JOURNAL OF COLOR SCIENCE AND TECHNOLOGY
Year:2023 | Volume:17 | Issue:2|Papers Count:6

This paper used three magnetic adsorbents, including polyaniline@NiFe2O4, polyaniline@MgFe2O4, and polyaniline@MnFe2O4 to remove congo red dye. The synthesized nanocomposites were identified using SEM, XRD, EDX, and FT-IR methods. Then the factors affecting the removal efficiency of congo red were optimized for all three adsorbents. Under optimum conditions, the removal efficiencies of congo red from aqueous media by polyaniline@NiFe2O4, polyaniline@MgFe2O4, and polyaniline@MnFe2O4 were calculated as 92, 90 and 89 %, respectively. The reusability of the used nanocomposites was investigated, so 1 M HCl as a recovery agent could recover up to 4 times all three nanocomposites. The synthesized sorbents performed the removal of congo red from real samples, including well water and dyeing wastewater. The results showed that the matrix does not significantly affect the efficiency of the nanocomposites so that they could be used in real samples with complex matrices.

In recent years, the dyeing of textiles, especially the fibers used in handmade carpets, with natural colorant and mordant, has attracted the attention of researchers. Hibiscus sabdariffa L. is a rich source of natural colorant from the anthocyanin class. This research has studied silk fibers' color and fastness parameters with the dye extracted from Hibiscus sabdariffa calyces in the presence of different metallic and natural mordants with pre-, meta- and post-mordanting methods. Metal salts such as iron (II) sulfate, aluminum potassium sulfate, calcium lignosulfonate, and natural materials such as tannic acid and sodium alginate were used as mordants. The results indicate that the meta-mordanting method, sodium alginate (4.01), and calcium lignosulfonate (4.49) have created the highest color strength. Also, the post-mordanting method and tannic acid and calcium lignosulfonate mordants provide the best washing fastness (grade 5 on grayscale), and the post-mordanting method and sodium alginate and calcium lignosulfonate mordants provide the best light fastness (grade 5-6 in blue scale).

Geopolymeric membranes were prepared by activating metakaolin using sodium hydroxide and silica fume solutions. The membrane was characterized using X-ray diffraction, Scanning electron microscopy, Fourier transform infrared spectroscopy, mercury intrusion porosimetry, and energy dispersion spectroscopy. The geopolymeric membrane had a porosity percentage of 33.5 and an average pore size of 327.67 nm. The cationic dye methylene blue was removed by emulsion filtration using this membrane. The dye binds to sodium dodecyl sulfate (SDS) as an anionic surfactant and then dissolves in the oil phase of the emulsion. So the dye is extracted from the aqueous solution, and the microfiltration membrane removes the emulsion droplets. The Box-Behnken experimental design was used to optimize the membrane separation performance. Results showed that the permeability was 70.28 L/m2.h.bar under the optimized conditions and a dye removal efficiency of 98.45% was achieved at a feed flow rate of 1.5 l/min, an SDS content of 5.33 %, and a methylene Blue concentration of 100 ppm.

The extraction process is very important in separating and purifying dye components from the natural plants. Various extraction methods have been used to obtain valuable natural compounds. Compared to the traditional extraction method, each has advantages, including less solvent consumption, shorter time, and less environmental pollution. This research studied the effect of non-ionic surfactants at various initial concentrations in extracting natural colorants from madder, weld, and walnut. The results showed that using surfactants improved the amount of extracted colored compounds in the extraction process. The efficiency of the extraction process in the presence of each surfactant is diverse due to the different color compounds in each colorant used. The extraction process of weld natural dye has been improved by 60 % in the presence of Keol surfactant. Also, the color strength of dyed wool yarns in the presence of surfactants has increased by 30-44 % compared to the control dyed sample (without surfactants). The results of this research clearly show that it is possible to use non-ionic surfactants to improve the extraction efficiency, color strength, and better leveling of the natural dyes on the wool yarn.

In this study, graphene oxide is functionalized with benzidine and zinc oxide nanoparticles to improve adhesion and corrosion resistance properties. Nanoparticles were dispersed in an epoxy-based coating and applied as a coating on steel panels. The corrosion resistance of nano composite coatings was evaluated by salt spray test during 45 days of exposure. The results showed that the anti-corrosion performance of the coating containing 0.01% graphene oxide containing amine-zinc oxide with a penetration depth of 1.2 mm from scratch showed the highest corrosion resistance. The results of the salt spray and EIS tests show that with the increase of nanoparticles up to 0.01%, the anti-corrosion properties increased.

This study aims to synthesize a novel low-cost adsorbent in the form of film prepared by natural and available sources of elderberry kernel, with an easy preparation method and an efficiency higher than 90% in the adsorption of crystal violet dye. By investigating the effects of various parameters, including pH, adsorbent dose, temperature, contact time and dye initial concentration, the optimum conditions to reach the maximum adsorption were determined. Results showed that the maximum adsorption efficiency is 94.24 %, which is obtained under optimal conditions ofpH = 8, adsorbent dose 1 g/l, temperature 25 °C, contact time 90 min and dye initial concentration 10 mg/l. Isotherm and kinetic models reveal that the adsorption is physical and favourable, and equilibrium data are more compatible with Langmuir isotherm and pseudo-second-order kinetic models. The maximum adsorption capacity of adsorbent was calculated to be 30.30 mg/g. Thermodynamic investigation showed that the adsorption is spontaneous and exothermically. Desorption studies also stated that after several consecutive removal steps, the adsorption capacity is still favourable.