نشریه علوم و فناوری رنگ
سال چهاردهم شماره 3 (پیاپی 53، پاییز 1399)

ZnO nanoparticles were synthesized from the purified solution form the residue of Zn melting factory in Bafgh. The synthesized nanoparticles were studied using TEM, XRD, FTIR and UV ray. The studied nanoparticles in comparison with the purchased one form Merck Company showed well photovoltaic properties in removal of NB21 reactive dye. In the color bleaching process, the dye solution was exposed to the UV rays for 5, 10 and 30 minutes by both purchased and synthesized nanoparticles. The results of this study indicated the crystalline and hexagonal structure of synthesized nanoparticles. Also, TEM results revealed that the fabricated nanoparticles have clear spherical shape and distinct hexagonal dimension in the range of 40-120 nm. The dye removal efficiency in the 30 minutes in B21 dye was 92% in synthesized nanoparticles in compassion with 89.21% for purchased one.

The aim of this research is to synthesis and modify the low cost MgAl2O4-based photocatalyst. For this purpose, MgAl2O4 was first synthesized by sol-gel combustion method and then the effect of calcination temperature on the photocatalytic performance of semiconductor was evaluated through the elimination of methylene blue. In the next step, magnesium aluminate/graphene oxide composite was synthesized by three methods; sol-gel combustion, surface grafting by APS and hydrothermal method. The obtained samples were also employed for dye degradation to understand the role of synthesis method on the composite activity. Samples were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy and Field emission scanning electron microscopy. The photocatalytic activity was evaluated by measuring the level of MB degradation by UV spectroscopy. Results show that the presence of amorphous phase has a considerable effect on the photocatalytic performance of magnesium aluminate. Furthermore, graphene oxide nanosheets play an important role in the improvement of photocatalytic activity. Synthesis of composite by addition of graphene to the precursor, in the hydrolysis step of sol-gel combustion method, yields significantly superior photocatalytic activity compared to those synthesized by other two methods, so that 79% and 98% of methylene blue elimination could be achieved under 180 minutes of lamp and sun light irradiation, respectively.

Photophysics of nano-micelles containing crystal violet dye using water-in-oil microemulsion at molar ratio of water- to-surfactant of 10 (W = 10) and different values of mass fraction of water nano-droplets (MFD) by means of spectroscopy was studied. Spectroscopy results showed that in 0.002 concentrations of crystal violet within the microemulsion system, the absorption spectrum of dye was deviated from the Beer's law. The fluorescence emission intensity of the dye at high concentrations of the molecules dye within the AOT microemulsion decreased. The Stokes shift of dye at 0.002 concentrations within the AOT nano-droplet decreased and at 0.00003125 concentrations, behavior of fluorescence was not regular. The polarity parameter (ET(30)) for dye molecules at high concentrations often  indicated a decrease, while in lower concentrations of dye, it generally remained constant. The ratio of the dipole moment ground state to the excited state of dye at high concentration decreased but for the low concentration, it often increased.

Nowadays, considering the quality of Iran handmade carpet and the economic importance of this industry, there is a growing need for research on the application of nanoparticles on natural fibers and the improvement of its physical and dyeing properties. In this study, firstly, woolen yarns were mordanted with alum and acetic acid, and then dyed with weld natural dye. After dyeing, carpet was woven and it was treatment in three stages with three types of Nano-silver, Nano-titanium dioxide and Nano-alumina oxide. Then, morphologic properties, color values and color strength of samples, self-cleaning, moisture absorption time, contact angle, deodorizing properties, chemical and anti-bacterial activities of samples have been investigated. The results showed that the hydrophilic properties and redness and brightness values of samples is improved. Also, color strength of samples was reduced. Evaluation of the deodorizing properties of the samples after finishing treatment was suitable. Moreover, the antimicrobial properties of the specimens against E. coli and S. aureus microbes were very good.

In this work, imidazoles derivatives as luminescent materials have been investigated. In continuation, light-emitting diodes (OLEDs) were prepared using these compounds in a guest environment containing PVK as a hole transport material and PBD as an electron transport material. A device with the structure of ITO/PEDOT:PSS (60 nm)/PVK:PBD:‌‌ Guest (80 nm)/Al (180 nm) was fabricated. The electroluminescence spectrum of device red-shifted respect in PVK:PBD. The overlap between the absorption spectrum of the imidazoles and the emission spectrum of PVK:PBD caused a redshift. By variation of functional groups on these compounds, a shift in wavelength toke placed in the electroluminescence spectrum. By mixing imidazoles derivatives, a white light-emitting devices was prepared. This happened due to the rare electroplex phenomena in the emitting layer.

In this research, black painted colorant of 13 mina'i ceramic (a kind of medieval Persian Islamic dynasty polychrome overglaze painting ceramic) shards from national museum in Iran and excavated shards from Rayy historical region and Alamut castle are considered. This paper focuses on black color to identify process, chemical composition, microstructure and layers based on experimental observations, modern technological studies and famous historical document (Abu’l Qasim’s treatise). Using SEM-EDS and MICRO-PIXE, the chemical composition and microstructure were investigated to characterize and identify the black colorants. The analytical and optical findings of this study points towards that while the majority of these shards featured three of black colors under a transparent glaze, ten of them are opacified and have overglaze decoration. Results indicate that chrome, iron, magnesia base color glazed for black has been applied to decoration and surrounded line over and under the areas. The results of this research confirms the ancient treatise information. Chromite (Muzarrad) and black haematite or magnetite, as black pigments, are observed in the shards.

The measurement geometry affects the results of the instrumental assessment of the color and appearance of objects. In the present study, the results of property measurement of different eight-glossy white samples and six-glossy color Munsell were considered with two variant forms of the geometries, i.e., 45°a:0° and di:8°. The color coordinates with the CIE whiteness index and tint were evaluated. These results shown for the glossy color Munsell samples; there is an average of 10 units of DE*ab in CIELAB color space between di:8° and 45°a:0° geometry, which can sometimes reach to about 15 units. For the glossy white samples, although the specular component was removed at 45°a:0° measuring results from the reflectance data, the lightness, hue, and chroma attributes did not show noticeable change. Therefore, an average of 0.88 units of DE*ab between two measurement geometry on glossy white samples proved the results of measuring could be, to some extent, device-geometry independent.