نشریه مطالعات در دنیای رنگ
سال سیزدهم شماره 3 (پیاپی 50، پاییز 1402)

The current research uses silica nanoparticles produced from rice husk through conventional and sonochemical precipitation to treat industrial tannery wastewater. The effects of NaOH concentration, precipitation pH, and ageing time on adsorption properties were studied via the central composite design (CCD) method. The obtained results indicated that rice husk ash, as a precursor used in the preparation of silica, should be dissolved in the dilute NaOH solution, 0.5 mol L-1, and precipitation pH should be controlled at the level of 9.0 to achieve an adsorbent with proper performance. Although the surface area of powder produced conventionally is larger than that obtained by the sonochemical method, the pore size distribution plays an effective role in the adsorption of Cr III compounds. The precipitation under sonication leads to large pores distributed in the 4-38 nm range, facilitating the diffusion of chromium compounds even in acidic environments.</em>

In recent times, the growth of various industries has led to an increase in the generation of colored wastes and effluents. Dyes, in particular, are significant water pollutants that contribute to the production of colored effluents. Physical, chemical, and biological methods have been employed to treat and purify colored wastewater. With the progress of polymer science, the fabrication of diverse types of membranes for dye removal has increased based on the properties of different dyes. By manufacturing membranes in varying sizes, dyes can be eliminated from wastewater. In addition, the use of clay and metal-organic frameworks has facilitated the development of membranes for efficient dye purification and removal. This article discusses the production and application of different types of polymer membranes for the removal of dyes while introducing dyes</em>

One of the most important types of pottery of the early Islamic era in Iran is the Slip-painted ‎pottery that was developed and ‎expanded in Iran in the third and fourth AH, especially in the ‎Samanid period. In this research, to understand the techniques ‎of slip coating in this pottery and ‎to identify the chemical composition of slip and the pigments used in them, some historical ‎‎samples of Slip-painted pottery ‎found from Sistan were studied in various laboratory ‎methods, including microscopic study, ‎spot ‎test, and Analysis by XRD and SEM-EDS‎ method‎‎. These laboratory ‎studies showed that clay slurry mixed with Lead ‎compounds was used in the preparation of slip, and it was used for pottery motifs and paints spectrum from red to dark ‎brown from ocher clay containing iron oxide mixed with manganese oxide and for green color, the earthy green pigment. In ‎addition, it was found that according to the analysis of the mineralogical ‎composition of the pottery bodies, they were fired ‎at a temperature of 850-900 degrees Celsius</em>.

Textile and dyeing industries have made significant progress in recent years, and a large amount of dyes are consumed by these industries. The poor stabilization of dyes leads to the entry of large amounts of them into wastewater. Between different processes for dyeing wastewater treatment, anaerobic treatment is considered an efficient method. Among the anaerobic processes, upflow anaerobic sludge blanket reactor (UASB) is very popular due to its high efficiency in removing dyes, chemical oxygen demand, and other pollutants in textile wastewater, as well as the ability to combine with other textile wastewater treatment methods to improve the quality of the effluent. This study investigates the performance of UASB reactor in dyeing wastewater treatment, dye removal mechanism, and operational parameters. Then, a review of the studies conducted in this field is conducted. Finally, the challenges and prospects ahead are stated. The results and achievements of UASB systems presented in this study can provide new insights into improving UASB performance in dye wastewater treatment with an environmental perspective.

Handmade carpets, whose design, pattern, colors, and textile structure express Iranian artistic identity and culture, are also considered a strategic economic product for job creation and currency exchange. The purpose of this research is to study and understand the strengths and opportunities in the use of dyes and appropriate and green dyeing methods in the preparation of raw materials, color scheme, and composition and to identify and analyze the weaknesses and threats due to the poor quality of the visual appearance in the Iranian handmade carpet trade and providing creative strategies to increase its competitiveness, sales, and export. The analytical process of SWOT matrix analysis was used to maximize strengths and opportunities and minimize weaknesses and threats. The data collection tool was a questionnaire completed using the Delphi method in a statistical community of 46 related experts, and their data were analyzed. The results indicate the necessity of following the conservative strategy of preserving and maintaining the strengths and taking advantage of the opportunities for the development of the business of this product in today's market conditions. Among the creative strategies for developing this product is branding and using the knowledge of modern marketing and e-commerce with the key points of the green product and, of course, the guarantee of its appearance quality and longevity.

Different graphene oxides (GO) (GO1.5, GO3, GO4.5, and GO6) were synthesized and characterized. Cationic dyes, including Methylene Blue (MB) and Crystal Violet (CV) were used as organic pollutants. The amount of dye adsorbed on the synthesized adsorbents increases by increasing the contaminant concentration. The results indicated that contaminant adsorption capacity is enhanced by enhancing the adsorbent dose and then decreases to some extent. As the adsorbent dose increases, the active sites will be more accessible. The adsorbent particles are agglomerated at values ​​higher than the optimal value of the absorbent. Thus, the amount of dye removal is reduced. The adsorption thermodynamic data presented that the negative ΔG of CV and MB removal by the synthesized adsorbents presented physical and spontaneous adsorption. Also, the positive values of ΔH and ΔS showed the endothermic properties of adsorption and the increase of dye irregularity on the adsorbent surface. The isotherm data indicated that MB and CV removal obeyed the Langmuir isotherm model. It means the adsorption process was carried out in specific homogeneous areas of the adsorbent. The results showed that MB and CV adsorption followed PSO kinetic.