KSEF R&D Excellence: Adsorption and Recovery of Dilute Fluorinated Surfactants for Nonaqueoys Cleaning Applications

Nontraditional cleaning processes based on chemically inert solvents have the potential to significantly reduce the energy consumption and environmental impact of traditional aqueousbased cleaning. However. surfactants are necessary to achieve cleaning in inert nonaqueous systems, such as fluorinated solvents. Fluorinated surfactants may be used to increase the detergency for both hydrophobic and hydrophilic species and to disperse particulate soils. The cost of fluorinated surfactants requires their removal from the solid surfaces and recovery from the nontraditional cleaning fluid. Approaches to recovering the fluorinated surfactants from the bulk cleaning solutions. such as the use of solid adsorbents. also involve solid surfaces that will need to be regenerated by removing the surfactant. Thus. knowledge of the self-assembly behavior of surfactants at liquid-solid interfaces is critical to the development of nontraditional cleaning processes. The goal of this research is to design fluorinated surfactant/solvent systems for surfactant-based cleaning and recovery from solid surfaces. This goal will be achieved by determining the bulk adsorption and residual fluorinated surfactants on planar surfaces and fibers as a function of nature of the surface. surfactant concentration. and solvent system. These macroscopic results will be interpreted v..iththe help of micro-scale experiments capable of measuring the extent and structureof surfactant aggregateson planar surfaces(ATR-FTlR). and knowledgeofthe selfassembled surfactant structures in solution. Success of this research will result in approaches to tailor the adsorption and recovery of fluorinated surfactants from solid surfaces based on the structure of the surfactant. the nature of the solid substrate. and the solution composition. In addition to the potential energy and environmental benefits. the proposed work complements existing research efforts in fluorinated solvent systems at the University of Kentucky and provides the groundwork for further collaborations that address issues critical to the use of fluorinated solvent systems for chemical processing.