation within 45min of electrolysis time. Moreover, in this condition, energy consumption was 8.37 KWh/kg of CODr. Finally, the ADMI method and maximum absorbance at wavelength of 400nm as two methods of color measurement were compared for decolorisation of real textile wastewater.

Enzymes are biological catalysts which are well known in textile wet processing to enhance the handling and appearance, desizing, bleaching, softening, shrink-proofing, dyeability and pilling behavior of various textile products. The aim of this work was to investigate the changes induced on nylon 6,6 fiber by enzymatic system using mixture of proteolytic and lipolytic enzymes. Technical measurements were studied including Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), weight loss (WL), bending lengths (BL), scanning electron microscopy, moisture absorbency (MA), and reflectance spectroscopy (RS). For this purpose, nylon 6,6 fabrics were first treated separately with different concentrations of protease and lipase mixtures in solution. The dyeing process was then carried out on the treated fabrics with two reactive and acid dyes. The intensity of major peaks in FTIR spectra of the protease treated samples are in favor of chemical changes of the polypeptide functional groups in fabric. Thermal studies also show significant decrease in thermal degradation temperature of the treated polymer at higher temperatures of 400°C. Protease and lipase mixtures decreased the weight of samples while lipase intensified the weight loss comparing with protease. The results of color measurements showed that the more concentration of lipase enzyme used in mixture, the darker the color of dyed sample is.

In this research, the superabsorption composite of zeolite/acrylic acid was investigated to remove the cationic dyes from textile effluent. Basic Red 46 (BR46) was used as cationic dye. The surface characteristics of composites were investigated using Fourier Transform infra-red and scanning electron microscope. The influence of process variables such as adsorbent dosage, initial dye concentration and pH were studied. The isotherm and kinetic of dye adsorption onto composites were studied. The results indicated that the data for adsorption of BR46 onto composites fitted well with Langmuir isotherms. The rates of sorption were found to conform to pseudo-second order kinetic with good correlation. Results indicated that composites could be used to remove the cationic basic dyes from contaminated watercourses.

In this research the effect of the scaterring mechanism of titanium dioxide incorporated ink printing inks on the fading behaviour of such inks was studied. Investigation, It was shown that increasing the amount of titanium dioxide present in the ink formulation may increase the observed fading rate of prints from pigment based inks and reduce the fading rate of dye based inks. There is an optimum amount of titanium dioxide which when added to such formulations, protect the prints from fading. In addition the effect of the absorption mechanism of UV absorber content present in the overprint clearcoat, on fading was also evaluated. It has been shown that for water-based inks, the fading rate of subsequent prints were reduced for overprint clearcoats containing organic and inorganic UV absorber.the synergistic effect of both mechanisms on fading was observed.

In this study,Silica-based anti-static nanocomposite hybrid coatings have been developed via sol-gel process on aluminum and glass substrates using dip coating techniques for mechanical and electrical evaluations. The hybrid sols were prepared by hydrolysis and condensation of 3-glycidoxypropyl-trimethoxysilane (GPTMS)and tetra methylorthosilicate (TMOS) in the presence of acidic catalyst and ethylen diamine (ED), as cross-linking agent. N-(2 aminoethyl)-3-aminopropyltrimethoxysilane (AAPM) is used as antistatic agent and the antistatic properties of the coatings were investigated via surface resistivity measurements. The surface morphology and size of the nanoparticles in the hybrid films were observed and determined by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) respectively. In addition, the hydrolysis and condensation reactions were followed by fourier transform infrared spectroscopy. Also investigation of the coating mechanical properties by cross-cut test revealed that these coatings have great adhesion towards the substrate.

The goal of this study was to survey the feasibility application of Wheat straw as a low cost adsorbent for the removal of Direct Red 12B from wastewater. The sub goals of the research were to determine the adsorption kinetic and adsorption isotherm, effects of primary concentration of dye, adsorbent dose, effect of contact time, and effect of pH for the adsorption of dye with WS. The maximum removal of Direct Red 12B was 99% obtained by passing an aliquot of the DR12B solution at pH 2.5 and 0.25 gr WS at room temperature. The effects of different parameters such as pH, dye concentration, amount of adsorbent, adsorbent particle size, temperature were studied. The efficiency of adsorbent was also tested for the removal of dye from Karoon River with 99.8% recovery. The results was showed that WS as an adsorbent is a low cost, potentially efficient and eco-friendly adsorbent for removal of DR 12B from industrial wastewater. It was observed that the pseudo-second-order kinetic model fits better with good correlation coefficient. Based on batch experiments, the adsorption data could be fitted by the Langmuir equation with a maximum adsorption amount of 26.38 mg/g.

In this study, magnetized activated carbon was synthesized due to quick and easy separation and no secondary pollution in solution, and was used as an adsorbent for the removal of Reactive Blue (RB5) from aqueous solution. Physical, surface and morphological properties of the synthesized adsorbent were analyzed by XRD, SEM, EDX, TEM and BET techniques. Furthermore, the efficiency of the adsorbent in removal of dye in a batch system was studied by investigating the impact of different parameters such as pH, contact time, adsorbent dosage, initial dye concentration and solution temperature. Langmuir and Freundlich isotherms and two models kinetically of pseudo first-order and pseudo second-order were used to investigate the experimental data. Results showed that at an optimum pH of 3 and an equilibrium time of 15 minutes, adsorption efficiency increases with increasing temperature and the amount of adsorbent used and decrease in the initial dye concentration. Results from studying the isotherms and kinetics of adsorption indicated that adsorption process follows Lungmuir isotherm (R2>0.999) and the kinetic model of pseudo second-order (R2>0.995). The maximum adsorption capacity was calculated 250 mg/g under optimum conditions based on Langmuir isotherm. Also, the calculated values from thermodynamic parameters showed that the adsorption of RB5 on AC-Fe3O4 is endothermic and spontaneous.

In Kubelka-Munk theory, there is a fairly linear relationship between (K/S) vs. concentration. To access this space, it is necessary to have reflectance data which obtain of expensive devices such as spectrophotometer or it is acceptable from spectral characterization of modern equipments like camera and scanner. The spectral characterization needs the spectral sensitivity of the device that is difficult and time consuming job to measure. The present work uses colorimetric characterization of a scanner and Cohen and Kappauf theory (Matrix R) to calculate fundamental stimulus space. The results showed the estimated fundamental stimulus space (N*) is not scalable and it can transfer to a more desirable scalable space, i.e. (K/S)* using non-linear transfer based Kubelka-Munk theory. With select extended regions of wavelengths, a desirable space was provided to have a suitable communication to study the behavior of dyes on textiles by using simple and inexpensive equipments at the specific lighting and viewing conditions.

The use of different papers in inkjet printers is a normal practice. However, due to the variety of the texture and gloss of such papers as well as the extent to which various papers enable the penetration of the ink into these papers would result in various results in the printed colors. In other words, such various in the papers affect the prediction accuracy of any model used for making the profiles in the color management process.In present article the effect of four paper types on the final printed papers as predicted by a cube nearest neighbor, prediction model in LUT profiles in an inkjet printer was investigated. The deciding parameters were repeatability and color gamut volume. The results show that this prediction model gave the best printed colors on the utilized matte paper.