The Specialty Separations Center (SSC) at Georgia Tech represents a highly interdisciplinary and collaborative effort of engineers and scientists from the School of Chemical & Biomolecular Engineering, School of Chemistry & Biochemistry , George W. Woodruff School of Mechanical Engineering, School of Civil & Environmental Engineering, and Georgia Tech Research Institute.
The projects undertaken in the SSC are directed toward numerous products and applications that range from commodity chemicals to pharmaceuticals, to nuclear fuels. These efforts are addressed by approaches that include the rational design, fabrication, characterization, and testing of innovative materials and processes such as permeation, sorption, diffusion, chromatography, flotation and crystallization. Brief descriptions of the projects and areas covered by Center members are given below.
One of the Bommarius group’s emphases is the integration of reaction (or fermentation) and separation in a single, continuous process step. The two current research areas focus on i) Continuous Synthesis, Crystallization, and Isolation (CSCI) of pharmaceutical ingredients, such as beta-lactam antibiotics, and ii) Continuous Aqueous Two-phase Extraction (CATPE) of proteins towards purification after fermentation. Regarding i), we were able to demonstrate improved yield, selectivity, and cycle time for simultaneous enzymatic synthesis of penicillins. Past efforts dealt with Organic-Aqueous Tunable Solvents (OATS) and Simulated-Moving Bed Reactors (SMBRs); both targeted enzyme-catalyzed or resin-based acid-base-catalyzed esterification and transesterification.
Professor Grover brings expertise in process systems engineering to crystallization. Applications include purification in pharmaceutical manufacturing and nuclear waste disposal. Her research builds upon recent advances in process analytical technologies, which provide new opportunities to monitor and control crystallization processes. Mathematical models of the crystallization process are constructed using data acquired online as well as offline. Depending upon the application, the models may be based on physical principles, or they may be empirical and constructed via machine learning. Optimal feedback control policies are calculated using the models, to rapidly meet target crystal properties and to optimize performance. This systems approach is applied to both batch and continuous crystallization.
The Koros group is a leader in the creation of materials for use in advanced membrane and sorbent applications involving gases. The underlying theme in all of these topics is the understanding and control of thermodynamic partitioning and penetrant movement processes. Polymers are generally a feature in all of the work in my group; however, the detailed materials can vary greatly depending upon the ultimate use that is desired. Highly glassy materials and hybrid inorganic-polymer materials in hollow fiber forms are often topics he considers, since they can be engineered into highly efficient modules. Pyrolysis of selected polymers to form glassy carbons is increasingly important in our work due to the combination of molecular sieving and ease of processing that carbons offer. Control of nanoscopic morphology in engineered fiber walls is critically important and is a special focus of our group.
Clean water, chemicals and advanced pharmaceuticals are vital pillars of modern life. These rely on chemistry-based discoveries that are inevitably dependent upon purification and separation processes. An astonishing fraction of all energy used in the world, approximately 10-15%, is currently used for these separation processes because of their reliance on heat and phase changes. This implies that game-changing technologies for chemical separations have potential to address the world’s energy mix at levels similar to that of the entire consumer vehicle market. Membrane and adsorption devices designed to separate molecules with molecular-scale resolution are 10x more efficient than existing thermal separators. However, revolutionary advances in materials chemistry and fabrication are needed for membranes and adsorbents to realize their potential. Using a combination of molecular-scale design, scalable materials fabrication, and chemical engineering, the Lively group is creating cross-cutting nanoporous materials to efficiently separate a wide variety of small molecules critical to the hydrocarbon processing and electric power generation industries.
Professor Nair’s research group – established in 2003 – focuses on bringing transformative change in separations processes via the chemistry and engineering of nanoporous materials and membranes. A key strength of his group lies in its integrated approach comprising nanoporous materials design and synthesis, innovative membrane processing strategies, and scalability of membrane and adsorption systems. His group emphasizes separation strategies for complex multicomponent mixtures in petrochemical production, biorefining, industrial water separations, and gas separations among others. Materials for challenging (corrosive, radioactive) operating environments are an important interest. The group is equipped with state-of-the-art characterization facilities for membranes (gas permeation, pervaporation, NF, RO) and adsorption materials/systems (fixed-beds and simulated moving beds).
Reducing the concentration of CO2 in the atmosphere will be one of the major challenges of the century. Professor Realff works on understanding the feasibility of implementing systems to remove CO2 from different sources, such as flue gas streams and directly from air, and designing systems to do this as efficiently as possible. This is a multi-scale design problem that integrates information from materials design, novel contactor architectures, adsorption cycle design and overall process configuration. These design problems lead to complex modeling challenges and require handling uncertainty seamlessly across
The focus of Rousseau’s research is crystallization, especially the roles it and associated phenomena play in processes ranging from recovery and purification of active pharmaceutical ingredients to mitigation of nuclear waste. Examples of the former include methodologies for separating chiral compounds, which often are synthesized as racemic mixtures, into enantiomerically pure fractions. His group’s research showed that under the right conditions it is possible to combine enzymatically catalyzed enantiomeric enrichment with simultaneous crystallization to produce a pure desired enantiomer. That work led to using simultaneous reaction and crystallization to produce desired b-lactam antibiotics at enhanced yield and productivity. Challenges in dealing with legacy nuclear wastes are complex. His team uses simulants of such waste in its efforts to identify processes for the removal of species detrimental to stabilizing and storing radioactive isotopes; Rousseau also uses such systems to explore means of monitoring solution and particulate characteristics important for safe and efficient processing.
modeling challenges and require handling uncertainty seamlessly across scales.
Professor Sholl’s group uses a wide range of materials modeling tools to develop new materials for chemical separations in complex environments. These tools include quantum chemistry, molecular modeling, coarse-grained approaches and process-level modeling. These methods are used in strong connection with experimental collaborators to drive development of new processes and materials.