(16j) Separation and Reaction Processes in Functional Nanostructured Porous Materials

The development of new-generation materials that extend the industrial applications of reactionseparation processes is being addressed in some applications like water treatment or fuel cells. The development of functionalized surfaces in highly porous materials can led to stimuli responsiveness such as ionization, electron and ion transfer, swelling, hydrophobicity/hydrophilicity or sorption. These new combination of techniques and materials prove to be effective in selective separations in various environmental conditions, enhancing reactivity, durability and permeation.

The main idea is how to increase the number of functional groups by unit of area on the material used in order to give and augment sensibility, reactivity, selectivity or sorptive characteristics and, at the same time not affecting or even improve the application performance. Polymers and biopolymers may display these different surface functionalities and due to their versatility, they can be applied in diverse research fields and
simultaneously be sustainable technologies.

Current Research

Currently, we are using â??greenâ? techniques to create nanocomposites based on polyvinylidene fluoride membranes. This post-manufacture modification relates to the incorporation of various nanomaterials into the structure of the membrane, usually a commercial one. This feature allows better conformation and distribution of the nanomaterial, avoiding aggregation, mixing problems and losses. Membrane pores can be functionalized with hydrophilic materials such as polyvinylpyrrolidone and poly(acrylic acid). Then, by double ion exchange and subsequent reduction, metallic and bimetallic nanoparticles can be synthesized for metal capture or reduction/oxidation of organic contaminants. Through layer-by-layer functionalization, membranes can also be loaded with protein channels (porins) and enzymes. These porins permit the separation of different molecular weights. In the case of enzymes, the objective is the oxidation of aryl halides, avoiding enzyme inactivity.

Dibakar Bhattacharyya, PhD leads this research and the grants associated are the Superfund Research Program of the NIEHS and the KY NSF EPSCoR.

Research Experience

To prepare for the career in separation-reaction process design and engineered materials for different treatment applications, I have worked for more than 10 years in elimination of hard microbial contamination from water, remediation of recalcitrant and harmful pollutants, combination of physicochemical and biological treatments, and plant design for different industries ranging from drinking water to foods to pharmaceutical. In addition, I have good experience in polymeric materials because it is a personal interest, the backbone support of my current research and I had taught this subject during my work as an adjunct professor in Chemical Engineering. My research work (MS, Faculty and PhD) in advanced oxidation processes and membrane functionalization with nanoparticles, respectively, used different platforms in both lab-scale and full-scale for environmentally benign syntheses and manufacture, and the establishment of individual and combined technology strategies to design suitable processes. As an adjunct professor, we succeeded in immobilizing Titania onto activated carbon and polyester for the photocatalytic degradation of wastewater of the printer cartridges reuse process. We advised, assessed equipment, engineered and designed processes for a Drinking Water Treatment and Supply in an Emergency and/or Disaster Scenario in Bogotá D.C., Colombia. In addition, we developed a pilot software Excel app for configuration of water treatment systems in pharmaceutical, food and soft drink applications.

Teaching Interests:

I have an extensive teaching experience. I spent 7 years teaching science and technology to a gifted youngsters in a special education institution, from middle to high school. I was also an adjunct professor in the Chemical Engineering Department at the Universidad de los Andes (Colombia) for 3 years after my masterâ??s degree. At los Andes, I taught Separation Processes, Material an Energy Balances, Physicochemical Aspects of
Polymers and Transport Phenomena. At University of Kentucky I was TA and have been guest-lecturer of undergraduate courses in Chemical Engineering such as Separation Processes, Chemical Reactor Design and Chemical Engineering Process Design. To finish, I have mentored graduate and undergraduate students in my group and overseas, including a masterâ??s student, REU-NSF and NSF Graduate Fellowship awardees.

Future plans

My research focus on the development of integrated, cost-effective technologies that allow targeted reaction, purification and selective separation of mixtures in different qualities. Likewise, the development of solutions for specific separations and reactions needs intensive research in functional polymers and bioinspired materials at micro and nano scale levels. Specifically I am interested in enabling and designing water treatment systems for specific needs without the need to build conventional, often unsustainable and expensive treatment systems. During the graduate studies and the research as an adjunct professor, I realized that much of the research in water applications focuses on development and study of nano and micro-materials, and how to apply these in current treatment processes. Although this approach has produced excellent developments such as aquaporins, metal nanoparticles or carbon nanotubes inserted into membranes, it has posed also new types of problems like contamination related to nanoparticle activity. In order to address this, it is necessary to develop new technologies based on responsive and immobilized nanostructured materials and to combine reaction and separation processes for each of the applications to increase their selectivity and effectivity. Specifically, start by understanding that the importance of the supporting material and how is functionalized determine the performance of the combined process and the materials used.

Selected Publications

Sebastián Hernández, Anthony Saad, Lindell Ormsbee and Dibakar Bhatacharyya: Nanocomposite and Responsive Membranes for Water Treatment, In Emerging Membrane Technology for Sustainable Water Treatment,
edited by Nicholas Hankins and Rajindar Singh, Elsevier, Boston, 2016, pages 389-431, ISBN 9780444633125. DOI:10.1016/B978-0-444-63312-5.00016-4

Sebastián Hernández, Shi Lei, Wang Rong, Lindell Ormsbee and Dibakar Bhattacharyya: Functionalization of Flat Sheet and Hollow Fiber Microfiltration Membranes for Water Applications. ACS Sustainable Chemistry &
Engineering. 2016; 4 (3): 907-918. DOI: 10.1021/acssuschemeng.5b01005

Sebastián Hernández, Joseph K. Papp and Dibakar Bhattacharyya: Iron-Based Redox Polymerization of Acrylic Acid for Direct Synthesis of Hydrogel/Membranes and Metal Nanoparticles for Water Treatment. Industrial &
Engineering Chemistry Research 2014; 53(3):1130-1142. DOI: 10.1021/ie403353g

Jenny Dussan Garzón, Martha Josefina Vives-Florez, Víctor Manuel Sarria, Oscar Fernando Sánchez Medina, Luis Fernando Delgado, Andrés Fernando González Barrios and Sebastián Hernández Sierra: Aproximaciones Biológicas y Fisicoquímicas en el tratamiento de contaminantes: un resumen del aporte de la Universidad de Los Andes. 2009; DOI: 10.16924/riua.v0i30.233

Sebastián Hernández Sierra, Maryhan Paola Villamil Rodríguez and Lady Liliana Miranda Gómez: Agua Potable. Evaluación de Tecnologías para Dotación de Servicios Vitales en Alojamientos Institucionales, edited by Universidad de Los Andes, Alcaldía Mayor de Bogotá D.C., 07/2010