نشریه علوم و فناوری رنگ
سال نهم شماره 2 (پیاپی 32، تابستان 1394)

In this research, modified zinc ferrite nanoparticle by 3-amino propyl triethoxysilane was synthesized and its dye removal ability was studied. The synthesized adsorbent was characterized using Fourier Transform Infrared and Scanning Electron Microscopy. Acid bule 25 (AB25), Direct green 6 (DG6) and Direct red 23 (DR23), were used as model compounds. The effect of operational parameter such as adsorbent dosage, pH, dye concentration and salt was evaluated. The isotherm and kinetic of dye adsorption were studied. The maximum dye adsorption capacity (Q0) of adsorbent for AB25, DG6 and DR23 was 333 mg/g, 53 mg/g and 167 mg/g, respectively. It was found that dye adsorption onto adsorbent followed with Langmuir isotherm. Adsorption kinetic of dyes was found to conform to pseudo-second order kinetics. The results showed that the modified zinc ferrite nanoparticle being a high dye adsorption capacity might be a suitable adsorbent.

Most studies on antimicrobial properties of nano-TiO2 in deionized water deal with its photocatalytic properties. Few studies have shown that the presence of nano-TiO2 can inhibit the growth of the bacteria and it ultimately kills them in a culture medium in the dark. In this study, the antibacterial effects of suspended in a culture medium and immobilized nano-TiO2 systems in cement bed (0.1-1%) were investigated on Thiobacillus thioparus as a bacterium involved in cement biodegradation. The pH and turbidity tests were carried out in order to monitor the viability of the bacteria in the culture medium. The results showed that T. thioparus did not grow in the presence of cements containing nano-TiO2 and at longer contact time the bacterial death occurred. The optimum concentration of nano-TiO2 has been found to be 1% to maintain antibacterial properties. Thus, with evaluation of the toxicity effects, the cementitious antimicrobial coatings could be produced by immobilized nano-TiO2 for self-protected against biodegradation.

In this research, the effects of changing in synthesis conditions on corrosion inhibition properties of the potassium phosphate pigment were studied. Processing parameters, including calcinations time, quiescent time, mixing rate and KOH/ZnCl2 mole ratio are selected as the influential parameters. Potassium zinc phosphate (PZP) pigments were prepared via co-precipitation method and their corrosion inhibition performance in a 3.5% NaCl solution was investigated during immersion time (1, 4 and 24 h). The synthesized pigments were characterized by x-ray diffraction (XRD) and Raman spectroscopy. Different analytical techniques including electrochemical impedance spectroscopy (EIS), inductively coupled plasma (ICP), pH measurement and surface analysis tests were employed in order to evaluate the corrosion inhibition performance of synthesized pigments in comparison with conventional zinc phosphate. The results revealed that the corrosion inhibitive performance of the PZP pigments is higher than that of the commercial zinc phosphate pigment. The evaluation of inhibition behavior in test solutions showed that by increasing the immersion time from 1 to 24 h charge transfer resistance of synthesized pigments increases. Considerable improvement in corrosion inhibition performance was observed by increasing the mixing rate and reducing the KOH/ZnCl2 mole ratio.

In this study four heteroaryl amines have been prepared from the reaction of aniline derivatives, potassium thiocyanate and bromine in acetic acid. Coupling of diazonium salts of corresponding amines with 2-methylindole led to hetaryl-azoindole dyes. These dyes have been characterized by UV–Visible, FT-IR and 1H NMR spectroscopy. The solvatochromism properties of dyes have been investigated in various solvents. In addition, the antimicrobial activity of the synthesized dyes has been evaluated against Escherichia coli, Bacillus subtilis, Micrococcus leuteus and Pseudomonas aeruginosa bacterial strains. The results showed that some of these dyes are potential antibacterial compounds.

In this study, the extract of Rhuem Ribes L. flowers was used for dyeing of wool fibers. Oxygen plasma was used as a pretreatment to enhance the dyeability of wool fibers and metal mordant was eliminated from the dyeing process. The surface morphology of the wool fibers before and after plasma treatment was investigated by SEM images. FTIR analysis was employed to study the chemical changes imparted to the wool fibers by plasma treatment. The surface of wool fibers was etched and oxygen containing groups were introduced to the surface of wool fibers. The fastness of the dyed samples to washing and light was measured. The plasma treated samples showed better dyeability as well as good fastness to washing and light.

In this research, the mixed metal oxides of lanthanum - zinc - aluminate nanoparticles were synthesized by combustion method and characterized by SEM, FTIR, XRD and EDAX. The surface of the synthesized nanoparticle was modified by aminosilane and used to remove Acid Blue 92 (AB 92) and Reactive Blue 19 (RB 19). The effect of adsorbent dosage, initial dye concentration, pH and salt on dye removal was investigated. The kinetics and isotherm of dye removal was studied. The results showed that dye removal followed pseudo-second order kinetics and the Langmuir isotherm.

In the printing process, paper and its characteristics are understood to have a major role in the final perceived color. At the present study, the effect of fluorescence in paper on color change of the printed samples was investigated. The 24 color patches from Macbeth chart were printed on an A4 white paper by using a laboratory color printer. The spectra reflectance curves of the samples were determined by a calibrated spectroradiometer under illuminant A and a combination of illuminant A and UV radiation at the visible region. CIELCH color space parameters were calculated from the measured reflectance values under standard illuminant D65/10˚. The results showed that fluorescence property of paper in many cases led to a noticeable color shift. In addition, it was shown that for achromatic samples, changes in hue were not significant but it was noticeable on lightness and chroma. Moreover, it was resulted that the selected color difference equation has a large impact to analyze acquired results.

In this research, the normality of reflectance spectra of two different black dataset including of printed papers and fabrics are investigated. Then, by applying of principal component analysis technique (PCA) the reflectance domain of both dataset are compressed and reconstructed in restricted spaces. Results show that none of black papers and fabrics obeys from normal distribution. Besides, while both dataset benefit from smooth reflectance behaviors, the black papers behave more linear than black fabrics and could be described by lower spectral dimensions.