نشریه علوم و فناوری رنگ
سال هفدهم شماره 3 (پیاپی 65، پاییز 1402)

This paper investigates the curing behavior of epoxy acrylate/graphene oxide UV curable nanocomposite. Also, the simultaneous reduction of GO nanoplates during UV curing of nanocomposite containing type II photoinitiator was studied. Optical and transmission electron microscopies showed good GO nanoplate dispersion in UV curable matrix. Rheological results illustrate the shear thinning behavior of UV-curable nanocomposites so that in high shear rates, the viscosity of nanocomposite is lower than that of UV-curable matrix. Real-time FTIR analysis shows that GO causes a reduction in the curing rate and final conversion of the UV-curable system. However, gel content results show that more UV intensity and curing time led to perfect UV curing of the nanocomposite. An electrical resistance study on the UV-curable nanocomposites made GO reduction during UV irradiation, evidenced by halved electrical resistance of the nanocomposite in less than 150 seconds. 

Concrete is one of the essential materials in road and building construction. The use of colored concrete in urban design projects can play a significant role in making more elegant Iranian architecture and Urban projects. This research aims to make turquoise-coloured concrete for the construction of concrete sidewalks, and for this matter, the combination of two blue and green pigments was used in a ratio of 70 to 30 percent. Then, pigments in various weight ratios of 3, 5 and 7 % replaced a part of white cement in concrete. The tests performed in this research included slump, compressive strength, tensile strength, water absorption in hardened concrete and abrasion durability. Also, The behavior of colored concrete was evaluated and analyzed using the deviation indices from standard data and the economic index. The microstructure of concrete samples was also examined using the SEM method. The results of this research show that using turquoise composite pigments will reduce the resistance of concrete. Using 3, 5, and 7 % ratios of pigments in concrete causes a decrease of 7.6, 7.12, and 8.25 % of 28-day compressive strength and causes a decrease of 8.23, 9.42 and 59.5 % of the abrasion resistance of concrete. In conclusion, it is possible to use concrete with turquoise pigments to construct structures such as urban water fountains, urban statutes and city walls that perform environmental graphic functions .

In this research, zinc oxide (ZnO) nanorods were grown by chemical bath deposition method on two types of electrospun polyacrylonitrile (PAN) nanofibers for photocatalytic decomposition of methyl orange dye. Various structures of ZnO were investigated to achieve the maximum rate of photocatalytic degradation by adjusting the growth variables of nanorods, including growth time, concentration of growth solution, and growth substrate, using the design of Expert (DOE) technique. The X-ray diffraction (XRD) pattern of the sample confirmed the wurtzite crystal structure, and diffuse reflectance spectroscopy (DRS) analysis showed an energy gap of 3.2 eV for ZnO. Also, the optimized sample with a growth time of 10 hours and a concentration of 62.5 mM of zinc nitrate and hexamethylenetetramine (HMTA) showed a decomposition rate constant (k) of 0.0038 min-1</sup>. Flexibility, quick and convenient recovery of photocatalyst from treated wastewater, and easy and cheap synthesis method promise the operational applications of the synthesized samples.

This study prepared a suspension of cellulose nanofibers with a concentration of 1% by weight with water, and samples were immersed in the treatment material for 30, 60, 90, 120, 150, and 180 seconds. The effect of parameters such as colorimetric, pH, tensile strength and contact angle before and after ageing was performed. The results showed that after treatment, the color of the samples became lighter than the control sample without treatment. </strong>But ageing has reduced the brightness of the paper. The color of the treated samples was lighter for 150 and 180 seconds than the other samples. The pH of the samples increased after treatment. The highest pH was related to the sample treated for 150 seconds before and after ageing. The highest tensile strength was obtained before and after ageing by increasing the samples' immersion period for 150 and 180 seconds. The results of measuring the contact angle showed that the treatment of cellulose nanofibers had no effect on increasing the paper resistance to wetting and did not prevent the paper surface from getting wet.

Wastewater from textile factories is one of the most important sources of environmental pollution, so it is necessary to treat these wastewater. Therefore, the decomposition of colors using photocatalysts, which is one of the advanced oxidation processes, has been studied. The present work introduces the synthesis of the magnetic mixed metal oxide La2</sub>CoFe2</sub>O7</sub> (LCoFO) nanocomposite as an effective photocatalyst by co-precipitation method. The synthesized metal oxide was characterized by infrared spectroscopy (FT-IR), X-ray diffraction pattern (XRD) and transmission electron microscopy (TEM). The alternating force gradient magnetometer (AGFM) shows the magnetic behavior of the LCoFO nanocomposite. In this research, the photocatalytic properties of LCoFO nanocomposites using photolysis of methyl violet (MV), malachite green oxalate (MG), and eriochrome black T (EBT) were investigated under ultraviolet light irradiation in different parameters such as temperature, solution pH, dye concentration, catalyst amount, and UV radiation time. The results showed that these nanocomposites have good photocatalytic performance.

The removal of the azo dye carmoisine from a synthetic dye wastewater medium, which contained starch and had a similar composition to the effluent from the de-sizing stage, was investigated by Klebsiella quasipneumoniae GT7. The measurements of dye concentration by spectrophotometry and starch concentration by the Anthrone method revealed that the anaerobic process at a temperature of 30 °C and pH 7, with an initial concentration of 50 mg/l of carmoisine, resulted in a decrease of approximately 96 % in the initial dye concentration within 48h. This was accompanied by a decrease of approximately 30 to 35 % in the initial starch concentration (1870 mg/l). Thin layer chromatography (TLC) showed that the bacteria degraded the carmoisine dye, which was removed during the anaerobic process, into its constituent aromatic amines. The continuation of the process under aerobic conditions, with and without re-inoculation of bacteria at the beginning of the aerobic stage, revealed that until day 23, aromatic amine molecules were not degraded and there was no significant reduction in the amount of dye or starch remaining from the anaerobic stage.