Ultrafiltration Of Oilywastewater By Electrospun Composite Membranes
Luciano Santillan, Texas Southern University, Benjamin Hsiao, and Kyunghwan Yoon, Department of Chemistry, Stony Brook University

A growing concern in today's society is the dramatic increase of water pollution. Large amounts of oily wastewater are generated daily by a variety of industrial sources which include factories, refineries, and large ships. A 300-Man Navy ship, for example, can produce as much as 6,000 gallons per day of oily wastewater alone. Ultrafiltration is increasingly being applied for the treatment of oily waste. It is a pressure-driven process that uses porous membranes for the separation of materials in the 1 nm to 50 ?m size range or compounds with molecular masses over 5000 Daltons. The membrane acts as a selective barrier allowing small molecules to pass through and rejecting larger macromolecules. The aim of the research is to produce a highly porous membrane that is able to get higher flux than commercial membranes with comparable oil rejection percent. The membrane used in this process is 3-layered made up of polyester, PAN (polyacrylonitrile), and chitosan. The PAN is electrospun onto the polyester commercial membrane support and later coated with chitosan. Electrospinning is a process used to produce a small diameter of fibers by applying electric fields to polymer solution. Chitosan coating is used for the top layer because chitosan is hydrophilic and has a good film-forming property. The chitosan layer acts as a hydrophilic surface reducing fouling and also gives a good mechanical property when coupled to PAN. Various surface densities of PAN nanofibrous membranes using 2 ~ 12 weight percent PAN solution were made by electrospinning onto the polyester membrane support. The chitosan layers were prepared by dip-coating technique using 0.5 ~ 1.7 weight percent chitosan solution. The filtration experiments were done by a cross-flow filtration apparatus. The pressure difference between inlet and outlet was used to calculate flux. This study was supported by a training grant from the Office of Naval Research (N000140310932).