JOURNAL OF COLOR SCIENCE AND TECHNOLOGY
Year:2008 | Volume:1 | Issue:2|Papers Count:8

In this work, protective properties of polypyrrole/polyaniline composite (as a conductive polymer) have been investigated in 3.5% sodium chloride solution via electrochemical techniques (electrochemical impedance spectroscopy, corrosion potential measurements and anodic polarization tests). Polypyrrole / polyaniline composite were deposited on carbon steel substrate by potentiostatic method. The electric capacitance and resistance of the films were monitored with the immersion time to investigate the water permeability of the paint films. Polypyrrole/polyaniline composite had a relatively low permeability and good catalytic behavior on passivation of carbon steel in longer periods. The results showed that the composite had better anticorrosive behavior compared to homopolymers (polypyrrole and polyaniline).

The one-bath dyeing of polyester and cotton fabrics with three disperse dyes based on naphthalimide derivatives and a reactive dye with together were investigated. Two of these disperse dyes have an ester group and one of them has an alkyl group. The disperse dyes containing of ester group and a reactive dye with together enable to dye polyester and cotton fabrics in two stages one-bath method, successfully. These dyes showed that they can be hydrolyzed in alkali media and convert to water soluble compositions. Thus, for removing loose dyed adsorption on the fabric, reduction clearing method was displaced by the alkali-clearing system. Disperse dyes containing ester groups showed that they have excellent wash fastness on the polyester component. Kinetic studies of hydrolysation of the disperse dyes containing ester group in alkali medium showed that the kinetic of the hydrolysation reaction is first order.

The retarding effect of gemini cationic surfactants in acrylic dyeing with a cationic dye (methylene blue) was studied by using UV-Vis spectroscopy. The dye adsorption rate increases with increasing temperature. The retarding action of gemini cationic surfactants is much stronger than that of the corresponding monomeric surfactants. In this work, a new empirical kinetic model based on simultaneous first and second order has been proposed.  The kinetic of acrylic dyeing with a cationic dye at different temperatures and in the presence of monomeric and gemini cationic surfactants was studied by using different empirical equations. The proposed equation showed a very good correlation with experimental data in comparison to the previous ones.

In this work, Fenton-like reagent (Fe3+/H2O2) that it is one of the advanced oxidation processes (AOPs) was used for the removal of mixture of dyes containing Malachite green (MG) and Orange II. Aim of this research is investigation of possibility of mixture of dyes decolorization by Fenton's reagent. In addition, effect of presence of one dyes on decolorization efficiency of another dye in mixture was examined. Results showed that in the presence of Orange II, removal efficiency of MG has been accelerated, whereas Orange II removal efficiency in the presence of Malachite green has been reduced. Influence of effective parameters on Fenton-like reaction such as H2O2 and Fe3+ concentration and initial concentration of dyes on the removal were investigated. Results showed that removal efficiency of dyes by increasing of Fe3+ concentration was increased. In addition, the best dye removal for both dyes were obtained at the molar ratio of H2O2/Fe3+=20.

In this research, the decolorization and toxicity reduction of colored solution (C.I. Reactive Orange 16, RO16) and real textile wastewater using nanophotocatalysis process were investigated. Effective decolorization parameters such as titania photocatalyst load, dye concentration, pH and inorganic salts were optimized. The toxicity reduction of wastewater was assessed by bioassay using Daphnia magna. At the beginning of the process, the toxicity of wastewater increased and its toxicity decreased at the end of the process. The results showed that the nanophotocatalysis process has the decolorization and toxicity reduction capabilities of real textile wastewater.

In this study, the characterization of a four-color halftone printer was carried out by original Neugebauer and n-modified Neugebauer models. According to the results, the modified Neugebauer method was led to a better outcome. Although the relation between target dot area and real dot area for a color inks were linear, the nonlinearity of target and real dot area for black ink caused some error especially in dark samples. In the n-modified Neugebauer model the nonlinearity between real and target dot area was considered. Therefore, this model was led to a better color reproduction accuracy as comparison with the original Neugebauer model. The results showed that the modified Neugebuer method is led to better outcome.

Carcinogenic and mutagenic potential of some azo dyes as a category of common dyes in different types of industries has been reported. Current study was designed to asses the DNA damage induced by some commonly used commercial grade acid azo dyes using single cell electrophoresis, comet assay, in human HL-60 cell lines. The results showed that DNA damage in HL-60 cells, namely comet positive cells, were not significantly increased after 12 and 24 hours treatment with azo dyes: Acid Red 14, Acid Blue 92, Acid Blue 5 and Acid Yellow 36 at concentration ranging 0.1- 1.2%. Considering complex metabolic mechanisms of azo dyes in mammalians, further evaluation of DNA damage using in vivo comet assay is suggested.