نشریه مطالعات در دنیای رنگ
سال چهاردهم شماره 1 (پیاپی 52، بهار 1403)

Dyeing wastewater is one of the most important environmental problems in the textile industry. This wastewater contains harmful pollutants that can damage human health and the environment. Electrocoagulation (EC) is a promising technology for dyeing wastewater treatment. This technology passes an electric current through the wastewater, which generates metal hydroxides that act as coagulants to remove pollutants. This article first introduces the EC system and its operation mechanism, then discusses the components that affect the system's performance in removing dye and chemical oxygen demand. The article also summarizes the studies that have been conducted on the use of this process in the treatment of textile dyeing wastewater. In addition, the economic aspects of the EC process and recommendations for its improvement are provided. Finally, the challenges and prospects of the process are discussed. This article provides an effective overview of the current advances and achievements in the EC process for dyeing wastewater treatment, which provides new insights into improving dyeing wastewater treatment with promising environmental applications.

Considering the importance of orpiment pigment in Persian Art, this research investigates yellow pigment derived from the orpiment mines in Tekab City, West Azerbaijan province. In this regard, spectroscopy and Microscopy methods were used to examine the pigments and colors made from them based on different treatises such as "Haliya al-Katab", "ink and Bookbinding", and also "Ink and Calligraphy". The results of Raman spectroscopy showed that Arabic gum and sesame oil did not interfere significantly with the pigment spectrum, making orpiment identification possible using this method. PLM also greatly assists in identifying orpiment based on its crystallographic features. SEM-EDX examinations also showed arsenic and sulfur content of 29.09% and 49.82% (wt%) in this pigment. Furthermore, FTIR spectroscopy results showed that the overall spectroscopic characteristics of orpiment were better preserved in combination with oil than gum. However, due to the absence of the absorption band of this pigment in the mid-infrared region, it is not a suitable method for identifying orpiment, but it can be used to identify the binder.

Colour studies in Iran have received the most attention, based on the ideas of western theorists such as Itten and Mansell, relying on human visual perceptions of color. In contrast, the cultural nature of colour has received less attention, resulting in the elements of colour beauty being neglected from the perspective of the local community. Therefore, in this research, we decided to answer this question with a field study with an aesthetic approach among the Tekke Turkmen tribe: what components affect the local aesthetics of color in the traditional self-decoration of the Tekke Turkmen tribe of Dovidukh village? This analytical-descriptive research has been conducted with a qualitative approach focusing on beauty in traditional self-decoration paint based on written sources and ethnography in the field. The findings of this research show that color is one of the distinguishing characteristics of these people in self-decoration, especially traditional. It is one of the most important cultural codes of this community, which expresses identity (individual/ethnic/social), emotional (sadness and happiness) and religious (reward). /age, guardians of religion, sanctity and transcendence). Also, in the opinion of these people, the main and secondary colors are defined by belonging or not belonging to an ethnic group, and in the belief of the people, preserving the historical power of this people has a direct relationship with the preservation of cultural codes, especially in the area of self-decoration.

This research aims to investigate the separation of dyes by using the combination of enzyme-containing organometallic nanostructure resulting from the enzymatic layering process on the organometallic compound. For this purpose, 15 experiments were designed with the surface response method (RSM) and using the Central Composite design by Design Expert 7.0.0 Trial software and three factors of time, amount of adsorbent and solution concentration at three levels (+1 , 0, -1) was selected. In each test, a specific amount of absorbent was placed in 10 ml of 6-cation green color solution, and the amount of color removal was measured. The bioactive nanoabsorbent has a porosity of 30 Angstroms and a specific surface area of 2500 g/m2. Instrumental methods investigated the physical properties of prepared nanoparticles. The conditions of the tests included contact time (5-60 minutes), amount of absorbent (1-5 g/l), dye concentration (up to 1000 g/l) and different pH. The electron microscope image confirmed the nanostructure of the adsorbent. The maximum dye removal was determined with the amount of enzyme nanoabsorbent at five mg/L and a contact time of 45 minutes.

One crucial aspect of object quality control involves assessing their visual properties. Objects possess three key properties that significantly contribute to their quality, beauty, and impressiveness. These properties can be primarily categorized into colorimetric characteristics and geometrical properties. Among these attributes, the gloss factor stands out as one of the most significant geometrical properties of surfaces. It profoundly impacts how people perceive an object's appearance, creating the impression of a bright and shiny surface. The evaluation of the gloss parameter holds great importance in quality control across various industries, including textiles, automotive, printing, packaging, and more. Numerous research studies have been conducted to harmonize the definition of the gloss concept, bridging the gap between instrumental measurement and human visual perception. The ultimate objective of these studies is to develop descriptive models that accurately quantify gloss and align with the results of human visual perception. This paper provides a comprehensive description and definition of the various perceptual aspects of gloss, highlighting its significance in diverse industries. Additionally, it reviews research carried out in the field, focusing on different evaluation methods and the quantification of gloss.

Tannins are natural biocompatible compounds and are abundantly available in plant sources. Tannins have a polyphenolic structure similar to chemical phenols. Various methods have been reported for the extraction of tannins, and the solid-liquid method with the use of water as a solvent is very common. Tannins also have antioxidant properties, and their health and medical applications are related to this property. The common uses of tannins are leather tanning, livestock and fishery feed, beverage production and wood glue preparation. Nowadays, due to the structure of polyphenol tannins and attention to environmental issues, studies are being conducted to develop its applications. Some of the emerging applications of tannins are corrosion inhibitors, improving the properties of dyed fibers, wood protective coatings, preparation of polyurethane resins, etc. This article introduces tannin, extraction methods, and the most important uses of tannins, as well as the latest published research. In the end, cost and commercialization limitations are examined.