Optimization of Semi-Permeable Conductive Carbon Nanotube-Polymer Thin Films
Authors:Alexander Dudchenko, Julianne Rolf, Kyle Russell
Mentor:David Jassby, Assistant Professor of Chemical & Environmental Engineering, University of California, Riverside
Membrane bio reactors (MBRs) are quickly becoming the treatment method of choice for wastewater treatment utilities and small-scale wastewater treatment operations. MBRs have a reduced physical footprint, produce higher effluent quality and allow for a greater degree of automation, making these systems preferable to conventional activated sludge wastewater treatment processes. Incorporating a membrane directly into the activated sludge process offers some significant advantages such as maintaining a higher microbial concentration and eliminating the need for a clarifier at the end of the wastewater treatment process. MBR performance is inhibited due to bio fouling, where bacteria irreversibly attach to the membrane surface. Air bubbling and turbulent flow are currently used to minimize the membrane fouling due to bacteria, but are very costly and cannot remove all of the bacteria from the surface. The application of an electrical potential has been shown to effectively inhibit biofilm formation. This technology can be applied to MBRs through the use of semi-permeable, electrically conductive thin films. Conductive thin films have been prepared from Poly(vinyl alcohol) (PVA) and functionalized multi-wall carbon nanotubes that were then deposited on industrial membrane supports using pressure deposition. The effect of various cross-linking agents, pH, and reaction temperatures on the strength and conductivity of the membranes was studied. Change in resistance was used as an indicator of membrane stability under various electrical fields and solutions through use of a model flow cell. Highly conductive and robust thin films were developed from this study that could potentially be used in MBRs in the future to eliminate the need for air bubbling and turbulent flow.