Functionalization of Polycarbonate Membranes with Anionic Azo Dyes

Annually, nearly 300,000 of the 7 × 10⁵ metric tons of synthetic textile dyes produced are discharged into the environment causing devastating effects to the surrounding ecosystem. Recent research shows that polycarbonate filters functionalized with anionic azo dyes have the potential to reject charged based dyes in solution. This azo-dye-functionalization of the polycarbonate filter provides an elegant solution to water pollution by textile dyes, demonstrating that the textile dyes, thus the contaminants themselves, are part of the solution to the problem. In this work, a series of nine azo dyes at 1000µM with a fixed intrinsic charge of negative two was studied. Each dye had differing chemical structures and functional end groups. Rejection as a function of time data illustrates a large variance in the initial functionalization rates is present, ranging from (0.14 – 3.74) % rejection per minute, demonstrating chemical structure plays an important role in the functionalization process. Direct red 37 and direct red 28 have been shown to have the highest potential as functionalizing dyes with the largest rate of functionalization rates of 3.68 %/min and 3.74%/min, respectively and each reaching maximum rejection values of 66.6% and 73.3%, respectively in 120 minutes.