نشریه علوم و فناوری رنگ
سال هفدهم شماره 4 (پیاپی 66، زمستان 1402)

The color sensitivity of the dyeing recipe is one of the most important parameters for controlling the dyeing process. This work studied the effect of color depth on the color sensitivity of a recipe of wool dyeing with weld natural dye. For this purpose, the woollen yarn was dyed with weld at low and high color depth using pre-mordanting method. The color sensitivity of the dyeing recipe was evaluated by measuring the color depth (K/S), color difference, and color sensitivity coefficient. The color sensitivity coefficient was measured by 10 % change in parameters of the dyeing recipe, such as dye concentration, mordant concentration, temperature, time, pH, and L.R. Also, the simultaneous color sensitivity of two, three, four, five, and six parameter combinations were measured by experimental and computational methods. The measured color sensitivity by the computational method was higher than the experimental method. In general, the color sensitivity at low color depth is more than high color depth.

In this study, to remove the acidic blue 92 during the heterogeneous electro-fenton process, the electrospinning method produced a nanofiber layer and used it as the cathode. Polyaniline/nylon66 nanofiber (PANI/PA66) was produced by the electrospinning method to produce such a nanofibrous electrode. Reduced graphene oxide nanoparticles were added to the polymeric solution to improve the conductivity of the nanofibrous electrode and the dye removal percentage. Magnetic iron nanoparticles were also used as fenton catalysts (PANI/PA66/rGO/Fe3O4). The optimal electrospinning conditions were determined by response surface methodology. Electro fenton process for dye removal was carried out in a two-electrode system using PANI/PA 66 / rGO 6 % / Fe3O4 as a cathode in 120 minutes, and the highest dye removal percentage achieved was 91.78 %. Also, the effect of selecting essential parameters on the dye removal efficiency, such as pH, initial dye concentration, and Fe3O4 dosage, was investigated.

This study investigated the adsorption of crystal violet by magnetic active carbon adsorbent synthesized from the abundant and low-cost Oleaster source. Carbon charcoal was first prepared from the seed and peal of Oleaster, and two different acidic and basic activating agents were used to activate it. Activated carbon synthesized under optimal conditions (using Oleaster seed and acidic activator) was modified by placing iron oxide nanoparticles on the surface. Effects of various parameters, including pH, adsorbent dose, contact time, temperature, and dye concentration, on the adsorption process of crystal violet were investigated. The maximum adsorption capacity was obtained as 91.7431 mg/g under pH=8, adsorbent dose 0.5 g/l, time 30 min, temperature 25 oC, and initial concentration 10 mg/l. Examining isotherms and adsorption kinetics showed a better data fit with Langmuir isotherm and second-order kinetics. Thermodynamic investigation indicated the physical and exothermic nature of adsorption and spontaneous degree reduction at high temperatures. The adsorbent regeneration tests confirmed its high ability to be reused during consecutive cycles.

This study used thermochemical and Fe particle co-precipitation methods to prepare a magnetic-activated carbon composite. The hard nutshell of Baneh from the Oraman region of Kurdistan province was used as raw material. The structural properties of the prepared adsorbent were investigated using SEM, FT-IR, EDAX, BET, and VSM analysis methods. The SEM images clearly showed the formation of a porous adsorbent with porosity in the range of micro- and mesopores. The results of the FT-IR and EDAX analyses proved the presence of Fe in the absorbent structure. The specific surface area of the adsorbent before and after the deposition of iron particles was determined to be 229.6 and 179.37 m2/g, respectively. Under the optimized conditions, the removal amount of the investigated dyes from the model solutions was 91.2 and 98.6 % for acid blue 113 and acid orange 10, respectively. The kinetic study revealed that the pseudo-second-order model best fits the obtained adsorption data. In addition, the Freundlich model was the best model to describe the adsorption process.

Considering the development of cosmetic products in Iran, the presence of heavy metals directly and indirectly (in the form of an organometallic color), side effects (skin allergies) and the risk of being carcinogenic have caused these colors to be considered and investigated by researchers. The purpose of this study, which was conducted by randomly selecting five Iranian brands in Tehran, is to determine the amount of heavy metals in the mentioned samples. This study was conducted on 20 samples from 4 brands and 5 types of selected products produced in the country. The concentration of heavy metals (lead, nickel, chromium, arsenic, mercury and cadmium) was measured using induced mass (ICP MASS) after performing the steps of acid digestion by plasma spectrometry. Statistical analysis was performed on the measured values, and the results showed that the concentration of heavy metals in 20 samples measured with three repetitions was less than 10 ppm and within the permissible limit. But the pollution level of brands is significantly different. Health risk assessment in exposure to heavy metals in terms of carcinogenicity and non-carcinogenicity was investigated in lipstick samples. The results showed that the risk of skin carcinogenesis through repeated use over time is serious and cannot be ignored.

This research aims to synthesize a novel adsorbent and reduce the contact time in removing methylene blue dye. Copper ferrite nanoparticles were prepared by solvothermal method and CuFe2O4/PVA/AG magnetic nanocomposite by freeze-thaw method and drying at room temperature. The structure and morphology of magnetic nanocomposite were investigated using FTIR, XRD, SEM, and EDX methods. CuFe2O4/PVA/AG adsorbent under optimal conditions of pH = 7, contact time 60 min, amount of adsorbent 40 mg, dye concentration 5ppm and temperature 25 ᵒC was investigated. The maximum absorption and absorption capacity were obtained as 81.1 % and 14.93 mg/g, respectively. In addition to investigating the recovery effect of the adsorbent for comparison, the PVA/AG adsorbent was investigated under the aforementioned optimal conditions, and the maximum removal efficiency was 63.5 %. Examining the isotherm of the equilibrium state of dye removal matches well with the Freundlich isotherm. The kinetics of surface adsorption were investigated, and observed that the adsorption process on the magnetic nanocomposite follows pseudo-second-order kinetic equations.