نشریه علوم و فناوری رنگ
سال دهم شماره 1 (پیاپی 35، بهار 1395)

In this research, graphene oxide nanosheets (GO) was synthesized via oxidation of graphite by Hummers method and it was used for the removal of Direct Yellow 50 (DY50) from aqueous solution. The chemical and crystalline structures of the adsorbent were studied along with influencing parameters (pH, temperature, contact time, adsorbent dosage, and initial dye concentration) on the adsorption process. The results showed that the uptake of DY50 onto GO surface is favored at lower pH values of solution, low temperatures, and higher dye concentrations. The pseudo-first order, pseudo- second order, intraparticle diffusion, Elovich, and fractional power kinetic models have been developed to predict the rate constants of adsorption and equilibrium capacity by non-linear method. Equilibrium adsorption data well fitted with pseudo-first-order kinetic model.

In this study, TiO2-graphene oxide composites with different weight ratio of Titanium (ІV) butoxide /Graphene Oxide were synthesized by sol-gel method. The products were characterized by X‐ray diffraction method and UV-Vis spectrophotometer. The TiO2-graphene oxide composites possessed a large adsorption capacity for methylene blue and extended light absorption range in comparison to the pure TiO2. Evaluation of non-linear adsorption isotherm models including Langmuir and Freundlich suggests that adsorption data can be well described by Freundlich isotherm models. Adsorption of methylene blue on the surface of composite is chemisorption.

In the present work, in order to decrease the calcination temperature and appraisal of mineralizer effect on final color properties of Hematite-Zircon pigment, the effect of NaF on pigment properties investigated. Mineralizer with 0.2 mole content added to pigment in solution preparation stage. The products of the sol-gel reaction with and without mineralizer were calcinated in different temperature from 650 to 1200°C. The structural, morphological and color characteristics of samples were determined by XRD, SEM, FTIR, STA and CIELab spectroscopy investigations. The results indicate that decrease of heat-treatment temperature with NaF mineralizer addition, despite the fact that addition of mineralizer do not have appropriate effect on color properties of pigment. The mineralizer with increasing the particle size of hematite have a negative effect on the pigment properties.

In this research polyaniline/Graphene nano-compoite has been prepared through in situ polymerization and was used as a photocatalist to degrade acid red 14 dye under visible light irradiation. SEM and XRD tests were used to characterize the morphological properties of nano-composite. The effect of different parameters such as initial dye concentration, nano-composite dosage, pH and temperature on the activity of the nano-composite towards the degradation process was investigated. The optimum efficiency of 98 percent and breaking of the main bonds of dye molecule was happened under dye concentration of 80 mg/L, PANI/Gr dosage of 0.6 gr/L, pH=7 and T= 25 oC after 150 min irradiation time. Over 95 percent of COD was also removed after 300 minutes.

Low quality current inks cause serious damages to valuable works of calligraphist after a while. Therefore, preventive protection of calligraphic works is of importance and it is essential to protect such works. Since former researches that have been done in this field did not reveal hidden aspects of ink construction, it seems necessary to do more investigation in this respect. The present study tried to investigate the impact of additive honey on Iranian traditional ink through (chemical and physical) laboratory techniques, and to answer questions such as how does additive honey affect calligraphy ink? Especially how does quantity of honey affects inks quality? And also what visual differences can be seen between honey-binder ink, gum Arabic binder ink and gum Arabic plus honey binder ink? In this study, after producing three samples of black ink using old books, according to the standards artificially accelerated aging including light, mold, and temperature tests were done on the samples. Then, pH and color of the samples were measured using a pH-meter and a colorimeter. After chemical examinations, the physical properties of samples, including viscosity, coverage and glossoness had been evaluated. The results showed that adding honey, not only increases the durability of ink, but also prevent it from fading, bleeding and even prevent the corrosion of the paper during the time. Additionally, a binder made up of proper proportion of honey and gum Arabic, improves glossiness and coverage of the ink on the paper surface.

This research aims to complete previous studies on advantages of stained glass used in traditional Persian architecture. A research method combined of laboratory measurements, field surveys and numerical calculations was employed. Firstly, spectral transmittance of glazing samples were measured by spectrophotometer. Next, percentage of using each glass in each Orosi window were specified by field surveys; ultimately, the solar transmittance factors of each Orosi window were quantified based on the optical characteristics of individual glass samples, and percentage of using each of them in the Orosi window. The results indicated that although Orosi windows decrease transmission of visible light, but they reduce transmission of wavelengths harmful to human skin and damaging for materials, more than the reduction of visible light transmittance.

Synthetic dyes are being employed by industries, especially by textile industries. About 10 to 15 percent of synthetic dyes are wasted during dying process and enter industrial wastewaters as toxic and harmful pollutants. These kind of dyes are not only a threat to water resources, soil and atmosphere, but also cause serious problems for living organisms particularly humans in the ecosystem. Therefore, removing them from environment is imperative. Various physical and chemical methods for textile dyes degradation from wastewaters have been developed but they are extremely costly. In recent years, biodegradation approach because of its cost-effectiveness and safety has been used as an alternative and safe method. In this method, microorganisms, particularly bacteria are used for removing dyes. In this study, however, we used Acinetobacter lwoffii bacteria. Decolorization by these bacteria was investigated by a system which contained both medium and dye. Furthermore, decolorization optimizing parameters of Indigo carmine including time, initial dye concentration, pH and temperature were investigated. The results demonstrated that over a period of 54 h, at 50 ° C, 150 mg/l of concentration and pH=9, maximum decolorization of 99.02 percent was performed.