نشریه علوم و فناوری رنگ
سال شانزدهم شماره 4 (پیاپی 62، زمستان 1401)

In the present study, the polyester-viscose fabric was dyed with dispersed dye and then reactive dye in the presence of β-cyclodextrin. The object of this study was to investigate the effect of β-cyclodextrin as an auxiliary and substitute for a commonly commercial dispersing agent on the dye-reactive dyeing of polyester-viscose fabric and its properties. Color strength was evaluated using tristimulus colorimetry. The results showed that β-cyclodextrin could be used satisfactorily as an additive in the dispersed dyebath without adding other auxiliaries. Also, the use of β -cyclodextrin, in comparison with the dispersing agent, improves the color strength of the samples (K/S) without loss in dyeing quality as dyeing uniformity and the fastness properties such as washing, light, and rubbing fastness.

Calix [4] resorcinarene belongs to the calixarenes group. Calix is synthesized via a condensation reaction of resorcinol and aldehydes in acidic conditions. These compounds can be suitable hosts for cations, anions, or neutral molecules. Selective absorption can be created in them by modifying and creating side groups. This research decided to study the optimal conditions for the absorption of cationic blue 41 dye by modified calix[4] resorcinarene oligomer. The optimal conditions were determined using the response surface methodology with three variables: adsorbent amount, time, and pH. The results showed that in the adsorption of dye by modified calix[4], resorcinarene oligomer is the most positive linear effect related to the adsorbent, followed by the time of adsorption process; however, pH has little effect. Also, for more than 61 % absorption, 3.9 % by weight of the adsorbent is required in 180 minutes or 5 % by weight in 127 minutes. Also, with the obtained contour diagram, the adsorption efficiency can be predicted with the amount of adsorbent and time.

This research aims to prepare a hybrid nanostructure including multi-layered graphene oxide and talc (MLGO/Talc) with hydrophobicity to obtain a corrosion-resistant epoxy coating with high adhesion to the steel substrate in low weight percentages. This coating was subjected to a detailed and long-term corrosion study. Three epoxy coatings containing 0.5, 1.5 and 1.5 wt. % of MLGO/Talc were prepared and analyzed using a salt spray, electrochemical impedance spectroscopy, polarization, contact angle, Fourier transform infrared spectroscopy, Atomic force microscopy, and Thermogravimetric analysis. Their analysis showed that the highest corrosion resistance performance is obtained in the presence of 1 wt. % of MLGO / Talc. Based on the water contact angle test, the contact angle value of 94.03 in this nano-coating indicates a hydrophobic property. Also, after 10 months of immersion in sodium chloride solution, 3.5 % by weight, the impedance resistance of the nano-coating was more than 108 Ω cm2, which indicates the high corrosion protection efficiency of this nano-coating.

Crystal violet dye removal was investigated using activated carbon adsorbent prepared from oleaster peel and seed. The effects of the various parameters were examined, including the adsorbent dosage, the contact time, the initial dye concentration, pH, and temperature. The results showed that the maximum dye removal capacity occurred at a contact time of 45 minutes, pH=8, ambient temperature, the dose of 1 g/L, and initial dye concentration of 50 ppm for the adsorbent prepared from oleaster seed and the dose of 1.5 g/L and initial dye concentration of 30 ppm for the adsorbent prepared from oleaster peel. Under optimal conditions, the crystal violet dye removal efficiencies were obtained as 98.67 % and 96.22 % for adsorbents prepared from seed and peel, respectively. The maximum adsorption capacity for adsorbents prepared from oleaster seed and peel was 89.2 and 44.8 mg/g, respectively. The experimental results were in good agreement with the Langmuir isotherm. Moreover, it was found that the crystal violet dye removal followed the pseudo-second-order kinetic model as a spontaneous process.

This research aims to evaluate consolidation using nanoparticles in historical and cultural stones. This, due to its different intrinsic properties, has become a serious and needed field in most areas. The tested stone samples belong to the dadu of Sheikh Haidar tomb tower in the meshkinshahr-Ardabil province. that is related to the Middle Ages of the Islamic period. During the research, petrography, XRD and XRF were performed to identify the bedrock, and the type of stone was identified in the calcareous carbonate category, and then to identify and evaluate the effectiveness of nanomaterials, physical resistance, aging and durability tests were performed. The final result showed that, contrary to the notion of nanoparticles, it did not enter the depth of the studied samples and only strengthened the surface of the stones, as a result of which, the stone surface was separated as integrated plates and the core was not consolidated. It went through aging cycles. However, in the persistence cycle, the treated sample had more resistance than the untreated one, which indicated an increase in its physical resistance.

This study used aromatic amines 4-aminoacetanilide, 4-ethyl aniline, 4-butyl aniline, 4-acetyl aniline, and 4-nitro aniline were diazotized using sodium nitride in the presence of hydrochloric acid at 0-5 °C and coupled with 4-amino coumarin to afford five corresponding aryl-azo dyes. The precise structures of the synthesized dyes were determined by using Fourier Transform Infrared (FTIR), proton nuclear magnetic resonance (1H NMR), and carbon nuclear magnetic resonance (13C NMR) spectroscopic techniques. The findings showed that all the dyes have hydrazone tautomeric structures exclusively among the suggested azo and hydrazone structures. Also, there is no evidence for the azo tautomer. In addition, the mass spectrum (MS) of the obtained dyes was recorded and confirmed the proposed structures. The solvatochromic behavior of the dyes was also evaluated in acetic acid, ethanol, chloroform, acetonitrile, dimethyl formamide, and dimethyl sulfoxide. The absorption changes were discussed according to possible electronic transitions in the compounds.

In this research, the first layered double hydroxide Ni /Al was synthesized by co -precipitation method, and then it was used to remove tartrazine dye from an aqueous solution. The synthesized adsorbent was characterized by X-ray diffraction and a scanning electron microscope. Initial concentration, contact time, pH, the dose of adsorbent and temperature were optimized in this adsorption process. The dye removal percentage and maximum adsorption capacity were 98 % and 3333.33 mg.g-1, respectively. The results showed that the adsorption kinetics follow pseudo - first - order model. According to thermodynamic results, the process of dye removal by synthesized adsorbent is exothermic, spontaneous, and accompanied by decreasing irregularity. This research showed that layered double hydroxide Ni - Al could be an efficient adsorbent for tartrazine removal from an aqueous solution.