Removal of dyestuff from aqueous solution by using the dispersive liquid liquid micro extraction method

With the rapid development of the industry, the production of waste water containing dyestuffs has increased over time. Dyestuff wastewater originates from a wide variety of industrial establishments. The dye and textile industries are the leading industries that produce and consume a significant amount of wastewater that pollutes water resources. Waste water emitted from these sources is one of the factors that cause environmental pollution the most. Dyestuff compositions are complex, difficult to biodegrade, and are toxic to the natural environment and human health. For this reason, it is of great importance to remove dyes from wastewater. In this thesis, some dyestuffs (Acid Blue 25, Chicago Sky Blue, Direct Blue 71, Direct Red 23, Direct Viola 51, Methylene Blue, Methyl Orange, Naphthol Blue Black, Reactive Black 5 and Rhodamine B) are based on calixarene. The extraction was carried out by Dispersive Liquid-Liquid Microextraction (DLLME) method with extractants. For this purpose, calix[4]arene derivatives containing ester, acid and amide groups to be used as extractants were synthesized according to the methods of the relevant literature. The structures of the synthesized calix[4]arene derivatives were characterized by FT-IR and 1H-NMR methods. Then, these compounds were used as extractants for the extraction of dyestuffs selected by DLLME method. Preliminary studies showed that calixarene-based extractants used were effective for Acid Blue 25 (AB25) dyestuff. Therefore, subsequent studies were carried out with AB25 dyestuff. For this purpose, some important parameters such as the most efficient pH value, type and volume of extraction solvent, type and volume of dispersant solvent, salt effect on extraction and dyestuff concentration were investigated in detail. The most suitable extractant for AB25 was determined as compound 6, a calix[4]arene derivative containing tetraimidazolyl amide group in its structure. As the optimum microextraction parameters; pH value, 6; extraction solvent, chloroform; extraction solvent volume, 200 µL; dispersant solvent, acetonitrile; dispersant solvent volume, 0.1 mL; dye concentration was determined as 10 ppm. When the effect of salt on the extraction yield was examined, no significant change was observed, but the highest removal was achieved when 40 mg of salt was used in 10 mL of dye solution.