(290c) On Demand Treatment of Wastewater Using 3D-Prined Membrane

Authors: 
Clifford, C., University of Pittsburgh
Wang, B., University of Pittsburgh
Baimoldina, A., University of Pittsburgh
Song, Y., University of Pittsburgh
Hung, T., University of Pittsburgh
Kowall, C., The Lubrizol Corporation
Li, L., University of Pittsburgh
Over the last 40 years, membrane-based separation processes have evolved from laboratory scale applications to a multibillion-dollar technology widely employed by the food processing, chemical production, and pharmaceutical industries. Fundamentally, these separation processes exploit the selective permeability of a membrane substrate to segregate multi-component mixtures, either via an imposed pressure (e.g., microfiltration and reverse osmosis) or concentration (e.g., dialysis and forward osmosis) gradient. While traditional membrane-based technologies represent an energy-efficient alternative to more robust methodologies (e.g., fractional distillation), such processes are inherently limited to a single separation mechanism (i.e., a single selectivity). Mixtures featuring three or more components, or those with multiple components and phases, cannot currently be separated in a single processing step. The single membrane selectivity also results from the present-day fabrication techniques, which limits the construction to a single material and pore distribution.

To combat the deficiencies in the current paradigm, a novel 3D-printed membrane capable of simultaneous multicomponent and multiphase separation is undergoing development in our lab. Taking advantage of innovations in additive manufacturing and 3D printing technology, the established fabrication technique permits localized control over membrane composition, as well as pore size and 3D topography so that single membrane will have multiple selectivity. Currently, two distinct separation mechanisms are being investigated in our lab, using a combination of experimental and computational methods. The first one is a gravity-fed separation of a multiphase oil-water mixture. With water-assisted separation or/and 3D topography design, we have shown that the wettability of the membrane can be tailored to enhance the separation efficiency. The second one is a diffusion-based separation of a miscible multicomponent mixture through a supported ionic-liquid membrane (SILM). With the optimization of both ionic liquid, which serves as the extraction solvent, and membrane structure/chemistry, the miscible liquid mixtures are separately successfully. Moving forward, we plan to combine the two mechanisms in single 3D-printed membrane and demonstrate the separation of multi-component and multi-phase liquid mixtures.