Azo Dye Functionalization of Polycarbonate Membranes for Molecular Dye Removal

Negatively charged contaminants enter our global freshwater reserves from a variety of sources including the agriculture, textile, and pharmaceutical industries. Molecular azo dyes are used heavily in the World's growing textile industry, which contributes to roughly one-fifth of the industrial water pollution. In aqueous solutions, azo dye compounds dissociate into positive sodium ions and a negatively charged dye molecule. The research presented illustrates that polycarbonate filtration membranes with 100 nanometer diameter holes functionalized with azo dye molecules can successfully remove the negatively charged azo dye components from water. Rejection measurements are made using Ultra Violet Visible light Spectroscopy on the pre and post filtered solution. The rejection and flowrate response of three filters functionalized using three separate azo dyes, each with a different intrinsic ionic charge will be presented. The rejections at 50 \textmu M are on par with polycarbonate filters functionalized with self-assembled gold nanoparticle membranes; however, the azo dye functionalized membranes at this concentration have an order of magnitude higher flow rate under the same testing conditions.