(6be) Advanced Membrane Materials for Energy Efficient Separations

          Ability to precisely control molecular transport in materials is the next paradigm in the separation technology development.  Design and implementation of the controlled functionality materials would transformationally improve the energy efficiency of the membrane-based separation processes much needed to meet the future clean energy and water demands.  In energy applications, the proposed carbon capture and sequestration approach would tremendously gain from materials having high H₂/CO₂ and CO₂/N₂ perm-selectivities.  Such membrane materials would enable an energy efficient CO₂ capture from the industrial gas streams without incurring the huge energy penalty currently estimated for using the industry standard cryogenics and sorption gas separation methods.  Exploiting abundant shale gas resources requires next generation high efficiency membranes for the CO₂/CH₄separations, and treatment of the produced high salinity water prior to disposal or re-injection.  Similarly, sea water desalination and wastewater treatment will also benefit from the development of advanced membrane materials having high water transport capacity together with anti-fouling, chlorine resistant, and high salt rejection characteristics.

          My research is focused on the advanced material design and cutting edge fabrication techniques development aimed at obtaining high performance membranes for the small molecule separations.  During my PhD at Colorado School of Mines, I applied molecular self-assembly (MSA) for designing the organic-inorganic hybrid membrane materials.  I demonstrated that by manipulating the surface functionality, membrane separation selectivity was tuned from molecular sieving to reverse selective.  For my postdoctoral work at Los Alamos National Laboratory (LANL), I systematically altered the molecular structure of the polybenzimidazole (PBI)-based H₂selective membranes and developed an extensive structure-permselectivity correlation for this unique class of the polymer membranes. 

          Advancements in the selective membrane materials development often require material specific fabrication techniques to enable their successful industrial deployment.  I have also developed novel methods and techniques for the membrane material transformation into industrially attractive hollow fiber and thin film platforms.  PBI hollow fiber membranes development project, I am currently working on as a Staff Scientist at LANL, is focused on understanding the underlying liquid-liquid demixing phenomena for the PBI phase inversion used in the fiber spinning process.  Recently, ground-breaking spinning methods were developed to achieve an unprecedented H₂/CO₂ separation performance at synthesis gas process conditions.  These PBI fibers are very attractive for efficient H₂production from coal, natural gas or biomass for the fuels, power and chemicals production.  As a LANL Co-PI for DOE ARPAe funded project, I have applied ultrasonic atomization assisted polymer deposition technique for thin (ca. ~100 nm) selective layer deposition on the porous polymer substrates.  Reducing selective layer thickness directly improves the membrane permeance, resulting in reduced membrane surface area requirements.  Therefore, this novel selective layer deposition technique enables the use of expensive high functionality materials for the large scale applications.

          My future research work will be focused on the design and development of advanced materials and deployment platforms for next generation membrane-based separation processes.  I plan to harness the extraordinary separation characteristics of the recently identified 2D and 3D materials including GOs, MOFs, ZIFs, ionic liquids, planar zeolites and polymers with intrinsic micro-porosity (PIMs) for gas, vapor and liquid separations, diffusion and reaction.  It is difficult to process these materials into the desired robust thin film platforms due to limited control on the grain and crystal size, defect density and morphology during their synthesis.  I would explore novel nano-composite, hybrid and MSA material fabrication design routes together with advanced membrane fabrication techniques to transform these materials into industrially attractive membranes.  I will develop a comprehensive understanding for controlling and effectively manipulating the interfacial, chemical and molecular interactions among membrane material constituents for molecular scale mixing to achieve the desired high separation performance.