Smart Methodologies for Efficient Separation of Liquid Mixtures.

Surface science;Separation;emulsion;Materials Science and Engineering;Engineering;Materials Science and Engineering

Kwon, GibumSangi Reddy, Pramod ;

University of Michigan

关键词: Surface science;    Separation;    emulsion;    Materials Science and Engineering;    Engineering;    Materials Science and Engineering;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/110317/gbkwon_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

There is a critical need for new energy-efficient solutions for separating liquid mixtures. Among the variety of current separation technologies, membrane-based operations are attractive because they are relatively energy-efficient, and are applicable to a wide range of industrial effluents. This research explores the systematic design of membranes, as well as, the development of smart methodologies that enable separation of a wide variety of both immiscible and miscible liquid mixtures.The first part of my thesis describes membranes that can separate oil-water mixtures, solely under gravity. Here, we have developed novel membranes with hygro-responsive surfaces, which are both superhydrophilic and superoleophobic. Utilizing these membranes, we have developed capillary force-based separation (CFS) methodology that can separate a range of different oil-water mixtures, with > 99% efficiency. We have also engineered an apparatus to achieve continuous, solely gravity-driven separation of oil-water emulsions, with a separation efficiency > 99.9%.In the second part, we describe that controlled silanization of cellulose-based filters can create a robust and homogeneous, hygro-responsive, coating on the filter surface. The developed membranes have unique self-cleaning abilities as water can displace oil from the membrane surface. This allows the membranes to be extremely fouling resistant. We have also demonstrated that our membranes can separate surfactant-stabilized oil-in-water emulsions with oil droplets diameter as small as 10 nm. In the third part of my thesis, we have developed a new separation methodology where the separation can be triggered by applying an electric field. We have also successfully estimated the voltage required to trigger the separation using a breakthrough pressure model that incorporates the Maxwell stress and the hydrostatic pressure. Finally, we have engineered a continuous oil-water emulsion separation apparatus that removes > 99% of the emulsified drops.In the final part of this thesis, we have developed a new energy-efficient methodology that combines liquid-liquid extraction using surfactant-stabilized emulsions, and solely gravity-driven separation of these emulsions into a single unit operation. We have demonstrated that our methodology is useful for a wide range of separations, including the separation of miscible dyes, alcohols and sulfur compounds from oils, as well as, separation of alcohol-hydrocarbon azeotropes.